So I’m new to the diesel life, I brought a 2008 Silverado 3500hd dually 6.6L Duramax turbo charged with 205k miles. So I brought it knowing it wasn’t starting, when I got the truck I started trying to do my own diagnostic lol. The check engine light was on and the scan tool obd2 codes the truck was putting out was p0113, p0676, p0677, p0678, p0102, p0675, p0533, p0166c. I change the batteries, glow plus and pumped up the purge canister. The truck cranks over very strong and long but no start. So I checked the fuse box and according to the diagram slot [20] is the fuel pump 20A. so I checked it and there is no power whether the key is on or off. So I manually powered the fuse box slot by hot wiring it directly to the battery, still nothing. So to me it should like the truck was looking for fuel. I went and brought start fluid and sprayed 3 shoots and the truck start right up with no problem, but it shut off after 2 to 3 minutes. I was told I have bad injectors what do you guys think
new to this life of LMM/diesel help wont start
- Thread starter flow11234
- Start date
No starting fluid ever....starting fluid is to be used if there is a fire breathing dragon chasing you and you have no other choice lol
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Get the truck to a diesel tech who can fix for you. My maigic wand that diagnosis diesel trucks over the internet is broken
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It's either plugs or the distributer cap. Cam lobe for the fuel pump might be worn too.
If you're really going to be working on the truck mostly by yourself, get a better scanner.
I would've saved a lot of money if I had bought the scanner I knew I needed from beginning. I have a entry level $100 scanner, then the mid-level $250 scanner, and the actual bi-directional scanner that you really need to work on these trucks. That one was about $500 and I should've bought that one first.
Watch that number while you're cranking. It should start at about 200 psi with key on, then climb into the mid 1400s while cranking, (the computer commands ignition at about 1400psi) then bump to about 5000 when the engine engine turns over--about 5000 psi at idle. If you're hanging out in the 700 or 800 psi range you've got a fuel rail pressure problem.
If you've got that low 800-1000 psi while cranking, I'd suspect a leaking fuel rail pressure relief valve. That's a pretty easy repair. The hardest part is finding the valve. I'd say 4-5 hours of actual time between troubleshooting flow charts and actual repair or replacement of the valve.
If the computer is not seeing that 1400ish number then it's not gonna command ignition. If you are working on the truck yourself, nothing beats good clean troubleshooting. There's lots of good competent mechanics out there, but in my opinion nobody's gonna do better work on your truck than you. I've come to that opinion the hard way. There are better mechanics out there for sure than me. But none that have the same investment in the truck that I do. And none of them work as cheap as me. Get yourself a good factory manual and a good scanner and dig in. I find 90% of the trouble with these trucks are simple issues that require a little elbow grease and some thinking. The factory manual (mine is 5 volumes) and a good scanner are the main tools you'll use and you can run down most engine problems with these two diagnostic aides. My experience in about 10 years of owning a Duramax has been that the big parts rarely fail. They're incredibly reliable engines.
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I would've saved a lot of money if I had bought the scanner I knew I needed from beginning. I have a entry level $100 scanner, then the mid-level $250 scanner, and the actual bi-directional scanner that you really need to work on these trucks. That one was about $500 and I should've bought that one first.
Watch that number while you're cranking. It should start at about 200 psi with key on, then climb into the mid 1400s while cranking, (the computer commands ignition at about 1400psi) then bump to about 5000 when the engine engine turns over--about 5000 psi at idle. If you're hanging out in the 700 or 800 psi range you've got a fuel rail pressure problem.
If you've got that low 800-1000 psi while cranking, I'd suspect a leaking fuel rail pressure relief valve. That's a pretty easy repair. The hardest part is finding the valve. I'd say 4-5 hours of actual time between troubleshooting flow charts and actual repair or replacement of the valve.
If the computer is not seeing that 1400ish number then it's not gonna command ignition. If you are working on the truck yourself, nothing beats good clean troubleshooting. There's lots of good competent mechanics out there, but in my opinion nobody's gonna do better work on your truck than you. I've come to that opinion the hard way. There are better mechanics out there for sure than me. But none that have the same investment in the truck that I do. And none of them work as cheap as me. Get yourself a good factory manual and a good scanner and dig in. I find 90% of the trouble with these trucks are simple issues that require a little elbow grease and some thinking. The factory manual (mine is 5 volumes) and a good scanner are the main tools you'll use and you can run down most engine problems with these two diagnostic aides. My experience in about 10 years of owning a Duramax has been that the big parts rarely fail. They're incredibly reliable engines.
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The ECM doesn't care what rail pressure is, it commands the INJECTORS to operate as soon as it knows via the cam and crank sensors what position the pistons are in in the firing order. The reason you need 1400 psi of pressure is you need that much pressure for the injectors to even open as they are a pressure differential valve.
I STRONGLY reccomend you get somebody to help you out with this as you have no idea how big of a bullet you dodged. Had the weather been a little cooler out, the intake heater would have kicked on, and you would have had a NICE fireball in the vicinity of the front passenger side of the engine compartment when the plastic intercooler cap blew off letting the fireball out.
OP, you really do need a good scanner, as has been said before. If it won't build rail, it could be injectors, CP3, or the relief valve. You do a return test ("bottle test") to determine which of them needs addressed.
That's interesting, I had always heard the ECU wouldn't command firing until it hit a certain pressure, but you're right. I looked at a log from my first start on the built motor, and as soon as the ECU sees RPM, it starts commanding pulsewidth, and nothing happens for another few seconds until rail hit ~5500 PSI, then RPM picked up. So I guess my oversized injectors take a bit more pressure to open than stock.
Most think our injectors work like a standard low pressure gas fuel injector where the solenoid directly operates the pintle of the injector. But they are actually a pressure differential valve arrangement. Pressure is feed into the injector body, when the solenoid opens, it opens the fuel on the back side of the pintle creating a pressure differential which causes the injector to pop open, and the fuel that is actually controlled by the solenoid goes out the bypass(hence why if somehow your bypass gets plugged, the injector can no longer open). This is why we have latency issues to tune around as were not directly controlling the fuel input, but instead there is a lag for the pressure to drop, the pintle to move, and then fuel is injected. And it takes at least 1300-1500 psi of pressure to get enough pressure differential for it to finally pop open.
If it fires and runs fine when using starting fluid I'd check to see if the fuel filter setup was sucking air. Seen many suck air and be the whole reason why a max is running one day and not the next.
Just recently a guy we know broke down in MS and dealer tried to sell him injectors, fuel pump etc. Truck was running fine and barely had over 100k. Said the truck was running great , then next day wouldn't start. Put new filter/housing fired right up.
Just recently a guy we know broke down in MS and dealer tried to sell him injectors, fuel pump etc. Truck was running fine and barely had over 100k. Said the truck was running great , then next day wouldn't start. Put new filter/housing fired right up.