Hi all,
I've been somewhat delayed with my project by a stuck open injector which had to be replaced. Anyway, I now have 6 injectors again and all seem to be working. Car is a Z32 VG30DETT, 550cc injectors, hybrid tubs, FMIC, AVC-r and a few other bits that won't have a big effect on the way it runs.
Problem is it's running extremely rich, to get it to idle and make it run marginally better than awful I have to drop the K constant right down to 70 (!) where it should be around 193 according to the resize function. Black smoke and black plugs. (all plugs are black so I don't believe this to be an injector problem). Could the latency have such a major effect? I've tried tweaking this to no avail.
Engine has been out and I've junked a few bits and pieces (EGR, AIVs carbon can, cats, standard recircs, air con, stock boost solenoids).
I'm of the opinion that an air leak would cause it to run lean rather than rich although I s'pose if it was leaking under boost then it would be running rich (hmm....)
Does anyone have any suggestions as to why it might be running so obscenely rich? I don't think that such a major problem with AFR is down to the ECU map (which should be approximately correct).
I should perhaps mention that I'm using Venom injectors which I know are not highly regarded by most, anyone know what the latency of these is - no tech info was supplied with them...
Any advice appreciated.
Cheers
RobH
Extremely rich
Moderator: Matt
Further to earlier post, I've dropped a fresh JDM DE30TT image into the ECU and modified only K constant and related TP values. Dropping the latency down below 1 millisecond seems to help a bit but the idle is still very 'up and down' when warm. It's not erratic, it's a steady low revs (300) and then high revs (1200) to compensate , revs drop, revs go up, cycling about once every 5 seconds.
I also tried disconnecting the MAF sensor, this gave me a much better idle but obviously wouldn't rev. Does this sound like a potentially knak'd MAS?
Cheers
RobH
I also tried disconnecting the MAF sensor, this gave me a much better idle but obviously wouldn't rev. Does this sound like a potentially knak'd MAS?
Cheers
RobH
If you disconnect the MAF then it uses 'limp MAF' values for base idle injection upto 2000rpm
It is a good test to see if the engine runs okay otherwise
I suspect vacuum leaks if running too lean (more air sucked in than can be measured) and dodgy MAF if its running too rich. Sounds like K constant just worknig around it
I would suggest cleaning your hotwire inside the MAF and see if that helps somewhat
It is a good test to see if the engine runs okay otherwise
I suspect vacuum leaks if running too lean (more air sucked in than can be measured) and dodgy MAF if its running too rich. Sounds like K constant just worknig around it
I would suggest cleaning your hotwire inside the MAF and see if that helps somewhat
Thanks Matt. I did some checks on the MAF last night, showing <0.5V engine not running, 1.8V at idle - these figures appear to be out of tolerances. I'll give it a clean and see if that helps.
Also, my MAF has only 4 pins (A is missing, NA version?) whilst the connector has 5 wires. It has run ok in the past
It's definately rich, fuel pressure has not been tested yet so I guess that's where I should have started...
Cheers
H
Also, my MAF has only 4 pins (A is missing, NA version?) whilst the connector has 5 wires. It has run ok in the past
It's definately rich, fuel pressure has not been tested yet so I guess that's where I should have started...
Cheers
H
Thanks Matt. I still think the readings are a little out of tolerance so will try a swap.
I thought I'd found the problem for sure - being the dunce I am, I'd plumbed the fuel pressure regulator in upside down - it was working in reverse. I put it right but was very disappointed that it made no difference. I guess I could have damaged it, a fuel pressure check is in order...just need to get my hands on a gauge...
Have a good weekend.
RobH
I thought I'd found the problem for sure - being the dunce I am, I'd plumbed the fuel pressure regulator in upside down - it was working in reverse. I put it right but was very disappointed that it made no difference. I guess I could have damaged it, a fuel pressure check is in order...just need to get my hands on a gauge...
Have a good weekend.
RobH