Quick Manual Glow Plug Override - How To?

[Diesel Blue]

Hello All,

I Just purchased a 1989 Suburban with a 6.2 liter "C" engine, with 179K miles. Having some warm start issues. The engine starts fairly easily when cold, but after it warms-up, it has trouble re-starting ... especially if I shut it off and let it sit for more than 10 minutes, in which case it will not re-start until the engine cools down, which can be several hours. (For reference, this time of year, the outside temperatures typically range between 60 and 95 degrees F).

After reading many posts dealing with warm re-start problems, I see that there can be many causes including weak batteries, poor electrical connections, starter not turning fast enough, worn injection pump (IP) and a number of other possible causes.

I read in some posts that glow plugs can help a warm engine re-start. Since my glow plugs do not operate when the engine is warm, I would like to try this possible solution.

Does anyone know how I can get my glow plugs to cycle when the engine is warm? Can I just jump the controller?

My glow plugs have the following printed on them:

AC DELCO 0-100-271-107
933
10.5 V

Thanks for any and all advice!!!

Alex

[BobND]

Those numbers MAY indicate the GOOD 60G glow plugs???

Start by jumpering around the "hot glow plug inhibit" switch at the rear of the RH head, behind the #8 intake port. (It's NOT needed.)

If that doesn't do the trick AND it's confirmed you do have the 60G's, extend the leads, and move the controller to the (relatively) cooler left fenderwell.

I have an '84 Sub that used to give hot starting problems, and the aforementioned mods cured them 100%. I also did the "extended glow time mod" for better cold starts. A WORLD of improvement.

[Diesel Blue]

Thanks BobND for your advice. I'm going to give it a try and will post again when finished.

There is also a switch/sensor screwed into the water cross-over pipe, near the thermostat. It has two wires (a yellow wire and a black wire). Does anyone know what this switch is for?

It's not for the temperature gauge, since my temp gauge continues to work if I disconnect the switch.

Thanks Again,

Alex

[cschneider]

There is no temp inhibit switch after '84. In '85 GM went to a new solid-state controller with a temp sensor built in. The wiring harness remained the same and on my '85 the switch is still there but does nothing. The controller will keep the plugs from firing when the temp at the controller is greater than 115 degrees. This is pretty cold for a worn engine and will make problems if you go on real short trips and need to restart. The best way for you to jump the controller would be to simply have a switch that sends power directly to the glow relay bypassing the controller.

[HH]

Peninsular engine sells a glow controller kit which you turn on to a time set by you or hold on via a momentary switch. It is an easy install. Most time consuming part is running the wiring. You can turn on no matter what the engine temp is.

[Diesel Blue]

Thanks for all information!!!

Before reading the last two posts, I tried jumpering two of the temperature switches on my 1989, but the glow plugs would not cycle.

Thanks "CSCHNEIDER" for confirming that there is no engine-mounted temp inhibit switch after 1984 and that beginning in 1985 a temperature sensor (for the glow plugs) is built into the glow plug controller.

I will try controlling the glow plugs manually to see if that helps. I will also look into the kit "HH" mentions ... thanks for letting me know about the kit.

In the mean time, I also tried the luke-warm water trick (i.e., carefully pour some luke-warm water over the injection pump to cool it off), and my engine did start right up. This seems to indicate a worn injection pump, but before I replace the pump, I'm going to try again to manually override the glow plugs.

Thanks Again to All Contributors ... will keep you posted!!!

Alex