Help with no start
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
Help with no start
OK guys I have nofuel pressure. I can force the pump on through hptuners. there are no DTCS. when i key on pump comes on for a second then turns off. I saw where the crank position sensor can cause this but it appears to be working properly. ie when i try to start the car rpms run around 100... what will cause the pcm to not turn on the fuel pump?
thanks
thanks
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
OK guys I have nofuel pressure. I can force the pump on through hptuners. there are no DTCS. when i key on pump comes on for a second then turns off. I saw where the crank position sensor can cause this but it appears to be working properly. ie when i try to start the car rpms run around 100... what will cause the pcm to not turn on the fuel pump?
thanks
thanks
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
I have a fuel pressure gauge. It reads 60 then drops to zero. It is a return style system.
Scanned codes on DIC and only codes are related to ABS and a park lamp relay.
How does it work? does the pump turn on to build pressure then turn back off and pressure holds then when car starts pump turns back on? or does the pump stay on the whole time?
Scanned codes on DIC and only codes are related to ABS and a park lamp relay.
How does it work? does the pump turn on to build pressure then turn back off and pressure holds then when car starts pump turns back on? or does the pump stay on the whole time?
Last edited by mobius; Nov 19, 2012 at 05:10 PM.
Pro
Joined: Aug 2010
Posts: 622
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From: Montgomery Texas
The fuel pressure should hold for some time. If it doesn't you may have problems starting the engine after a hot soak.
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
Ok , fuel pressure drops immediately so that must be the problem , now just need to figure out why. But when i start cranking the engine it should turn back on right?
Last edited by mobius; Nov 19, 2012 at 07:34 PM.
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Pro
Joined: Aug 2010
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From: Montgomery Texas
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
OK so i commanded fuel pump on and no start still. Here are all the codes
tcs had 1214,1225,1232 and 1278 all H on the ends so not active.
no BCM or PCM codes
sdm had a u1016 H code and DCM 2252 H code
thats it. Nothing! On hptuners when cranking i was looking at rpm and crank cylinder current firng and crank sensor current cylinder
rpms were around 100
crank cylinder current firing seemed to be counting through 1-8
crank sensor current cylinder was changing but very high numbers it stopped on 5,460 and i saw 8k something as well. is this correct???
thanks
tcs had 1214,1225,1232 and 1278 all H on the ends so not active.
no BCM or PCM codes
sdm had a u1016 H code and DCM 2252 H code
thats it. Nothing! On hptuners when cranking i was looking at rpm and crank cylinder current firng and crank sensor current cylinder
rpms were around 100
crank cylinder current firing seemed to be counting through 1-8
crank sensor current cylinder was changing but very high numbers it stopped on 5,460 and i saw 8k something as well. is this correct???
thanks
Pro
Joined: Aug 2010
Posts: 622
Likes: 169
From: Montgomery Texas
I just had a look at you profile. It looks like there have been quite a few modifications to the car. Would you care to give us an overview of the mods? Additionally, what was happening just prior to the present concern? Was the car running fine and out of the blue wouldn't start, or did it die while driving, or are you in the middle of new mods, or etc.?
If you haven't already done so, have a look at your various temp sensors and ensure that the readings are plausible.
I personally have not seen a cam sensor failure on a C5, but I would check that you have a signal. Most engines will continue to run if the cam signal goes away, but many will not start without said signal. The WSM states only that there will be a long crank without a cam signal input, but I'm not sure what "long" means.
Can we assume that you have eliminated all of the mechanical possibilities?
If you haven't already done so, have a look at your various temp sensors and ensure that the readings are plausible.
I personally have not seen a cam sensor failure on a C5, but I would check that you have a signal. Most engines will continue to run if the cam signal goes away, but many will not start without said signal. The WSM states only that there will be a long crank without a cam signal input, but I'm not sure what "long" means.
Can we assume that you have eliminated all of the mechanical possibilities?
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
I just had a look at you profile. It looks like there have been quite a few modifications to the car. Would you care to give us an overview of the mods? Additionally, what was happening just prior to the present concern? Was the car running fine and out of the blue wouldn't start, or did it die while driving, or are you in the middle of new mods, or etc.?
If you haven't already done so, have a look at your various temp sensors and ensure that the readings are plausible.
I personally have not seen a cam sensor failure on a C5, but I would check that you have a signal. Most engines will continue to run if the cam signal goes away, but many will not start without said signal. The WSM states only that there will be a long crank without a cam signal input, but I'm not sure what "long" means.
Can we assume that you have eliminated all of the mechanical possibilities?
If you haven't already done so, have a look at your various temp sensors and ensure that the readings are plausible.
I personally have not seen a cam sensor failure on a C5, but I would check that you have a signal. Most engines will continue to run if the cam signal goes away, but many will not start without said signal. The WSM states only that there will be a long crank without a cam signal input, but I'm not sure what "long" means.
Can we assume that you have eliminated all of the mechanical possibilities?
Thread Starter
Pro
Joined: Jun 2007
Posts: 501
Likes: 3
From: Valdosta GA
ok more info. I have spark and looking at a scan of trying to start the injectors are pulsing.
Is there a check valve in the fuel system that could be stuck open?
I dont think it is fouled plugs as it doesnt even try to start....?
Is there a check valve in the fuel system that could be stuck open?
I dont think it is fouled plugs as it doesnt even try to start....?