1998 Dodge Ram Fails to Start

Tiny
SETTLE789
  • MEMBER
  • 1998 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
The truck runs fine. I can start the truck and drive it all over town and run my errands all day long for weeks and then out of the blue when I jump in and try to start the truck it will start for a split second then die it will do this for a few cranks then just turn over and spin. All 3 times I have left the truck sitting in the parking lot called for help and went home to get my other Dodge Ram and the trailer to load it up and carry it home. But each time when I return the truck has started right up and I drive it like there is nothing wrong. There has been no check engine light to come on nor any type of warning that it is going to fail to start. Can you give me some ideas what this problem might be.
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Saturday, November 8th, 2008 AT 9:51 PM

15 Replies

Tiny
IMPALASS
  • EXPERT
Hello

For one, please go to Auto Zone or O'Reilly's and for free they can pull the codes to the car. Most important. Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for free also they can bring their tester out and check your battery, alternator and starter.

We need to figure out if it is electrical or fuel related. Next time it does this pull a plug wire and insert something into the end of it and have someone try to start the car and have the metal object really close to a piece of metal on the engine and see if you are getting a good strong popping blue spark. Don't have your hands on any part of the metal! If there is no spark, then it is electrical. If you are getting good spark then you need to get a fuel pressure check on the fuel pump to ensure it is putting out okay.

That would be a starting point.
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Sunday, November 9th, 2008 AT 12:39 AM
Tiny
SETTLE789
  • MEMBER
Went to pick up the truck and it started right up after sitting a few hours? Drove strait to Advance Auto and had them do a scan. No problems found. Truck runs fine gas tank level is just between quarter and half of a tank after reviewing the last time it did this the gas level was near a quarter tank also. I filled the the tank up right after it happened. I have driven roughly 200 miles on this tank so far and then it did it again last night. I will leave the gas level as it is and not fillup to see if it will do it again sooner.
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Sunday, November 9th, 2008 AT 5:52 PM
Tiny
IMPALASS
  • EXPERT
Thanks for the update - when it did it again were you able to check to see if you had a spark?

Will you be able to check the fuel pressure?

Again, thanks for the update.
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Sunday, November 9th, 2008 AT 7:05 PM
Tiny
SETTLE789
  • MEMBER
It has not done it again.

I will check the spark and the fuel pressure when it does it again. The spark test will be easy. The only way I can check fuel pressure is to have it towed to a mech or just pull the fuel line and see if its getting fuel. I will keep you updated as the problem continues.
What are your thoughts on the possibility of trash in the tank and its picking up the trash the lower the tank gets on fuel and then releases it as the truck sits for awhile.

Thanks
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Sunday, November 9th, 2008 AT 9:22 PM
Tiny
IMPALASS
  • EXPERT
Hello

First, I never asked, is this a 1500, 1500 etc? And what is the specific engine by liter and the 8th digit of your VIN.

Next, for the fuel pressure you will need to put a gauge on it. Just a quick look at one of the RAMs was about 49.5 psi +-5. So to be accurate you will need a fuel pressure check. The bad thing here is it could be putting out great when checked. Ie when you are driving it around town and it is okay. Then it shuts down. If it would just quit that would be better. With 200K on the truck I lean to the fuel pump. But don't want to jump. But that is the direction I am looking.

As for the trash.I have seen it. After countless hours of work, checking things etc, I pulled the tank and there it was.A round cardboard piece from the inside of a cap of fuel cleaner. It would suck against the pick-up tube and stop the fuel. Once things relaxed. It would float around for a bit. It was heavy enough to move around in the tank no matter how much fuel.

As for yours, wow, based off of the pump I looked at it would have to wrap around it. Most pumps have a sock on the bottom making it impossible for this to happen.

So unless you have put something in the tank or have reason to think there is something in there, due to the mileage I think it is more the pump is tired verse something being in the tank.

That's my thought.

But lets not put that out keep the brainstorm coming. It takes all sometimes to figure these things out.
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Sunday, November 9th, 2008 AT 9:51 PM
Tiny
SETTLE789
  • MEMBER
1998 1500 318cid 8th letter VIN is Y.

Where can I pick up a fuel pressure gauge and the location as to where I need to check the fuel pressure. If the fuel pressure is lower than 49.5 psi would the engine still run for example say 35 psi?

Thanks
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Monday, November 10th, 2008 AT 8:45 AM
Tiny
SETTLE789
  • MEMBER
Drove the truck today about 25 miles to run errands stopped and restarted 6 times on the 7th time it has done the same thing it will start for a split second and die then it will just spin over. I am down to about 6 gallons of gas. As you asked I pulled the coil wire plenty of fire it was arching about an inch. I noticed the valve stem on the fuel rail is this where you check the fuel pressure? Should gas squirt out when you have the needle valve depressed as you try to crank? I will try to locate a fuel pressure gauge.
Will keep you posted.
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Monday, November 10th, 2008 AT 2:24 PM
Tiny
IMPALASS
  • EXPERT
Hello

Okay, great with the spark........so that is confirmed. As for the pressure....good question...

On many vehicles if the car doesn't start in 2 seconds, the fuel pump is turned off. In this case, if the pump is not putting out enough to start the truck then nothing. Also, you may have some pressure at the rail, but that doesn't mean you have enough to run the truck. The regulator keeps the pressure 44.2-54.2 psi......anything above 49 the regulator bypasses it back to the tank.

I look at it like a water sprinkler; you may have water coming out of it but not enough pressure to make it turn.

Fuel Pressure
Engine at curb idle 339 34 kPa (49.2 5 psi)

Pressure Leakdown (fuel pump not engaged) Not fall below 30 psi for 5 minutes

As for the valve stem - I recently had a Tahoe with a fuel pump go out did the same thing. Drove then would die, drove then die. On the way here it quit 100 yards away. Probably not the safest thing, but I took a electric fuel pump I have, put one end into a gas container, took the other end, removed the valve stem on the fuel rail (it still had pressure) and jammed the hose on the end of it. Hooked it up to the battery and the pump was pumping away. I got in the truck, it started right up and drove it on in.

Hope that helps.

I also put the info on the fuel system for your review. It may be say, the regulator, or something else. I just lean to the pump due to the mileage and what it is doing.

Thanks for the update


http://www.2carpros.com/forum/automotive_pictures/248015_1_23.gif



Fuel Pump Module

FUEL PUMP MODULE
The fuel pump module on all gas powered engines is installed in the top of the fuel tank. The fuel pump module contains the following:

A combination fuel filter/fuel pressure regulator
Electric fuel pump
Fuel pump reservoir
A separate in-tank fuel pick-up filter (strainer)
Pressure relief/rollover valve
Fuel gauge sending unit (fuel level sensor)
Fuel supply line connection
auxiliary non-pressurized fuel supply fitting (not all engines)
FUEL PUMP
The fuel pump used in this system has a permanent magnet electric motor. The pump is part of the fuel pump module. Fuel is drawn in through a filter at the bottom of the module and pushed through the electric motor gearset to the pump outlet.

Check Valve Operation: The pump outlet contains a one-way check valve to prevent fuel flow back into the tank and to maintain fuel supply line pressure (engine warm) when pump is not operational. It is also used to keep the fuel supply line full of gasoline when pump is not operational. After the vehicle has cooled down, fuel pressure may drop to 0 psi (cold fluid contracts), but liquid gasoline will remain in fuel supply line between the check valve and fuel injectors. Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine off) is a normal condition. Refer to the Fuel Pressure Leak Down Test in this group for more information.

Voltage to operate the electric pump is supplied through the fuel pump relay.

FUEL GAUGE SENDING UNIT
The fuel gauge sending unit (fuel level sensor) is attached to the side of the fuel pump module. The sending unit consists of a float, an arm, and a variable resistor (track). The resistor track is used to send electrical signals for both fuel gauge operation and OBD II emission requirements.

For fuel gauge operation: As fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the fuel gauge to read full. As fuel level decreases, the float and arm move down. This increases the sending unit resistance causing the fuel gauge to read empty.

For OBD II emission requirements: The voltage signal is sent from the resistor track to the Power train Control Module (PCM) to indicate fuel level. The purpose of this feature is to prevent a false setting of misfire and fuel system monitor trouble codes if the fuel level in the tank is less than approximately 15 percent of its rated capacity.


http://www.2carpros.com/forum/automotive_pictures/248015_2_33.gif



FUEL FILTER/FUEL PRESSURE REGULATOR
A combination fuel filter and fuel pressure regulator is used on all engines. It is located on the top of the fuel pump module. A separate frame mounted fuel filter is not used with any engine.

Both fuel filters (at bottom of fuel pump module and within fuel pressure regulator) are designed for extended service. They do not require normal scheduled maintenance. Filters should only be replaced if a diagnostic procedure indicates to do so.

Fuel Pressure Regulator Operation: The pressure regulator is a mechanical device that is not controlled by engine vacuum or the Powertrain control module (PCM).

The regulator is calibrated to maintain fuel system operating pressure of approximately 339 kPa +/- 34 kPa (49.2 psi +/- 5 psi) at the fuel injectors. It contains a diaphragm, calibrated springs and a fuel return valve. The internal fuel filter (Fig. 3) is also part of the assembly.

Fuel is supplied to the filter/regulator by the electric fuel pump through an opening tube at the bottom of filter/regulator.

The regulator acts as a check valve to maintain some fuel pressure when the engine is not operating.

This will help to start the engine. A second check valve is located at the outlet end of the electric fuel pump. Refer to Fuel Pump-Description and Operation for more information. Also refer to the Fuel Pressure Leak Down Test and the Fuel Pump Pressure Tests.

If fuel pressure at the pressure regulator exceeds approximately 49.2 psi, an internal diaphragm opens and excess fuel pressure is routed back into the tank through the bottom of pressure regulator.
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Monday, November 10th, 2008 AT 3:43 PM
Tiny
SETTLE789
  • MEMBER
After I emailed you the last items. I let the truck sit for 3 hrs and it cranked right up. When the truck started I pressed on the valve stem and fuel sprayed. Lots of pressure. Earlier when the truck would not start and with the key in the on position ther was no pressure at the valve stem on the rail.

Your thoughts on that.

Are you confident that we have narrowed it down to a fuel pump problem. The only thing that I have an issue with is that the truck does not stall out. It runs great until I shut it off and won't restart. This is what has me puzzeled and the fact that it acurring when the fuel level is low.
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Monday, November 10th, 2008 AT 5:14 PM
Tiny
IMPALASS
  • EXPERT
Hello

It may be the check valve on top of the fuel pump.

I don't recall in the previous info back and forth, unless I missed it, that this only occurred when the fuel was low. Is this the only time it happens?

Also, I have requested the assistance from another moderator. So you might answer the above and then let's see what he says.
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Monday, November 10th, 2008 AT 7:06 PM
Tiny
RASMATAZ
  • MEMBER
Sir-You need to physically check and monitor the fuel pressure with a gauge and get back with the readings-for me it sounds more like a fuel pump problem
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Tuesday, November 11th, 2008 AT 5:30 PM
Tiny
SETTLE789
  • MEMBER
It only seems to do it when the fuel is around a quarter tank or less. On the diagram that you sent I did not see a check valve can you be more specific and how to check. Is the check valve part of the fuel pump or is it seperate. When the truck is running fuel pressure is great there is no fuel pressure when it is not running with the key on.

Thanks
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Friday, November 14th, 2008 AT 3:27 AM
Tiny
RASMATAZ
  • MEMBER
When the truck is running fuel pressure is great there is no fuel pressure when it is not running with the key on.

I don't comprehend this-the fuel pressure is great but not running its no good -Please! Explain
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Friday, November 14th, 2008 AT 4:35 AM
Tiny
SETTLE789
  • MEMBER
I am assuming that there should be fuel pressure at the rail as soon as you turn the ignition on?
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Friday, November 14th, 2008 AT 11:19 AM
Tiny
RASMATAZ
  • MEMBER
When you turn key on-you should hear the F/P come on for 2secs

It should have pressure, this is called static and should be within specs and shouldn't leakdown fast.
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Friday, November 14th, 2008 AT 2:51 PM

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