'87 Chevy Blazer K5 - No Spark - HELP please!

I could really use some help about now. Not getting a Spark from my '87 K-5 Blazer. Has a 350 in it. The whole problem started when I would start the vehicle cold. If I gave it a little gas, it would stall instantly. If I started
it and did NOT touch the accelerator, it would idle for 5 to 10 seconds and then stall. Now the engine will not start at all and it is not getting a spark. I already changed the distributer cap, rotor, coil and control module. No luck there. Checked the wire from the Distributer into the fuse box and looks good. All the fuses in the main fuse box are A-OK. What next? I'm going crazy here! Thanks for your input!!!
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K-5 Blazer. Has a 350 in it. The whole problem started when I would start the vehicle cold. If I gave it a little gas, it would stall instantly. If I started it and did NOT touch the accelerator, it would idle for 5 to 10 seconds and then stall. Now the engine will not start at all and it is not getting a spark. I already changed the distributer cap, rotor, coil and control module. No luck there. Checked the wire from the Distributer into the fuse box and looks good. All the fuses in the main fuse box are A-OK. What next? I'm going crazy here! Thanks for your input!!!

A few thing's I'd check:
1) Inductive pick-up coil (inside the dizzy, must yank the entire unit to get it out). 2) Grounded tach lead off negative side of coil (if equipped)
Doc
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I
Good points. Wouldn't an 87' have to have some kind of tach sensor? I believe the 87' has a CCC or ECM, IE some kind of computer that needs to know the RPM?
~KJ~
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'87
start
If
not
into
A-OK.
to
KJ,
There is no such thing as a "tach sensor." All the tach lead off the coil does is feed a tach. If the truck is equipped with a factory tach, the white wire that runs off the ignition coil goes thru the firewall and to the tach in the dash panel. If it's not equipped with a tach, the wire is still there but will be tucked up inside or taped to the side of the coil harness. The computer on a TBI system doesn't need to know engine RPM, just engine load (MAP), vehicle speed (VSS) and throttle position (TPS) to determine timing and fuel delivery.
Doc

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10
and
unit
the
still
harness.
My '85 4.3 Q-jet had a feedback system and spark retard system that would stop it from sparking (the retarded part, not the feedback part) if there was a problem with the ECM (over rev it and it would kill the computer, what kind of system is that?!? lol) When I got the truck, the 4 wire plug that goes into the dist was mangled and the 2 center wires were actually cut and twisted together on the dist end. I was told by a tech at one point that that was done to prevent it from getting confused by the 'puter.
HTH
Jeremy

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You always catch me with my bad choice of words (since I often just know what it does, not a real name) But at least you knew what I meant.

the
still
harness.
Forgot to mention MAP does double duty because it measures from a true vacuum, so it measures the engine's vacuum and the barometric pressure? But I thought an 87' was a feedback carb year? Or was it a transitionary year?
~KJ~
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engine
MAP measures true atmospheric pressure in the brief instant of 'key on' before you turn it to 'start'
this gives it a baseline from which to work
I think 87 is an ECM with TBI year
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On Fri, 05 Dec 2003 01:35:27 GMT, "KJ"

the MAP or Manifold Absolute Pressure sensor gives manifold vacuum/pressure on an absolute scale, from a true vacuum (zero molecules in a given container). it can only read barometric pressure when the engine is off. if you've got a scanner (i use a Snap-On MT2500) hooked up to the truck with the key on but not running, the MAP sensor will read from 27-33 In/Mg, depending on the weather. as soon as I start up my 88 K2500, the map starts reading between 9 and 11 in/Mg (19-21 In/Mg vacuum). so, no it can't read both baro and manifold pressures at the same time. '87 was the intro year for the TBI engines, I think you could only get carb'd engines on HD emissions vehicles. the last carb'd GM V8 was produced in '91.
-Bret
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The fuses are good, but do they have juice going to them? What's the operating voltage on the battery? I'm thinking some kind of blown inline fuse. They look like a block of rubber in the wire. But don't take my word for it....
Doc, scribb, steve?
~KJ~

K-5 Blazer. Has a 350 in it. The whole problem started when I would start the vehicle cold. If I gave it a little gas, it would stall instantly. If I started it and did NOT touch the accelerator, it would idle for 5 to 10 seconds and then stall. Now the engine will not start at all and it is not getting a spark. I already changed the distributer cap, rotor, coil and control module. No luck there. Checked the wire from the Distributer into the fuse box and looks good. All the fuses in the main fuse box are A-OK. What next? I'm going crazy here! Thanks for your input!!!

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