And I thought it was all over
Discussion
and that the gremlins had been banished but not so.
Last ten drives each time the car is started and warmed up the idle has been different. Got to the point where I carry a multimeter and allen key set to adjust each time.
However I have now managed to identify a "faulty" condition and a "correct" condition.
When faulty it idles at 900, is very rough below 2000 with a lot of drive train shunt and performance is slightly subdued. More mechanical type noise from the exhaust with a real thumping howl on the overun.
When correct it idles at 1100, is smooth throughout and performance is crisp. Pops and crackles on the overun.
Only managed to identify these conditions as this morning at part throttle at 1500 in traffic it was faulty and then suddenly it started to accelerate with no change in throttle position and started behaving in the correct mode.
Can anyone point me in a direction to look ?
Things I know are ok - major mechanical, main ecu earth, alternator cabling, battery, immobiliser wiring, TPS, throttle assembly not sticking, CSV disconnected, AAV removed and plugged, overun valve set to 15psi and seating ok, no other air leaks to plenum, battery, fuel pump and pressure.
Could water temp sender to ecu be the cause ? It seems to change from faulty to correct once really warmed up - ecu board bad connection making once warm ?
I would appreciate any advice as there is a lack of expertise in these parts and I don't want to write a blank cheque.
PS Coming to the UK on Thursday for a month and hope to try and meet up with some wedges somewhere as I will be in severe withdrawl whilst driving the rental hack.
Last ten drives each time the car is started and warmed up the idle has been different. Got to the point where I carry a multimeter and allen key set to adjust each time.
However I have now managed to identify a "faulty" condition and a "correct" condition.
When faulty it idles at 900, is very rough below 2000 with a lot of drive train shunt and performance is slightly subdued. More mechanical type noise from the exhaust with a real thumping howl on the overun.
When correct it idles at 1100, is smooth throughout and performance is crisp. Pops and crackles on the overun.
Only managed to identify these conditions as this morning at part throttle at 1500 in traffic it was faulty and then suddenly it started to accelerate with no change in throttle position and started behaving in the correct mode.
Can anyone point me in a direction to look ?
Things I know are ok - major mechanical, main ecu earth, alternator cabling, battery, immobiliser wiring, TPS, throttle assembly not sticking, CSV disconnected, AAV removed and plugged, overun valve set to 15psi and seating ok, no other air leaks to plenum, battery, fuel pump and pressure.
Could water temp sender to ecu be the cause ? It seems to change from faulty to correct once really warmed up - ecu board bad connection making once warm ?
I would appreciate any advice as there is a lack of expertise in these parts and I don't want to write a blank cheque.
PS Coming to the UK on Thursday for a month and hope to try and meet up with some wedges somewhere as I will be in severe withdrawl whilst driving the rental hack.
19560 said:
PS Coming to the UK on Thursday for a month and hope to try and meet up with some wedges somewhere as I will be in severe withdrawl whilst driving the rental hack.
It's got to be Oulton Park then. See the thread with the sticky. J
Unfortunately I will be in Cornwall on the 2nd no doubt enduring a 3 day long downpour !
I had an intermittent problem, which persisted for about a year. Attempting to fault find it taught me a lot about efi. Though I am by no means an expert. Just a talented fiddler.
One test I am quite proud of, was to eliminate the water temp sender as the culprit by taping a replacement one to a nearby coolant hose and wrapping with insulation. You can then continue to drive normally with the original sender and when the fault rears its ugly head you can jump out and switch over to the replacement item and see if the problem goes away! Unfortunately for me it didn't but it did give me confidence in the sender unit (unless they both have exactly the same fault!)
The day that I solved the problem I decided to remove the ECU and retouch every single solder joint. This was quite a desperate measure but I had exhausted every other possibility by this time. So with fear and trepidation I set too with my soldering iron.......
When finished and I had gone nearly blind looking through a magnifying glass to spot any solder bridges I replaced the ECU and observed that it clicked home into the connector with a very positive action which seemed to be different to when I disconnected it. I played with plugging in and out and convinced myself that there was a possibility that the connector was not originally located fully home!!!
So to conclude, two things changed to solve the problem which over a year later has still not reoccurred!!
1. Make sure the ecu multi-way plug is fully home
2. Re-solder entire ecu.
Once you have satisfied yourself that everything else is in order, I strongly recommend you try these, one at a time, but be prepared to spend out on a replacement ecu as the re-soldering is a risky approach even for someone accomplished at waving a soldering iron about.
Though it took me a long time to solve, I have learnt a lot, acquired some useful tools (Fuel pressure guage, compression tester, spare coolant temp sender, vacuum tester ……) and saved myself some money, as I am sure that a specialist would have changed all sensors,leads,plugs,caps...., cost hours of labour, and resorted to replacing the ecu.
All the best and I hope this helps
Leo
One test I am quite proud of, was to eliminate the water temp sender as the culprit by taping a replacement one to a nearby coolant hose and wrapping with insulation. You can then continue to drive normally with the original sender and when the fault rears its ugly head you can jump out and switch over to the replacement item and see if the problem goes away! Unfortunately for me it didn't but it did give me confidence in the sender unit (unless they both have exactly the same fault!)
The day that I solved the problem I decided to remove the ECU and retouch every single solder joint. This was quite a desperate measure but I had exhausted every other possibility by this time. So with fear and trepidation I set too with my soldering iron.......
When finished and I had gone nearly blind looking through a magnifying glass to spot any solder bridges I replaced the ECU and observed that it clicked home into the connector with a very positive action which seemed to be different to when I disconnected it. I played with plugging in and out and convinced myself that there was a possibility that the connector was not originally located fully home!!!
So to conclude, two things changed to solve the problem which over a year later has still not reoccurred!!
1. Make sure the ecu multi-way plug is fully home
2. Re-solder entire ecu.
Once you have satisfied yourself that everything else is in order, I strongly recommend you try these, one at a time, but be prepared to spend out on a replacement ecu as the re-soldering is a risky approach even for someone accomplished at waving a soldering iron about.
Though it took me a long time to solve, I have learnt a lot, acquired some useful tools (Fuel pressure guage, compression tester, spare coolant temp sender, vacuum tester ……) and saved myself some money, as I am sure that a specialist would have changed all sensors,leads,plugs,caps...., cost hours of labour, and resorted to replacing the ecu.
All the best and I hope this helps
Leo
I have a check list downloaded from a Rover SD1 site, which may help. Sorry I forgot to save the link, but I can send you a copy if you mail me off-line. It provides a step by step guide to checking all of the sensors and connections for the efi system.
How do you check / adjust the over-run valve to 15psi????
How do you check / adjust the over-run valve to 15psi????
Check the injector resistor pack. On my 390 this is mounted on the inner wing near the airflow meter. It is a metallic box about 4 inches by 2.5 by 1, there are 8+ thick wires going into it.
I sometimes get rough running and it changes when I wiggle the connector going into this pack.
Recently I resorted to a good spray of contect cleaner on both plug and socket followed by a bit of vaseline to slow down corrosion. These contacts flow a fair bit of current and the slightest resistance makes a difference.
Russ
I sometimes get rough running and it changes when I wiggle the connector going into this pack.
Recently I resorted to a good spray of contect cleaner on both plug and socket followed by a bit of vaseline to slow down corrosion. These contacts flow a fair bit of current and the slightest resistance makes a difference.
Russ
To all of the above thank you for your help.
Ian / Leo - I think the ECU is favourite at the moment as I have the relay holder hanging out and all the wiring sitting there in the footwell as I slowly reduce the cables that don't actually go anywhere anymore. I did pull the ECU plug around recently - maybe it didn't go back right and will check tomorrow before I take my last drive for a month.
Don - thanks for the offer - the bible has the sensor temp/resistance values and TPS and AFM voltages so I can check against them - was hoping for an easy fix first before doing this. As for the overun valve it is a mod suggested in the bible to give the full advantage to a rising rate fuel regulator of the increase in vacuum caused by increasing the point at which it will open. I tightened the nut on the bolt right up to the non threaded part and then flattened the threads behind it to stop it coming undone - according to the book this gives a -15psi setting. Now all I need to do is pick up the new fuel regulator whilst in the UK !
Rus - I have just moved this resistor pack to a new location after relocating the AFM - cleaned the contacts up when I moved it but will have a wiggle tomorrow.
Thanks again.
Ian / Leo - I think the ECU is favourite at the moment as I have the relay holder hanging out and all the wiring sitting there in the footwell as I slowly reduce the cables that don't actually go anywhere anymore. I did pull the ECU plug around recently - maybe it didn't go back right and will check tomorrow before I take my last drive for a month.
Don - thanks for the offer - the bible has the sensor temp/resistance values and TPS and AFM voltages so I can check against them - was hoping for an easy fix first before doing this. As for the overun valve it is a mod suggested in the bible to give the full advantage to a rising rate fuel regulator of the increase in vacuum caused by increasing the point at which it will open. I tightened the nut on the bolt right up to the non threaded part and then flattened the threads behind it to stop it coming undone - according to the book this gives a -15psi setting. Now all I need to do is pick up the new fuel regulator whilst in the UK !
Rus - I have just moved this resistor pack to a new location after relocating the AFM - cleaned the contacts up when I moved it but will have a wiggle tomorrow.
Thanks again.
This weekend I finally put my "rough running when cold" problem to bed (fingers crossed) Mine too would run perfect when up to temperature, 80 C plus. Any temperature below this and it would sound like a bag of spanners and missfire around 2500rpm. Suspect temp sensor i thought so bought a new one, tried it (just connected to plug) and still the same. Took the ECU apart to inspect but couldn't get the 2 PCB's apart so quickly put in back together for fear of breaking it! On Wedg1e's advice suspected it was either over or under fuelling. Not knowing in which way to adjust it I took a guess and screwed it 1/4 turn clockwise - Lucky guess as it now runs perfect. Still don't know if i have increased or decreased the fuel pressure and indeed by how much but hey-ho job done
toby noble said:
Bob, happy to test drive the car for you while you're away
Toby,
After seeing you drive yours in the manner in which it should be enjoyed I think you would put the mileage over the insurance limit for the year.
Happy wedging !
As for the car isn't it a bugger how you can never fully identify the fault.
Adjusted fuel pressure as suggested, wiggled connectors and took it out - perfect !
Enjoyed a great drive to work in beautiful weather and was fine coming home until cruising at 2000 in 4th and then suddenly a drop in revs and back to the same.
It's got to be electrical the way it comes and goes - I reckon I may be losing a cylinder or even a fault to a bank of injectors. If I don't spend too much in the next month maybe a decent rr session may solve a few problems.
If I cut back on the fish and chips and the cream teas (and especially the Stella) maybe I can save enough for a motec !
ok may get flamed as i dont know what i'm talkin about here!
intermittent electrical faults on my car traced to coil and ignition module (amplifier)
coil: clue was oily dribble out of the front of the actual coil
ignition module: borrowed another one to try and it worked!
just my personal experiences, at least they dont cost anything to check out.
good luck, dean
intermittent electrical faults on my car traced to coil and ignition module (amplifier)
coil: clue was oily dribble out of the front of the actual coil
ignition module: borrowed another one to try and it worked!
just my personal experiences, at least they dont cost anything to check out.
good luck, dean
See www.pistonheads.com/gassing/topic.asp?t=127559&f=12&h=0 for the information to which I refered. It may help.
Read through but didn't see it mentioned so here's one that worked for me.
Check the wiring associated with the throttle position sensor. On my car, one of the pins in the snap together plug a few inches from the sensor had got shoved out enough to break contact with the female side of the junction block.
My symptoms were poor tickover, poor throttle response and a flat spot around 2250-2500 revs.
Worth a clean of the block and a vaselining before reassambly.
Good luck and hope you trace it.
Check the wiring associated with the throttle position sensor. On my car, one of the pins in the snap together plug a few inches from the sensor had got shoved out enough to break contact with the female side of the junction block.
My symptoms were poor tickover, poor throttle response and a flat spot around 2250-2500 revs.
Worth a clean of the block and a vaselining before reassambly.
Good luck and hope you trace it.
I've been working on the rough dle, poor running fault for a while now. I made sure I had no air leaks then did all the electrical checks I could using the guide on the Rover SD1 site (I posted the URL earlier). I found nothing wrong, reconnected the ECU and hey presto it runs fine. Leorest noted a bad ECU connection was his problem so I may have the same thing? Moving the connection in and out a few times may have sorted it. I may just go ahead and pull the ECU to bits.....
Nigel_350I said:
I've been working on the rough idle, poor running fault for a while now. I made sure I had no air leaks then did all the electrical checks I could using the guide on the Rover SD1 site (I posted the URL earlier). I found nothing wrong, reconnected the ECU and hey presto it runs fine. Leorest noted a bad ECU connection was his problem so I may have the same thing? Moving the connection in and out a few times may have sorted it. I may just go ahead and pull the ECU to bits.....
A service engineer's maxim is...
"If it ain't broke don't fix it"
It is entirely likely that exercising the connector a few times has wiped the oxide from the contacts and this may be all that was needed.
If you want to be a little more pro-active then you can buy a can of electrical switch/contact cleaner (Maplin) give the connectors a good soak and let them dry naturally, re-assemble and you should have put off any re-occurrence for a good few years.
I should emphasise that re-soldering the entire ECU was something I didn't enter into lightly for fear of doing more harm than good.
First I made sure that there was no other posibilities air/vacuume leaks, HT breakdown, plugs, leads, coil, cap, etc...etc... then I spent literally two hours with a magnifying glass inspecting every solder joint for oxide, cracks, dry joints.
Finally I gave up and set too with the iron.
At this point I had decided that I was prepared to risk dammage to the ecu because the next step would be replacement£££
Note that I also kept all the old parts so that in the future they can be used as diagnostic spares
All the best and I hope this helps
Leo
I think caution is indeed the best route! I didn't want to induce any (expensive) damage so I limited myself to taking the ECU cover off last night and just checking where the connector enters the board (most mechanical stress/movement) and it looks fine so I did the cover back up and left alone. I also discovered that that the connector to the resistor pack is iffy/poor contact. If I had a high resistance contact there it would drop more volts = less volts to injector = poor operation = lean. So I think bewtween the two things I've discovered my problem. With the contacts cleaned up it runs fine and I can screw back the co screw from fully closed without it killing the engine. Also manually moving the air flap forward makes the car die rather than get better so I think I'm running with a decent mixture now.
Thanks for the help, appreciate it.
Thanks for the help, appreciate it.
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