Need help with fuel & possible spark issue

Bigtruck80 · 11-02-2009, 08:33 PM

My truck died last week (1997 chevy crew cab k3500, 4x4, 7.4, auto).
I thought it was the fuel pump, because it was not priming, when I use a jumper wire to the fuel pump prime wire it works, but will not run if i try to start it(with the jumper wire on the prime). I changed the FP relay. Also, the green/white wire for fp prime is not hot for the initial 2 seconds.
It does not appear to be getting spark, also my gauges (tach, bat) are not registering anything. I have also replaced the ICM.
Do any of you have any Ideas, or possibly a good schematic for this engine?

Thanks in advanced.

abigassbowtie · 11-03-2009, 12:05 AM

Im not positive about the 454s but my 97 5.7 would not let the truck run with less than I believe 59 lbs of fuel pressure so there would be no spark if the fuel pressure was down below that so check fuel pressure and if you have power to it and its not kicking on most likely bad fuel pump

the way my truck died was wierd it just kept slowing down till it wouldnt go past 25 then just died. had to walk 3 miles home on my birthday I was pist

Grumpy_old_fart · 11-03-2009, 12:06 AM

did you check the fuse to the ignition yet?

Bigtruck80 · 11-03-2009, 06:54 AM

Quote:

Originally Posted by abigassbowtie

Im not positive about the 454s but my 97 5.7 would not let the truck run with less than I believe 59 lbs of fuel pressure so there would be no spark if the fuel pressure was down below that so check fuel pressure and if you have power to it and its not kicking on most likely bad fuel pump

the way my truck died was wierd it just kept slowing down till it wouldnt go past 25 then just died. had to walk 3 miles home on my birthday I was pist

When I use the fuel pump prime lead (red with black female end near drivers side firewall) the pump kicks on, and puts pressure to 60

Quote:

Originally Posted by Grumpy_old_fart

did you check the fuse to the ignition yet?

Yes all fuses in both boxes are good.

abigassbowtie · 11-03-2009, 11:57 AM

maybe thats not high enough pressure for the 454

Grumpy_old_fart · 11-03-2009, 12:12 PM

stick your tongue on the coil wire and have someone crank the engine over.

HAPPYJOHN · 11-03-2009, 12:14 PM

Quote:

Originally Posted by Grumpy_old_fart

stick your penis on the coil wire and have someone crank the engine over.

Fixed it for you, Grumpy!

Grumpy_old_fart · 11-03-2009, 12:20 PM

Thanks...

Bigtruck80 · 11-04-2009, 09:04 PM

Quote:

Originally Posted by Grumpy_old_fart

stick your penis on the coil wire and have someone crank the engine over.

Quote:

Originally Posted by HAPPYJOHN

Fixed it for you, Grumpy!

Sorry guys its a Chevy not a PETERbuilt

Anyhow, I did some more testing this evening, I have no power to the gauges fuse, turn signal fuse, ecm1, eng1, or the ignE fuses. These are of course not supplying any current to any of the major sensors.

Anyone have any Ideas? Im kinda leaning towards the ECM. Thoughts?

HAPPYJOHN · 11-04-2009, 11:17 PM

Quote:

Originally Posted by Bigtruck80

Sorry guys its a Chevy not a PETERbuilt

Nice.

Anyhow, I did some more testing this evening, I have no power to the gauges fuse, turn signal fuse, ecm1, eng1, or the ignE fuses. These are of course not supplying any current to any of the major sensors.

Anyone have any Ideas? Im kinda leaning towards the ECM. Thoughts?

If you don't you have power to ecm1, why do you suspect ecm?
Are there "main" fuses underhood? or powerblock?

Bigtruck80 · 11-05-2009, 07:50 AM

Quote:

Originally Posted by HAPPYJOHN

If you don't you have power to ecm1, why do you suspect ecm?

Honestly, I was getting frustrated and wrongfully jumping to conclusions.

Quote:

Originally Posted by HAPPYJOHN

Are there "main" fuses underhood? or powerblock?

There are main fuses under the hood.

Here is a diagram of the wiring, 2 of the fuses with no power are located at the top. ecm 1, and ign e. however it does not show where the draw current from.
any ideas?

[IMG]

[/IMG]

Undecided4x4 · 11-05-2009, 08:41 PM

Check your frame to cab ground, add a thick wire from the frame to the cab. I have seen something similar to this on a truck I have worked on.

Bigtruck80 · 11-05-2009, 08:52 PM

A guy on another forum that I frequent pointed me to an excellent online library of many wiring diagrams and repair procedures. The diagrams were far more detailed than the chiltons diagram that I previously posted. It is very apparent after reviewing those, that I need a new ignition switch.

Bigtruck80 · 11-11-2009, 07:17 PM

Turned out it was the ignition switch that went bad. Got it up and rolling. Thanks Guys.

11-02-2009, 08:33 PM	#1
Bigtruck80 Registered User Join Date: May 2009 Member # 135209 Posts: 6	Need help with fuel & possible spark issue My truck died last week (1997 chevy crew cab k3500, 4x4, 7.4, auto). I thought it was the fuel pump, because it was not priming, when I use a jumper wire to the fuel pump prime wire it works, but will not run if i try to start it(with the jumper wire on the prime). I changed the FP relay. Also, the green/white wire for fp prime is not hot for the initial 2 seconds. It does not appear to be getting spark, also my gauges (tach, bat) are not registering anything. I have also replaced the ICM. Do any of you have any Ideas, or possibly a good schematic for this engine? Thanks in advanced.

11-03-2009, 12:05 AM	#2
abigassbowtie Registered User Join Date: Oct 2008 Member # 122116 Location: Medford OR Posts: 126	Im not positive about the 454s but my 97 5.7 would not let the truck run with less than I believe 59 lbs of fuel pressure so there would be no spark if the fuel pressure was down below that so check fuel pressure and if you have power to it and its not kicking on most likely bad fuel pump the way my truck died was wierd it just kept slowing down till it wouldnt go past 25 then just died. had to walk 3 miles home on my birthday I was pist Last edited by abigassbowtie; 11-03-2009 at 12:07 AM.

11-03-2009, 12:06 AM	#3
Grumpy_old_fart unconcerned onlooker Join Date: Jun 2003 Member # 20147 Location: Oakland Orygun Posts: 3,838	did you check the fuse to the ignition yet? __________________ MySpace sympathy, empathy and apathy... i dont know which one is which.... But i know you can find sympathy between shit and syphilis in the dictionary.

11-03-2009, 12:12 PM	#6
Grumpy_old_fart unconcerned onlooker Join Date: Jun 2003 Member # 20147 Location: Oakland Orygun Posts: 3,838	stick your tongue on the coil wire and have someone crank the engine over. __________________ MySpace sympathy, empathy and apathy... i dont know which one is which.... But i know you can find sympathy between shit and syphilis in the dictionary.

11-03-2009, 12:20 PM	#8
Grumpy_old_fart unconcerned onlooker Join Date: Jun 2003 Member # 20147 Location: Oakland Orygun Posts: 3,838	Thanks... __________________ MySpace sympathy, empathy and apathy... i dont know which one is which.... But i know you can find sympathy between shit and syphilis in the dictionary.

11-03-2009, 11:57 AM	#5
abigassbowtie Registered User Join Date: Oct 2008 Member # 122116 Location: Medford OR Posts: 126	maybe thats not high enough pressure for the 454

11-05-2009, 08:41 PM	#12
Undecided4x4 Registered User Join Date: Oct 2009 Member # 144303 Posts: 29	ground Check your frame to cab ground, add a thick wire from the frame to the cab. I have seen something similar to this on a truck I have worked on.

11-05-2009, 08:52 PM	#13
Bigtruck80 Registered User Join Date: May 2009 Member # 135209 Posts: 6	A guy on another forum that I frequent pointed me to an excellent online library of many wiring diagrams and repair procedures. The diagrams were far more detailed than the chiltons diagram that I previously posted. It is very apparent after reviewing those, that I need a new ignition switch.

11-11-2009, 07:17 PM	#14
Bigtruck80 Registered User Join Date: May 2009 Member # 135209 Posts: 6	Turned out it was the ignition switch that went bad. Got it up and rolling. Thanks Guys.

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