Ellis03

Bought a 86 944 turbo about 5 months ago with a spun rod bearing. Got another block because the cylinder walls were scored and got it all back togather then after about 200 miles the timing belt tensioner stud broke and bent 4 intake valves. So I spent another month getting that fixed.

Now so far its holding up and I am trying to get it running correctly.
It has a air fuel gauge (not wideband) and I have a little problem with it surging when it goes to the lean area. It should go rich lean rich lean but its cycling slower than most cars and surges like loss of power when it hits the lean area. Under boost it stays rich the entire time unless it goes over 15#s which is max for the injectors I think.

I'll give ya what I know and maybe someone has some ideas.

It has a ported head, bigger turbo, stock injectors, stock airbox and "bov".
I went through all the vac. lines according to the manual and they seem correct.
I have to run way more than 35ish fuel pressure to get it to run correctly. Its currently at about 60 at idle with the line connected. I found out my afm was messed up and one of the shops here had a non turbo one laying around so I stuck that on it. After searching it seems they are diffrent and I will get the correct one here this week. The old one just stays lean at all times except for under boost. Or is this correct for the cars and they run lean unless under boost?

hp18racer

It should not run lean off boost. What chips are you running? Checked for vacuum leaks? Possibly bad Throttle Position Sensor?

Tom M'Guinn

60psi fuel and an n/a afm? Yikes! Start by getting a stock afm and returning the fuel pressure to stock with stock chips/injectors/boost. The n/a afm is set up for different chips and injectors. If is still runs odd with stock engine management, then it's time to diagnose further.

Ellis03

Ok I got a turbo afm and it is alot better but I still have to run 60psi or more fuel to get it off the lean end. I have chips that say eurochips (Crap I cant remember if thats right Ill look again tomarrow...I know it was euro something). I also put in the stock chips and it made no diffrence. Gonna barrow a smoke machine here next couple days to see if I have any leaks anywhere but I wouldn't think that would be giving me this kind of problem but then again I am new to these cars. The normal idle fuel pressure should be around 40 right?

xsboost90

do you have the BOV running open to atmosphere? try tying it back into the Jboot- mine did not like it at all.

Ellis03

Yea the "bov" is brand new and the jboot is also. I don't think you can run the stock valve outside the jboot would it even work correctly without the vaccume on the exit portion of the valve?
Everything is hooked up stock except I had to do a little custom work to the jboot to get it to fit on the bigger turbo inlet.
I don't know if any of you have access to worldpac parts but do they sell the boots for the charge pipes there?

dillon410021

there should be a tube going from bottom of bov back into the intake to recirculate the air.

Ellis03

Yea the hose is connected to the side of the valve. The hose goes to the intake right before the throttle body.
A intake/vaccume leak would not be giving me these problems would it? I mean normally you would have a loping/illregular idle?
What sensors tell the cpu how much fuel to drop.....is there a coolant temp sensor that would cause this?

2bridges

Is the air/fuel guage is what you are using to determine it is lean? stop now.

Those guages are great to identify a difference after you have determined how it normally responds under different conditions, but are not good to determine actual

if the o2 is not up to temp your readings will be off...... if you are in open/closed loop the guage will read differently.... also the response time is a problem for real time tuning based solely on the guage.

you need a good baseline to start with.
I must say if it requires that much fuel pressure - something is way off.
chip is likely not intended for that setup

Ellis03

Yea I know wideband is the correct way to go but it should be showing me if I am lean or rich and its a good huntley one. I always get the car up to temp before I start messing with it, and the a/f meter even shows incorrect readings until it is warm.
When I do turn the fuel pressure down I its stops running as smooth as if I have more pressure so I know something is up. I could take header temps and see if they are climbing at idle while running "lean" by the a/f meter I guess.
At running temp and at idle it should be in open loop correct?
I do not know what all is done to the chips they may only be ones that remove the boost limit in the lower gears and other limiters from what the previous owner had said.