View Full Version : 2 years and $2300 later my truck starts

05-17-2006, 02:14 PM
I have this 2000 GMC van that was my work truck. The last two years everytime it rained or the humidity was very high the truck would not start in the mornings.When it would run on a rainy day it would hesitate and buck when going over 60 mph and the check engine light would come on.
I had two local garages and a dealer working on it. 2 sets of plugwires, cap and rotor, 4 sets of plugs, a fuel pump, an oxygen sensor, a throttle position sensor, a air mass meter, software update and a few other bits. At least twice during that time I asked if there could be an ignition coil problem , They all said "oh no! a faulty ignition coil won't cause this problem"

Of course with all the rain we had the van has not started the last 3 days. I was pretty pissed this morning so I went and bought a new $60 coil , I spent about an hour changing out the coil (hell to get to) and the truck started right up! I drove it on the expressway and it accelerated smoothly right up to 70 mph. I just looked at the old coil and it had green corrsion inside of the coil wire terminal.

What happened to all the good mechanics ? Other than the guy who works on my Volvo I can't seem to find a wrench who know what he is doing anymore

05-17-2006, 02:42 PM
had a similar problem with the 92 Eagle Summit wagon prominently displayed in an earlier thread ;), except that the culprit was a hole in the distributor cap. Thing is the hole was designed to be there, so when I lookd at the cap, and changed it twice along with the plugs, plugwires, rotor etc. I didn't notice anything amiss - it was supposed to be there.

A mechanic buddy of mine saw the hole, plugged it with a toothpick and we never had a problem again.... automotive engineers puting holes in distributor caps, sheeesh! ;)

Nicholas Carey
05-17-2006, 03:08 PM
I had a similar problem whilst on a trip with my old VW Scirroco.

It happened, of course, on the Sunday of a holiday weekend in the middle of nowhere. Car started sputtering and couldn't keep up freeway speed. Gradually got worse and worse until I had to pull over.

Got a towing service and found a garage that was actually open and relatively nearby.

Guy changed out spark plugs, spark plug wires, distributor cap, rotor, fuel filter, etc., etc., etc. Seemed to run OK.

Started back down the road with my wallet several hundred dollars lighter.

Almost got to where I was going -- wound up having my brother tow me in the last 50 miles. We took the thing over to his VW mechanic.

It took the VW guy about 30 seconds to diagnose the problem.

It worked out that the fuel pump was dying and the fuel pressure had dropped too low. That particular vintage VW Scirroco used Bosch K-Jetronic -- or was it L-Jetronic? Can't remember -- fuel injection which which required the injection loop to be pressurized to something like 250 psi. Since the fuel pressure was too low, the injectors weren't delivering enough fuel to the cylinder. As a result, the computer noticed (exhaust gas sensors?) that the mixture was too lean and compensated by moving the choke plate to enrich the mixture (as if it was a cold start). Since that didn't really fix things, the feedback loop kept increasing the amount of choke with predictable results.

A simple (though not cheap!) fuel pump replacement and the car was right as rain.