glow plug problem

[diesel1978]

My engine light came on and computer showed # 8 glow plug was bad. Had it replaced and engine light came back on the next day again showing # 8 glow plug? It starts fine and always has. Going around 45-55 mph it acts like it isn't getting enough fuel and runs choppy. What else could it be?

[Fishermedic]

Could be a number of things. Are you using anything to monitor the engine? It's pretty much impossible to diagnose and fix the truck if you don't know what's going on with it. It'll cost a lot to throw parts at it till it's fixed!

Are there any other symptoms? How's it idling etc.?

Without knowing any more I'd start with load testing the batteries and checking FICM voltage. Some more info/history might help though...

[diesel1978]

It idles great and runs great otherwise. Maybe it needs the egr delete? Why would the computer show the #8 glow plug after we just replaced it?

[Fishermedic]

Well... "Does it need an EGR delete?" is kind of my point about more info. Just deleting the EGR won't necessarily fix you problem unless the EGR valve needs cleaning or you have a blown EGR cooler and if the EGR valve is the problem cleaning it or replacing it is a LOT less money and hastle than a delete. If it's a blown EGR cooler then there is a reason it blew. If you don't fix the cause you'll have more/bigger issues down the road.

It could be an EGR problem, but it could also be a glow plug problem (like the code says), an FICM problem, fuel problem, computer problem, turbo problem, and on and on. If you can check some temperatures, boost readings, pressures and voltages you'd be much more likely to find the root problem and be able to fix it rather than just try to replace parts and get lucky. That's why I was asking about the monitor and suggesting you start with some things you can check on easy enough on your own without spending money for nothing.

As for the #8 glow plug code. IIRC it's most likely the glow plug control module not the plug itself, since you changed it and the code is still there. You can swap the module out with one you know works or you can check the red wire on the black connector, it's the #8 circuit. Compare the resistance on a few of the circuits, if #8 is close to the others you know it's a bad module.

Sorry about the long wait for a reply, I don't always have much time for an answer! Also the Ex forum isn't heavily traveled, you might try the General Discussion forum for quicker results, most of the Ex owners only seem to come in here once a week or so.