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1998 Dodge Ram 1500 5.9 died while driving...?

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New User

Jun 5, 2011, 8:43 AM

Post #1 of 4 (9550 views)
1998 Dodge Ram 1500 5.9 died while driving...? Sign In

I have a dodge ram 98 5.9, I have checked the fuel pump which works great (It is fairly new as it was replaced 3 months ago) , I have tested the fuel pump relay and it seems to work right when testing but doesn't work right when actually ON the truck. Anyone have any idea what could cause the relay to work right OHM/volt testing but not work on the truck?

Summery: The truck died at 55 MPH now cranks but will not start, the fuel pump IS working , the Fuel relay works ONLY when OHM tested. Currently there is no gas getting to the engine but I have gas, no power to the fuel pump. I have checked all fuses and they all work.

Any help would be greatly appreciated! Thanks!

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 5, 2011, 10:35 AM

Post #2 of 4 (9523 views)
Re: 1998 Dodge Ram 1500 5.9 died while driving...? Sign In

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.


We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

New User

Jun 5, 2011, 10:48 AM

Post #3 of 4 (9518 views)
Re: 1998 Dodge Ram 1500 5.9 died while driving...? Sign In

Thanks, we did just get the truck running, the truck was fully tested. It turns out to be a malfunction of the fuel relay. The prongs are not connecting well, my wife had an idea to jiggle the fuel relay and sure enough that worked, the truck is now running perfectly. Looks like we need to purchase a new fuel relay as this one is probably the original and has been pulled and tested many times in it's lifetime. I just hope it's the relay itself and not the box. Thanks again!

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jun 5, 2011, 11:46 AM

Post #4 of 4 (9514 views)
Re: 1998 Dodge Ram 1500 5.9 died while driving...? Sign In

Don't know my Mopars as well as others but same stuff really. Relays can be funky by - failures points inside that not serviceable and can work with a tap of a screwdriver handle. I wouldn't expect most folks to know which one where so if stuck on the road your wife would to have been taught to check like most anyone would.

If spade prongs on this relay and box is worn before going too nuts with replacing the box try just putting a slight twist on the spades better contact. Use judgement not to overdo tricks like that if that can work at all?


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