Had the car out today and every time I come off the gas the revs drop so low it cuts out
I'm guessing its probably something to do with the ecu but it seems fine when I start it up and just leave it running
It was also starting to pop from the exhaust a lot I'm thinking its probably giving to much fuel anyone any ideas?
cutting out problem
Re: cutting out problem
No idling could be IACV. If it's stuck, the engine won't idle properly. Popping could also be an air leak in the exhaust.
Coolant sensor could also be malfunctioning, leading the ECU to overfuel. Would doubt it would be an ECU fault.
Coolant sensor could also be malfunctioning, leading the ECU to overfuel. Would doubt it would be an ECU fault.
2010 Honda VFR1200F
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R
1990 Honda VFR400 NC30
2000 Honda VTR1000 SP1
2000 Kawasaki ZX-7R
Re: cutting out problem
What car?
Or the throttle position sensor.
Try this - start the engine, let it idle until the dash shows normal running temperature. Note the RPM should now be <1000 RPM (I think 800 is the target for most normal elises).
Now press the throttle gently and get the revs up to say 4,000 RPM.
Take your foot off the accelerator sharply and pay careful attention to what happens. The revs should drop like a stone to 1,600 RPM or there abouts and then there should be a slight burble as the ECU starts to fire the engine again (the ECU cuts off fuelling/ignition on the engine on closed throttle overrun for emissions and economy purposes) - the revs should now drop more slowly.
If you can detect the ECU firing the engine again at 1,600 RPM it's not your throttle position sensor. If it doesn't cut back in at 1,600 it's because it doesn't think the throttle is fully closed - i.e. it sees the throttle as slightly open and assumes you are trying to drive the car so won't engage the idle control loop. Chances are this is because your TPS is broken, there's a broken wire or maybe because the TPS calibration has drifted too far. If you think it might be the TPS it's worth doing the TPS recalibration. To do this, turn ignition off for at least 30s, then turn ignition to run position (i.e. don't crank). Then move the throttle quickly (i.e. about twice per second, not once every other second) from no throttle to full throttle 10 times (actually you don't need as many as 10, but it won't hurt). Then turn the ignition off completely and wait at least another 30s.
Report back ...
Cheers,
Robin
Or the throttle position sensor.
Try this - start the engine, let it idle until the dash shows normal running temperature. Note the RPM should now be <1000 RPM (I think 800 is the target for most normal elises).
Now press the throttle gently and get the revs up to say 4,000 RPM.
Take your foot off the accelerator sharply and pay careful attention to what happens. The revs should drop like a stone to 1,600 RPM or there abouts and then there should be a slight burble as the ECU starts to fire the engine again (the ECU cuts off fuelling/ignition on the engine on closed throttle overrun for emissions and economy purposes) - the revs should now drop more slowly.
If you can detect the ECU firing the engine again at 1,600 RPM it's not your throttle position sensor. If it doesn't cut back in at 1,600 it's because it doesn't think the throttle is fully closed - i.e. it sees the throttle as slightly open and assumes you are trying to drive the car so won't engage the idle control loop. Chances are this is because your TPS is broken, there's a broken wire or maybe because the TPS calibration has drifted too far. If you think it might be the TPS it's worth doing the TPS recalibration. To do this, turn ignition off for at least 30s, then turn ignition to run position (i.e. don't crank). Then move the throttle quickly (i.e. about twice per second, not once every other second) from no throttle to full throttle 10 times (actually you don't need as many as 10, but it won't hurt). Then turn the ignition off completely and wait at least another 30s.
Report back ...
Cheers,
Robin
I is in your loomz nibblin ur wirez
#bemoretut
#bemoretut
Re: cutting out problem
Oh, just read about the popping. Unburnt fuel in the exhaust is what makes it pop - does rather sound like the ECU thinks the throttle is open when it isn't so even more likely to be TPS related fault.
Cheers,
Robin
Cheers,
Robin
I is in your loomz nibblin ur wirez
#bemoretut
#bemoretut
Re: cutting out problem
I started the car this morning and tried what you said but strangely it seems to be running fine i tried reving it past 4,000rpm and it just dropped straight back to around 900rpm done this a few times with the same result 
The car then spluttered a few times and sort of gave a few pops which i guess is fuel burning in the exhaust
Dont think my neighbours appreciated it at 9am though
As the car was lying for a few months is it possibly something to do with that ?
I didnt take it a run as i was out earlier in the golf and was starting to get a bit slippy.
The car is an early S2 Robin if that helps any ?
The car then spluttered a few times and sort of gave a few pops which i guess is fuel burning in the exhaust
Dont think my neighbours appreciated it at 9am though
As the car was lying for a few months is it possibly something to do with that ?
I didnt take it a run as i was out earlier in the golf and was starting to get a bit slippy.
The car is an early S2 Robin if that helps any ?
Re: cutting out problem
I guess you need to wait until it becomes more reproducible then .... you might be able to hook up the OBDII diagnostic tool to the ECU and observe the TPS motion and see if it skips about or stays level. An inspection of the TPS wiring would also make sense, though I think for the S2 they modified the loom to prevent the wire breakage issues that the S1 suffers from.
Cheers,
Robin
Cheers,
Robin
I is in your loomz nibblin ur wirez
#bemoretut
#bemoretut