Hesitation/shunting help.
Discussion
natben said:
SORTED
Massive, massive thanks to Dom at TVR Power, one quick chat with him and he had the issue diagnosed!! Throttle pots!!! he sent me them up (2) I fitted them, then using the software and the help of local TVR owner who brought his old lap top to allow the software to run, the addaptives were re set and all is well again. The car idols perfectly and is silky smooth.
So no need to spend £1k on new throttle bodies! thank feck!!.
Thanks Dom.
Glad you are sorted. Word of caution though if the throttle bodies were worn thay could have contributed to your throttle pots failing, and if this is the case they could fail quicker this time. Massive, massive thanks to Dom at TVR Power, one quick chat with him and he had the issue diagnosed!! Throttle pots!!! he sent me them up (2) I fitted them, then using the software and the help of local TVR owner who brought his old lap top to allow the software to run, the addaptives were re set and all is well again. The car idols perfectly and is silky smooth.
So no need to spend £1k on new throttle bodies! thank feck!!.
Thanks Dom.
...and where did you get the idea it was £1k to fix tb's??!
Robertjp said:
natben said:
SORTED
Massive, massive thanks to Dom at TVR Power, one quick chat with him and he had the issue diagnosed!! Throttle pots!!! he sent me them up (2) I fitted them, then using the software and the help of local TVR owner who brought his old lap top to allow the software to run, the addaptives were re set and all is well again. The car idols perfectly and is silky smooth.
So no need to spend £1k on new throttle bodies! thank feck!!.
Thanks Dom.
Glad you are sorted. Word of caution though if the throttle bodies were worn thay could have contributed to your throttle pots failing, and if this is the case they could fail quicker this time. Massive, massive thanks to Dom at TVR Power, one quick chat with him and he had the issue diagnosed!! Throttle pots!!! he sent me them up (2) I fitted them, then using the software and the help of local TVR owner who brought his old lap top to allow the software to run, the addaptives were re set and all is well again. The car idols perfectly and is silky smooth.
So no need to spend £1k on new throttle bodies! thank feck!!.
Thanks Dom.
...and wh
ere did you get the idea it was £1k to fix tb's??!
Thank goodness Dom got in touch and diagnosed the problem instantly over the phone. I can't thank him enough and Grant who came over and showed me how to use the software.
I will keep an eye on the throttle bodies over the next few months and now I have the software working I monitor the set up more accurately.
George
Hi, I am a bit late on this but think you may have two issues here and perhaps only sorted one. As mentioned previously the tb's on 3 and 4 do look open more than the others. Also as mentioned previously you should balance the tb's with syncrometer to ensure you are pulling even air volumes. I wind the idle up to around 2/3k and set the tb's to be pulling even air, then wind the idle back to 750/775 and reset throttle pots on the software. Then deal with neighbours who want to moan about the noise....
I find I get a better response at cruise when set this way as opposed to set at idle, I spend more time at mild throttle than idle (ignore the full bore moments!) so figure this is where I need balance. The whole six pot set up is a mare as it goes out of balance so easily so expect to do every couple of thousand miles.
The pots, if worn, will give major eratic readings at cruise as high inlet vacuums pull on the butterflys so this does sound like you have cracked your original problem.
Did you hear a relay click in the ECU when this happened?
Nice clean looking motor btw.
J
I find I get a better response at cruise when set this way as opposed to set at idle, I spend more time at mild throttle than idle (ignore the full bore moments!) so figure this is where I need balance. The whole six pot set up is a mare as it goes out of balance so easily so expect to do every couple of thousand miles.
The pots, if worn, will give major eratic readings at cruise as high inlet vacuums pull on the butterflys so this does sound like you have cracked your original problem.
Did you hear a relay click in the ECU when this happened?
Nice clean looking motor btw.
J
Hi Sagi,
I did balance the throttle bodys with a syncrometer and they were all level, but at IDOL not as you suggested at 2/3000rpm. I have also tonight replaced the HT leads but unfortunatley there is still a shunting at low rpm, I thought it was solved but it is still there not as bad but still noticable I can feel it through the accelerator pedal and it is not the smooth drive that it once was.
I am away from home now until the end of the Sept and as the Tax is up on the 1st October I think I will SORN it for the winter and revisit it in the spring.
Thanks for taking the time to comment.
George
I did balance the throttle bodys with a syncrometer and they were all level, but at IDOL not as you suggested at 2/3000rpm. I have also tonight replaced the HT leads but unfortunatley there is still a shunting at low rpm, I thought it was solved but it is still there not as bad but still noticable I can feel it through the accelerator pedal and it is not the smooth drive that it once was.
I am away from home now until the end of the Sept and as the Tax is up on the 1st October I think I will SORN it for the winter and revisit it in the spring.
Thanks for taking the time to comment.
George
George,
No trouble mate, just interested as my Sag does do a similar thing every now and then. I have tried balancing at higher revs and this does help but suspect I may be countering an air leak between the throttle bodies and the head. Powers make a gasket or you can seal with RTV. There is a thread running on this already.
The other thing could be clatter or play on the adjusters. They are spring loaded, bit like an old Ford part to counter wear, but suspect that after a few thoushand open and closes wear will occur and the spring soften. The throttle plates will pull against the springs and I think could jiggle about a tiny bit. In my opinion it is a bit poor but then special cars need special care. I am working on a mod over winter so will tell all if it works....
Let me know how you get on, I would email you so you could reply but being an IT div I dont know how, pehaps you are a bit more advanced than me..! Anyway I will keep an eye out for your progress.
Best,
John
No trouble mate, just interested as my Sag does do a similar thing every now and then. I have tried balancing at higher revs and this does help but suspect I may be countering an air leak between the throttle bodies and the head. Powers make a gasket or you can seal with RTV. There is a thread running on this already.
The other thing could be clatter or play on the adjusters. They are spring loaded, bit like an old Ford part to counter wear, but suspect that after a few thoushand open and closes wear will occur and the spring soften. The throttle plates will pull against the springs and I think could jiggle about a tiny bit. In my opinion it is a bit poor but then special cars need special care. I am working on a mod over winter so will tell all if it works....
Let me know how you get on, I would email you so you could reply but being an IT div I dont know how, pehaps you are a bit more advanced than me..! Anyway I will keep an eye out for your progress.
Best,
John
I started the Cerb today after 3 months lying idol due to work and it was running very very rough. I went around the block for a quick drive and it was hopeless, backfiring and very very lumpy. I made it back to the house where I left the car ticking over on the drive while I got the lap top connected to the ECU and as soon as I did this the car got very lumpy on tick over and eventually stalled. It will not re-start.
The car has been in a dry garage and connected to a battery charger over the winter. My fuel was very low and I thought this may have been the problem so I filled up a Jerry can with V -power and poured it in but the car still refuses to start.
Dom kindly sent me some throttle pots that I thought had initially helped but hasn't, I also replaced the HT leads, my second set within a year but still no real difference. should I go for a new coil pack now, but I don't really want to just go replacing things that wont sort the issue as I spent virtually £9k on it last year and I can't spend much on it at this time.
Any pointers to try and get it started first would be a help, then I can see about getting this rough running sorted once and for all.
Any ideas guys.
George
This is how the software looked just after the car stalled on the drive
The car has been in a dry garage and connected to a battery charger over the winter. My fuel was very low and I thought this may have been the problem so I filled up a Jerry can with V -power and poured it in but the car still refuses to start.
Dom kindly sent me some throttle pots that I thought had initially helped but hasn't, I also replaced the HT leads, my second set within a year but still no real difference. should I go for a new coil pack now, but I don't really want to just go replacing things that wont sort the issue as I spent virtually £9k on it last year and I can't spend much on it at this time.
Any pointers to try and get it started first would be a help, then I can see about getting this rough running sorted once and for all.
Any ideas guys.
George
This is how the software looked just after the car stalled on the drive
Edited by natben on Saturday 16th February 18:34
George,
Your injector open times are very long. Coupled with your described symptoms, which sound like lack of fuel, I reckon you have a low fuel pressue or an air leak. The temp is up so why would you have over double the open time? Although, I dont know what the open times read on a stationary engine, do they show last or current? Guess you will not know until it is running so I will hook up tomorrow and find out and let you know.
Shame you are so far away I fancy a bacon roll for looking at your car!
Not got Saggo out yet, got new neighbours so an early Sunday wake up call I reckon...Chuckle
Best,
J
Your injector open times are very long. Coupled with your described symptoms, which sound like lack of fuel, I reckon you have a low fuel pressue or an air leak. The temp is up so why would you have over double the open time? Although, I dont know what the open times read on a stationary engine, do they show last or current? Guess you will not know until it is running so I will hook up tomorrow and find out and let you know.
Shame you are so far away I fancy a bacon roll for looking at your car!
Not got Saggo out yet, got new neighbours so an early Sunday wake up call I reckon...Chuckle
Best,
J
natben said:
I started the Cerb today after 3 months lying idol due to work and it was running very very rough. I went around the block for a quick drive and it was hopeless, backfiring and very very lumpy. I made it back to the house where I left the car ticking over on the drive while I got the lap top connected to the ECU and as soon as I did this the car got very lumpy on tick over and eventually stalled. It will not re-start.
The car has been in a dry garage and connected to a battery charger over the winter. My fuel was very low and I thought this may have been the problem so I filled up a Jerry can with V -power and poured it in but the car still refuses to start.
Dom kindly sent me some throttle pots that I thought had initially helped but hasn't, I also replaced the HT leads, my second set within a year but still no real difference. should I go for a new coil pack now, but I don't really want to just go replacing things that wont sort the issue as I spent virtually £9k on it last year and I can't spend much on it at this time.
Any pointers to try and get it started first would be a help, then I can see about getting this rough running sorted once and for all.
Any ideas guys.
George
This is how the software looked just after the car stalled on the drive
Stale arab juice if she has been sat for 3 months without use maybe? petrol oxidises and absorbs water if not in an airtight environment.The car has been in a dry garage and connected to a battery charger over the winter. My fuel was very low and I thought this may have been the problem so I filled up a Jerry can with V -power and poured it in but the car still refuses to start.
Dom kindly sent me some throttle pots that I thought had initially helped but hasn't, I also replaced the HT leads, my second set within a year but still no real difference. should I go for a new coil pack now, but I don't really want to just go replacing things that wont sort the issue as I spent virtually £9k on it last year and I can't spend much on it at this time.
Any pointers to try and get it started first would be a help, then I can see about getting this rough running sorted once and for all.
Any ideas guys.
George
This is how the software looked just after the car stalled on the drive
Edited by natben on Saturday 16th February 18:34
Well I managed to get the car started 3rd or 4th time this morning and had to hold the revs above 2000rpm to prevent it stalling for 10sec or so but then it settled down and tickover was back to being stable around 850rpm. It looks like the small amount of fuel sitting in the tank may have got contaminated (thanks Shep101 for your reply above)and then running out of fuel on the drive had prevented the car re starting.
I went for a short run this morning and it is still a bit lumpy around 2000-2500rpm but the fact it has sat still since mid Sept may have something to do with that but I will get it to TVR Power soon for a service and get them to look at the hesitation around 2000rpm.
I have attached a picture from the diagnostic screen below, if anyone spots anything out the ordinary please let me know.
I went for a short run this morning and it is still a bit lumpy around 2000-2500rpm but the fact it has sat still since mid Sept may have something to do with that but I will get it to TVR Power soon for a service and get them to look at the hesitation around 2000rpm.
I have attached a picture from the diagnostic screen below, if anyone spots anything out the ordinary please let me know.
Edited by natben on Sunday 17th February 13:00
natben said:
Well I managed to get the car started 3rd or 4th time this morning and had to hold the revs above 2000rpm to prevent it stalling for 10sec or so but then it settled down and tickover was back to being stable around 850rpm. It looks like the small amount of fuel sitting in the tank may have got contaminated (thanks Shep101 for your reply above)and then running out of fuel on the drive had prevented the car re starting.
I went for a short run this morning and it is still a bit lumpy around 2000-2500rpm but the fact it has sat still since mid Sept may have something to do with that but I will get it to TVR Power soon for a service and get them to look at the hesitation around 2000rpm.
I have attached a picture from the diagnostic screen below, if anyone spots anything out the ordinary please let me know.
Adaptives look a bit wide, do the lambda sensor switch quickly when you rev the engine?. I would expect them a little closer together if you had recently done a reset. Also what do the throttle pot values do you see over the range of travel on the accelerator? you can do this with the engine off (apart from idle!), they should stay near identical. I guess everybody's engine will be different but mine are 12.5% closed 15.8% on idle & 96.2% fully open, they are near identical on both banks. Mine ran rough as anything in the rev range you mentioned until I got the throttle bodies re-balanced, if you have a syncrometer may be worth a check.I went for a short run this morning and it is still a bit lumpy around 2000-2500rpm but the fact it has sat still since mid Sept may have something to do with that but I will get it to TVR Power soon for a service and get them to look at the hesitation around 2000rpm.
I have attached a picture from the diagnostic screen below, if anyone spots anything out the ordinary please let me know.
Edited by natben on Sunday 17th February 13:00
Also the fuel filter could be blocked(ish) having sucked all the crap out of the bottom of the tank when you ran out?
Shep
Edited by shep1001 on Sunday 17th February 13:20
Thanks for the reply Shep,
I think I will take your advise and change the fuel filter as it is very likley that some crap may have got into the filter from the tank and I will order a synchroniser up and have a go at balancing the throttle bodies.
I have to drive 350 miles to TVR Power for the service so probably worth trying to get the engine as well set up as I can before embarking on that trip.
I may be back for advice on how to balance the throttles!!
Thanks for taking the time to reply.
George
I think I will take your advise and change the fuel filter as it is very likley that some crap may have got into the filter from the tank and I will order a synchroniser up and have a go at balancing the throttle bodies.
I have to drive 350 miles to TVR Power for the service so probably worth trying to get the engine as well set up as I can before embarking on that trip.
I may be back for advice on how to balance the throttles!!
Thanks for taking the time to reply.
George
George,
Your second screen shot looks healthier although the adaptives do look a bit apart. I ran mine on the lap top this morning and when switched off the injector open time is similar to yours, which surprised me as I somehow expected it to read either last the run period just before stall/engine off or closed/zero. I know petrol can run out of beans but I've not had it happen to me thankfully, yet.
Glad you got it running but my gut feel from what you described last year I suspect there is an air leak somewhere.
J
Your second screen shot looks healthier although the adaptives do look a bit apart. I ran mine on the lap top this morning and when switched off the injector open time is similar to yours, which surprised me as I somehow expected it to read either last the run period just before stall/engine off or closed/zero. I know petrol can run out of beans but I've not had it happen to me thankfully, yet.
Glad you got it running but my gut feel from what you described last year I suspect there is an air leak somewhere.
J
Glad the OP got the problem sorted...the roller bearing throttle bodies are a great help - i found i also had to seal mine between the head and mounting flange to completely resolve the issues.
natben - another vote for throttle balancing from me - looks like one of the banks might be a little out.
Have a look through some of my past posts and PetrolHeadPete's / BGB Autosport - we all went through an iteration of throttle body balancing.
Any problems post up here...
These may help...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
natben - another vote for throttle balancing from me - looks like one of the banks might be a little out.
Have a look through some of my past posts and PetrolHeadPete's / BGB Autosport - we all went through an iteration of throttle body balancing.
Any problems post up here...
These may help...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Edited by Robertjp on Monday 18th February 13:12
Still no joy..........
Throttles are all balanced ok, but still the car is shunting badly around 2000rpm. It drives ok on the motorway at cruising speeds of 70-80Mph but in slow traffic around 20-30 mph it is a b
h!.
I am thinking I will fit the TVR Power TB gaskets to see if that helps, is this something I could do being a novice with the spanners?
Has anyone fitted them that could advise?
Failing that I will have to get the credit card out and take it somewhere that can set it up properly......aaggghhhh.
George
Throttles are all balanced ok, but still the car is shunting badly around 2000rpm. It drives ok on the motorway at cruising speeds of 70-80Mph but in slow traffic around 20-30 mph it is a b
h!.I am thinking I will fit the TVR Power TB gaskets to see if that helps, is this something I could do being a novice with the spanners?
Has anyone fitted them that could advise?
Failing that I will have to get the credit card out and take it somewhere that can set it up properly......aaggghhhh.
George
I have had the throttle bodies off a few times, once to fit the gaskets and they a do make a hell of a difference. No more backfiring in the throttle bodies. A tip is to remove all the throttle bodies as one while still attached to the fuel rail. It takes a bit of rocking back and fore to loosen them where they are located on the dowels but it’s relatively easy and on the occasions I have done it this way I have not disturbed the throttle settings when I have checked with the syncrometer.
Paul
Paul
paulvx220T said:
I have had the throttle bodies off a few times, once to fit the gaskets and they a do make a hell of a difference. No more backfiring in the throttle bodies. A tip is to remove all the throttle bodies as one while still attached to the fuel rail. It takes a bit of rocking back and fore to loosen them where they are located on the dowels but it’s relatively easy and on the occasions I have done it this way I have not disturbed the throttle settings when I have checked with the syncrometer.
Paul
Paul thanks for your advise, the throttle body's are balanced even at about 6, but I do get some backfire through throttle body 3 when I increase revs with the air box off. If the body's are drawing in air would they stay balanced at say 6 across all of them or would one show up wildly out?Paul
I would like to fit the gaskets myself as I have a family holiday coming up and I have just spent on a12k service so I can do without sending the car down south and spending another £700 at this time.
But can I do it without making things worse! I have removed the fuel rail before when I had it powder coated but this feels like a far bigger job.
Edited by natben on Monday 22 April 22:23
Robertjp said:
Its a piece of cake to fit the gaskets, a little time consuming but very easy.
The slightly tricky bit is refitting the throttle bodies, you will need to set the clearances from scratch. They need to look almost closed.
Then you are looking at 6-9 kg/min through the syncrometer.
Thanks for your continued advise on this subject Robert, as you have probably relished I am very much learning as I go, having had very little contact with engines previously.The slightly tricky bit is refitting the throttle bodies, you will need to set the clearances from scratch. They need to look almost closed.
Then you are looking at 6-9 kg/min through the syncrometer.
I would like to do this as a last attempt to fix before I send it down south at more expense!
Just need to pluck up the courage, the fact you guys have done it may just give me the confidence to give it a go.
George
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