MatthewMI
Member
Guys,
I have a weird issue with fuel pressure on a 1988 C4. Just put the car back together (it came in boxes) so it is fresh from the intake manifold up. New injectors were there when I got it, put them back in (I kno, I should have checked to see exactly what they were). New fuel pressure regulator and fuel pump/sock when reassembled as well as fuel filter. When firing, found the pulse dampener was bad, replaced with hose and was able to hold 40 LBS of pressure at the rail. It would hold the pressure for more than 30 minutes. Fired the car after an extended crank and let it warm up. Ran well. On the next firing which was cold, the crank was extended and a hard start. Checked the rail pressure and it got pressure at the 2 second prime but them bled off in 30 seconds and it seems to have a miss. Last night I had the same bleed of fuel pressure cold, started hard, miss is there still. Fuel pressure 38 LBS at idle. But, when i shut it down some what warm now, the fuel pressure stayed high... for as long as I cared to look at it.
Any ideas? Maybe the cold start valve? I neglected to clean it when I pulled the manifold (never crossed my mind) but did flush some nasty fuel from the fuel rail and lines. Maybe a sticky injector from the nasty in the fuel rail that flushed itself out while running?
I'll try to see if it holds pressure cold tonight.
Thanks!
Matt
I have a weird issue with fuel pressure on a 1988 C4. Just put the car back together (it came in boxes) so it is fresh from the intake manifold up. New injectors were there when I got it, put them back in (I kno, I should have checked to see exactly what they were). New fuel pressure regulator and fuel pump/sock when reassembled as well as fuel filter. When firing, found the pulse dampener was bad, replaced with hose and was able to hold 40 LBS of pressure at the rail. It would hold the pressure for more than 30 minutes. Fired the car after an extended crank and let it warm up. Ran well. On the next firing which was cold, the crank was extended and a hard start. Checked the rail pressure and it got pressure at the 2 second prime but them bled off in 30 seconds and it seems to have a miss. Last night I had the same bleed of fuel pressure cold, started hard, miss is there still. Fuel pressure 38 LBS at idle. But, when i shut it down some what warm now, the fuel pressure stayed high... for as long as I cared to look at it.
Any ideas? Maybe the cold start valve? I neglected to clean it when I pulled the manifold (never crossed my mind) but did flush some nasty fuel from the fuel rail and lines. Maybe a sticky injector from the nasty in the fuel rail that flushed itself out while running?
I'll try to see if it holds pressure cold tonight.
Thanks!
Matt