Car is stalling at junctions - intermittently
Discussion
Car is acting strange over the last couple of days. It has been running perfectly in normal driving, I have been using it every day for the last couple of weeks, then out of the blue coming to a stop, the idle drops down to near zero.
The car runs well for the first 10 - 20 mins or so and idles perfectly then this starts happening and after that it stays like that until I restart.
The steeper rescues it, raising it back up again but then the idle drops again and the engine dies. So suspecting the stepper I waited for a steady idle and then disconnected it and was pleased that I had found the problem, car idled smoothly and thus I planned to clean it again tomorrow morning.
But about 15 mins later, same thing, revs dropping at idle and it dies.
Bosch HT leads and sparks are 2 months old, amp and coil changed last year (again Bosch), no extenders and heat socks. Injectors also recently cleaned and vacuum tight and sealed. No hesitating or misfires while driving, nor shunts or any other weird behavior, it pulls like a train on wot.
Funny thing I noticed last night when starting it, the tacho needle bounced about more flamboyantly than normal when I blipped the throttle pedal a few times. Not sure if that is relevant.
Any ideas?
The car runs well for the first 10 - 20 mins or so and idles perfectly then this starts happening and after that it stays like that until I restart.
The steeper rescues it, raising it back up again but then the idle drops again and the engine dies. So suspecting the stepper I waited for a steady idle and then disconnected it and was pleased that I had found the problem, car idled smoothly and thus I planned to clean it again tomorrow morning.
But about 15 mins later, same thing, revs dropping at idle and it dies.
Bosch HT leads and sparks are 2 months old, amp and coil changed last year (again Bosch), no extenders and heat socks. Injectors also recently cleaned and vacuum tight and sealed. No hesitating or misfires while driving, nor shunts or any other weird behavior, it pulls like a train on wot.
Funny thing I noticed last night when starting it, the tacho needle bounced about more flamboyantly than normal when I blipped the throttle pedal a few times. Not sure if that is relevant.
Any ideas?
Do you get a slightly higher idle as you slow down then at walking pace it drops to 900 when stepper is working ok.
If it stalls base idle might be too low but if Ecu is in a muddle fuelling might get far to rich.
Temp sensor used to be sited as a cause of uneaven running in the past so take a look at that anyway.
Earth behind the dash might be the cause of your bouncing tacho but I’m guessing.
I’d check all earths and can you run it with diagnostics plugged in.
Faulty lambda, loads of things come to mind.
Goodluck
If it stalls base idle might be too low but if Ecu is in a muddle fuelling might get far to rich.
Temp sensor used to be sited as a cause of uneaven running in the past so take a look at that anyway.
Earth behind the dash might be the cause of your bouncing tacho but I’m guessing.
I’d check all earths and can you run it with diagnostics plugged in.
Faulty lambda, loads of things come to mind.
Goodluck
I know it could be loads of things
Car is running map 2 so lambdas not being used. I might try putting it back to map 5 and seeing if it is a fuelling issue with rovergauge connected but it runs so well at the moment and this kicks in after it has been driven for 10 odd minutes and after that does not recover. It was running quite rich on map 2, something I was going to deal with, so perhaps sooty plugs?
Heat thing?
Bouncing tacho, a one off last night, it was OK today.
Car is running map 2 so lambdas not being used. I might try putting it back to map 5 and seeing if it is a fuelling issue with rovergauge connected but it runs so well at the moment and this kicks in after it has been driven for 10 odd minutes and after that does not recover. It was running quite rich on map 2, something I was going to deal with, so perhaps sooty plugs?
Heat thing?
Bouncing tacho, a one off last night, it was OK today.
A friend in another hot country, Bulgaria, had this about a week ago, and his car was also running like the local wine, ie rough.
He did an ECU reset, sorted it.
He is on the standard 14 CUX. Are you? It just needed a Re-boot, like any computer does from time to time.
Worth trying, takes a minute or two
He did an ECU reset, sorted it.
He is on the standard 14 CUX. Are you? It just needed a Re-boot, like any computer does from time to time.
Worth trying, takes a minute or two
Does the idle stay slightly higher ( by design) until you get down to walking pace.
Black box and or speed indicator issue and that can surely play havoc with the stepper motor position and or fuelling at lower revs if this signal is confused or missing. We need the great Blitz again,,,, CUX is just to difficult for me to understand lol.
If Ecu is on non Cat map I don’t think a re set does much but I might be quite wrong.
Are you happy with the Ecu temp sender and it’s readings
Black box and or speed indicator issue and that can surely play havoc with the stepper motor position and or fuelling at lower revs if this signal is confused or missing. We need the great Blitz again,,,, CUX is just to difficult for me to understand lol.
If Ecu is on non Cat map I don’t think a re set does much but I might be quite wrong.
Are you happy with the Ecu temp sender and it’s readings
^^^^^^^ 
Another one to check.
I had a problem with my regulator shortly after Mbe install as in it would whine for a few seconds on start ups. A bit of Redex fuel treatment and it’s never done it since. I’m using the stuff a bit more than I used to as my injectors are most def quieter since. Once every four tank fulls now and it’s never been quieter.
Worth adding a bit just to lubricate the parts. My fuel pump makes less noise too.
I only did it cos the stuff was so cheap in Asda when looking for someth8mg else... glad I did I’ll say that
Another one to check.
I had a problem with my regulator shortly after Mbe install as in it would whine for a few seconds on start ups. A bit of Redex fuel treatment and it’s never done it since. I’m using the stuff a bit more than I used to as my injectors are most def quieter since. Once every four tank fulls now and it’s never been quieter.
Worth adding a bit just to lubricate the parts. My fuel pump makes less noise too.
I only did it cos the stuff was so cheap in Asda when looking for someth8mg else... glad I did I’ll say that
My experience on this one is a shift in mixture- too rich and the engine bogs down as a result. Check the plug colours on map 2 to make sure they are not sooting up. One thing an over heating / failing AFM can skew the fuelling as its voltage goes to high, and so puts in too much fuel and map 2 cant compensate. You could try putting a heat shield or insulation around the AFM body and see if things improve. It would make sense considering the time taken for the fault to occur as the engine bay and AFM gets hotter.
A few things to think about but as I know it's running rich my thoughts are going in that direction.
Never had a problem with the AFM to be honest but then it always had run rich on map 2, at 1.32v. Was going to try two things, one go back to map 5 for a while to see if the issue happens again, and the other to experiment with the AFM voltage back on map 2, perhaps to lower it slightly so that the fuelling is a little leaner.
Will pull out a plug to make sure, Give the rest a clean and the stepper motor and will see if the problem comes back. Then I suppose it's process of elimination time.
Never had a problem with the AFM to be honest but then it always had run rich on map 2, at 1.32v. Was going to try two things, one go back to map 5 for a while to see if the issue happens again, and the other to experiment with the AFM voltage back on map 2, perhaps to lower it slightly so that the fuelling is a little leaner.
Will pull out a plug to make sure, Give the rest a clean and the stepper motor and will see if the problem comes back. Then I suppose it's process of elimination time.
QBee said:
Would being in a hot country make any difference to the thinking of those advising. IIRC, you are in Cyprus, so 30-40 degrees C daytime temperature?
I really don't think that is the issue Anthony, I had it in the summer heat last year at over 40 deg, with a/c and it was fine. This week we have had a relatively cool week with Temps not higher than about 26 degrees. I initially suspected the stepper as I said because for the last couple of weeks it has been slower to settle from fast idle to normal when rolling up to junctions so I was surprised when after disconnecting the stepper that the stall still happened, again after a little time.
Mine ran rich on map 2 when I tried a Catted Y before Mbe and the fuel economy was very poor.
So your not bothered if the black box works behind the dash as you’ve not confirmed if it actually works as it should when slowing down?
If the idle control works correctly as Ive mentioned then it can be discounted as an issue but without answering the question it just leaves another possible fault not being diagnosed.
Only trying to help!
So your not bothered if the black box works behind the dash as you’ve not confirmed if it actually works as it should when slowing down?
If the idle control works correctly as Ive mentioned then it can be discounted as an issue but without answering the question it just leaves another possible fault not being diagnosed.
Only trying to help!
Classic Chim said:
Mine ran rich on map 2 when I tried a Catted Y before Mbe and the fuel economy was very poor.
So your not bothered if the black box works behind the dash as you’ve not confirmed if it actually works as it should when slowing down?
If the idle control works correctly as Ive mentioned then it can be discounted as an issue but without answering the question it just leaves another possible fault not being diagnosed.
Only trying to help!
As far as I know, the black box does work correctly, the idle drops to the normal level when coming to a stop.
I will though reconnect the stepper after cleaning it, to be on the safe side, and I will test the speedo more carefully and will get back to you.
So your not bothered if the black box works behind the dash as you’ve not confirmed if it actually works as it should when slowing down?
If the idle control works correctly as Ive mentioned then it can be discounted as an issue but without answering the question it just leaves another possible fault not being diagnosed.
Only trying to help!
As far as I know, the black box does work correctly, the idle drops to the normal level when coming to a stop.
I will though reconnect the stepper after cleaning it, to be on the safe side, and I will test the speedo more carefully and will get back to you.
So got stuck in over the weekend, cleaned the stepper, but also changed the tune resistor back to map 5 and as I had a spare brand new ignition amp lying around, also changed that.
Spent the day in it today in mixed driving and it did not stall once, which to me suggests that perhaps the problem was with the overly rich running I was experiencing from map 2. I also adjusted the timing slightly, up from 28 deg to 30 deg at 4k rpm and as my distributor only has 14 deg of mech advance, this got me at 16 deg at idle, and the engine idles more smoothly than before.
It is interesting that like this, that the map 5 is behaving as well as map 2 as far as the smoothness of driving goes and frankly I would not mind leaving it like this, for now, to be honest, until I work out why map 2 always runs so rich with the CO trim set up at 1.32V.
Spent the day in it today in mixed driving and it did not stall once, which to me suggests that perhaps the problem was with the overly rich running I was experiencing from map 2. I also adjusted the timing slightly, up from 28 deg to 30 deg at 4k rpm and as my distributor only has 14 deg of mech advance, this got me at 16 deg at idle, and the engine idles more smoothly than before.
It is interesting that like this, that the map 5 is behaving as well as map 2 as far as the smoothness of driving goes and frankly I would not mind leaving it like this, for now, to be honest, until I work out why map 2 always runs so rich with the CO trim set up at 1.32V.
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