Duramax wont start without using starting fluid help!
#61
07-08-2012, 02:33 PM
there are three possibilities. the first one being the injectors. 2nd cp3. third is the pressure relief valve. see attached.
injectors are the most common for the LB7, then the CP3, then the least is the pressure relief valve. being that you replaced the CP3, that leaves only the injectors and the relief valve.
is it possible that the burning oil smell is diesel leaking out somewhere and getting on the exhaust? most of the leaks will likely end up in the valley of the engine and drip out the back of the engine where all of the exhaust lines join up
injectors are the most common for the LB7, then the CP3, then the least is the pressure relief valve. being that you replaced the CP3, that leaves only the injectors and the relief valve.
is it possible that the burning oil smell is diesel leaking out somewhere and getting on the exhaust? most of the leaks will likely end up in the valley of the engine and drip out the back of the engine where all of the exhaust lines join up
#62
07-08-2012, 02:46 PM
pressure relief valve? where is that located? theres a deal on the return line with wires goin into it where it splits off. is this it?? any way of checkin this valve?
an ya, i thought bout it possibly bein diesel. but i honestly dont know. motor oil level hasnt changed any since i changed it. its a pretty rich smell and it seems to be more strong if im driving the truck hard but that could still be either fuel or oil i think.
do you know where that return line goes and what it is for that goes back behind the drivers side of the motor by the head? it look like it had a bolt on it all the way at the back.
an ya, i thought bout it possibly bein diesel. but i honestly dont know. motor oil level hasnt changed any since i changed it. its a pretty rich smell and it seems to be more strong if im driving the truck hard but that could still be either fuel or oil i think.
do you know where that return line goes and what it is for that goes back behind the drivers side of the motor by the head? it look like it had a bolt on it all the way at the back.
#63
07-09-2012, 12:47 AM
check this out: Fuel pressure relief valve.. Where is it? - Page 2 - Chevy and GMC Duramax Diesel Forum
the return line routs unused fuel back to the fuel tank
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interesting read. similar to your problem. Help lb7 will not start when hot - Diesel Place : Chevrolet and GMC Diesel Truck Forums
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and another: LB7 Fuel System Diagnosis - High Pressure Side
the return line routs unused fuel back to the fuel tank
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interesting read. similar to your problem. Help lb7 will not start when hot - Diesel Place : Chevrolet and GMC Diesel Truck Forums
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and another: LB7 Fuel System Diagnosis - High Pressure Side
Last edited by 2004LB7; 07-09-2012 at 12:47 AM. Reason: Automerged Doublepost
#64
07-09-2012, 07:29 AM
okay so its either injectors or fprv.
its most likely injectors but not sure yet. i suppose i could shim the fprv or buy a new one probably.
otherwise ill do a return fuel test. or would it be posssible to cap off like the paasenger side injectors and see if it builds pressure? then if it does i know the problem is there right? or no?
its most likely injectors but not sure yet. i suppose i could shim the fprv or buy a new one probably.
otherwise ill do a return fuel test. or would it be posssible to cap off like the paasenger side injectors and see if it builds pressure? then if it does i know the problem is there right? or no?
#65
07-09-2012, 08:35 AM
#66
07-09-2012, 08:37 PM
well i narraowed it down to injectors. because i took that banjo bolt off that screw into the fprv and then i cranked the motor over. all the return fuel comin was from the line coming from the injectors. none came out of the fprv.
so i guess i just needa figure which injectors are bad. ill prolly try buy some hose and stuff and do some testing
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well i did a quick test today. i unhooked the return line at that quick disconnect and hooked a line up to it and cranked motor over till line was full then stuck it in a container and cranked motor over for 15 seconds. i measured the fluid in the container and there was a little over 70 CCs. i did it a couple times to make sure.
with that said, it looks like its definetly injectors. im thinkin bout not even tryin to figure out which ones are bad and just replacing them all. Is this a good idea? i would really like to put some like 50hp injectors in it.. would like some input on this. is it worth the money for the bigger ones? im gonna be using the truck for pullin once in a while but mostly on long trips and just driving it. heres a couple links to some injectors i found. one is just stock and the others are bigger but do cost more.
2001 - 2004.5 GM Duramax LB7 Injector Superkit | eBay
Chevy Gmc Duramax Diesel USAFD Injectors W USAFD 50 HP Nozzels 2001-2004 LB7 | eBay
so i guess i just needa figure which injectors are bad. ill prolly try buy some hose and stuff and do some testing
---AutoMerged DoublePost---
well i did a quick test today. i unhooked the return line at that quick disconnect and hooked a line up to it and cranked motor over till line was full then stuck it in a container and cranked motor over for 15 seconds. i measured the fluid in the container and there was a little over 70 CCs. i did it a couple times to make sure.
with that said, it looks like its definetly injectors. im thinkin bout not even tryin to figure out which ones are bad and just replacing them all. Is this a good idea? i would really like to put some like 50hp injectors in it.. would like some input on this. is it worth the money for the bigger ones? im gonna be using the truck for pullin once in a while but mostly on long trips and just driving it. heres a couple links to some injectors i found. one is just stock and the others are bigger but do cost more.
2001 - 2004.5 GM Duramax LB7 Injector Superkit | eBay
Chevy Gmc Duramax Diesel USAFD Injectors W USAFD 50 HP Nozzels 2001-2004 LB7 | eBay
Last edited by joshpete; 07-09-2012 at 08:37 PM. Reason: Automerged Doublepost
#67
07-10-2012, 01:32 AM
stay away from injectors on ebay. too much rick, bad warrenty, etc. LB7 injectors are a touchy bunch so dont chance it.
try Lincoln diesel, merchant diesel, or one of the other reputable dealers.
generally it is good practice to replace all 8 or at least the 4 on one bank as if one is bad the others are likely not far behind
what are your HP goals? stock injectors can provide enough fuel to bend rods, blow head gaskets and destroy transmissions. i would say that once you approach around 500 HP then you can look into larger injectors to keep your timing under control & keep more of the fuel jet in the bowl.
larger injectors can also get pricey. you will also need to tune them with something like Efi Live to make light throttle and idle manageable.
PS, Pensacola injectors have a reputation for high failure rate. the larger ebay injectors look to good to be true, the description is also pushing the truth some with statements like: "550 HP with out draining the rails" which makes me not trust them any.
good luck with your repairs
Jason
try Lincoln diesel, merchant diesel, or one of the other reputable dealers.
generally it is good practice to replace all 8 or at least the 4 on one bank as if one is bad the others are likely not far behind
what are your HP goals? stock injectors can provide enough fuel to bend rods, blow head gaskets and destroy transmissions. i would say that once you approach around 500 HP then you can look into larger injectors to keep your timing under control & keep more of the fuel jet in the bowl.
larger injectors can also get pricey. you will also need to tune them with something like Efi Live to make light throttle and idle manageable.
PS, Pensacola injectors have a reputation for high failure rate. the larger ebay injectors look to good to be true, the description is also pushing the truth some with statements like: "550 HP with out draining the rails" which makes me not trust them any.
good luck with your repairs
Jason
#69
06-04-2016, 11:10 PM
#70
09-04-2016, 02:28 PM
i jus recently bought a 2001 duramax from a guy who sold it to me fairly cheap because it wont start unless u squirt a lil starting fluid in the air filter. it runs great once it starts. he was thinking the injectors need replaced. Im wondering if this is a common problem when the injectors go bad?? er could it be like the line getting air locked or bad fuel filter?? I haven't looked into it much. any input is greatly appreciated
I'm having the same problem and I'd bet money that that stupid fuel filter housing/primer setup on the right side of the engine has an internal leak in it. If the injectors were bad it wouldn't start - period.
Where you start looking at the injectors is when the exhaust starts belching clouds of white smoke, or when it won't idle smoothly.
I looked around on the net and this seems to be a common problem with these Duramaxes.
