The engine could be warm or cold. I can't get the afr's to be stioch during start-up, they usually hover in the 18.0-19.0 range. If I drive the car for about .5 mile everything seems fine, my idle is perfect along with my cruise. I have no codes except for the P0300 because of the tilton clutch.

Here are my ideas:

front 02 sensor shot
fuel pump bad
fpr bad

I have the walbro in for about a year now and seems to work fine under load and high boost. I have had the fpr vacuum line off and dint smell any fuel around or under the hood. Any other suggestions? I have a 1300 mile trip coming up in 2 weeks and this needs to get resolved.

 

you sure the sensor has warmed up enough to be reading correctly when you start up.
try turning the key to run for a minute before starting and see if you get quicker stioch.

 

Tried that, still get the same lean condition.

 

What modifications on the car?

This is cold start, when the car is first started before it goes into closed loop, it runs off the ECUs map during that time.. there probably needs to be some adjustment, if you have an OBD-II scanner, your trims are probably +15 or higher..

 

Another thought.. A friend had a bad ISCV (Idle stepper/speed control valve) where his cold idle was terrible (it was jammed all the way open and would of course run really lean)

 

It doesn't matter if the car is cold or hot. I have logged the start-up with Evoscan and a pocket logger and the trims are within -/+10. The lean condition will stay until I start moving the car, if I let it idle after start-up it will remain lean until the car is moved for about 2 blocks. Then after that the car runs perfectly, it will be stioch at cruise and at idle.

 

your describing exactly what used to happen to my car... look at your maf reading at idle.. if your idle speed is around 1000rpm and your maf reading is around 30hz, it may need adjustment..

 

It is the open loop operation, when you first start the car it runs in open loop for as long as 3 minutes when completely cold, 30 seconds if the car is already warm

 

Yup 1049 idle speed and (edit) anywhere from 37.74-44.03 via Evoscan and 34-35 via UTEC

 

First column is 02 feedback trim and the second is 02 sensor (my guess is voltage)


175 0.507
176.5625 0.546
175.78125 0.546
175 0.5265
176.5625 0.507
178.125 0.5265
178.125 0.546
176.5625 0.585
175 0.585
173.4375 0.585
171.875 0.5655
170.3125 0.5655
168.75 0.546
168.75 0.5265
170.3125 0.507
171.875 0.4875
173.4375 0.4875
175 0.4875
176.5625 0.4875
178.125 0.507
180.46875 0.5265

 

It takes some time for the ecu to activate closed loop operation - many cars run lean or rich during this time frame and it may require recalibrating the maf sesnor to correct

Also see if you have oil in your maf sesnor

 

I think I might have found my problem. My front 02 sensor wasn't screwed all the way into the 02 housing. When the bung was welded to the housing (BR turbo kit) there was a piece of slag that must have got in there, from the angle I welded it at it's really hard to see if it's leaking or not, I might have to pull everything back out, get the piece of metal out of there and re-try everything.

 

I had noted something similar on my Turbine turndown, I added the O2 bung because it didn't come with it and I intentionally went in and deburred/cleared the slag to be sure something like that didn't happen.. It might not be that its leaking, but it may be that its not seated all the way down in the exhaust stream..

However my lean start went away when I rescaled my injectors and made some of the typical idle adjustments.

Thats actually the hardest part of dialing in this stuff.. You have to force open loop so you can make the necessary adjustments, but if you can get your idle fuel trims close to zero by making the necessary fuel mapping, scaling, timing adjustments in the ECU at idle, or force open loop and get 14.3 or so at idle.. You will hit both the cold start and fuel trim thing at the same time... Then when the car cold-starts, the coolant temp will be lower and there will be some additional enrichment if the car is very cold, but it should run alot better until it warms up.

 

Forcing open loop isn't hard, all you need to do is unplug the front 02 sensor, start the car, plug the sensor back in to get a voltage reading.

Although back on topic, the sensor is about 3 threads away from being completely seated. Getting the wastegate off is a PITA with the engine hot. Ill post up a pic in a few minutes.

 

Alright here is the pic of the 02 sensor not seated correctly in the 02 bung. Im sure this is enough space for the sensor to give false readings, correct?