I have a 1997 Dodge Ram 5.9 Gas Engine that is flooding out.

I recent replaced the transmission power supply connector due to the wires in the plug being bare and grounding out and killing the engine just like someone turned off the key.

After replacing this the engine floods out something fierce. I can remove the fuel pump relay from the power distribution center. Start the engine and it will run as it did before until it loses enough pressure the engine dies because it is out of fuel. If I plug the relay back in, the fuel pump will kick on for a bit until the fuel system pressures up. If I leave the relay switch in, the engine goes back to flooding itself out. I have switched the horn relay with the fuel relay in the PDC and there is no difference in the way the fuel pump and fuel system acts.

I do not have a check engine light at the moment. I am puzzled and running out of ideas.

The fuel pump is about 1.5 years old, but I am curious about some of the electrical going to the fuel pump at the moment. If I remember right, there is a fuel return line ghat goes from the fuel rail back to the tank.

I have also disconnected the throttle position sensor at start up, but I am not seeing a distinctive change with this attempt.

Any new thoughts and ideas are greatly appreciated.

Thanks
CounterPoint

 

sounds like you have a stuck injector..or two..unplug injectors one at a time and note changes in rpm and preformance..

 

Interesting thought. I will give this a try. but it runs well without the fuel pressure being at a lower pressure when I pull the fuel relay.

Would a stuck injector just make the one or 2 cylinders miss? or would it cause the whole system to flood out? It will barely start with the fuel relay in service.

Thanks
CP

 

there is not a return line in these trucks. there's a pressure regulator built into the pump somehow.

you might want to check fuel pressure at the rail just to rule out the pump. it should be about 49psi.

you can unplug the injectors and check them with an ohmeter. the procedure is in the 01 service manual at the top. i think the resistance is supposed to be 69

with no other info, you can pull your plugs and look for fouling.

fuel control is from front O2 sensors in closed loop only. injectors all the time. and fuel pump.

 

Nope. It's a returnless system, with the regulator built into the top of the pump/sender assembly. Check your fuel pressure first (no more than 50 PSI)

If not that, you need to get a scanner on it and see what your O2's, MAP, TPS and ECT are reading. If the O2's are lazy, or the MAP or TPS is telling the PCM there is high engine load, or if the ECT is reporting very cold, you will have an over rich condition.

Also look at the long-term fuel trims.

If it's as rich as it sounds and not throwing P0172 and P0173, I suspect one or both of the O2's have gone retarded.

 

ok, I tried to give all the pertinent information originally, but I think we might be on to something now.

I recently had to replace the power connections to the transmission due to the wires being bare and grounding out with one another.

I have since replaced this connection. My gut tells me there is some wiring that is related to the fuel system some where here now. I am wondering if possibly the shorted wires may have fried part of the fuel pump and the pressure regulator. I will be testing the fuel pressure next. I will be back with the results.

Thank you all for the help so fare.

CP

 

The pressure regulator is mechanical. I'd be looking at the o2 sensor wires. Hopefully you didn't tie the signal wire into a battery voltage wire and fry a VLSI chip in the the PCM. I don't think they're protected on that circuit.

 

Get a fuel pressure tester. Screw it on and start the truck. Check the pressure. Pinch off the rubber supply line to the fuel rail with a clamp and turn the motor off. The pressure will hold if you don't have leaking injectors.

 

I feel pretty confident about the wire splices, did the basics, disconnected the battery, match colors and stripes on the wires, checked them after splicing each one, checked them when all were done, got out from underneath, got back down and checked them again. These wires were grounding out severely with one another prior to the splice repair, and I really believe this to be the source of the problem.

The original issue:

Driving down the highway and the truck shut off just like someone turned off the key, no hesitations, no sputters, just dead. Well, was getting a code for the crankshaft position sensor, so this was replaced. No codes anymore and worked good for 3 days. Half a block from the house one evening, deader than a hammer like the key was turned off again. Cranked it over, a few times started running. Alternator was not charging. Replaced alternator.

After the alternator replacement it would no longer start. After a couple hours of swearing like a sailor and making my neighbors a bit miserable, I found the shorted wires down on the transmission power supply. Struck me as really odd, but ok. Found a salvage wire harness, cut the connection off and spliced in. Since this fix, the truck runs as before when the fuel pump relay is not plugged in.

My concern is with the new alternator, may the PCM did take an electrical hit. Now my lingo here is not perfect, but I would call the PCM the computer or brain box of the pickup correct?

When it is spitting and sputtering with the fuel relay in service. The exhaust is so lean my clothes start smelling like I have been at the drag strip all day.

I plan on testing the fuel pressure tomorrow morning.

Thanks

CounterPoint

 

Yes you are right. PCM= power train control module.

Are you sure the battery is good?