9d1d250

Purchased the truck a few months ago, and it only had about 1/4 tank of fuel. When I filled it, the needle was going crazy, bouncing back and forth until it was under half tank, and began to function somewhat normally again. Finally got sick of it and decided to change the sending unit. When I was attempting to remove the old tank module, the fittings where the fuel lines connect were so brittle that they broke off. Therefore, I had to replace the entire unit and went with a Airtex E7046M from ebay, that the seller's description claimed fit.

Put everything back together, turned the key, after about 10 seconds of cranking the engine turned over, ran for about 45 seconds and died. I assumed air in the system was my culprit, so I browsed various youtube vids and threads on how to bleed the system but could really only find procedures for the 24v, so here's what I tried.

A) Cracked the bleed screw above lift pump and cycled the priming lever 50 or so times, tightened the screw back down, motor cranked for about 10 seconds, turned over, ran for 30, died again wouldn't restart. Repeated this procedure a couple times, no dice on the motor staying running.

B) Cracked each fuel injector line (one at a time) while cranking for 30 seconds or so. Each time, the motor would kick over after about 10-15 secs of cranking and spraying fuel everywhere, but would eventually kick back off. After doing this on all 6 lines, I performed procedure (A) again, and it ran for about 30 seconds before dying.

C) Cracked all of the injector lines a bit, cranked for 30 seconds and sprayed lots of fuel everywhere. Tightened lines, performed step (A) again. Motor turned right over, ran for about a minute, I had a feeling of relief, until it died, and would not turn over again.

Talked to a buddy who works at a dodge dealer, he consulted a few coworkers that said first gen cummins are an absolute pain to bleed and that it takes some time, and just keep repeating the process. This morning I cracked the bleed screw above the lift pump and cycled the lever at least 1000 times, well over 20 mins, enough to really get the carpal tunnel going, and although it was a pretty steady stream of fuel (ran at least a half gallon out of it, probably more) I would still get the slightest few bubbles after every 30 seconds of straight fuel. I closed the bleed screw, pumped the lever another 100 times or so, but this time did not the the "hiss" sound that I heard in the past signifying that the low pressure side was primed. Decided to crank it over with the #1 & #3 injectors open. After about 20 seconds of cranking it ran for about 10 seconds and choked out again.

Some other forums I've been browsing discuss the FSS being a possible culprit, where is that located and how do I troubleshoot it?

Also, the new tank module that I installed did not come with part #6 in the diagram below.

I removed it from the old module and switched it over, but in the process I heard what sounded like it may have cracked internally. Additionally, #1 in the diagram appears to be capped, but I believe it was just an open port on the unit I installed. #6 is also just an open port as shown in the picture, theres not cap or line connected to it. Could either of these be factors in the truck refusing to bleed/start?

I apologize in advance if I sound like a noob here, this is my first diesel truck and really haven't dealt with diesels since auto shop in high school. Any input would be much appreciated.
Thanks.

patdaly

Before you go any further, try this.

Prime normally and start, BUT, this time leave the fuel cap off of your fuel tank.

See if that doesn't let it run........ Index 6 is a vent, and from what you describe, it sounds as if your tank is not venting and allowing the fuel to be pulled. That being said, i would think it would take a lot longer than 30-45 seconds to starve it, but who knows.

The next thing I would closely inspect is with the tank up in position, that you don't have one of your rubber lines folded over ( pinched) . I screwed up on a 99 one time and did that , tooke me a whole day of screwing around before I got smart and looked up there with the tank up........

SCRATCH ALL THAT!!!!!!!!!!!!!!!!!

You said an Airtex E7046M? The seller is full of it! That unit has an electric fuel pump, and you will NEVER drag enough fuel thru it to keep it running. You either need to pull the pump out and replace with a piece of rubber hose, or blend the fuel pickup from your old one into the new unit, but you HAVE to get that electric fuel pump out of there...........

patdaly

Oh yea, whoever told you a 12 valve is hard to prime hasn't done many, I find them some of the easiest to prime.........

9d1d250

Cant thank you enough for the input, i had a suspicion that the new unit itself was to blame. Tried 2 other forums with no helpful feedback, so again many thanks. Ill try and grab a mopar unit from the dealer tomorrow and toss it in. The bleed procedure seemed pretty straight forward so it was driving me insane that i couldn't get it to kick over. If the mopar unit solves the problem i guess ill have to raise some hell with that ebay seller.
cheers.

patdaly

Oh it will solve your issue, but how much is the Mopar unit?

All you really need to do is get rid of that fuel pump. Another useful thing would be to just get the fuel level sender from Mopar for your old unit and throw a Vulcan draw straw 1 in there, all it does is replace the rotted line portion.

Draw Straw™ 1 1/2 in. draw tube and 1/2 in. pushlock fitting

9d1d250

Hey,
Just wanted to thank you again for the info. I pulled the unit out today, gutted the electric pump and threw a straw in. After 30 seconds of bleeding it runs like a champ!

patdaly

Cool!

Always glad to help out, now go enjoy that truck!

MARF75

Is that draw straw specific for a first Gen ? I am having issues with my truck and I believe they are fuel pickup related.
I would like to install a draw straw, how was it to install 91d250? ?

NJTman

IIRC,

The fuel pickup with the airtex pump in it is actually for a gasser..


I sort of remember looking for one when I did my fuel sending unit, and only found gassers available online. I eventually bought one from Dodge.

Jim Lane

This last weekend I was chasing leaks on my truck and replaced all of the gaskets on the side of the engine so I had to remove all of the injector lines and the injection pump, I knew I was going to have air in my system and was probably going to have fun trying to bleed it out so around 10:00 P.M. on Sunday I got ready for the worst, I loosened all of the nuts on the injectors and began pumping the manual priming lever on the fuel pump, I did not open the bleed screw but pushed through the filter, after about 50-60 pumps of the handle I looked over at the injectors and all of them had fuel running from the tops, I stopped, tightened all of the injector lines and after I cleaned up the fuel spill, I cranked the starter for probably less that 10 seconds and the engine came to life.

I was surprised it started so easily, for the next 20 minuets I was trying t stop a few leaks at the top of the injectors.

I have never had any difficulties starting my engine after all of the times I have had my injection pump off, maybe I am just lucky.

One thing that makes a big difference is you need to have a good hot battery since a diesel is a compression ignition engine you must be able to turn it over fast enough to heat the cylinders for combustion to occur.

Jim

thrashingcows

Much like yourself Jim, I've never had an issue firing my motor after having the injection system open.

jimbo486

Never an issue bleeding the system on my '90. Not even the '91.5 before I sold it. The '91.5 sat for a few years with an empty tank. Who knows if any of the fuel that was in the supply line had flowed back into the tank. Regardless, I put 10gals. of fuel in it, actuated the priming lever on the lift pump with the bleeder screw loose until I saw the smallest amount of fuel dribble out but with no bubbles. Depressed the clutch pedal, turned the key and it fired to life as if it was running just hours before. Never died or even coughed!

These old 12v's are so simple to prime. I'll bet the guys at the dealer have never even touched one!