Completely stock and running lean...

[86MCSS]

Ok I have almost everything fixed and just wanted some advise before hand just for my own personal well being. Keep in mind the car was basically just rebuilt and is completely stock other than the fuel pump re-wire and a 255 walbro pump. It has new fuel filter and everything else needed for a tune-up.

The car is running good but seems to hesitate under a heavy load [full throttle]. I have no check engine codes either. I have a data logger and its showing me never going over .88 on my 02 readings at wide open throttle. I do have 2 leaks that I know of so far. I did a boost leak and my blow off valve and my thorttle body are leaking at about 10 psi [not the gaskets either]. I know this would cause the car to run lean but also the car never wants to go over 5500 RPM [under a load] and feels really slugish. When I go to wide open throttle it seems like it takes forever for it to reach 5k RPMs. Even with the car in nuetral it does not have a snappy throttle response but it does rev to 7k RPM. If I left out info please feel free to ask. Any and all help is appreciated.

 

[RyanTSi]

How many miles ya got? Does it always hesitate or does it do it less once the engine warms up? (exhaust leak, clogged cat). if its a stock exhaust manifold on there it may have a leak too. Probly due for exhaust work anyhow. Have you looked at the I/C yet. Lemme know.

 

[86MCSS]

The intercooler checks out, I pressure tested it to 30 PSI and it held fine. There are no exhaust leaks either I checked the exhaust manifold and everything else when it was off and Im sure I would hear an exhaust leak too. I may have to check the CAT though have not done that. The car has like 212k on it, but the engine was redone around 170k I was told and the compression is 165 +/- all the way through from when I checked it.

I was thinking too...even if the blow off valve is leaking the air it leaks is getting recurculated back into the intake so it should not run that lean should it?

 

[RyanTSi]

My car has got like 130k on it and I was running lean. Dont have a logger though, my tip off was the plugs. Had a dirtied up fuel filter. Also blew a hole in the flex tubing of the down pipe and had a clogged cat. When the car was cold, and at random when it was warm, Id go WOT and the car would dip forwarward and do the same thing yours is doing. Replaced the cat-back, cat, and hacked off the down pipe in front of the flex and ran straight welded 3" from there, still does it cold, but Im leaking from the Exhaust manifold. You never mentioned if it happens mostly cold or what though. Thats cool. This has just been my experience. If you got 212k you have alot of probly overdue replacing to do, but with a DSM, you gotta go a lil' at a time. Hope I can help out in the end. Lemme know whats up.
-Ryan

 

[RyanTSi]

Also, I forgot, the Air Filter mod listed in the tuning guide really helps with the air/fuel mix i.e. you force more air in and have more availiable by modifying the stock air can (for free). If all else fails look at that.

 

[86MCSS]

Yeah on the engine everything is replaced as far as belts and what not. I replaced the plugs and wires as well. I also have a new fuel filter. Tomarrow or when I get time ill take off the exhaust pipe before the cat and see how it does.

Oh yeah it also does this all the time. I have only had it a couple months and completely re-done it all. I got it with a blown engine.

 

[BGRIPTP]

Fix the boost leak and reset the ECU. That should fix it.

 

[RyanTSi]

Good luck bro.
-Ryan

 

[86MCSS]

Well I removed that CAT and it didnt rev any faster but was a shit load louder My 02s still didnt do any better. I guess I gotta fix my throttle body now since its leaking. Do any sponsors fix throttle bodies? Or should I just do it myself? Is there a way to fix my blow off valve?

 

[project94tsi]

You could be over running your stock FPR with that 255 pump, and running really rich

 

[InjenTalon96]

yes get a aeromotive fpr, that will solve ur richness problem

 

[86MCSS]

I thought .88 was lean? From what I have been reading .92 is what im aiming for and anything over is rich and anything under is lean...or do I have it backwards?

 

[PaleDSM]

Do not trust our stock narrow band O2 sensor to tell you if you are rich or lean. It is not accurate.

Any boost leaks will cause a rich condition. A leak between the turbo and the MAS will cause a lean condition. The large pump rewired would also contribute to the car running rich.

All of this loss of performance may very well be from a rich condition and not a lean condition. Pull the plugs and look them over. I'll bet they are all sooty.