Mombu the Chevrolet Forum sponsored links

Go Back   Mombu the Chevrolet Forum > Chevrolet > '87 Chevy Blazer K5 - No Spark - HELP please!
User Name
Password
REGISTER NOW! Mark Forums Read

sponsored links


Reply
 
1 9th December 08:37
edub70
External User
 
Posts: 1
Default '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!!!
  Reply With Quote


  sponsored links


2 9th December 08:38
\doc\
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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
  Reply With Quote
3 9th December 08:38
kj
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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!!!
  Reply With Quote
4 9th December 08:38
kj
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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~
  Reply With Quote
5 9th December 08:38
\doc\
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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
  Reply With Quote
6 9th December 08:39
jeremy chavers
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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
  Reply With Quote
7 9th December 08:40
kj
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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~
  Reply With Quote
8 9th December 08:40
gary glaenzer
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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
  Reply With Quote
9 9th December 08:40
bret chase
External User
 
Posts: 1
Default '87 Chevy Blazer K5 - No Spark - HELP please!


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
  Reply With Quote
Reply


Thread Tools
Display Modes




Copyright 2006 SmartyDevil.com - Dies Mies Jeschet Boenedoesef Douvema Enitemaus -
666