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'90 Ram 50 will not start (which is an unhappy situation)

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Old 07-15-2014, 05:22 PM
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Default '90 Ram 50 will not start (which is an unhappy situation)

I'll try this again without the "smiley." Maybe everyone thought my problem had been solved or something. Heck, I don't know.

Trying to figure out why my 1990 Dodge Ram 50 2.4L, 2-wheel drive, bottom-of-the-rung model fails to start. It just refused one day to do so: when I repeatedly tried to start it, the engine just kept turning over but that was it. (Questions below are followed by diagnosis procedure already used.)

1. Haynes refers to a fuel pump check terminal” located behind the fuse box (adjacent to the drivers left knee), to which B+ is applied in order to check the pump. Chilton, however, refers to a "test connector" somewhere in the engine compartment. Which is correct? And any specifics on how to find the darn thing, what it looks like, and where to stick the B+ "probe" would be of IMMENSE aid.

2. If the fuel pump relay is shot, the FP will not work, is that correct? (Any idea where the relay is and what it looks like?)

3. Is there a fuel pump fuse in here somewhere other than in the fuse box located by the driver's left knee? (All fuses in the “box” look good.)

4. Is the fuel pump ground located back by the fuel tank?

Initial diagnosis by local barnyard mechanics (and one very friendly 18-wheeler guy):

A.) Starter fluid sprayed in air-cleaner: engine wanted to start for a moment, but couldn’t.

B.) Fuses under the dash all look good.

C.) Was told the fuel filter was the problem. Fuel filter was replaced. The fuel filter was not the problem.

D.) Turned ignition key to ON, listened for clicking noise from pump, no clicking noise.
Conclusion by barnyard mechanics: "It's the fuel pump."

Among my concerns is that, this being an electrical pump, everybody is jumping to the conclusion that the *pump* is bad, seemingly without taking into account the electronic circuit leading to the pump. Or do I have no idea what I'm talking about?

There are no “certified” mechanics within 60 miles or so; just two friends who have worked "extensively" (I guess) on vehicles. My mechanical expertise goes only so far as having "rebuilt" the top end of a SAAB Sonnet V4.

Any help, suggestions, or tips on the Lotto will be *much* appreciated. / Christopher The Old Guy.
 
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Old 07-21-2014, 08:46 PM
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Man those Haynes always leave out the pic of the most important thing or use a bad pic.
I don"t have a Ram I have a 1st gen Dakota. On it there is a test port on the passenger side of the engine compartment near the firewall. It is pretty obvious poking out from behind an AC tube in the corner. I was screwing around under the dash today and saw two female connectors just hanging there and I have no idea what they are. They were closer to the steering column and up behind the dash just above the bottom piece that covers the column. Could be they are the version of that check terminal for my vehicle. They are definitely not behind the fuse box, more like above and toward the cab from it.
The relays in my truck are in a box near the battery on the drivers side. There is a diagram inside the top of it. If a relay fails I'm pretty sure whatever it is for won't work.
If it is carb fed look inside to see if gas is flowing when you manually floor it. If it is injected check the schraeder valve to see if there is fuel in the rail. get a rag and a screwdriver and push in the center pin about 1/8 teaspoon of gas should come out. If there is no gas I'd probably go ahead and change the pump. If you need more diagnostic tests try asking a dealer by phone or email this site http://dodgeram.info/ see if they will offer some ideas.

Good Luck
 
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Old 07-22-2014, 10:27 AM
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Good morning Christopher ASA. Seems I read the Ram50 2.4L in your title as Ram 5.2.
I have no idea about how the 90 Ram 50 works. I know my 85 ram 50 had problems that seems like they came from somewhere else, lead to me discovering a broken balancer belt and rebuilding the carb but it ended up after all the work I did that the problem was still there until I replaced the fuel pump. It is mechanical and when I removed the old one I found someone had connected the fuel return to the vent and plugged the return outlet. This made the vehicle more susceptible to vapor lock. Anyway what I posted yesterday is probably useless to you. If there is a library closer than the closest mechanic you can see if they have a Chilton's manual or the FSM.
I've seen the relay on Rock Auto for $47 US and I think the fuel pump is more expensive so I understand your desire to make sure before throwing money at it. Good Luck at the library.
 
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Old 07-25-2014, 11:21 PM
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Onemore94dak: Was laid up for a bit so could not reply immediately. My pardons.

Oddly enough, there are two female “connectors” on the passenger side firewall sprouting from what is about 1.5-inch-diameter plastic electric-wire conduit.

One is red plastic with a female “spade” connector (now called “universal?), fed by a black and white wire leading to it.

The other is black plastic, don’t know what type of connector, same b/w wire leading to it.

I suspect one of the might be the fuel pump test terminal, unless I find something under the dash, which I’ll check per your comment.

FSM. Field-service Manual?

You’ve provided some *great* sources of material, onemore94dak. For that and the rest of your response(s), I really do thank you, sir.

I may not be working on the Ram for a bit: it was 117 degrees today.
 
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Old 07-26-2014, 02:50 AM
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Sorry: FACTORY Service Manual
 


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