1988 chevy 4 wheel drive, 350,4-speed with starting issues?
when the weather cools off, it has issues with starting, here’s the lay out. supposedly it has around 13000 miles on a new engine, GM crate from what i was told. it has the stock throttle body perched on top on a aluminum weland intake. 2.5 inch single exhaust with nothing but a glass pack in the flow. i can splash a lil raw fuel in on top on the pots and it will fire right up, other wise it will Just crank till the battery is dead. it seems to get worse as the temperature drops. once the engine warms up it tends to be better but there are still times when i Just won;t start on it’s own, splash of raw fuel and it’s fine. the idle is real erratic too, some times it fine other times it’s way high. the idle was cranked up when i got the truck in august and turned it down, ran fine till it cooled off. i am thinking that it is a air intake sensor gone bad, but i am not familiar enough with GM’s throttle body system to really be confident in my diagnoses. am i on the right track??
first thing to look at would be your coolant temp sensor,this should be screwed into the top of your intake,just to the left of the thermostathousingg,it will be a two wire sensor,usually yellow and a blackit sits very possible that it is reading higher than it should causing the computer to lean the fuel,there is an ohm. reading for according to ambient temperature but i cant remember of the top of my head(i usually just use my scan tool),when the engine is cold,have someone crank the engine over while you look at the injectors in the throttle body,see if they are spraying fuel,it may be that the fuel pump relay is not running for the initial start up,and once you dribble fuel in it will stay running because once the vehicle is running the fuel pump circuit is switched over to run off of the oil pressure sending unit,look toward the passenger side of the engine behind your radiator overflow tank there is a plastic cover ,and the relay should be located under it,cycle the key off then on to see if the relay clicks,or energizes, as for the high idle it sounds like you may have a couple of issues ,you should not have had to adjust the idle unless it had beenpreviouslyy messed with,if you cannot locate anyobvioussvacuumm leaks,one real common problem with that system is the throttle body gasket splitting or sucking in,easy enough to check by spraying carb cleaner around the base of it while its running and payattentionn to any change in idle or smoothness, i hope some of this helps Rock
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