Re: Need help troubleshooting an ignition problem.

Try replacing the ignition module. Obviously, your truck is failing when hot...did you test your ICM when hot? Nope...
Sam


Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
gm may not use one, but in my xj cherokee, it was the timing sensor that simply screwed onto the back of the bell housing. wires from it update the timing to fire right. after three tow jobs, i found this and it fired up and is still ok 1 year later. aa possibility john

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The tester used puts a load on the module. By the time they do the test the third time, it's plenty hot. And since we've done that on two seperate occasions, we're fairly certain that isn't the problem.
I checked the wiring yesterday, and it all seems to be in order. I guess we're down to checking on the possiblity we were sold a bad coil.
- Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Replace the ICM, or have a tech put it on a scope and tell you for sure what's wrong with it.
No matter how many times you check the ICM on a load tester, it won't even come close to the conditions under the hood. ICMs are the most sensitive ignition part to heat and vibration.
Sam

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

We replaced the ignition module, and it doesn't appear to have fixed the problem. The wiring is good, everything in the distributor has been replaced, and we have no clue what else it could be. The guy at Napa is wondering if it could be a spark control module or the computer. We don't think it has a SCM, and we're not 100% sure it has a computer. Did the '84 Blazer have either? If not, what in the world else could be wrong with this thing?
Now I'm down to buying something else to drive while I scratch my head...
- Rob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

even
Rob,
1) It doesn't have a SCM 2) It <might> have an ECC if it's stock. Do you have a fully manual carb or a computer controlled carb (will have idle mixture solenoid, 02 sensor, CTS). 3) Read the suggestion made in my prior post.
Doc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I hope you put thermal (heat sink) grease under the module when you re-installed it. Dan
On 28 Jul 2003 12:07:11 -0700, hikeeba snipped-for-privacy@yahoo.com (Hikeeba Jones) wrote:

Colorado Springs, CO My advice may be worth what you paid for it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sounds like a loose connection somewhere, maybe even the ignition switch itself.
Martin

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hikeeba,
Here's my $0.02. Electrical connections are sensitive to heat. The hotter the temps, the higher the resistance. This is the cause of "heat soak" where the starter turns VERY slowly when the engine is nice and hot (say you pull off the higway to grabe a coke, then restart and it really lugs) due to the starter and wiring being so damn hot.
Because yours is dead only when hot, I'd start looking for wire<s> related to the ignition system that may have made their way close to a source of heat.
Doc

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Well here's mine(.02).I had a 2.8 that did the same thing. After many modules I bought a rebuilt distributer and that worked. My Nephew (Mr. Goodwrench) said the aftermarket modules were not as good as they could be. Wayne

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.