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Gm Tech (Cam)
Gm Tech (Cam), GMC Mechanic
Category: GMC
Satisfied Customers: 29515
Experience:  GM Grand Master Technician 2007. 14 year experience.
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Gmc: good afternoon. I have a 2002 2500hd 4x4 6.6l codes are:

Customer Question

good afternoon. I have a 2002 2500hd 4x4 6.6l codes are: p0380,p0540,p0090,u1800,u1000. wont start cold unless you use start fluid. when it does start it runs sluggish. After it is in service for a while its fine, until you shut it of for a while then it wont start. Any suggestions?
Submitted: 2 years ago.
Category: GMC
Expert:  Gm Tech (Cam) replied 2 years ago.
Hello, I'm Cam.
Can I get your first name please?
Sorry to hear about this. Let's see what we can do.
To start, do you have a test light?
If so let's test power into the glow plug controller. This is on the valve cover behind the turbo pipe. The front most cable/stud is the power into it. Does that have power all the time?
When you turn the key on/ do you feel any clicking inside that assembly?
Customer: replied 2 years ago.
David. Yes. Not at work right now. Had to leave shop. I can perform this test in the am. what should I do next if we have power and then if we don't?
Expert:  Gm Tech (Cam) replied 2 years ago.
No power means the mega fuse under the fuse block is bad.
power means possibly the issue is inside the glow plug controller. Basically its 2 relays under there. The power splits off under the cover from that stud and heads to 2 relays. I have seen many where the terminals under there are bad. I would take it apart and have a look if I was you after confirming no power.
Customer: replied 2 years ago.
Thank you. Does this cover the p0380 code? Should we be concerned about the other codes based on the symptoms?
Expert:  Gm Tech (Cam) replied 2 years ago.
Yes, lets see what that does for power and go from there.
Customer: replied 2 years ago.
Ok, thank you. What time slot are you on-line, just in case?
Expert:  Gm Tech (Cam) replied 2 years ago.
I get up around 6 and log on. Then my computer is on my tool box throughout the day so I am around almost all day.
Customer: replied 2 years ago.
I can't seem to remember what the voltage should be for the GP controller, and can't find my book
Expert:  Gm Tech (Cam) replied 2 years ago.
its battery voltage.
Customer: replied 2 years ago.
with the key on and wait to start light is on, putting the positive lead on the post I am pointing to it reads 12.15 volts
Expert:  Gm Tech (Cam) replied 2 years ago.
This has california emissions. So that means that the module in the back is likely bad and needs to be replaced. Do you have the Vin handy?
Customer: replied 2 years ago.
Yes I do, it is as follows:1GTHK23142F124396
Expert:  Gm Tech (Cam) replied 2 years ago.
i think you may have multiple issues going on here. AT the controller there, do you get power with the key on in the small pink wire?
Customer: replied 2 years ago.
Yes there is, I rechecked the stud, the nut holding the stud, and the lead of the wire connected to the Stud. I am checking in the right place correct? Or is it elsewhere
Expert:  Gm Tech (Cam) replied 2 years ago.
This is the small control wire in not the main power in, its in one of the smaller connectors.
Customer: replied 2 years ago.
Found a wire that is not connected. Traced it from near the main power in to this spot
Expert:  Gm Tech (Cam) replied 2 years ago.
What colour is the wire? How thick?
Customer: replied 2 years ago.
It's in a grey/silver mesh sleeve
Expert:  Gm Tech (Cam) replied 2 years ago.
that is supposed to have power and it comes off the stud we tested at the glow plug controller.
Customer: replied 2 years ago.
It's a black wire, found the actual wire in a plastic cover near where it was connected in that picture
Expert:  Gm Tech (Cam) replied 2 years ago.
Reconnect it and see what happens. I think that will correct your P0540.
Customer: replied 2 years ago.
Reconnected the wire, cleared the codes, turned the key back on. Scanned for codes, in the failed this ignition section it only shows the P0380 one still.
Expert:  Gm Tech (Cam) replied 2 years ago.
Glow plug module!! Great work so far.
Customer: replied 2 years ago.
Ok, so that means the module is bad and needs replaced?
Expert:  Gm Tech (Cam) replied 2 years ago.
YEs, that is correct.
Customer: replied 2 years ago.
Ok, would that solve the crank but no start while the engine is cold?
Expert:  Gm Tech (Cam) replied 2 years ago.
Yes, right now the glow plugs are not working nor was the intake heater. Add the glow plugs and she should work like new.
Customer: replied 2 years ago.
Would I replace the glow plugs even though they were replaced not too long ago
Expert:  Gm Tech (Cam) replied 2 years ago.
Glow p[lug module. Not glow plugs.
Customer: replied 2 years ago.
Ok, sounds good
Expert:  Gm Tech (Cam) replied 2 years ago.
Is there more that I can get you today?
Customer: replied 2 years ago.
How do I get to and check the cam and crank sensors
Expert:  Gm Tech (Cam) replied 2 years ago.
Are they setting codes? They are best accessed by taking out the passengers front wheel well and reaching in through.
Customer: replied 2 years ago.
They aren't throwing codes, but it's reading misses on scanner
Expert:  Gm Tech (Cam) replied 2 years ago.
Sorry the reply did not show through. What are the balancing rates on your engine?
Customer: replied 2 years ago.
What should the resistance be for the camshaft position sensor, got it out and it doesn't look damaged. Which pins do I check? It's a 3 pin
Expert:  Gm Tech (Cam) replied 2 years ago.
ITs not a sensor we simply check resistance on. Its a solid state device and a hall effect sesnor. One pin has power, one has ground and the third is a signal wire.
Customer: replied 2 years ago.
I've ne checked Hall effect before how do I do that? And did you have a good weekend?
Expert:  Gm Tech (Cam) replied 2 years ago.
Weekend was ok. not long enough. To check that sensor you verify wiring and replace. Its not one that you can check using a meter.,
Customer: replied 2 years ago.
Ahh ok
Expert:  Gm Tech (Cam) replied 2 years ago.
Remind me why we are checking the cam and crank sensors again?
Customer: replied 2 years ago.
Boss thinks that is what's causing the problem, and can't argue with him. Just gotta do it lol
Expert:  Gm Tech (Cam) replied 2 years ago.
YUp. Did you replace the glow plug module?
Customer: replied 2 years ago.
Was told not to mess with it as it was just changed
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, I think we need to deal with that.
Customer: replied 2 years ago.
Ok, I'll let him know and will get back to you as soon as I get an answer. Tho he can be pretty stubborn at times
Expert:  Gm Tech (Cam) replied 2 years ago.
LOL, I won't comment.
Customer: replied 2 years ago.
Lol it's all good
Expert:  Gm Tech (Cam) replied 2 years ago.
Is there more I can get you?
Customer: replied 2 years ago.
I remember you asked earlier as to what the Balancing rates were for the engine, is that the same thing as cylinder contribution? If so our scanner doesn't give us that information
Expert:  Gm Tech (Cam) replied 2 years ago.
I Am not sure what others call it. This tells me how much fuel each cylinder is adding to keep it idling smooth.
Customer: replied 2 years ago.
I don't see that info on there
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, IT would range from -4 to +4 normally.
Customer: replied 2 years ago.
Thank you, ***** ***** back to you in a bit
Expert:  Gm Tech (Cam) replied 2 years ago.
Sure thing. How am I doing so far? We have been working through this for a bit. I like to know if I am on track as far as ratings go.
Customer: replied 2 years ago.
Doing great so far, looks like my boss is gonna get the glow plug control module. If after replacing that it still doesn't start, what should I check?
Expert:  Gm Tech (Cam) replied 2 years ago.
After that we follow the codes. right now it starts hard when cold, I am 99% sure the module will fix it. Just wanted to mention that the rating you provide is how I get paid. No rating means I don't get paid.
Customer: replied 2 years ago.
It's a crank no start
Expert:  Gm Tech (Cam) replied 2 years ago.
ok, did we check return rates yet?
Customer: replied 2 years ago.
No
Expert:  Gm Tech (Cam) replied 2 years ago.
Find the 2 fuel lines on the rear drivers side valve cover. Take the smaller one off and attach your hose to the metal pipe coming from the engine. Put the other end into the container and run the engine to fill that line. Then shut it off and remove the IGN 1 relay from beside the starter relay. If the engine will not start at that time, crank it ti fill the line, then empty out the container and keep the line full. Crank the engine for 15 seconds fully and measure the amount of fuel that comes out of that line. More than 24cc means the injectors have failed.
Customer: replied 2 years ago.
And this can be done even if it will not start at first?
Customer: replied 2 years ago.
* should say at all
Expert:  Gm Tech (Cam) replied 2 years ago.
Yes, I really need to edit that post. You can crank it to get the fuel lines full.
Customer: replied 2 years ago.
When looking at the scanner, in the fuel data display, with ignition clicked to on(not start), it says: fuel rate(mm3).....-1
Expert:  Gm Tech (Cam) replied 2 years ago.
What does that say when you do get that running?
Customer: replied 2 years ago.
Can't get the truck running to check
Expert:  Gm Tech (Cam) replied 2 years ago.
Ok, do the return test when its not starting and lets see where this goes.
Customer: replied 2 years ago.
Ok, I'll have to reconnect the cam position sensor, so might have to get back to you tomorrow for that
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, sounds good.
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, sounds good.
Customer: replied 2 years ago.
If I remember right this is a free week trial right, I want to make sure that there is plenty of time left on it. Does it show how much time is left?
Expert:  Gm Tech (Cam) replied 2 years ago.
In this thread, the timer has been removed so its not relevant.
Customer: replied 2 years ago.
Hey sorry for the long wait in getting back to you, been side tracked on a few emergency jobs at the shop. Starting to get it out back together to do the return rate test
Expert:  Gm Tech (Cam) replied 2 years ago.
No problem. I am not online full time this weekend anyway. I will try to reply as quick as I can.
Customer: replied 2 years ago.
No worries, gonna begin the return rate test now. What should I be ge as a reading
Customer: replied 2 years ago.
The fuel lines that I check are the ones right in front of the glow plug control module correct?
Expert:  Gm Tech (Cam) replied 2 years ago.
Yes to the location of the lines and we want to see low numbers. Over 24cc total is bad.
Customer: replied 2 years ago.
There has also been a lift pump installed on it, and I know it's gett fuel to the filter and we haven't lost any prime. How do I check if the fuel is getting to the fuel rail? Can't really do the return rate test because the truck will not start. It's still a crank no start
Expert:  Gm Tech (Cam) replied 2 years ago.
The return rate test only requires crankibg. I would ask to run the engine to fill the line so we get an accurate measurement so just crank till the line is full then start the test.
Customer: replied 2 years ago.
Will give that a shot
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, sounds good.
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, sounds good.
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, sounds good.
Expert:  Gm Tech (Cam) replied 2 years ago.
OK, sounds good.
Customer: replied 2 years ago.
So we its disconnect the feed line for the fuel and put it back on. Went to start it after a bit. Started right up, ran cherry for a bit and shut it off. Went to start it again and started right up. Then it started dropping fuel pressure and died. Primed it up a bit, ( tho primer was still a bit soft,) and it started up, but died again due to dropping fuel pressure.
Customer: replied 2 years ago.
The feed line was the one coming from the filter
Expert:  Gm Tech (Cam) replied 2 years ago.
I dont suppose you have the means to check the vacuum on the system at the vacuum port?
Customer: replied 2 years ago.
Possibly, tho can't say for sure. Could it be a faulty fuel pressure relief valve?
Customer: replied 2 years ago.
No I do not have the ability to check the vacuum
Expert:  Gm Tech (Cam) replied 2 years ago.
It's not likely the relief valve or it would not run if you kept pumping the plunger.
Is there a way you can borrow a vacuum gauge and attach it to the hose into the bottom of that test port and measure the vacuum with it cranking.
Customer: replied 2 years ago.
Will find out
Customer: replied 2 years ago.
I do have a vacuum gauge available, how do we test it with the gauge? And how do I test the regulator?