chevy 5.7 350 engine diagnosis

UniqueTouch

PlowSite.com Addict
Location
Jersey *****
Hey all , need a little help. I have a 5.7 350. If you go to start it up for the first time in the day. It wants to stall out if you try to drive it right away. After a couple minutes of warming up its good to go and youd have no idea. Also if you start it first time of the day and try to raise dump it wants to stall out. Anyone have any idea? thanks
 
Hey all , need a little help. I have a 5.7 350. If you go to start it up for the first time in the day. It wants to stall out if you try to drive it right away. After a couple minutes of warming up its good to go and youd have no idea. Also if you start it first time of the day and try to raise dump it wants to stall out. Anyone have any idea? thanks

Well if you have no dash lights on maybe you can just let it warm up. I don't think I would be overly concerned. Maybe one of the mechanics will respond.
 

Brettny

Senior Member
Change and clean out your IAC valve. It looks like a small aluminum drum with a plug anf 4 wires on the passenger side.
Spray some carb cleaner in the hole and get any carbon build up off.
You will also need to relearn the valve position. Change valve and disconnect battery for 1min. Re connect battery ,Jump out terminal A and B on OBD connector (two upper right ones) turn key to run for 1min. Turn key off and remove jumper. Then start the truck.

Same thing happened to my 95 5.7l. Would randomly stall and stumble it idle. Still runs a bit rough off idle when cold but never stalls.
 

TJS

2000 Club Member
Location
Fairfield,CT.
Ok these TBI engines have been known to have distributor problems acting like a fuel system problems (albeit, they have there share of fuel probs too). A couple of things to note. Take off the distributor cap and rotor, then look for a kind of fuzzy green stuff on the components. If you see this or even if all the components are all original then it is time to change them. The components I am referring to are the pickup coil and module. The green fuzzy stuff is the copper windings breaking down. Remember the distributor pulse signal talks to the ECM and that is how the injectors are fired by the pulse input. To change the pickup coil the distrubutor has to come out and the shaft be removed. When the shaft is removed inspect the magnets on top of the shaft for cracks. If they are cracked then the shaft is garbage. Also DO NOT buy aftermarket modules or pickup coils. Replace new cap and rotor and any other poor looking components. I have done this so many times I can do it in my sleep. I used to work at a Chevy dealer back in the late 90s.
 

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