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Discussion Starter #1
Hey guys and gals; Ive done everything I can think of to fix my s-10 blazer; 4.3 tbi. It cranks just fine when it hasnt run for a couple of hrs. If you try to crank after driving,it wont . Also it dies at idle. Ive changed throttle position sensor, fuel filter, fuel pump,oxygen sensor, spark plugs. I'm sure its something simple it runs smooth while its running. PLEASE HELP!
 

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I don't know what yr your ride is, but if it's a 1st Gen or early
2nd Gens, and it has the orig ign module inside the dist, there's
a real good chance the module is getting a heat sink, The
dielectric grease that isolates the ign module form the dist
mount base will dry up after a few yrs and allow a heat sink
into the ign module..You can ck it by disconnectiong the NEG
side of the battery, pull the cap, pull the two screws that hold
the ign module out and remove the module..

Look at the grease on the module's base and the dist base. If
it's dry, hard and yellow or even looks a bit nasty, it's no good.

Most times it's cheaper to just repalce the module, Once they get
a heat sink you'll never know when they will crap..The
new module comes with a small tube of dielectric grease.
You want to make sure you clean the dist base REAL good
and smear the grease COMPLETETLY over the dist ign module mounting base.

The more the better..Put it all back together and see what happens...

The module is critical for fuel delivery and oil
press voltage to the ECM. If the ECM doesn't see a good rpm
signal from the module, it will not fire. A heat sink can cause this.

Running the engine until it gets warmed up will allow a heat sink
from the dist's mount base for the ign module to the module's
base, IF the grease and ign are old resulting in a hard or no
start after running for a while...There may be something else
wrong but this is what I have run into more times than not..
 

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Discussion Starter #3
Thanks BG that's about the only thing I have'nt tried. Its a 92 S-10 Blazer, could that be the problem It does get worse the longer you drive.
 

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Yea I believe it's getting a heat sink. Plus the mod is 11 yrs
going on 12 yrs old if it's the orig..The grease just can't stand
up for that length of time with all the heat from the rotor
sending a spark to each dist terminal..If you decide to do this
and replace it, make sure you disconnect the NEG side of the
battery before you do it. You don't want an elec spike to kill the
new ign module before you get in going..Once done you can
hook up the cable and go for a ride..HTH's..Merry X-mas.
 

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Discussion Starter #5
Thank's aain BG, Cranking good now, even at operating temperature. But it wants to cut out if I put a load on it. At Idle and revving it runs great! Get on the accelarator going up a hill it cuts out. Whats the psi supposed to be from the gas lines into the throttle body.
 

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9 to 14# I believe. You might want to ck the vacuum lines going
to the MAP sensor for splits or tears. It also may not be advancing
as far as timing. Once again back at the dist, ESC or knock sensor
since all timing is done via the ECM. When it gets a load the
timing will increase as will the injector on-time. Manifold vacuum
is highest at idle and decel. When under a load vacuum lowers.
The MAP will see this decrease in vacuum and send voltage to
the ECM to increase timing and give out more fuel.. Ck the small
vacuum lines off the back of the TBI going to the MAP sensor
on the right side of the engine between the valve cover and
TBI. If there a clogged line or a split it in the lines or a bad MAP
itself it will cause trouble too..
 
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