I have a Jimmy with a 4.3L and I'm experiencing starting problems, I beleive that I've narrowed it down to a leaky injector(s).
Fuel pressure is about 55psi starting so I'm sure that it's enough(does leak down hot). I have been releiving fuel pressure when stopping and the problem does not exist............so
What I did on my wife's sunfire when I had the same problem was I pulled the fuel rail off and keyed the pump with the rail and injectors sitting on a piece of cardboard. It didn't take but a few minutes to spot the leaky injectors. I would like to do the same test with the 4.3.
Has anyone had the "spider" out, and do you think that I could do the same test without running the vehicle? Do I have to pull the intake or does the "spider" come out by just taking out the top cover?
It is my DD, so I don't want to tear into it without having all the parts as I'm in a small town. Any help appreciated. Floyd.
Ed M said
Apr 27, 2008
I had a simmilar experience with a 5.7l. It had a leaky fuel pressure regulater, and a leaky injecter. On the 5.7 you can look into the throttle body with a mirror and see the F.P.R. and cycle the key to build fuel pressure. This one was dripping, and the maniflod was washed clean where it was dripping. When I pulled the electrical connecter off of the top of the injecters it was soaked in fuel, so i replaced the injecter seals. A few days later he came back with the same problem, and could smell fuel, So I unhooked the electrical connecter only to find fuel again. So I dried it off and cycled the key, and found one injecter to be leaking up. We ordered a new injecter and no more problem.
The next time I have a problem with that system I'm going to recomend the customer replace the complete spider because its quite fragile and not too expensive. All of the parts are available through GM, and some are aftermarket.
You only have to remove the plastic cover to gain access, but the seal between the upper plenum and the injectors will be expanded and diffucult to seperate the two. I recomend all of the seals be replaced if it gets taken apart.
Hope that helps.
Lemans64 said
Apr 27, 2008
Hi Floyd, u should be able to do that, u have to pull the upper plenum to do it though. 55 psi is minimum fuel pressure on those. they are quiet tempermental about fuel pressure. if not enough it will not overcome the check ball on the end of injector line. Be carefull with the injector lines as they get hard and can break easy. As mentioned the pressure reg does give a few problems.
64 Canso said
Apr 27, 2008
I forgot one thing, while it was running yesterday the fuel pressure gauge needle was bouncing about 10psi. This is the first time I have seen this and I thought it might have been some air in my gauge line.
Have you guys ever seen this? I wonder if the regulator could be faulty. Or maybe a sticky poppit valve? It does go up to about 64psi when revved(and steady) so I eliminated the regulator or I thought.
Thoughts?
-- Edited by 64 Canso at 01:16, 2008-04-28
-- Edited by 64 Canso at 01:21, 2008-04-28
4SPEED427 said
Apr 27, 2008
What vehicle are you on exactly? I assume likely an S10 in the mid 90's maybe? 8th digit of the VIN a W or a Z? I am guessing W.
64 Canso said
Apr 28, 2008
1996 jimmy/auto, 195hp I believe.
4SPEED427 said
Apr 28, 2008
Ok,I will try to remember to ask our service manager about it tomorrow.
I have a Jimmy with a 4.3L and I'm experiencing starting problems, I beleive that I've narrowed it down to a leaky injector(s).
Fuel pressure is about 55psi starting so I'm sure that it's enough(does leak down hot). I have been releiving fuel pressure when stopping and the problem does not exist............so
What I did on my wife's sunfire when I had the same problem was I pulled the fuel rail off and keyed the pump with the rail and injectors sitting on a piece of cardboard. It didn't take but a few minutes to spot the leaky injectors. I would like to do the same test with the 4.3.
Has anyone had the "spider" out, and do you think that I could do the same test without running the vehicle? Do I have to pull the intake or does the "spider" come out by just taking out the top cover?
It is my DD, so I don't want to tear into it without having all the parts as I'm in a small town. Any help appreciated. Floyd.
Have you guys ever seen this? I wonder if the regulator could be faulty. Or maybe a sticky poppit valve? It does go up to about 64psi when revved(and steady) so I eliminated the regulator or I thought.
Thoughts?
-- Edited by 64 Canso at 01:16, 2008-04-28
-- Edited by 64 Canso at 01:21, 2008-04-28