Last week my truck started acting up. Its taking longer to start but it does eventually start. Also if you turn it off and start it right back up then it starts right away. Also there is a strong gas smell but no visible leaks. What could it be?
04 Denali, long cranking before starting
- Thread starter mhorn0817
- Start date
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Tonyrodz
Resident Resident
I'm guessing fuel pump. Have you checked your cranking fuel pressure?
sumo
dn ʇǝƃ ʇuɐɔ & llǝɟ ı
Yea have fuel pressure checked.
Your FPR could be letting the fuel pressure bleed off when you turn the truck off. Not sure if yours is on the fuel rail or on the pump itself. If it's on the pump, the whole unit (pump and FPR) has to be replaced. Mine was doing that on my 02 and I bought a FPR rebuild kit. As long as it wasn't turned off for too long, the pressure held. Mine's a return system so it just bled into the return line. Try cycling the key to on a couple times before engaging the starter and see if it fires right up that way. Not sure what the pressure should but yes perform a test. You should be able to see if it's bleeding off that way too.
iamdub
Full Access Member
FPR or check valve on the pump. Since smelling gas, I'd say FPR is leaking. Next time you go to start it after it's been sitting for a while, turn the key "on" (not start), then off, then on, off, then straight to start as normal and see if the engine starts much faster with less cranking.
iamdub
Full Access Member
I've never heard of the FPR being on the pump module, but I've never had a reason to look into that, either.
I'd say you'd smell the fuel more if it was on the intake manifold. I don't see how you'd smell the fuel leaking from an in-tank FPR that's leaking into a tank full of fuel.
Pop the hood and take a sniff, particularly on the top drivers side of the engine.
iamdub
Full Access Member
Ooooooof course they did.
asand
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Could be one or more leaking injectors. Pintle leaking pressure into the intake manifold causing a really rich mix on one cylinder and leaving no pressure in the lines overnight. Try keying it on and off a few times to prime the system before starting.
willinnashville
Full Access Member
Keep us posted on what you did to fix it please
latvius
Full Access Member
I recently had a similar issue in my 05 Tahoe, bought a $40 HF fuel pressure gauge and found the return check valve was stuck open. Once you turn the key the fuel pressure comes up and after the pump stops it drops just as fast. Check valve is on the fuel pump so ended up replacing fuel pump. Starts first time every time now and fuel pressure stays up after pumps stops when you turn the key.
mhorn0817
Full Access Member
Symptoms point to fpr, fp, or the cv...but the strong gas smell doesnt
There are no visible leaks and i cant smell so im relying on others to tell me where the smell is coming from, in which they say front and back so who knows
There are no visible leaks and i cant smell so im relying on others to tell me where the smell is coming from, in which they say front and back so who knows
latvius
Full Access Member
Now that I think about it I used to get a fuel smell every once in a while, never found the problem but have not had it since replacing the FP. I don't have an explanation of why it was there and why it is gone but if you get a FP reading it will help you get some more clues for diagnosis.
latvius
Full Access Member
Well you have two known symptoms, a gas smell and it takes longer than normal to start. Could be the same problem, could be two different problems. Fuel smell is when gas is exposed to air so you might be able to see visible signs of leak. If you don't I'd move on to the hard start problem check it with FP gauge and go from there. Maybe when you fix the hard start problem the gas smell goes away or maybe it makes it easier to identify.
That's how I would approach the problem.
That's how I would approach the problem.
iamdub
Full Access Member
You may have an external leak, like a line or connection somewhere from the bulkhead on top of the tank to the many fittings on the EVAP stuff and on up to the fuel rail. After it has sat for a while, turn the key on for about 5 seconds to pressurize the system, then turn it off for about 5 seconds. Repeat this a few times then look and sniff around underneath for any wetness.
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