6.9 glow plug problem

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Feb 27, 2003 | 10:30 PM

BRUCE_M_73651

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6.9 glow plug problem

Hey guys, I have an 87' F250 6.9 that is having problems with the glow plugs firing long enough. Pulled the glow plugs, they all have continunity, checked the plug wires, they are all getting fire,, replaced the relay,, no change,, changed out the water temp switch, since its also in the glow plug loop, no change,, have had this pickup since new, now has 360,000 on it. Any suggestions?

Feb 28, 2003 | 06:09 AM

bilder12

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From: Northeastern Pa - USA

6.9 glow plug problem

Did you change the correct temp sensor? I believe there are two fo them in the engine, one for the tmp guage and the other for the glow plug system.
ARe you sure the glow plugs are ok? Are you sure its the glow plugs causing the hard starting problem? How does it act once it fires up?

Feb 28, 2003 | 05:45 PM

BRUCE_M_73651

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6.9 glow plug problem

The hard starting is definatly the glow plugs, they only cycle for about 3 seconds, and its been around 15 degrees some mornings. On start it runs rough till all cylinders fire as they should,,, the other sensor on that loop goes to the temp gauge, that works fine.

Feb 28, 2003 | 07:20 PM

wolfmanagh

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6.9 glow plug problem

Does it do this when its plugged in? If the truck is plugged in you don't even need the plugs to start it. I once had the problem where the left side didn't work, it turned out to be a inline fuse. But that truck started every time when it was plugged in with no stutter.

Feb 28, 2003 | 07:22 PM

xcopterdoc

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From: "tween the cotton and tob

6.9 glow plug problem

Have you changed the glow plug controller? where is the location of the temp sw that you replaced?

Feb 28, 2003 | 10:09 PM

BRUCE_M_73651

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6.9 glow plug problem

The controler, (relay) was changed, its behind the air cleaner mount, the sender that was changed is on the drivers side of the engine just above the exh. manifold.

Mar 1, 2003 | 09:22 AM

bilder12

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6.9 glow plug problem

I had a similar problem with the glow plugs. It turned out that the problem was at the controller. One of the power wires got coroded, dont know how-but it did- By loosening it and retightening it fixed the problem. Be careful doing this, there is hot wires near metal objects and the wrench will short out.
DUDE, what kind of light is that????????
Also, one glow plug will give the thing a hissy fit.
Are you sure you changed the right sensor?

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Mar 1, 2003 | 02:02 PM

xcopterdoc

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From: "tween the cotton and tob

6.9 glow plug problem

There are about 3 different glow plug systems for the older 6.9s and the 7.3 IDI engines. All use different glow plugs and ways to control the on time. Is there a sealed box under the relay you changed? If so, that is what controls the glow plug on time. When you turn on the key, the relay will latch and the wait light will come on,then go out after about 10 seconds, then the relay should cycle in 2 second increments. A Haynes manual will give you specifc test procedures for each different types of systems. A quick test I use to see if the glow plugs are good or not is to connect a test light to the + on the battery and then, with the wires disconnected from the glow plugs, touch the tit on top of the plug where the wire connects. The test light should light. If not, the plug is bad. Also make sure that you have installed the correct plug for your application.