My '96 Chevy Z71 w/ 5.7L engine runs great, but starts hard. Somedays are worse than others. Hot or cold doesn't matter. It cranks and cranks and always eventually fires, but it just takes much, much longer than it used to. You can smell raw fuel after it starts if you are outside the passenger side.
I've replaced the fuel pump, fuel filter, battery, taken all battery cables (+ and -) off and removed any corrosion and reconnected with dielectric grease, replaced cap and rotor and plugs. I took the IAR (idle air control) valve out and cleaned with carb cleaner. I've performed every check my Haynes repair manual recommends in it's troubleshooting section.
A shop checked the computer for errors codes and came up with no errors. They had no idea what might be causing the problem and admitted they'd just start replacing parts until it was fixed.
Suggestions and/or thoughts? This one has me stumped.
I had these same exact symptoms with a 96 Vortec 454.
It turned out to be the fuel pump. In fact I had the shop that I go to put a fuel pump in because it gave a low fuel pressure check, got it back and had same problem within a day. Took it back and fuel pressure was low again. They put another pump on and it's been good for 20K. So fuel pumps aren't necessarily good because they're new. Check it out.
As for the fuel pump chevy's are bad. Make sure you use an AC delco pump if you do change it. The aftermarket ones are even worse than the factory ones. I had a similar problem with my 97 Z71 with the 5.7. I ended up up changing the coil and the ignition module. Been over 60k miles since and haven't had a problem. Also if you don't want to keep changing fuel pumps, make sure to always keep the tank over a quarter full. Those pumps rely on the gas to keep them cool, cause they don't like heat.
I had the same problem with my 96 3/4 ton and it was the ignition switch. Sometime's it would start right up and other times it would crank for a half an hour and nothin. Good luck!
Your problem could be the fuel regulator (I think that's what it is)...it is under the intake manifold and 5.7's are famous for them going out...Our 5.7 '97 Suburban would start 1st thing in the morning fine...but if for whatever reason ya shut it off...it was a biatch to restart....problem solved by changing the regulator....a $50 or so item with a much larger labor bill because of where it's at.......
ECeptor,
What Party Cat said. I had a 98 with a 5.7. Replaced everything from fuel pump, battery, cap & rotor and it didn't fix the problem. Took it in every week for a few weeks to the shop to see if they could diagnose the problem but nothing showed up on the codes. Luckily a shop by my parents house had a mechanic that used to work for a chevy dealer and he said without looking at it it was the fuel regulator. Good news it the part is cheap, bad news is the labor to get to the part and replace. $50 part and somewhere near $500 by time he was done. Never had a problem with it again.
Just spent the better part of the day replacing the fuel regulator valve and now the 'ol gal start like she used - problem fixed.
But I somehow managed to open up a vacuum leak (idles and runs rough). I think it's between the upper intake manifold and the fuel injector module. It's a kinda twinky joint (sort of a large diameter o-ring sealed press fit) and it sounds like that's where the leak is coming from.
I'll try to fix that tomorrow. Thanks to everyone for the advice!
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