2001 GMC Yukon 2500 8.1 - Problems

Hope someone can help - I will try to keep this brief but detailed:

FYI - 2001 GMC Yukon 2500 8.1 with about 105,000 miles - Vehicle has a Clifford Alarm with Remote Starter on it.

About a month or so ago started the truck with the remote start - the truck would not start - tried to start it with key still nothing - would crank but acted like it wasn't getting enough fuel. Changed the fuel filter - Ran great for about 2 weeks. Husband was at work started with remote start came out and it wasn't running once again. Kept trying after about 10 minutes of waiting truck started. Took it to repair shop....they suggested a fuel pump & filter (not sure if they even checked the pressure). Ended up paying 700 for a new fuel pump & filter. Took the truck to KY on vacation ran great for a whole week. Back from vacation husband was leaving for work and truck would not start again. Called tow truck - Tow Truck driver stuck key in and it started. Went in to get our stuff came out and vehicle had died. Restarted truck and it died again. Restarted truck and it spitted and sputtered when you pressed on the gas. Ended up calling tow truck driver back out. Repair shop had the truck from Tuesday to Saturday - ran codes, cleared codes, drove truck - said the codes didn't come up with anything particular that would be causing this. And he said he drove it a couple times without any problems. Picked up truck on Saturday - drove it to the gas station right next door - drove down not even a mile and it died again!! Called repair shop they sent 2 of their guys down about 20 minutes later. Stuck key in it and it started right up drove truck home and around neighborhood the next day no problems. Monday morning truck would not start again. About 2 hours later it started (kept truck at home - unreliable). Took truck in to repair shop that night to have codes scanned again. Died on us less than a mile from home going about 30 mph - Died again on the hwy going about 55 - truck restarted all by itself after it died on the hwy (demons?? or angels??). Repair shop scanned codes once again nothing in particular. WHAT ARE WE TO DO???? Any ideas??? HELP!!!! PLEASE!!!!!

This sounds like something electrical to me. After reading your entire post, most of it didn't help pick out any ideas until you mentioned that it died on the highway and then restarted by itself.

I make no promises here, but I would start by looking into a few sensors. The one's I'd test would be the camshaft position sensor, crankshaft position sensor, and throttle position sensor. When those crap out, it really confuses the computer. Those sensors also tend to crap out intermittenly before they just completely don't work. EXTREMELY frustrating! The reason these come to mind is because I've experienced this same situation on a Dodge Avenger once. Culprit was the Camshaft Position Sensor.

If the truck fired up and you were able to drive it home... well, head towards home after leaving the repair shop, it's possible they didn't have any problem starting the vehicle at that particular time (just like what you've personally experienced), which in turn wouldn't have presented any codes. At that particular time, the sensors were "working".

I would also starting looking around for any loose wires or wires that might have come in contact with the exhaust, which would melt the sheathing and cause the respecitve wire to ground out. Similarly, also look for any opportunities for a wire(s) to have been chaffed, causing a similar situation.

Back Again

:mad2: I'm back again!!

Well we ended up changing out the Crankshaft Position Sensor. Truck ran great for.......ONCE AGAIN A LITTLE OVER A WEEK!!!

Went out that morning and it wouldn't start again. Waited almost 10 minutes and it started right up. Went and got gas and started up again. Went to work after work came out and once again wouldn't start. Called the mechanic he sent a tow truck. Tow truck driver started it right up drove it up on the truck. It is once again at the shop. They are looking at the wiring now. Why is it that after we replace something it runs great for a little over a week and then back to square one. It is getting very aggrevating and EXPENSIVE. Maybe it is the Clifford System....I just don't know.

Any other ideas would be great.


Thanks!

This definitely sounds electrical to me. Something grounding and cutting out, and then running again when cooled or settles. Intermittent problems, I agree, are a nightmare. Ignition related most likely. I can't remember if this truck has seperate coil packs for each cylinder or just the one? If it is indeed only one then this is the jumping off point. Possible alarm starter kill circuit? Maybe try disconnecting the alarm completely for a bit. I hope that this helps.
My 2 cents.

John

YukonXL01 said:

Maybe it is the Clifford System....I just don't know.

Any other ideas would be great.


Thanks!

Click to expand...

There should be a Passkey bypass module integrated with your remote start system in order for the remote start to work properly. If for some reason this module goes bad, it can cause the remote start not to work at all, or it can cause intermittent starting problems when using the key. Even if the vehicle started fine and is already running, a bad module can send another resistance value to the Passkey system and trigger an incorrect value, sometimes possibly shutting down the fuel system. Of course, I'm not sure if this is it, but it's another idea to add to your troubleshooting arsenal. You should be able to unplug the module and see if you have any problems thereafter.
Also, the remote start system should not interrupt any ignition circuits, unless the installation was shady and the wires were cut and spliced back together with connectors. There could be a loose connection at the point where the remote start ties into the ignition circuits, which is usually at the ign harness under the dash.

Whatever the problem, I hope you find out. Good luck.