fuel issue or ?

[89supra7mgte]

Ok this one has me stumped and irritated. My idle afrs were 14.6 along with cruise. Well today ran into something strange idle was 9.8 and would drop every now and then. Pulled an injector and no change. I am using an lc1 also. Fuel pressure never changed what could be the cause of this?

Drove home it cleared up and started acting right again. I went and installed a recirc tip on bov thinking maybe it was being stuck open causing ecu to act up, not sure if that would cause that or not though. Now my idle is up to 1000 were normally it was at 750 without the recirc.

No codes vac leaks or anything i can see that might cause this. Any ideas?

 

[jetjock]

Well, if you pulled an injector and there was no change I'd be relying on something else instead of that LC1. In fact you should be using the NB to troubleshoot closed loop issues anyway. More accurate.

 

[89supra7mgte]

Nb (narrowband) that would be the same as checking the vf signal correct? This was on a cold engine so open loop I would assume. Temp outside was 90 and don't believe the csi would be in affect and if so I ran the car at idle until op temp where csi should be off right? I will check on NB when I restart it and see where its at.

You could smell how rich it was too but finally cleared up after driving which is what gets me.

---------- Post added at 10:07 PM ---------- Previous post was at 10:06 PM ----------

Nb (narrowband) that would be the same as checking the vf signal correct? This was on a cold engine so open loop I would assume. Temp outside was 90 and don't believe the csi would be in affect and if so I ran the car at idle until op temp where csi should be off right? I will check on NB when I restart it and see where its at.

You could smell how rich it was too but finally cleared up after driving which is what gets me.

 

[jetjock]

Mixture is going to be richer on a cold engine and the CSI doesn't operate unless the key is in the start position. Doesn't mean it can't leak though.

You could use the Vf emulation of the NB but I prefer to use OX (didn't we just go through this?) as it can be employed without being in diag mode. What exactly is the problem anyway? Is there a driveability issue?

 

[89supra7mgte]

OK ill rule out the csi unless since when i had checked it before has started to leak. I do understand a cold engine is gonna run richer for a short time. As far as going over this before i dont believe you and i have? So to check vf you want it in diag mode? I have not heard of OX? Sorry for my ignorrance. And diag mode is just jumping te1 and e1 correct? I know how to check codes and use the meter when checking certain areas but did not know that some require being in diag mode.

But like i said right now it is idling at 14.6-14.8. It will only do it sometimes and regain but earlier it would not. hot or cold would not move.

 

[jetjock]

Sorry, thought I covered this with you a few days back. Must have been someone with a similar handle.

OX is the raw signal from the O2 sensor. You can find it in the diag block. Vf emulates OX (but at a higher signal level) when in diag mode (same as when checking codes) and whenever the IDL contact is open eg; the engine is off idle.

Assuming you have some sort of driveability issue I've said this many times but it bears repeating: An unmodified TCCS is more than capable of getting the mixture very close (within 1%) on a hot engine with nothing more than the load and speed signals. The O2 sensor isn't needed except for the trimming required primarily to service the catalyst. Put another way the engine should run just fine with little to no driveability issues with all the trim sensors unplugged. Emissions and fuel economy will suffer but that's about it.

As long as you're confident the AFM and CPS are working correctly stop fooling with the EFI system and look elsewhere. Zero out any piggybacks, etc, and look for/repair non-EFI problems until the engine seems to run normally. Then worry about fuel trim. Until then I suspect you're barking up the wrong tree...

 

[89supra7mgte]

Ok that makes sense. Now being I have modded the car with Turbo fuel pump injectors maf and ic kit, zeroing out my Safc will not hurt engine will it? Tccs should rum stock being components Are calibrated right?

As far as drivability issues haven't really noticed anything severe minor stall from bov but that's about it. Fuel economy sucks balls (175 on 3/4 tank)

 

[89supra7mgte]

Ok so I measured ox1 to ground engine running it cycles from like .15 to .68 or so and afr reads 14.5. Afr dropped to 12 And ox was consistent at .85 little to no change but still at .8 car started to idle different to. All this was done with Safc zeroed out.

There are 3 sensors on the coolant neck and not sure which is which? One is for AC one for coolant temp And one for csi right? All being inputs to tccs. Can I have a bad sensor telling tccs to go rich?

 

[89supra7mgte]

Ok so some maybe all of my methods are unorthodox, but in some cases they work. My car started acting up again, found that the safc was showing 3hz on the afm, with the afrs really rich. well i started thinking for some reson maybe my iscv was bad (too many beers) pinched the line car died gave me code 31. Not sure if its supposed to do that or not. Anyways threw on another afm, have quite a few, hz at idle are 20-23 pinch off line no stall. Afrs good do not fluctuate anymore.

What should a good afm read for hz? tried looking found nothing. I have been told to test hz prior to any of my upgrades for afm issues but found no specs.