Hello everyone...

I've been having an issue with a 2005 Evo 8 for a while now. You could call the car somewhat of a scrap project - atleast looking at the big picture - as it was standing still for 7 years after an accident and now has been repaired and refurbed and reassembled completely.

Spec of the car:
Built 4g64 2.4L 9:1 CR with Evo 8 head
BC Racing 272 cams, springs retainers
Drop-in filter
3" exhaust complete with o2 housing
FMIC + piping kit
Evo 8 Turbo
Fuel pump (Walbro 255/Deatchwerks 300, tried both)

The problem:
No matter what I write in the map - the car goes extremely rich instantly when getting on the gas it goes EXTREMELY rich and misfires. And I mean even feathering the throttle at the point of slight acceleration will yield AFR's of 12s and 11s, while as soon as you would try to get on the boost, it just goes rich in to the 9s and misfires.

The only code I get out of the ECU is P0069

We have tried the following:

Swapped:
Injectors
Fuel Pressure Regulator
MAF
MAP
Front o2 sensor
Fuel Relays
Plug gap
Some fuses were faulty but didn't cure the issue

Checked:
Leakdown test, compression test
Boost leak test

I also tried to run the car in open loop - wrote 14,7s across the board and it would still do the same thing. Tried to re-scale the MAF sensor. Didnt' change anything - the moment you touch the gas, it's rich and misfires.

However one thing I can see is as soon as I would touch the gas the STFT starts going 0 - 5 - 10 - 20 and it's by far too rich at that point, however cruising at 3000 rpms or idling or whatever stable state the car is in - the fuel trims are going to be within 3%.

I'm out of ideas, so it would be very helpful if anyone has any idea what else to try...

 

what injectors are you running? idk if its even possible but you may be using high z's with the resistor or low z's without the resistor... like I said idk if its possible but its a though

 

Stock injectors - tried 2 sets.

 

Are the injectors correctly defined in the rom?
What rom version are you using?

 

I tried multiple roms. Tephramod roms aswell. No change.

 

This issue is likely electrical rather than mechanical
If you have a P0069 CEL then it has to do with the map sensor, since you've swapped sensors then the fault might be in the electrical connection to the sensor.

It also might be a bad baro sensor.

 

he swapped maf's

I think its a mechanical matter. ESP since this is a built motor.

How's your fuel pressure?
Your cam timing isn't off or sensor 180 out?

 

I know you said you swapped the Fuel Regulator, but have you tried putting a pressure gauge on the fuel rail input line and seeing just what the fuel pressure is doing?

 

Solved the issue. The fuel return line was completely clogged up, hence causing stupid amounts of fuel pressure. If anyone has a similar issue ever, I reckon this topic might do him some good, instead of wasting a few days on a car.

Thx for all the help everyone.

 

good job, but clogged with what exactly?

You probably wont believe it but my daughters Starion had a dead lizard stuck in the fuel line when we first got it home.

 

Have no idea what it was... We couldn't locate it but it was in the pipes under the car. You could blow air through it with a compressor but it was HARD (5bar plus to get air through it) while normally you can breathe air through it with your mouth and hear bubbles in the tank, so we replaced the whole copper(i think) piping under the car and now it works perfectly.