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98 chevy 2500 wont start

This is a discussion on 98 chevy 2500 wont start within the Automotive Support forums, part of the Tech Support Forum category. I have a 98 chevy 2500 that has fuel pressure spark and everything else but will not start. I can


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Old 07-10-2009, 12:26 PM   #1
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I have a 98 chevy 2500 that has fuel pressure spark and everything else but will not start. I can put fuel in the t-body and it'll start for a few seconds but will not start otherwise. All i can come up with is that the injectors arent firing. I went through a cycle to reset the computer and that didnt work so now I have know idea what to do. Any help would be great.


Tim

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Old 07-10-2009, 04:26 PM   #2
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If it runs on fuel sprayed in the TB it seems to rule out ignition. Need to know more about your motor.... what size, which fuel injection system, etc. Some FI systems like GM CPI can seem to have enough fuel pressure when in fact it is below spec, due to weak fuel pump or bad regulator.... causing just the type of no start you have. Could be other stuff, too but need more info.

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Old 07-10-2009, 05:58 PM   #3
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its a vortec 350. the fuel lines go into the intake (cant see any injectors). changed the fuel pump last fall.
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Old 07-11-2009, 06:09 AM   #4
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If you don't have individual injectors for each cylinder it could be CPI or TBI. These have vastly different fuel pressure specs and issues. Someone here more familiar with that motor may know but I can't tell from your limited description. In any case, you should definitely check the fuel pressure as a next step no matter what system you have.
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Old 07-12-2009, 12:46 AM   #5
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Hi guys,

I have a 2004 silverado and a Haynes repair manual for it. Unfortunately, it starts at 1999, not 98. They started moving to the multiport injection in 96, so its very likely that you have the multiport injection system. All V8 engines (except for vin Z engine designed for ethanol) have a pressure of 55 to 62 psi. Thats for years 1999 through 2005.

Make sure your fuel pump is running. Move the ignition from off to on (not start) and listen for the fuel pump. It should run about 2 seconds then turn off. It will repeat this each time you move the ignition from off to on. Get someone to listen back at the tank if you can't hear it from the drivers seat. If the pump don't run, check your fuses and pump relay. If the pump runs, check the pressure with a pressure guage. You might be able to rent a pressure gauge if you don't have one. Compared to repair costs, the cost of a guage isn't that high and they tell you a lot about your fuel pump and fuel system. There's a check valve in the pump that won't let the fuel leak back into the tank from the supply side of the system. The pressure should stay up after the pump pumps. If not, it could be the pressure regulator on the return pipe from the fuel rail on the engine. It has a spring and diaphram to regulate the pressure and if the diaphram leaks, the fuel will drain into the intake system and down into the oil pan. You can normally smell gas on the oil dipstick if you pull it out and take a whif. In that case, you would replace the regulator and the oil.

It could be that your fuel filter is simply stopped up. If the pump runs, pressure is low, and there is no fuel smell on the oil dipstick, I think I would replace it first of all.

Hope this helps,
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Old 07-13-2009, 05:51 PM   #6
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Thanks for all the information. I will start by replacing the fuel filter.
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Old 07-14-2009, 06:07 PM   #7
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Changed the fuel filter wih no avail today. Also put a fuel pressure gauge on it today and it reads 60 psi with no leak down.
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Old 07-14-2009, 08:19 PM   #8
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Hi Tim,

Again, my book starts at 1999, but the prints are quite likely to apply to yours. They show typical electrical prints, implying that it applys to all the engines in that group 99 through 2005.

It shows that there are two fuses for the injectors in the underhood electrical center. Power to them is hot at start and run. 12 volts is applied from them to each of the injectors and from there to the PCM. See if you are getting 12 volts to the injectors. Unplug the multi connector and measure the pins with the key on. If the connector has several wires to and from it, you have multi port injection system. If there are only about 4 wires, you will have throttle body injection.

If you get 12 volts at the injectors, see if you can measure the wires from the injectors to the PCM. You should be able to see some signal on the AC scale if the PCM is plusing the injectors.

I can post the print if you like.

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Old 07-17-2009, 07:55 PM   #9
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Figured it out. Someone played a bad joke on me and put 3 gallons of water in the fuel tank. If I figure out who it was Im going to kill them.
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Old 07-17-2009, 09:16 PM   #10
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Quote:
If I figure out who it was Im going to kill them.
I hear you. Glad you got it worked out.

Have a nice day.

Mack1

edited because I forgot how to spell hear.
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Old 07-18-2009, 08:24 AM   #11
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ooh if they put water in the tank you may need to drop the tank and put fresh fuel in. in case you haven't heard, water will not compress and if you suck water in the engine that could cause major engine problems like bent rods, which could bend valves, and even worse, put a hole in the engine with a rod sticking out.

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