Hello all. I have just gotten my first chevy truck. Its a 1994 silverado 1500 4wd automatic, with a 350 TBI engine. Real nice truck, comfortable, cold air... All was fine until yesterday. On a trip to Montrose from GJ(60 miles), the truck just died on the highway. At 70 mph, it just died. So, I put her in neutral, coasted to a stop, and popped the hood. No leaks, steam or smoke of any kind. Let the truck cool down for 20 minutes, and started right up and got home no problems.


Truck is a 94, has 150 thousand miles. Coolant is full, oil level fine. We were running the air cond all the way, and pressing fairly hard at 70 mph. I figured 70 was a reasonable speed for a 94 though.

I do not have maintenance records for this vehicle. Temp gauge reads around 180-190 after warming up, and it never read "hot" at all. I did notice my voltage output had declined to an indicated 12 volts on the dash gauge.

I am pretty sure its a heat issue,, because it was 103 out there today, and this is the first time the vehicle has ever faulted in the 2 months I have owned it.

I am normally an import or ford guy,, so I know nothing about these engines and systems.

I just need pointed in the right direction..waterpump? radiator? fan clutch? electronics? Throttle sensor? vapor lock? tuning issue?

Engine seems perhaps a little tired as it will pull about 35mph at cero sumit and thats in 2nd gear and not pushing too hard, loaded down with motorcycles and camping gear. I figure its a little tired,, but should still have plenty of life left. As far as I can tell,, no head gasket issues. No leaks, very clean engine.

HELP! This is supposed to be my camping and adventuring vehicle this summer!

 

did it shut off like you turned off the key?????? if so it sounds like the control module overheated.

 

Yes, shut off just like I did it myself. Also,, it tends to idle real low but it never died at idle.

Any cure for overheated control module? Just replace it?

EDIT: I just looked up control module,, and looks like 3 different items for that truck. Ignition control, spark control, and engine control...Which one is likely to overheat and fail?

 

what I would do is get some dielectric grease and clean each one and reapply a nice helping to each of them.....dielectric grease helps disapate heat

 

I did a little more internet searching and found its usually the ignition module right in the distributer cap that fails. So, I went ahead and bought a new one from napa,, the spendy one... plus new cap and rotor. New parts installed, plenty of dielectric grease used.

Truck now reads a healthy 13.5 volts indicated even after a good long warmup. I tried a short stint at 75 mph, about 10 minutes after the truck was warm from an in town trip. No problems. Idles fine at about 650-750 rpm indicated.

So, I am going to assume it was the ignition module, and leave it at that.

The old module tested good at the parts store, but it never got real hot like on a 103 deg day at 70 mph on hot asphalt...

Hope this helps the next guy!

 

Problem came back. Hasnt died on me again yet,, but I have not trusted it on the highway yet either. Just today tried a trip, and same low voltage, and scary low idle. We just turned home and got a GOOD VEHICLE to make our little trip. Not solved!

 

OFG, you still having an overheat problem? I struggled with an overheating problem on a 1990 Suburban 454 (big-block) a few years back. changed every component that touches coolant (pump, radiator, thermostat, fan-clutch, hoses, etc..). Was ready to dump the vehicle until an independant mechanic discovered that the bearings on the distributor rotor were shot. He changed the whole distributor assembly (with new bushing bearings), and suddenly the vehicle had a lot more power, and doesn't overheat any more. Now I also put in a Griffith aluminum radiator, and I am sure that helps also. I tow a large travel trailer up hills with no problems.