going over 100ve. reduce kinjflow or increase injector volt

[V8hilux]

Good thinking Darcy.

I'll just have to wait till it all cools down again and I will watch it in the dash as it gets hot at idle... then shutdown for 5 mins and check again.
Cheers.

[V8hilux]

engine was still warm but here is the findings with a startup, get hot, shutdown, and a restart running lean. all points at idle/openloop:

0.59pulsewidth @14.0afr. 71 charge temp. 70 coolant, 80 manifold temp. 37mapcell. 93.4 baro, 13.4batt volts. 45.3 ve.

0.54pulsewidth @14.0afr. 85 charge temp. 84 coolant, 92 manifold temp. 35mapcell. 93.4 baro, 13.4batt volts. 45.3ve

at shutdown:
0.51pulsewidth @14.5afr. 90 charge temp. 90 coolant, 98 manifold temp. 34mapcell. 93.4 baro, 13.4batt volts, 45.3ve. iac90.
apon restart with 5-10min heatsoak:
0.60pulsewidth dropping to .50 18afr 88chargetemp 87.5coolant 92mantemp 35map 93.4baro 13.2volts 45.3ve 196iac

any one see the problem here? or should i go to town and buy a fuel pressure gauge to check that?

[Jayme]

more pulsewidth on the lean one, yet its still leaner than the others....... something sus there, the lean out isnt the tune, go get a fuel pressure guage.

[V8hilux]

I rang every shop in town and no one sells an efi fuel pressure tester. I could probably steal the gauge of my air compressor and rig it up but I might just have to get a proper one at ebay and wait for it.

I just done the warmup, and shutdown again... sure enough seeing 18:1 at restart and light throtttle.
So I revved it straight up to 3500rpm and held it and after about 30seconds... the afr was back to normal 14.

I'm not a mechanic but that is almost telling me that it is injector heatsoak...as in, after the rev and hold,cool fuel runs through the injector and cools it and it then deliveres the right amount of fuel again.

Is it even possible that the injectors give less fuel through the pintel at different injector internal temperatures? and more importantly? is there a setting in the tune that i could use to fix it? or am i doomed to babying the car after every hot restart until the fuel has time to cool the injectors?

I havent checked the fuel pressure yet but now i'm starting to wonder if the fuel regulator is even the problem. wtf is wrong with it... AAAHHHHH!

[V8hilux]

I still believe there is 2 different problems, one is that the car seems to get a little lean...0.5 afr lean as engine gets hot, which i am yet to figure out how to fix. and the other heatsoak one.

all ideas put to use.. cheers

[antus]

I'd be checking the fuel pressure, get the ebay gauge from in aus and express post it if your in a hurry. Most the temperature things would happen the same on a running car (except fuel between the T in the fuel pipe and the end of the injector warming up) but its not so much fuel and I dont think that'd cause it. The pressure reg gets quite a different situation though when the efi pump turns off for a few mins, and if that is acting differently because of it, then it would be causing something like that.

Beware your measuring gear though. An ebay pressure sensor may not be accurate, and is it possible that the issue is the wideband sensor cooling down and your reading lean off it before it comes back up to temp, eg no problem at all?

[V8hilux]

alright I'll get a gauge and see.

I first thought it could have just been the wideband giving funny readings but the way the iac goes fully open and the surging ect apon restart tells me it really is running lean.

I'll stop playing with it till i check the pressure.. I can fix the idle leanout on startup by changing the desired idle afr's vs temperature and would probably work as the only time the engine gets coolant gets that hot is after the shutdown so it probably wouldn't affect anything else.

thanks for the suggestions.

[V8hilux]

the only other times I've seen such a big drop in afr's is when i foul a plug and it does roughly the same thing. I replaced all the leads, plugs and carry a spare and a spanner in the car as it feels like a wheel falling off it top gear when she drops a plug. lol.

[kojab]

What type of fuel pressure regulator are you using?

[V8hilux]

it's just the original (20 years old) holden vp v8 one.