Hey guys, been having problems with my car, was told I may have a fuel pump issue so I had a fuel pressure test done. While car was idling gauge would jump back and forth between 60sh and 70ish and when the car made the clock tick sound it would jump from 60ish to about 90 really quick during the tick then back down to jumping from 60ish to 70ish. Is this normal?

 

Not at all normal. Rail pressure at idle in closed loop should steadily rise and fall roughly in the 315-400psi range. It will basically make a sawtooth patern if you graph it. So yeah, the 60-70psi you're seeing is terrible.

 

Name says LSJ, thread says LNF. Those numbers seem more in line with an LSJ's port injection...

 

Is there a spot to connect on the low pressure side? I thought there was a connection that zzp uses for the 5th injector

 

Yes, there's a schrader valve located before the hpfp where you can take tank pressure readings with a mechanical gauge. Maybe I interpreted his post incorrectly and assumed he was taking rail pressure readings using a scan gauge and not a mechanical gauge.. lol

If that's the case then he's not reading fuel rail pressure at all at that point. Good catch.

 

there is some sort of tsb or recall going on over fuel leaking into the engine and loss of pressure fyi. i will try and get details tomorrow

 

From his post it's hard to tell which he took, OP where did you take the fuel pressure reading at?

 

I took the pressure from right by the hpfp, and yea my name says lsj cause I used to have a supercharged balt a long time ago when I made the account but now I have a turbo one lol..... soooo is that normal for reading the pressure there? My car just doesn't run smooth and sometimes at full throttle and high rpm I lose power and sometimes it throws misfire on all cyclinders. I've replaced everything I know to and cleaned valves. Next thing I was told to test was fuel

 

So new plugs didn't help the misfires? Gap should be .32-.35 for stock/GM stage or .32 for tuned

 

I've tried plugs gapped at .27, .32, and .35 replaced all the coil packs, changed injector seals and nothing is working. Mine is tuned. Anyone know any bomb ass mechanics I can take it to? My Chevy dealer said my aftermarket parts (intake, downpipe, etc) was causing it so they wouldn't even check it out

 

Official TSB and Recall Thread - Chevy HHR Network