Thread: Fuel Pressure Prime Question

Yeah i assume it holding pressure after the car is turned off is mainly just so it starts up faster, but normally pressure drops eventually anyway say over night. Which means even if the FPR is the cause of the rapid dropping pressure when the car is turned off, it wouldnt be causing my slightly rough idle which is why i'm hoping its either just a small vac leak somewhere or perhaps I need a tune (previous owner had tuned it but I'm not sure how well as i know very little about tuning with the Calum RT or in general)

Post your setup and I can get you a bin tonight. make sure you say whether it is obd1 or obd2 ecu. post your injectors, maf

Engine is stock bluebird i believe, stock injectors, T25, Its a 95 but has a step down harness so OBD1, N60 MAF currently running blow through

You need to find the leak on the mani that will explain your lean idle afr and your low vacuum

Yeah I had a few minutes today so I grabbed a black and mild and blew smoke in through the BOV hose and I saw no leaks. The charcoal canister is gone so that nipple was just plugged. I made it the source for my boost gauge so that the FPR source wasn't split and only went to the FPR. I even sprayed around th engine a little bit with carb cleaner and heard no rise in RPMs. I guess the only thing left to do is try the boost leak tester I made and get some soapy water to see if there are any small leaks anywhere.

Havent gotten to boost leak testing it yet, but for shit and giggles i popped out the spark plugs to took a look and they all looked fine. Damn car has me feeling severely beat down. Here is a short video I took showing the issue. You can hear how rough it idles, the big bright numbers is the wideband and you can see my vacuum on the boost gauge is like -10 and the vacuum goes up "more negative" when I rev it. Then when i take the key out (forgot the turbo timer was still on) so you can see it drop to almost the point of cutting out but I shut it off. I'm at a real loss here =\

to me, it doesnt seem like a fuel pressure problem, it seems more like a huge vac leak and or possibly even blown gasket between the head an manifold or turbo and manifold..

however, i cant help but wonder how it would run on a draw through recirc setup.. my car runs night an day different between the 2 setups..

So here is an update....the other day I cold compression tested the engine then warmed it up about 10 mins then tested again. I was getting about 100 across the board cold and about 105 across when i warm tested it. Non of the cylinders were outside 3 psi of each other. I know the consistency is good, but thats really low? I used a brand new compression tester from harbor freight so to be sure is wasnt the tester I hooked it directly to my air compressor (picture below). Reads off id say at most 15 or 20psi which would only put my engine compression at like 120. Im going to rent one from the local auto parts store just to have tested it with another to be safe it isnt the gauge. I also posted below how my spark plugs looked, which as far as i can tell, is fine? I was gonna try and get a leak down test done at some point soon to arrow this down.

**UPDATE**

Went to advanced and got a better comp tester, ASE Certified and shit, retested and im getting 145, 144, 143, 143 at a quick glance. Guess the HBF comp tester crap (who'd have guessed it lol). So now im guessing my engine is healthy enough, so at least this issue isnt internal

Well I put on the stock FPR, cleaned the MAF and tried again, still the same issue......WTF!