WingleBeast

iTrader: (1)

I've been looking around for a few weeks. Here is my issue:

My 83 GSL has been running like a champ for over 3 years. Driving it daily from time to time, long road trips, no problems. Had my trailing ignitor die over a year ago and replaced with a spare, but I know I did not properly use thermal grease due to being in the middle of a trip.

I figured my leading would be sure to be on its last legs soon as well. But I was expecting a complete failure like I had with the trailing. Instead I moved across country to Oklahoma and during a 110 degree heat wave. Once I got the car off the trailer, I drove about 19 miles before it started to miss and buck under load. The tach died again (my fault for not thermal greasing the replacement trailing igniter). The symptoms would creep down to lower and lower RPMs until a stall. After sitting for 5 or so min I could start it up and start the whole process over again for 5 more miles. I immediately guessed fuel pump and had that replaced (it was the original anyway). Now I have started driving the car again I have not run into the same problems, but during a 6 hour trip in 70 degree weather I did notice a few issues under load going up a hill. It only kicked in after a few hours of driving and I was able to feather the throttle and keep moving along. My tach also started working again from 0-3500 RPM after the car warms up.

Has anyone had something like this? I thought when an igniter went, it was a complete failure. Would the ambient temp play a part? Keep in mind I did not change igniters from last summer, so whatever was failing in 112 degrees was 80% fine in 70 degrees.

Joekaistoe

Might want to check your ignition coils, heat increases the resistance in coils, which can cause weak spark. 1985 FSM says you should have 1.35 plus or minus 10% ohms across the primary coil at operating temperature.

WingleBeast

iTrader: (1)

Thanks! Something to test out tonight.

I have some thermal paste coming this weekend. I figure that is a quick fix for less than 5 bucks.

j9fd3s

iTrader: (3)

i've seen ignitors get intermittent i think, hard to diagnose, but complete failure will soon follow

you also might change the fuel filter, i've seen that cause a thing where the car would run fine and then gradually loose power

t_g_farrell

iTrader: (1)

This is classic ignitor failure mode. It will get worse and worse over time until it leaves you stranded. What happens is the ignitor (big transistor basically) under heat stress starts to have failures in the substrate. Each time it gets hot the failure gets worse. At first it will seem like a blue moon thing but after awhile, anytime it gets hot it will have these issues. I see you moved from Michigan to Oklahoma where it gets a lot hotter, so you will notice this more there if its an issue.

Toruki

In the early 90's, in my poor little 83 GS, I stumbled my way down Route 128 to 93 (it was bumpah ta bumpah) to get a J109 off a donor engine in my parents' garage. Screw/swap/snap and the drive back North was easy.

Back then I had no idea that I could have just swapped the trailing ignitor into the leading position.

Banzai

iTrader: (13)

Is there a way to bench test an ignitor to verify its integrity?

LongDuck

Someone made a bench test circuit, but it would likely test fine and then fail on the car when it heats up. That's the nature of a transister with increasing resistance when hot.

The fix has always been a dab of conductive electronics grease on the metal heatsink of the Ignitor when installed. This allows the distributor to become part of the heat sink.