Hello everyone, we need some help asap since this is my buddies dd. It’s a heads and cam car, it has prc stg 2.5 5.3l heads with a ms3 cam, fast 103mm combo, intake and exhaust. The car was put together almost 3 years ago and it’s been running fine until just recently when he was doing a pull. After the pull, it started to hesitate and was lacking power, it also smells like fuel pretty bad. We checked codes and this is what we found: P0301, P3500, P0074, P001D, P0135, and P0103 but car was converted to speed density and maf deleted.

We replaced all the spark plugs and wires, 02's, and swapped out coil on cylinder one but its still hesitant and lacking power. We are out of ideas and don't know what to do. If anyone has anymore ideas, please let me know. Thanks in advance



leak down test results:
cylinder 1: 0%
cylinder 2: 0%
cylinder 3: 20%
cylinder 4: 0%
cylinder 5: 0%
cylinder 6: 0%
cylinder 7: 30%
cylinder 8: 5%

 

Damn, over 60 views and nobody has any input?

 

I'm no expert but it looks like you answered your own question. Pull motor

 

i really hope not

 

Im new to EFI tuning (just bought HPT Pro) but not new to engines. Sorry to reaffirm what DanielOne said but it may be time to pull the engine. Cylinders 3 and 7... not good at all.

 

0% leakdown on 5 cyls? Really? No, I don't think so. The world is an imperfect place.With a minimum reference pressure of 100psi normal leakdown would be in the 5 - 10% range.I suspect that your 2 low cyls are really much lower. Where is the pressure going? Past intake valves? Past exhaust valves? OR cyl blowby? Figure this out first.Also keep in mind that if the problem is cyl blowby it could be caused by excess fuel in the affected cyls washing down the cyl walls and lowering compression and raising leakdown. This will help you decide whether you need to pull just the heads or a complete teardown.

 

If you have access to HP Tuners, setup the scanner to log individual cylinder misfire. That will quickly point you to the cylinder you need to concentrate on.

 

What JP said^^^^^^^^ no way at zero.

 

Maybe not but pulling the valve covers and looking for a broken valve spring to start may be in order?