Please help. Im loosing all my hair. s52 runs rich

[dunebuggyjay]

Hi Guys,

OBD1 s52. Gt35 Turbo, VMP 5000 slot maf, 60lb injectors , RK Tunes tune (bought used and worked on previous owners car)

Symptoms:
AFR too rich. Cold start I see high 9 low 10 afr. Cant go wide open throttle. Car breaks up. see 9 at WOT.
Cruise seems ok. 14-15 afr on highway.

idles okay, has pops and burbles though. If i unplug maf, it idles smoother (no pops and burbles) AND I can go WOT. VMP says if maf sensor is producing voltage (I see .6 and .7 volts at idle) and goes up with throttle opening, its fine.

Have replaced:
Cam sensor
Crank sensor
TPS
Coils (bosch)
IAT sensor
CLT sensor to DME
Plugs (Gapped to .020)
Vanos seals
All new vacuum lines
new manifold and throttle body seals
cleaned ICV
new O2 sensor (bosch)
Tried another DME
Tried a whole other wiring harness

Compression checked cold 120 psi all cylinders (I have copper spacer and cut rings under head ...hence low compression numbers)

I have the crank case open to atmosphere. Plugged all vaccum lines that went to oem oil seperator. (so no vacuum leaks caused by valve cover gasket, oil filler cap etc)

I have boost tested to 25 psi. Couldn't find anything.

Any ideas?

[berlow94]

Sounds like an engine management problem to me.

[dunebuggyjay]

Sounds like an engine management problem to me.

Yeah, had I known i would be having so much trouble, i would have went stand alone from the start.

At least with stand alone, i could probably find out what the problem is in minutes looking at live data.

Probably going to jump on the group buy for MSPNP on one of the other forums.

Just undecided if I should go back to OBD2, or keep the car at OBD1. Not sure if there is any benefit going back to obd2 when running a stand alone though.

Jay

[berlow94]

If the engine is already wired for OBD 1 then I would leave it alone. Vipec (Link) makes a new PNP standalone that is a way better value than MS.
All the options of most $3k ECU's (including VE fueling) for almost a third the price.


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