Replaced fuel pump and strainer this weekend,thoght it was goin
bad. I placed a fuel pressure gage on the schrader and it said 42psi. Approx.
1-2 min. later it was down at 30psi or less. Are my injector or 's
leaking?? The car has always had a long crank time. Should i get
them rebuilt if it is?? I have a bookmark for a place in Texas
that does them for i think $50. I don't drag race so stock should be
fine. I do run it hard,just wanna be reliable again.
Thanks,
Matt :chevy :chevy
I did a resistance check earlier this year,they were all
very close to one another.I checked hot and cold reading's.
Thanks,
Matt

 

Hopefully someone will help!!!
These things just take time,I guess
Matt :confused:

 

Was the pressure dropping off? It could be a bad pressure regulator. When you said hard to crank, is this hot or cold? This could be bad injectors. For $50 to get them all rebuilt it might not be a bad idea.
:seeya

 

I went thru the same problem in my 88 IROC. I had them rebuilt but still ended up with a leaker. I put new Accel's 23# in 2 months ago and it starts up just like new now.

Bob

 

Yes,hard to start when cold. Start's better when hot,almost
immediately. Pressure was dropping off within 30 seconds or so.
I remember reading that i can "modify" my regulator to be
adjustable. Can i rebuild my reg??
Thanks,
Matt

 

Did you have this problem before you replaced the pump? If not, suspect the pump or maybe a fuel line leaking at the tank. Otherwise, one test is to pinch the rubber outlet hose after you prime the rail. If the pressure no longer drops it's the regulator. If it continues to drop, it's the injector(s). Another method is to start pulling plugs to check for fuel saturation; ie, a leaky injector. Since you will need to remove the rail and injectors to fix either, pulling the plenum and runners and then lifting the rail and pressurizing the system is probably easiest. Any injector that forms a droplet of fuel is bad. If none leak, it's the regulator. If it is the regulator, be sure to retest for a leaky injector once a new regulator is installed. Who knows what the injectors might do with proper pressure.

 

There's also a check valve in the fuel line running back to the tank. Test that the same way as the regulator test described above.

Jim-K

 

Is the check valve on the top of the tank? I am assuming it is the
valve to the left when behind the car(driver side). Just a guess.
Thanks, Matt

 

Check valve on our '89's is on the pump and keeps gas from returning via the rail inlet to the tank. The idea is to keep the gas flowing only one way; ie, to the rail, with any excess being returned via the rail outlet (after the regulator). The test is opposite of the regulator test in that you pinch the flexible rubber inlet hose (at the block - it helps if you remove the tensioner to get at it). If pressure holds, it's the check valve. However, since you replaced the pump, you'd hope it be good. By the way, my '89 had similar delayed starts when cold, nice and easy when warm and the same easy starts if it sat for a couple of days. Turned out to be a leaking head gasket. Just enough coolant was getting in overnight and sitting on the piston which weakened the mixture making the next morning's start difficult. Once it was blown out through the exhaust valve, everything was fine until it sat overnight and a few more drops seeped in. After a couple of days of sitting, whatever was there either evaporated (highly unlikely) or made it past the rings and into the pan. Never noticed it (compression and vacuum were always normal) until the gasket completely let go and taking the heads off was real eye opener. #7 was the slight leak which became the big one; but passageways on the gasket at #1, #2 & #6 were cracked near the compression ring and ready to pop. All the leaks were on the gasket water passages that are located about an 1/8 of an inch south of the cylinder (the gasket is designed to restrict flow and allow coolant to stay in the heads). GM changed the materials used in the gasket early into the '90 model run (December '89), but typical of GM, they only issued a Bulletin to the Dealers, nothing to loyal Vette owners, so if you didn't bring it in and bitch, it probably never got fixed. Hopefully, this isn't your problem, but here's a few things you might want to check: ugly coolant, say six months after a flush and fill. Exhaust gasses destroy it causing corrosion which can show up as a plugged heater core (since those passageways are the smallest in the cooling system). Rust on the threads of any plug. Use engine oil or machine oil to install them (an old trick for keeping tabs on the health of a marine engine used in a saltwater environment) - no anti-seize. If there's any coolant in the combustion chamber the threads will either show rust within a couple a hundred miles or the threads will be dry because coolant washed away the oil. If there's no coolant, the oil on the threads will still be visible and your plugs will still be easy to remove. Hope this helps.