I'm trying to help out my brother in law. He's got an 88 half ton about as non optioned as you can get. 350tbi no overdrive truck. He was trying to start it after work the other night but no luck, well it started briefly then died. Spins over, has fuel from the injectors, pulled a plug no spark. What direction does one go from here. I'm at his house so tools are limited, and would like to have an idea before I make a tools run to my place. Thanks for any help you can give.

First guess- ignition module.

That seems to be the common answer. I read somewhere napa will test it. Is there anything else I should do to pinpoint. First guess is to see if there is power at the coil to eliminate it. Then I read to move the distributor shaft to check for play to see if it is loose and took out the pickup coil. How does one check the pickup coil? Lastly a friend of mine said(before this all happened) that the distributors are prone to failure and when in doubt just put in a rebuilt. What would you guys do? Thanks for the help

I would pull the module and have it tested and when installing make sure it is grounded good. These are bad on going out and even worse at getting corrosion under them.

I think thats the route we are gonna go, thanks for your help

Even if the module tests good i would still replace it. I work at a part store and we have tested some that showed good and it still ended up being the problem. the module is only $34. the modules are very common to go out on those. good luck

Thanks for the tip. Unfortunately the modules here aren't as cheap, about 95 bucks after tax, still cheaper than a car payment though!

Okay changed the module in the distributor with one i grabbed while at the wreckers for something else, still no spark. It was out of a 94 van, truck is an 88. No idea if it was a good ecm of course, so tomorow will take my original one to get tested and most likely will buy a new one if it comes up bad. Am I headed in the right direction? I really hate just throwing parts at something and not knowing what I'm after.

You might check the pickup coil if you have access to an ohmmeter. The two wires attach to two terminals on the one end of the module (yellow & green on a 1986). Those pickup coils do go bad from heat and old age. It should show about 160 ohms when you check with an ohmmeter and if it's bad it will not start. They are easy to check but a pain in the arse to replace since you have to pull the distributor and dismantle it.:)

Make sure your coil wire is good and making good connection. I had something as simple as that keep my 95 from starting.

fireout, funny you should say that. when I had my brother in law turn the truck over so I could see if there was a spark on the plug, I could swear I heard a crack, like the wires were grounding somewhere else. Thanks for the help guys, will check the pickup coil too. I took the whole distributor when I got the module, it was twelve bucks.

Are you getting 12v to the coil. Could be a wiring problem on the column.

Ok, a little confused. The module that I took out of the truck tests bad, the used one I put in tests good. I do have power to the coil, and from the coil to the distributor. When i put in the different module last night still would not start and no spark. I used an ohm meter and tested both pickup coils the one in the truck showed .670 and the spare showed .780. The meter was set to 2000k. I can't make heads or tails of the ohm meter readings. Old Dave said to make sure it had 160 ohms, but Im not sure I have the meter set right. Anybody's 2 cents is welcome. I think I'll change the distributor to the spare one and see what happens.

Ok, put in the spare distributor with it's module that tested ok and tried it, nothing. Reread the post and bcj67chevy said that some ecm's will test ok but will still be the problem. So I went and got a new module installed it and still nothing. I'm all out of ideas now, any thoughts fellas?

Don’t overlook the possibility that the ignition coil has failed.

Here are links to AUTOZONE test information. Not the greatest sites but better then nothing.


http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/08/5d/3a/0900823d80085d3a.jsp


http://autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/08/5c/0c/0900823d80085c0c.jsp

Thanks. I started to wonder that too. I forgot to check the coil wire as well. I talked to a friend of mine tonight who is very informed. His recomendations were to not look past the little stuff. He said a bad cap and rotor will do this too, and if they were real bad, that would cause the module to go out premature. The ones on it are no screamin hell thats for sure so I will change them too. As it turns out the distributor was a rebuilt unit, found the tag underneath. Thanks

I have seen coil wires go bad on those models more than once.

Also:
If the secondary winding voltage leaks or arks to the primary winding of the ignition coil, distributor module damage will occur.

If you are hearing a spark crack your ignition system is grounding out somewhere and it won't start.

Might be a silly question but.....have you checked if the distributor is actually turning?

Ok the truck is fixed, and chevytech wins the prize. The coil was bad. First i tested the coil wire, but had it on the high scale (i was being lazy and waited for the beep) but no beep so I guessed coil wire. Got a new set of wires, put them on, laughed about how simple it was and then cried cause it wouldn't start. I clued in that the wires may have some resistance and changed the setting, wires were fine. I checked the coil in the truck according to the autozone link, test showed it was bad. Ran out got a new coil and bench tested both side by side, they both failed the 3rd part of the test! I did this again and again and on the 3rd part it says to check with the ohm meter between the switched power and spark output stud and if it is infinite replace coil. The test says to do this on the high scale, it was infinite. But on the low scale they did show a reading, both about the same. Scratching my head, I had a good pickup, new module, new coil wire. Why no spark? I figured I would try it lightly so I could return it if need be. I hooked up the junkyard distributor plugged in the new coil, used booster cables to ground the distributor and the coil(so as to not mark it by installing it) turned on the ignition and gave the distributor a spin and it sparked the coil wire I set up. Beats me! I guess it's the only thing left in the equation. So I guess the moral of the story is if you tested everything and are down to the suspected coil spend 50 and get a new one even if the test is inconclusive. Thank you all for your help. This board is truly invaluble, better than any book., I I have learned something, which my dad would say is the important part. Thanks again. Dave

Glad to here you got it fixed and thanks for the detailed feedback.

71/454 I apologize for the wrong info. on the pickup coil resistance. I read the link that Chevy Tech had for Autozone and I went and checked the resistance of the pickup coil from my 86 Suburban tonight and it was 794 Ohms. Guess I am going to have to quit relying on my memory...:banghead:
I'm glad you got it going.:)

No sweat, you got me started on testing it thats the part i was looking for.