1998 Dodge Ram Engine will not start

Tiny
SSOJOAT
  • MEMBER
  • 1998 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 185,000 MILES
(5.9L fuel injected all original) Truck was running fine throughout a 450 mile road trip. Truck was shut off for less than 5 minutes at my destination and upon attempting to restart, it ran extremely rough (as if only 2 or 3 cylinders were firing) and would not rev above ~600rpm. Any press on the accelerator killed the engine. The check engine light came on and my code reader showed the #2 oxygen sensor failed with high voltage. That was the only error code generated.

After the truck sat overnight, when cranked it would just turn over normally without any sign of starting. So, new oxygen sensors were bought and installed, figuring that 185,000 miles was about time to go ahead and replace both of them. This did not solve the problem, as the engine just spins over (sounds normal) but there is no attempt to fire off.

This truck had 1 prior event of failing to start about 5 years ago. During that ordeal, no code reader was available and both the cam and crank position sensors were blindly replaced. The problem was the cam position sensor. The distributor cap & rotor were replaced during routine maintenance shortly afterward. IIRC, that all happened somwhere around 90-100K miles. The platnum plugs have been in since about 50K miles.

Wondering if it is possible that a failing O2 sensor caused an over-rich condition which may have fouled all 8 of the old plugs or if there may be something more sinister going on. Repair resources are extremely limited at my current location (there's 1 NAPA store) in a one-mechanic town.
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Thursday, September 2nd, 2010 AT 10:06 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
If the plugs have 139K on them, they could be fouled. Has the check engine light come on? Have you checked to see if there is spark and fuel to the engine?

Let me know.
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Friday, September 3rd, 2010 AT 7:12 AM
Tiny
SSOJOAT
  • MEMBER
Last winter, during extreme cold spells (below zero), the truck occasionally registered cyl 1 and/or 8 misfires during warm up. A couple times these were coupled with an O2 #2 out of range. The engine gave no symptoms of a problem and after clearing the MIL, the lite would stay off for days to weeks before repeating. It was limited to the cold and come Spring, it quit generating those codes.

Currently, I have good spark readings at the coil output and at the plug wires using an inductive pickup. So the electrical appears to be good at least up to the plugs. Due to the heat shields, I can't pull a plug without obtaining an appropriate plug socket.

What I'm now noticing is a lack of any noise from the fuel side. IIRC, when the ignition is turned on the fuel rails are pressured up and there should be a noise associated with it. I'm not hearing that. Perhaps the fuel pump died? Unfortunately it is an in-tank pump. I don't suppose that can be replaced very easily with minimal tools while sitting in the driveway. Any quick & dirty tips for checking if the fuel pump or some other fuel system component is bad? I don't have a pressure gauge, but have my multi-meter available.
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Friday, September 3rd, 2010 AT 11:27 AM
Tiny
SSOJOAT
  • MEMBER
I checked the fuel system fuse & relay. The fuse is good and I swapped the relay with the known-good fog lamp relay that is the same item. No change.
With the ignition on, I pulled the fuel system fuse and got a bunch of clicking from the round module with small wiring harness and 2 rubber (vacuum?) Hoses mounted to the right fender. After plugging the fuse back in, there is a noise in the injectors or fuel rail area. Doing this generated a P0505 code (Idle System Malfunction), which I suspect was caused simply by my pulling the fuse. I attempted to start the engine and it fired off for about a second and then died. Each time I tried to start it, this repeated. Sounds more and more like a lack of fuel.
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Friday, September 3rd, 2010 AT 12:07 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Here is how to check fuel pump pressure:

http://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

There is no quick way to remove the pump. The tank needs to come out. You could do it in your driveway.

You will need a gauge to check fuel pressure. Most parts stores will lend or rent one to you.
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Friday, September 3rd, 2010 AT 12:54 PM
Tiny
SSOJOAT
  • MEMBER
Fuel pressure is zero.

Put a meter on the "fuel system relay" socket as the relay clearly isn't operating (I direct jumped the relay to the battery and it functions just fine). I'm getting 12v on the hot rail side of the relay coil and one of the switch side contacts. The other side of the coil side is cold and open to ground. The other side of the switch is also cold and open to ground. I jumped across the switch side contacts and nothing happens.

What does this relay control, the fuel pump? And if so, shouldn't it be switching on when the ignition is in the run position? And if it controls the fuel pump, shouldn't jumping the switch side turn the fuel pump on?

I don't have a shop manual for this truck, so I don't have any wiring diagrams. I could check at NAPA and see if they have the Chilton's for this truck if it has decent schematics in it. I don't want to dump over $300 on a fuel pump if it is a control problem with the circuit.
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Saturday, September 4th, 2010 AT 12:39 PM
Tiny
SSOJOAT
  • MEMBER
Bought access to the online manual at eautorepair. Net and now have all the wiring diagrams. According to those, the dead wire that should be triggering the fuel system relay goes to the PCM. It should be a switched ground when the PCM tells the fuel pump to run. So I'll be tracing some wiring this morning to verify conncetion from the PCM to the relay and the relay to the fuel pump. Logic says that I should also be able to apply current to the fuel pump with a jumper wire to verify if the pump itself is or isn't working and nail down a pump vs. Wiring/PCM problem.
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Sunday, September 5th, 2010 AT 6:23 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
You are correct. You should be able to jump it to make the fuel pump run. Let me know what you find.

Joe
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Sunday, September 5th, 2010 AT 11:23 PM
Tiny
SSOJOAT
  • MEMBER
Finally starting to get somewhere. I acquired a current probe and plugged it into the coil side of the relay. When I turn on the key, she lights up for a couple seconds. Hence, my confusion was over the fact that the PCM only runs the pump briefly when the key is first turned on and then waits for an engine crank signal before turning the fuel pump back on. Thus the PCM and relay side are all functioning correctly. That pins the problem down to the pump, which does nothing when I jumper from the battery and feed 12v straight to it.

So, the tank's coming out and as soon as NAPA opens this morning (thankfully, they are going to be open today) I'll get a replacement pump ordered (I'd be shocked if they actually stock one). Just need to be sure I order the right one as I have the 26-gallon tank and there are 5 different fuel pumps for the 1500 series listed in the NAPA online catalog, but it doesn't clearly spell out what fits what. Figure it will be best to get the tank dropped and compare the actual pump to the pictures to verify.

Light at the end of the tunnel!
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Monday, September 6th, 2010 AT 10:29 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I think you're on the right track. Let me know what you find.
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Monday, September 6th, 2010 AT 9:30 PM
Tiny
SSOJOAT
  • MEMBER
Got the new fuel pump installed. Went very well. Tank came out quite easily and wasn't too difficult to get back in after swapping pumps.

Jumped the fuel pump relay and the pump ran, though the schrader valve started leaking. Apparently when I checked for fuel pressure the other day, the valve didn't want to reseal. Fortunately I had a bunch of new schrader valves in my tire repair kit, so I put in a new one and fixed that real quick.

Finished buttoning everything up and after cranking for a bit the truck fired off. Ran pretty rough for the first several minutes but finally smoothed out. Did a road test and everything appears to be in working order.
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Thursday, September 9th, 2010 AT 3:35 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I'm glad to hear it. Let us know if you have questions in the future.

Joe
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Friday, September 10th, 2010 AT 7:36 AM

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