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Related Medium and Heavy Trucks Questions
1999 C7500 CAT 3126. THE COMPUTER FRIED. I installed a reman
1999 C7500 CAT 3126. THE COMPUTER FRIED. I installed a reman one programmed to my engine serial #. The engine starts and runs for about 30 seconds and shuts off. I connected my cheap scanner and it is… read more
Mike Mcmillan
Mike Mcmillan
Triage Tech/Shop Foreman
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Gm I have a 04 GMC c7500 7.2 Diesel engine cranks but will
Gm I have a 04 GMC c7500 7.2 Diesel engine cranks but will not start, I replaced the Heui pump, and no fuel coming … read more
Cat Man
Cat Man
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Vocational, Technical or Trade Scho
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I have a Chevy C7500 with a Cat 3126. Tachometer only works
I have a Chevy C7500 with a Cat 3126. Tachometer only works when cranking over the engine. The oil pressure gauge is also pegged out at 100 psi when you turn on the key. Do I have a bad gauge cluster?… read more
AaronF721
AaronF721
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I have a 1999 gmc c7500 starter will not engage to crank all
i have a 1999 gmc c7500 starter will not engage to crank all the gages tack,temp gage,fuel ,all peg all the way … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
4,737 satisfied customers
I have a 2000 gmc c7500. 3126 cat 2000 gmc. I am broke down
i am broke down in NM driving a long acted like some one just shut the key off, now be for this i had a charging problem over charged cooked the battery's and blow the low beams out also blow the radio, now i put 2 new battery's in the truck and a new alternator start right up drive it from little rock to NM boarder and it just shut off do you know of a ecm fuse or fuse-able link might be in this circuit and location thanks *****: Sometimes things that you think will be really complicated end up being easy to fix. The Heavy Truck Mechanic I'm going to connect you with knows all the tricks and shortcuts.… read more
Wayne
Wayne
Journeyman
Vocational, Technical or Trade Scho
4,023 satisfied customers
Im looking at a 1999 chevy c7500 with a 3126 cat motor. it
im looking at a 1999 chevy c7500 with a 3126 cat motor. it was driven last fall and then sat over the winter. I went to start it but no start just cranks. unplugged the grid heater and it will run on … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
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Got a 2001 gmc topkick with 3126 in it. Was running fine.
Got a 2001 gmc topkick with 3126 in it. Was running fine. Went to start long cranking. Had already run into bad inj actuation sensor couple weeks back. Fixed that. I unplugged the sensor again to test… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
Cat 3126 is not staying running it'll start and run for 30
Cat 3126 is not staying running it'll start and run for 30 to 60 sec then will shut off then not run at all I have tried to run a scan on the computer but it comes back no ecm but after 4 of 5 hours i… read more
Cat Man
Cat Man
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Vocational, Technical or Trade Scho
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Cat C7 in a 2005 GMC C7500. Preheat light will not go out.
Cat C7 in a 2005 GMC C7500. Preheat light will not go out. Check engine light on. ABS light on (shows bad LR sensor). No other fault codes … read more
Jeremy
Jeremy
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My 1999 gmc c7500 dump truck the abs light flashes 3 times
my 1999 gmc c7500 dump truck the abs light flashes 3 times when you turn the key on. then it stays on after truck starts … read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
4,737 satisfied customers
I have a 2003 GMC 7500 with a 3126 cat, truck came in no
Hello, I have a 2003 GMC 7500 with a 3126 cat, truck came in no start no crank, could not communicate with ecm, checked power and grounds found all ok, replace ecm, now I can communicate with ecm and … read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
I have a 3126 and a c-7. 3127 came out of a 2003 6500 and we
i have a 3126 and a c-7. 3127 came out of a 2003 6500 and we put it in a 05 7500 that has a c-7. When we put the wiring and computer out of thr 3126 all the lights in the dash are on and runs like cra… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
I installed a different ECM on my 3126 cat and it still
I installed a different ECM on my 3126 cat and it still reads no ECM detected on scanner, just wondering what pins go to plug underneath the dash… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
I have 3126 cat in 2000 gmc top kick, it died on highway, i
i have 3126 cat in 2000 gmc top kick, it died on highway, i had it scanned no ECM detected, check power at pins on harness that connected to ECM and they had power, i then borrowed a used ECM, it stil… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
I have a 1999 C7500 with a 3126 Cat engine. The truck can be
I have a 1999 C7500 with a 3126 Cat engine. The truck can be running fine then out of the blue it will shut off. This may happen while it is being driven or while it is idling. Is there a circuit brea… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
I have a 2000 gmc c7500 with a 3126 cat in it. We hooked a
I have a 2000 gmc c7500 with a 3126 cat in it. We hooked a Cat Et up to it this evening with the right adapter I assume...7x-1714. The Cat et program says 1 ECM detected...initializing but not does an… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
2000 GMC topkick with a 3126 cat engine. Shut off while running,
2000 GMC topkick with a 3126 cat engine. Shut off while running, will not restart. Checked voltage to ecm. 12 volts to pins 52 an 53 .I have 1200 psi. pressure in high pressure manifold while cranking… read more
Cat Man
Cat Man
Cat Engine Expert
Vocational, Technical or Trade Scho
10,245 satisfied customers
i have a md3060 Allison trans just put a new transmission in
i have a md3060 Allison trans just put a new transmission in it and a new shift selector i can not get power to the selector the truck will not start in less you jump it at the starter silinoid and th… read more
Daniel Wilson
Daniel Wilson
Auto Mechanics 1&2/diesel mech
4,737 satisfied customers
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Meet the Experts:

Daniel Wilson

Daniel Wilson

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worked on, Gmc, Macks, Freight liner,Mercedes Benz,,Ford, sterling

Jeremy

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Chris (aka-Moose)

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Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

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