Idle and stalling issue
Discussion
Been having problems with an intermittent idle/stalling problem which came to a head tonight resulting a long recovery trip home!
Quick history is that after the last engine disintegrated, got this replacement engine. Had troubles setting it up, which lead to me replacing the rose joints on the throttle linkage cable. It's also had new plugs and leads just a few miles ago.
Engine has now been set up as per the engine manual and was running lovely last night. However this morning, drove through town, then 10-15 minutes of brisk motorway driving. Came off the motorway, sat at traffic lights then went off round a roundabout, car suddenly wants to die. Manage to keep it going by dipping the clutch and revving it (a lot). Get on to the dual carriageway and straighten up, splutters a bit and is then fine again. Go through town, fine. Get to my destination and as soon as I'm going slowly, manoeuvring to park again it starts to die on me and stalls on multiple occasions. No misfire, no bangs or backfires, just feels like I've suddenly stuck my hand over the intake. This isn't the first time it's done it either (in fact this is twice either side of being laid up for a month or two).
I've also had the problem where by I can leave it to idle, which it will do fine, and then all of a sudden it will die after several minutes. Not always. Sometimes it will keep going, sometimes it will die sooner.
I've also noticed that generally, from cold it will idle at roughly 1200rpm. After a long run and being properly warmed up it will idle at about 1800rpm.
Haven't had time to put the laptop on the car tonight but I'll do that tomorrow to see if there are any sensor faults.
Any one had issues like this before?
Quick history is that after the last engine disintegrated, got this replacement engine. Had troubles setting it up, which lead to me replacing the rose joints on the throttle linkage cable. It's also had new plugs and leads just a few miles ago.
Engine has now been set up as per the engine manual and was running lovely last night. However this morning, drove through town, then 10-15 minutes of brisk motorway driving. Came off the motorway, sat at traffic lights then went off round a roundabout, car suddenly wants to die. Manage to keep it going by dipping the clutch and revving it (a lot). Get on to the dual carriageway and straighten up, splutters a bit and is then fine again. Go through town, fine. Get to my destination and as soon as I'm going slowly, manoeuvring to park again it starts to die on me and stalls on multiple occasions. No misfire, no bangs or backfires, just feels like I've suddenly stuck my hand over the intake. This isn't the first time it's done it either (in fact this is twice either side of being laid up for a month or two).
I've also had the problem where by I can leave it to idle, which it will do fine, and then all of a sudden it will die after several minutes. Not always. Sometimes it will keep going, sometimes it will die sooner.
I've also noticed that generally, from cold it will idle at roughly 1200rpm. After a long run and being properly warmed up it will idle at about 1800rpm.
Haven't had time to put the laptop on the car tonight but I'll do that tomorrow to see if there are any sensor faults.
Any one had issues like this before?
As said get it on the lap top first, does sound a bit like being on open loop all the time and chucking Heep's of extra fuel in and killing it?? Worth checking lamda connections, or dirty injectors? Have you ever had them cleaned, mine where filthy after 55k 4 of mine were dribbling more or less.
Duff throttle pot?
But only speculation lap top first for sure as it really could be anything.
Duff throttle pot?
But only speculation lap top first for sure as it really could be anything.
Thanks guys.
I did wonder whether it might be a fuel venting issue, especially as it generally occurs after a long run, not necessarily just when the engine is hot.
I would have thought anything else might be apparent all the time, like dirty injectors - though I doubt they've ever been cleaned so probably good to get them cleaned. I'll get the laptop on it this morning to check for fault codes and report back!
I did wonder whether it might be a fuel venting issue, especially as it generally occurs after a long run, not necessarily just when the engine is hot.
I would have thought anything else might be apparent all the time, like dirty injectors - though I doubt they've ever been cleaned so probably good to get them cleaned. I'll get the laptop on it this morning to check for fault codes and report back!
Just managed to get the laptop on it. Two faults logged, one is the battery and one is the "BaroPressure".
Is the BaroPressure the rubber pipe that comes from the passenger side of the bulkhead and connects to the airbox?
From my searches on PistonHeads (it is the rubber pipe), it seems, as it is only measuring atmospheric pressure, I think it is unlikely that the pipe being disconnected (just noticed the plastic connector has snapped) would be the cause of the car not starting!
Is the BaroPressure the rubber pipe that comes from the passenger side of the bulkhead and connects to the airbox?
From my searches on PistonHeads (it is the rubber pipe), it seems, as it is only measuring atmospheric pressure, I think it is unlikely that the pipe being disconnected (just noticed the plastic connector has snapped) would be the cause of the car not starting!Edited by jammy_basturd on Monday 1st December 14:59
I did wonder about coil packs, however, news flash...
Just had to drive across town. Had the same problems about half way through my journey. Luckily there was a place to pull in and I already had my laptop plugged in. I'd cleared the faults before I set off, but the BaroPressureLog fault was back. Looking at the reading it was fluctuating quite quickly from around 200 to 350+. After a couple of minutes I turned the ignition off and back on, the reading was back up to 900+ and when I started the car it seemed fine again - got to my destination OK after that.
So I guess the barometric sensor is my first port of call in tracing the problem.
Could the pipe being disconnected cause these fluctuations in readings?
When I got to my destination I blocked the pipe with my finger and it made very little difference to the reading on the laptop. Which suggests two things to me:
1) The pipe maybe blocked.
2) It takes more than a finger over the hose to change the reading, which suggests a faulty sensor/wiring for me to get such a wild fluctuation in reading?
Just had to drive across town. Had the same problems about half way through my journey. Luckily there was a place to pull in and I already had my laptop plugged in. I'd cleared the faults before I set off, but the BaroPressureLog fault was back. Looking at the reading it was fluctuating quite quickly from around 200 to 350+. After a couple of minutes I turned the ignition off and back on, the reading was back up to 900+ and when I started the car it seemed fine again - got to my destination OK after that.
So I guess the barometric sensor is my first port of call in tracing the problem.
Could the pipe being disconnected cause these fluctuations in readings?
When I got to my destination I blocked the pipe with my finger and it made very little difference to the reading on the laptop. Which suggests two things to me:
1) The pipe maybe blocked.
2) It takes more than a finger over the hose to change the reading, which suggests a faulty sensor/wiring for me to get such a wild fluctuation in reading?
(Disclaimer: I'm new to the world of TVRs but have experience setting up engine management)
TVR engines are mapped by TPS and the baro sensor is of the type usually used to gauge manifold pressure - one of the two primary engine sensors without which the thing can't run. On the TVR, it's used to correct for altitude and/or a blocked air filter.
I presume that by providing the ECU no feedback, it will log a fault on the sensor and assume 100kPa - ie standard pressure at sea level. Try unplugging the sensor, if the readout is still jumping around, you have a wiring problem. I reckon the adapatives have more than enough ability to adjust for any baro pressure difference, assuming you dont live halfway up a mountain? so if your air filter is clean, it'll be fine to drive like that.
TVR engines are mapped by TPS and the baro sensor is of the type usually used to gauge manifold pressure - one of the two primary engine sensors without which the thing can't run. On the TVR, it's used to correct for altitude and/or a blocked air filter.
I presume that by providing the ECU no feedback, it will log a fault on the sensor and assume 100kPa - ie standard pressure at sea level. Try unplugging the sensor, if the readout is still jumping around, you have a wiring problem. I reckon the adapatives have more than enough ability to adjust for any baro pressure difference, assuming you dont live halfway up a mountain? so if your air filter is clean, it'll be fine to drive like that.
Yes it shouldn't make much difference whether the pipe is plugged into the airbox, or unplugged (open to atmosphere) or the pipe is blocked. Assuming your air filter is ok, the pressure inside the airbox should be fairly similar to atmospheric, especially at idle. Sounds like a bad sensor or its wiring. Not sure where the sensor is, presumably somewhere in the passenger footwell(?).
If the sensor is telling the ecu 200mB instead of 1000mB, it will think you are on top of Everest! As baro pressure drops, the ecu will put less fuel in (or that's how I understand baro sensor corrections) to correct for the air getting thinner. However if the ecu has detected that it is faulty, it should ignore the sensor. IIRC it's only a standard baro/map sensor so quite easy to get hold of.
Daz
Daz
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