2G Running lean and low vacuum after warming up weird symptoms.

[Mike s 95 gst]

So if you check my previous threads I had completely tore down my motor looking for an overheating issue which has been resolved. In the process I did a complete rebuild including new piston rings, valve job, new rods, new main/rod bearings & head/block shaved thinking I had a leaky head gasket which obviously wasn't the case. I did compensate with a thicker head gasket as instructed by the machine shop to do so as to not change the compression too much.

Now I've finally got the car running but when it does warm up I'm getting a lean condition 16.7 on the wide band fluctuating between normal when gas is slightly pressed and released then back to lean idling with around 10lbs of vacuum super low. I know even with 272 cams @ 1,000 rpm it shouldn't be that low.

Needless to say the car is not driving well, it even wants to shut down at certain times. Could this be due to a leaky exhaust system? I'm thinking if I have any vacuum leaks they are very minimal due to the fact that I replaced every hose with HPS hoses and steel braided lines.

Is it possible that an old intercooler or pipe coupler could be the culprit? The symptoms are leading me to believe otherwise.

This all started when I drove into a puddle a little deeper than I thought wet the whole inside of the engine, immediately the car shut off and wouldn't run after replacing the O2 sensor in the front and the MAF sensor. I was able to get it running but that's when it started running lean. I figured the engine rebuild would hopefully fix it cause my rings were pretty bad but now that I got everything back together and it's still doing the same thing especially while cruising if I'm around 3,000 rpm and hit the gas to the floor it goes dead lean till the turbo starts to spool up around 4500 rpm then it goes into the rich.

Also feels like it's almost going to misfire at idle. I did pull the ECU and had it tested, Supposedly it checked out fine last year when it happened. I took the ECU out and physically examined the board last week. I couldn't see anything burnt or any leaking caps I'm no ECU guy by any means, shouldn't I see/smell if there was any issues

Could this be a bad ground somewhere?

Where should I start testing? I'm thinking my leaky flex pipe needs to be fixed, if it is leaking, first just to rule that out because my O2 and wideband are located after it. For some stupid reason I guess 15 yrs ago when I had the exhaust done I wasn't thinking of that one .

Anything you guys can think of to help me that'd be great. This is not easy for me, I am an amputee missing my leg doing all this work in a prosthetic . Lots of time and money put into this thing for it to just sit in my drive way. It's killing me just trying to figure out why my ECU wouldn't tell the injectors to work more if it's seeing a lean condition & get better driveablity.

As of now when it warms up it drives like crap. Compression was exactly where it was last time I had to rebuild. Yes, a bit low, but I also have bigger cams with the head and block shaved. I'm guessing that could be a contributing factor. My starter cranking seriously slow which is why I was thinking a ground problem BTW, but even with the slow starter the compression was 112.5 exactly in each cylinder. The rings were gapped for higher horsepower according to Wiseco's specs. As far as I've been told the more important thing is that all the cylinders are within 10% of each other which 112.5 every cylinder I'd say that's dead on no?

Thank you in advance for any input guys!! Also, I am running the Greddy emanage or I'd offer to post logs. I know most people don't mess with those anymore but if someone can read a log for me plz feel free to message me . I'm praying it's not some loose wire somewhere from yrs ago. I know if certain things are working then the car should be running ok.

Any diagnostic information would really help . I already tested the injectors with a noid light they're all working normally. Also tested crank and cam sensors, they checked out perfectly. Water temp sensor is working properly according to my logs. I didn't see any dips in fuel pressure while it's running lean but I am going to rewire the fuel pump just to also rule that out.

I'm hoping Steve sees this one as a lot of his info has helped me tremendously in the past

 

[Mike s 95 gst]

Resolved turbo seals were bad allowing exhaust into the charge pipes overheating the engine and causing a lean condition.

Wish I could've gotten more help on here but hopefully this will help someone on the future thanks to all who attempted to help.