runs rich cold, then leans out when warm

[Bastard1g]

I started the car up and it was really rich (780's compensated by keydiver) so I tried to lean her out by dropping the fuel preasure, i only got her a lil bit leaner and then the car started to warm up and started leaning out real bad. So i reset the fuel preasure to stock 2g specs. I have not set my base timing yet (will do that tommorow) but I dont know how my base timing being off will make me run rich though. I will also test for boost leaks tommorow. Anyone ever have this problem?

 

[Boiler2]

I had the same issue. I have a theory that my battery voltage is 14.5v when the car is ran at startup to about 15 minutes in and the voltage drops after the car has been running for some time to 13.7v. Plus mine fluctuates at idle. I believe this is from my UR underdrive pulley. This changes the voltage the fuel pump sees which possibly changes the flow rate of the pump at a certain psi. On cold runs at the track, I run rich. When I say cold, I mean the car is warmed up but has not been running for a while.

Of course, this is all a theory which may not be sound, but the battery voltage I do monitor via SAFC2.

On a side note ... I have a Supra pump which pulls a lot of amps which is likely why I have a voltage drop with the underdrive pulley. Time for me to go back.

Actually, this was something I was looking to post on for the wisemen to comment on.

 

[90AWDTalon]

Check your coolant temps when its lean and when its rich. I'm having the same problem, I've determined that it runs rich when below 175 degrees and lean when above that. After doing to research it turns out atleast on a 1G, don't know for sure if the same thing is true on 2G, when below 176 degrees the ECU adds extra fuel.

I did my tunning this winter when it was cold, I had the car running great. Then when it warmed up some times it would still run great and some times it would run extreamly lean. Turns out it would run great when the coolant was 172 degrees and would be lean when the coolant was 180 degrees.

 

[Bastard1g]

I think that I may have a boost leak somewhere but being that I have an fmic kit, I would hoe that my piping or couplers are messed up. I will boost leak test and set my timing tommorow.

 

[Bastard1g]

I dont have a logger right now, all I have is a wideband. I need to figure out how to set the iming on my car. Being that I did a 6 bolt swap, I dont know what to set my timing at. Further more, I need to know if there is a jumper wire for setting the timing like 1g's.
I read something about only 95's being able to adjust timing, what should I do?

 

[Bohrn]

also have a look at your fuel pressure solenoid.

Not sure if the 2g works the same way, but if it does this could be your problem.

I had mine start crapping out on me and it would do that. One day it just quit. No vacuum/boost signal to the fpr!! No rising rate.

you can easily bypass it and see if the problem goes away.

 

[Bastard1g]

Actually, I spoke with a friend of mine that reminded me that the dsm's actually are supposed to run that rich on start up. I still need to set my timing and stuff though. I also need to find out why I am overheating with all new stuff.