Misfire and TPS sensor question
Discussion
Hi all, having some trouble with my 97 4.5 AJP Cerb with original MBE ecu.
Ive had the car 3 years, but known it 15 before. Its ran well for my 3 years, slightly rich, but well. When plugged in to the diagnostic software on the laptop, it would however always show the map on the lhs bank higher the the right with about 5% in it.
Now on 100k miles, sent it into a specialist for 12k including clearance check - did not need adjustment
When i got it back it was idling a little high, with the specialist saying it was a bit tough to set. A little lurchy lower in the revs, but when pressed felt WAY quicker -good fun. Unfortunately not long after i got it back had master cylinder failure resulting in lots of fluid drawn into the engine and smoke. Now fixed and smoke cleared by its self once burnt off, however this seems to have exaggerated the above running trouble massively.
So the issue is:
- High idle even with the idle stop completely wound out the way. (about 1250rpm), but about 25% of the time will idle more normally but cant seem to influence when it settles high vs normal.
- When idling it will miss a beat a make a bang (backfire) on the rhs drivers side exhaust (worth noting each exhaust servs each bank only - straight). Also does this misfire under partial throttle.
- Really lumpy, missing, lurchy running under part throttle. Under full load - perfect, fast, amazing, no misses.
What ive done:
- Cant get my software to connect, it finds the correct coms port, but doesn't connect. Com port it looks at changes from 1 to 3 with the usb port on the laptop. (windows 11 - Bluetooth off. USB to 9 pin cable)
- But, to try and get some headway, with it running ive doused the throttle body area in degreaser, no change to revs = no air leaks in.
- I then unplugged the throttle position sensor from the drivers side bank - cable reads "evens", which i believe to be correct - this results in no change at all to the running. I do the same to the passenger side, misfires erratically then cuts out.
- So i swapped the plugs over to the other bank. Still the misfire and backfire is on the driver side bank. I unplugged the drivers bank again whilst running, engine misfired then cut out. plug in and restart, tried the passenger bank and no change and still running.
So the misfire remains on the driver bank even with swapping the TPS leads over BUT the none effect from unplugging moves with the lead rather than staying with the sensor. To my mind this means the cable for the drivers bank TPS is faulty but still not sure as to why the misfire remains on the drivers side.
My questions:
- Do people agree with my conclusion of faulty TPS lead on the Drivers bank.
- Any suggestions RE the connection to computer - i have ordered a new lead to rule that out, will try it this week when it arrives.
- Any other thoughts, suggests etc.
-Any ideas as to why the misfire remains on the same bank (my current theory being i have 2 separate issues, one with the TPS cable, and 1 with general setup - need to connect to the computer to find out)
(Worth mentioning, happy my specialist and the work he does, nothing negative there. he is very good, but suggested if trouble persists after a good drive trying joolz - he is more equipped and experienced with this sort of issue - knows joolz would get to the root much faster. If i have no joy or it gets more involved than bolt on parts and setup i will book in with joolz but would like to exhaust my abilities first, also with peaks to the beach just a week away... i wont get in that soon)
Ive had the car 3 years, but known it 15 before. Its ran well for my 3 years, slightly rich, but well. When plugged in to the diagnostic software on the laptop, it would however always show the map on the lhs bank higher the the right with about 5% in it.
Now on 100k miles, sent it into a specialist for 12k including clearance check - did not need adjustment
When i got it back it was idling a little high, with the specialist saying it was a bit tough to set. A little lurchy lower in the revs, but when pressed felt WAY quicker -good fun. Unfortunately not long after i got it back had master cylinder failure resulting in lots of fluid drawn into the engine and smoke. Now fixed and smoke cleared by its self once burnt off, however this seems to have exaggerated the above running trouble massively.
So the issue is:
- High idle even with the idle stop completely wound out the way. (about 1250rpm), but about 25% of the time will idle more normally but cant seem to influence when it settles high vs normal.
- When idling it will miss a beat a make a bang (backfire) on the rhs drivers side exhaust (worth noting each exhaust servs each bank only - straight). Also does this misfire under partial throttle.
- Really lumpy, missing, lurchy running under part throttle. Under full load - perfect, fast, amazing, no misses.
What ive done:
- Cant get my software to connect, it finds the correct coms port, but doesn't connect. Com port it looks at changes from 1 to 3 with the usb port on the laptop. (windows 11 - Bluetooth off. USB to 9 pin cable)
- But, to try and get some headway, with it running ive doused the throttle body area in degreaser, no change to revs = no air leaks in.
- I then unplugged the throttle position sensor from the drivers side bank - cable reads "evens", which i believe to be correct - this results in no change at all to the running. I do the same to the passenger side, misfires erratically then cuts out.
- So i swapped the plugs over to the other bank. Still the misfire and backfire is on the driver side bank. I unplugged the drivers bank again whilst running, engine misfired then cut out. plug in and restart, tried the passenger bank and no change and still running.
So the misfire remains on the driver bank even with swapping the TPS leads over BUT the none effect from unplugging moves with the lead rather than staying with the sensor. To my mind this means the cable for the drivers bank TPS is faulty but still not sure as to why the misfire remains on the drivers side.
My questions:
- Do people agree with my conclusion of faulty TPS lead on the Drivers bank.
- Any suggestions RE the connection to computer - i have ordered a new lead to rule that out, will try it this week when it arrives.
- Any other thoughts, suggests etc.
-Any ideas as to why the misfire remains on the same bank (my current theory being i have 2 separate issues, one with the TPS cable, and 1 with general setup - need to connect to the computer to find out)
(Worth mentioning, happy my specialist and the work he does, nothing negative there. he is very good, but suggested if trouble persists after a good drive trying joolz - he is more equipped and experienced with this sort of issue - knows joolz would get to the root much faster. If i have no joy or it gets more involved than bolt on parts and setup i will book in with joolz but would like to exhaust my abilities first, also with peaks to the beach just a week away... i wont get in that soon)
Check that the throttle cable is running free and slack when at idle position. If the cable is snagging on something, badly adjusted at the throttle bodies or the pedal is fouling on something then it can hold the idle high and the throttle cam does not even touch the stop screw. You say it idles normally for 25% of the time but is unpredictable. Disconnect the cable from the engine and turn the throttle cam by hand - see if it is a more consistent idle and the cam rests on the stop screw.
For the computer - Open the Device Manager in Windows and delete all listed COM ports.
Then with the USB cable unplugged - reboot the machine. When Windows has started plug in the USB cable and windows should reload the device. Make sure Bluetooth is turned off and then try to connect to the MBE. Also try a different USB port on the computer.
The misfire is more likely to be a bad HT lead on the even bank and the TP sensors are a red hearing. Check the HT leads for loose/broken connectors in the the spark plug end. At my last service I found a bad lead and replaced the set. It now runs much smoother.
One other thing - and I don't want to scare you, but 100k miles is a high number. When was the engine last rebuilt? I know they're all different, but mine needed a rebuild at just over 50k when it became untunable. If all else fails have it compression checked. It might just be tired.
For the computer - Open the Device Manager in Windows and delete all listed COM ports.
Then with the USB cable unplugged - reboot the machine. When Windows has started plug in the USB cable and windows should reload the device. Make sure Bluetooth is turned off and then try to connect to the MBE. Also try a different USB port on the computer.
The misfire is more likely to be a bad HT lead on the even bank and the TP sensors are a red hearing. Check the HT leads for loose/broken connectors in the the spark plug end. At my last service I found a bad lead and replaced the set. It now runs much smoother.
One other thing - and I don't want to scare you, but 100k miles is a high number. When was the engine last rebuilt? I know they're all different, but mine needed a rebuild at just over 50k when it became untunable. If all else fails have it compression checked. It might just be tired.
Hi, thanks for the fast responses:
- I will try with the hose clamped and then with the throttle cable disconnected tonight. The throttle cable however has been changed alongside the brake servo (whilst pedal box is out) and the issue existed to some extent before - but worth a check for how easy it is to do.
- I will also retry with the above steps on the computer.
- On general engine health, it is on its original engine, never rebuilt. at 75k miles ish it was tuned by joolz and performed well at 409bhp. Still goes like hell on flat out, and prior to this issue (200 mile ago tops) drove really well all round and doesn't burn much oil (or at least... not much for a TVR). At last valve clearance check (just the other month) the specialist also commented the shim levels are not too bad. But yes, i know the day will come and it is on borrowed time at 100k.
- I will try with the hose clamped and then with the throttle cable disconnected tonight. The throttle cable however has been changed alongside the brake servo (whilst pedal box is out) and the issue existed to some extent before - but worth a check for how easy it is to do.
- I will also retry with the above steps on the computer.
- On general engine health, it is on its original engine, never rebuilt. at 75k miles ish it was tuned by joolz and performed well at 409bhp. Still goes like hell on flat out, and prior to this issue (200 mile ago tops) drove really well all round and doesn't burn much oil (or at least... not much for a TVR). At last valve clearance check (just the other month) the specialist also commented the shim levels are not too bad. But yes, i know the day will come and it is on borrowed time at 100k.
Another theory . The brake fluid has ruined the driver’s side lambda sensor. This can cause high idle, lumpy running below 3k rpm with part throttle (but not at higher revs or wider throttle openings).
After swapping it out, it may take a little while for the ECU to learn the right adaptives so it will continue to run a bit lumpy for a bit.
. The brake fluid has ruined the driver’s side lambda sensor. This can cause high idle, lumpy running below 3k rpm with part throttle (but not at higher revs or wider throttle openings).After swapping it out, it may take a little while for the ECU to learn the right adaptives so it will continue to run a bit lumpy for a bit.
So had a play last night,
- sadly still the computer refuses to connect
but my hope is the new cable will fix this... whenever it arrives
- Ive ordered some new plugs and leads, the ones on do look quite old. however feeling the cables.... ive not had a shock, but they could be poor inside.
- Started up and ran with the throttle cable disconnected, idles low and nice, but then once warmed up started to rise again.
- Tried clamping off the vac pipe for the servo, didn't make any difference (cant believe how much this pulses with engine beat)
- Removed the airboxes and short induction pipes - didnt make note of which goes where, i feel like future me will regret that on reassembly.
- Checking the flows at idle (around 900 rpm at point of test as still a little cold), Drivers bank (misfiring) measures 3, passenger side running cleaner measures 7. So im well out of balance. BUT, with the idle stop on the drivers bank completely out of the way, it must therefor be stopping at bottom on the passenger bank.... so how is this still flowing so much more!?!?
- Also... just a note, the passenger bank when running, splashes fuel up out of the top, where as drivers bank is far far less.
- Also... another observation, the drivers bank is free from dirt or deposits on the trumpets and TBs, the passenger side is quite blackened, particularly on the middle 2 (one of these also popped back when revved).
Not sure what sense can be made of this.... the computer would be most helpful...
Ref the lambda, that would make sense, however the bank it draws vacuum from is passenger side.
My thoughts on next steps:
- Remove the link rod, and see what happens to the flow on the passenger side with no influence. HOPEFULLY this will then go lower and allow me to set both up to match at idle, then set the idle with the screw.
- I will then NEED the computer to adjust the throttle pots and reset adaptive.
- Test drive.... hope its fixed. If not, then change HT leads (looks fiddly - cant even see how to get the plugs out)
What do people think, all opinions welcome :P
Video link below
https://drive.google.com/file/d/1hmHepLOgQTvp4iPaK...
- sadly still the computer refuses to connect
but my hope is the new cable will fix this... whenever it arrives- Ive ordered some new plugs and leads, the ones on do look quite old. however feeling the cables.... ive not had a shock, but they could be poor inside.
- Started up and ran with the throttle cable disconnected, idles low and nice, but then once warmed up started to rise again.
- Tried clamping off the vac pipe for the servo, didn't make any difference (cant believe how much this pulses with engine beat)
- Removed the airboxes and short induction pipes - didnt make note of which goes where, i feel like future me will regret that on reassembly.
- Checking the flows at idle (around 900 rpm at point of test as still a little cold), Drivers bank (misfiring) measures 3, passenger side running cleaner measures 7. So im well out of balance. BUT, with the idle stop on the drivers bank completely out of the way, it must therefor be stopping at bottom on the passenger bank.... so how is this still flowing so much more!?!?
- Also... just a note, the passenger bank when running, splashes fuel up out of the top, where as drivers bank is far far less.
- Also... another observation, the drivers bank is free from dirt or deposits on the trumpets and TBs, the passenger side is quite blackened, particularly on the middle 2 (one of these also popped back when revved).
Not sure what sense can be made of this.... the computer would be most helpful...
Ref the lambda, that would make sense, however the bank it draws vacuum from is passenger side.
My thoughts on next steps:
- Remove the link rod, and see what happens to the flow on the passenger side with no influence. HOPEFULLY this will then go lower and allow me to set both up to match at idle, then set the idle with the screw.
- I will then NEED the computer to adjust the throttle pots and reset adaptive.
- Test drive.... hope its fixed. If not, then change HT leads (looks fiddly - cant even see how to get the plugs out)
What do people think, all opinions welcome :P
Video link below
https://drive.google.com/file/d/1hmHepLOgQTvp4iPaK...
Edited by Car.Fool.James on Tuesday 23 June 11:04
Hi. I think you're best to wait until you get the software running. It should point you in a better direction.
If one side gets more fuel than the other that does suggest either throttle pot or injector issues and you're right in suspecting the TPs first. It might be that the even side TP has started to go bad in the low range and needs replaced. Either the software or perhaps a multi meter will verify if the pot has gone noisy.
I'm not sure removing the link rod and trying to fix the idle will work (without the software). Remember the bad side will always be affecting the good side and without seeing the values it's kind of just a stab in the dark. Also - the stored adaptive values will probably be throwing everything off. Especially if it updated the values while burning off oil etc. Before trying to balance/setup the engine you really should zero the adaptives.
e.g I've just fixed a loose connection with my lamda1 - which recorded the following. Idling was problematic and it would always stall until warm. . .
Guess which values were screwing up the idle
https://www.pistonheads.com/gassing/topic.asp?h=0&...
If one side gets more fuel than the other that does suggest either throttle pot or injector issues and you're right in suspecting the TPs first. It might be that the even side TP has started to go bad in the low range and needs replaced. Either the software or perhaps a multi meter will verify if the pot has gone noisy.
I'm not sure removing the link rod and trying to fix the idle will work (without the software). Remember the bad side will always be affecting the good side and without seeing the values it's kind of just a stab in the dark. Also - the stored adaptive values will probably be throwing everything off. Especially if it updated the values while burning off oil etc. Before trying to balance/setup the engine you really should zero the adaptives.
e.g I've just fixed a loose connection with my lamda1 - which recorded the following. Idling was problematic and it would always stall until warm. . .
Guess which values were screwing up the idle
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Good News....
Story time, 45 degrees in the garage, 5 hours messing with it, commitment to peaks to the beach weekend going ahead!!
My cable arrived today, and it worked, connected fine to the software. lots of errors, adaptives sky high on the odd bank. So reset the adaptives, and started up and warmed up. Running much better, but popping back lots, mainly on the odd bank. After 15 mins running and some revving up (sorry neighbors!) adaptives again running wild on the odd bank. TP % fairly stable and around 14.5 both of them! Lambdas both read.
So, made a decision, lets take off the link bar, and check the flows
- Link bar removed, still flowing 6 ish on the odd bank, and even bank is at 2, 3 at best. Interestingly it pulses more on the odd bank, TPs read 14.5%...
- Freed up a very stuck link rod adjusters, when re fitting decided to fit it on the back side of the odd bank and front side of the even bank (was front of both before) and added a small spacer as it was fowling slightly on the odd bank. Seemed to sit happier this way. Set it bang bang middle, so not influencing anything. Both before and after fitting bar readings on both banks are 14.5%.
Going off the TVR manual, then i wound up the idle speed until it read 18%. However, with the even bank at 18, the odd bank was only at 15. When you open the throttle up more this difference does get slightly worse being about 10% off at 95% throttle.
- Fired her up anyway. What a difference! Running smoothish, not popping back at all, but still the adaptives increasing on the odd bank. Running better tho, no missed beats, and not popping back, and also not splashing fuel around nearly as much. Result. This few % difference now shown on the TPs must be slop in a 100k old link rod i would guess. Happily however at idle (which for now is at a manageable 1050RPM) both banks pull the same 4 or 5 ish on the syncrometer flow gauge. And now the even bank is pulsing (possibly a little more than the odd, but not much in it)
- Now, going off various postings online, and my slightly iffy lodgic... the adaptivs raising means that odd bank has too smaller % on the TP for the air actualy flowing. Therefore i need to raise that TPs % slightly. This also ties in to the fact this one reads lower. So, brave pill taken, afterall i now have synchronized air flows at idle. Cracked off the rusty steel slot head screws (after some snake oil, tapping and general battle) and adjusted the odd bank TP to read 19 at idle. When you press the pedal this now keeps fairly even throughout the rev range matching perfectly at around 40% throttle, and the even starting overtaking by a little from this point on.
I couldn't start up to test... its 11pm, and my neighbors will throw things at me XD
So, after work tomorrow, lets see how it runs, rebuild all the induction pipes etc, and go a drive. Fingers crossed... i will report back.
Thanks, James
Story time, 45 degrees in the garage, 5 hours messing with it, commitment to peaks to the beach weekend going ahead!!
My cable arrived today, and it worked, connected fine to the software. lots of errors, adaptives sky high on the odd bank. So reset the adaptives, and started up and warmed up. Running much better, but popping back lots, mainly on the odd bank. After 15 mins running and some revving up (sorry neighbors!) adaptives again running wild on the odd bank. TP % fairly stable and around 14.5 both of them! Lambdas both read.
So, made a decision, lets take off the link bar, and check the flows
- Link bar removed, still flowing 6 ish on the odd bank, and even bank is at 2, 3 at best. Interestingly it pulses more on the odd bank, TPs read 14.5%...
- Freed up a very stuck link rod adjusters, when re fitting decided to fit it on the back side of the odd bank and front side of the even bank (was front of both before) and added a small spacer as it was fowling slightly on the odd bank. Seemed to sit happier this way. Set it bang bang middle, so not influencing anything. Both before and after fitting bar readings on both banks are 14.5%.
Going off the TVR manual, then i wound up the idle speed until it read 18%. However, with the even bank at 18, the odd bank was only at 15. When you open the throttle up more this difference does get slightly worse being about 10% off at 95% throttle.
- Fired her up anyway. What a difference! Running smoothish, not popping back at all, but still the adaptives increasing on the odd bank. Running better tho, no missed beats, and not popping back, and also not splashing fuel around nearly as much. Result. This few % difference now shown on the TPs must be slop in a 100k old link rod i would guess. Happily however at idle (which for now is at a manageable 1050RPM) both banks pull the same 4 or 5 ish on the syncrometer flow gauge. And now the even bank is pulsing (possibly a little more than the odd, but not much in it)
- Now, going off various postings online, and my slightly iffy lodgic... the adaptivs raising means that odd bank has too smaller % on the TP for the air actualy flowing. Therefore i need to raise that TPs % slightly. This also ties in to the fact this one reads lower. So, brave pill taken, afterall i now have synchronized air flows at idle. Cracked off the rusty steel slot head screws (after some snake oil, tapping and general battle) and adjusted the odd bank TP to read 19 at idle. When you press the pedal this now keeps fairly even throughout the rev range matching perfectly at around 40% throttle, and the even starting overtaking by a little from this point on.
I couldn't start up to test... its 11pm, and my neighbors will throw things at me XD
So, after work tomorrow, lets see how it runs, rebuild all the induction pipes etc, and go a drive. Fingers crossed... i will report back.
Thanks, James
Now that you pointed it out, I do see in your original pic the link rod going at a slight angle. Good catch. Sounds like you're on top of it.
I found the threads in my link rod to be completely buggered on the RH threads, so only the LH threaded side turned. Someone who fixes objects with hammers, had just shoved the RH threaded side in with some glue and said "that'll do"...how nice of them.
So I made a link rod from Carbon with working 5M RH and LH threads...what a concept. Now I just have to get over this flu to get everything sorted.
I found the threads in my link rod to be completely buggered on the RH threads, so only the LH threaded side turned. Someone who fixes objects with hammers, had just shoved the RH threaded side in with some glue and said "that'll do"...how nice of them.
So I made a link rod from Carbon with working 5M RH and LH threads...what a concept. Now I just have to get over this flu to get everything sorted.
I don't think I'd be overly pleased with it coming back from the specialist with new running issues, that you're now diagnosing and fixing yourself.
Having said that, it's a great way to learn about your car, and it looks like you're doing good things.
Having working software is imperative, RS-AJP is a dream to work with, tablet or phone.
Having said that, it's a great way to learn about your car, and it looks like you're doing good things.
Having working software is imperative, RS-AJP is a dream to work with, tablet or phone.
jstx said:
Now that you pointed it out, I do see in your original pic the link rod going at a slight angle. Good catch. Sounds like you're on top of it.
I found the threads in my link rod to be completely buggered on the RH threads, so only the LH threaded side turned. Someone who fixes objects with hammers, had just shoved the RH threaded side in with some glue and said "that'll do"...how nice of them.
So I made a link rod from Carbon with working 5M RH and LH threads...what a concept. Now I just have to get over this flu to get everything sorted.
I think my link rod, with rose joints, runs to the other side of the throttle body on the offside, opposite side to yours in the pic, as it was just fouling/rubbing on the fuel manifold otherwiseI found the threads in my link rod to be completely buggered on the RH threads, so only the LH threaded side turned. Someone who fixes objects with hammers, had just shoved the RH threaded side in with some glue and said "that'll do"...how nice of them.
So I made a link rod from Carbon with working 5M RH and LH threads...what a concept. Now I just have to get over this flu to get everything sorted.
Love the carbon rod, and yes mine was in a state, not overly pretty now but works! Also it is close to the pipe but not touching, seemed the best orientation on mine.
So today i gave it a try, so so so much better. Ran smooth, no misses, pulled well, id argue it perhaps has lost a tiny bit of top end out and out speed from how it was when running terribly the rest of the time. but a small price to pay for drivability and.. well actually running. Adaptives all (to my very untrained eye) look okay ishh... for a first propper play. most the time under 10, however spiking on deceleration quite badly. Smells less fuely than before, and drives smooth (or as smooth as it ever does).
So, off to tesco for fuel tomorrow afterwork, then a wash ready for peaks to the beach. Many swirl marks and small scratches from time in the garage, but no time left for polishing, so anyone who see's me there, please forgive me - but running yet ugly is better than pretty but in the garage.
Only area im toying with faffing some more tomorrow night is try turning back the idle stop slightly, currently it rests at around 1000rpm... i know the manual says 950, but i always had it more like 850 so 1000 sounds high to me. But i will see how it goes tomorrow and go from there.
Any suggestions or analysis help with the below is much appreciated.
So today i gave it a try, so so so much better. Ran smooth, no misses, pulled well, id argue it perhaps has lost a tiny bit of top end out and out speed from how it was when running terribly the rest of the time. but a small price to pay for drivability and.. well actually running. Adaptives all (to my very untrained eye) look okay ishh... for a first propper play. most the time under 10, however spiking on deceleration quite badly. Smells less fuely than before, and drives smooth (or as smooth as it ever does).
So, off to tesco for fuel tomorrow afterwork, then a wash ready for peaks to the beach. Many swirl marks and small scratches from time in the garage, but no time left for polishing, so anyone who see's me there, please forgive me - but running yet ugly is better than pretty but in the garage.
Only area im toying with faffing some more tomorrow night is try turning back the idle stop slightly, currently it rests at around 1000rpm... i know the manual says 950, but i always had it more like 850 so 1000 sounds high to me. But i will see how it goes tomorrow and go from there.
Any suggestions or analysis help with the below is much appreciated.
Yes - well done, hope you have a great drive at the weekend.
Before setting the idle too low consider what your typical driving will be. If you're going to be in a built up area with the fans keeping the engine cool you might want to leave the idle at 1050 - 1100. When both fans are active on mine at idle the extra draw on the alternator and engine drop the voltage to about 11v, and the idle can go down to 900rpm. I'm constantly trying to keep the engine from bogging down and feathering the throttle to keep it alive. You can see the voltage drop when the fans kick in on this trace and the resulting drop to 900rpm on the idle.
I'm going to wind it up again this weekend - to about 1100. Just makes it less problematic when burbling through towns/villages.
Your plot looks fine. Don't get too hung up on the stored adaptive values. They will constantly be changing anyway. If it starts to run rough at idle - just reset the adaptives and it removes any of the large out of range values from the map.
Before setting the idle too low consider what your typical driving will be. If you're going to be in a built up area with the fans keeping the engine cool you might want to leave the idle at 1050 - 1100. When both fans are active on mine at idle the extra draw on the alternator and engine drop the voltage to about 11v, and the idle can go down to 900rpm. I'm constantly trying to keep the engine from bogging down and feathering the throttle to keep it alive. You can see the voltage drop when the fans kick in on this trace and the resulting drop to 900rpm on the idle.
I'm going to wind it up again this weekend - to about 1100. Just makes it less problematic when burbling through towns/villages.
Your plot looks fine. Don't get too hung up on the stored adaptive values. They will constantly be changing anyway. If it starts to run rough at idle - just reset the adaptives and it removes any of the large out of range values from the map.
Edited by notaping on Friday 26th June 13:12
notaping said:
One other thing - and I don't want to scare you, but 100k miles is a high number. When was the engine last rebuilt? I know they're all different, but mine needed a rebuild at just over 50k when it became untunable. If all else fails have it compression checked. It might just be tired.
I wouldn't overly worry about milage, its more about how its been looked after, My engine has done 180k miles and the only reason I've taken it apart is because I'm doing a body off refurb. The engine was running fine and I was just going to put it back in, but a leakdown test showed low values on a few cylinders. Some of the rings were carbon-gummed into their grooves, but overall I've been surprised at how little wear there has been on many components. Andy at APM changed my cam chain at 100k miles simply as no-one knew what the service limit was and it seemed like a good idea.Forums | Cerbera | Top of Page | What's New | My Stuff