BigBadJap

Alright. So, I've been driving with the rebuilt motor for about a month now. But it seems like everytime I drive it, it seems to be running great, BUT then, out of nowhere the engine will stumble/miss - like maybe once per trip. It'll be a VERY quick miss, it almost feel like you hit a small bump on the highway and then the check engine light turns on. Aside from this problem, the engine runs like a top.

I put the code reader on it the other day and it showed me a code 42 - Electronic Spark Timing Monitor. So I checked that all my boots were plugged in properly (I have all new wires, spark plugs, cap/rotor) and made sure that the timing setting wire was plugged in properly.

It actually happened again this morning on the way to work, but I haven't had a chance to throw the code reader on it.

Any ideas on what could be the problem??


I am not sure if this is related or not, but on occasion, I find that when I put my key in the ignition to start the truck, I have absolutely ZERO power and I know that my battery is good. I was messing around and discovered that if I move the thick positive cable from the battery to the starter, power is restored. I haven't had a chance to see what the problem is there.

nick harmon

well, i cant help you on the timing issue, but maybe i can on the power- are your connections tight?if not tighten them. if they are i would suggest new cables positive and negative. i suggest this because my 79 dodge truck has fell to the same problem before,burnt up two starters and a solenoid before i finaly listened to my dad ( auto mech. teacher 13 yr. retired now) and replaced my cables. havent had a problem since.

BigBadJap

For the no power issue, what would cause a zero power problem?

Is it that something isn't connecting at all, as in a broken wire or could it be that the two posts on the starter are shorting out or something like that?

nick harmon

what year is your truck?

BigBadJap

It's an 1989 GMC Jimmy

BigBadJap

I checked the error codes during my break. It is in fact a code 42 that occured this morning...

nick harmon

its very likely that your power problem is your cables. i would start by replacing those. they're pretty cheap and easy to install,and new parts are usually a good idea, and since you said you could wiggle the wire and power comes back, then its a good place to start. hope you get it right.

Frik92RS

I got a code 42 awile back, I fixed mine by replacing the ignition control module located in the distributor cap under the rotor. The part's not cheap but it sounds like you need it. The module is responsible for controling the timing advance/retard on the motor AND its also responsible for controling when the coil fires as well.

Good luck!

BigBadJap

I was afraid you were going to say that.

Is there such thing as an aftermarket ignition module I can swap in there? Ideally, I'd like to end up with a nice accel 300+ system or parts that complement that system.

nick harmon

dude, the ac delco ignition modual is only 53 dollars, thats not that expensive- is it?

BigBadJap

Actually, I was quoted $133 CDN for oem replacement, but I was later able to find an accel module for only $65. ...and you're right, even $65 cdn isn't that much, but I sure hate dropping cash on something, then have it not fix the problem.

I believe my problem may be solved anyway. The truck hasn't acted up at all in the past few days.

I found that my main ground cable to then engine was very loose AND the grounding strap from the back of the passenger side cylinder head was not even attached to the firewall. (It wasn't attached before I r&r'd the motor either) It also may just be the cooler temps around here lately too so I'm waiting to see.

BigBadJap

Well, it turns out that my problem has not been solved by merely tightening some ground bolts. It did it again on the way back from lunch. (As well as the weird torque lockup converter thing)

I think it might be temperature related. The past several days have been quite cold - as in we got 4" of snow and it still on the ground, but today is quite a bit warmer.

I'll be swapping in the new battery cables this weekend to elimate that possibilty. If that doesn't work, I'll do the accel ignition module thing.

nick harmon

good luck, dude. remember those are my thoughts on what i would do in your situation. obviously no one else had any ideas so i hope mine help.