Engine/Transmission (1994 - 1998) Low power

[KMott]

Hi all. New to the site, and cant believe all the good info on here. I recently bought my first dodge, a 94 ram 2500 4x4.

When i first got it i had issues with hard starting and white smoke at high rpm's. It died on the way home one night and i quickly found my problem was a leaking fuel line. So i replaced all the lines, and still had white smoke issues at high rpm's. To fix that problem i had the injection pump timed. It ran ok until recently when the fuel solenoid began to fail. I replaced that last week and its running a lot better, but is still a dog compared to my buddys 91 cummins dually. I read up on the overflow valves, and did some tests tonight. I cant get a fuel pressure reading when the truck is running (it jumps all over) but if i manually press the primer when the truck is off, i can see (and hear) the vavle releasing the pressure at 15 psi. Just to be sure i clamped off the fuel return line and i primed it a couple times and the pressure built right up to 50psi (didnt want to pust it too high, lol) I measuered the fuel pressure as the manual showed, by removing the banjo bolt on the fuel filter.

My manual is saying the pressure should be a minumum of 25psi, so its quite a bit lower than it should be.

Just wondering where is the best place to get his vavle? How much difference in performance am i going to see? Thanks for any help!

 

[HLEschenko]

Welcome to TDR. Don't know where to get the best deal for the overflow valve. I shimmed my overflow valve in Feb of 03 with . 065 thousands shim stock and have had no problems with fuel pressure since. My fuel gage runs from 20 to 32 psi depending on RPM. The spring looses its resiliency overtime. I've read where some folks will stretch the spring for more resistance. I believe this is temporary fix. Kinda bending a piece of wire back and forth till its breaks. Yours may take more or less.

A snubber valve will dampen the fuel pump pulsations and protect the gage from damage. I drilled and tapped a 1/8" NPT hole into the injector pump banjo bolt. Leave NO metal cuttings in that part of the fuel system.

Best of luck and enjoy the reading.

 

[MLee]

You might give Marty Tompkins a call @ Precision Diesel Injection & Turbo Inc. 1286 Ceder st Holt Mi. 48842 517-694-1522 He had the best price a while back, i believe $35. 00 pluse shipping. The OV are set @ 30 PSI.

Marv.

 

[CTD12V]

A snubber valve will dampen the fuel pump pulsations and protect the gage from damage.

What exactly is a snubber valve? I know what a needle valve is (like Joe G. has shown in pics of his setup), but what does a snubber look like? Sorry for the dumb question.



CTD12V

 

[KMott]

Thanks for the info. I removed the vavle tonight, but unfortunately its all one piece and does not come apart (the end is pressed in). So i cant shim or stretch the spring. I retested the fuel pressure and also noticed that the vavle wont even hold the 10-15 psi for more than a couple seconds before it drops back down to zero. Ill give Precision Diesel a call tomorrow and see if they are still selling the vavles.

A snubber valve will dampen the fuel pump pulsations and protect the gage from damage. I drilled and tapped a 1/8" NPT hole into the injector pump banjo bolt.

Im also interested in permanently mounting my fuel gauge. Where did you get the snubber vavle from? Did you just thread the vavle into the banjo bolt and attach the gauge onto the vavle?

 

[HLEschenko]

A snubber valve is the same thing as a needle valve and can be picked up at most good hardware stores. I picked up the snubber term in a Navy hydraulics class.

I mounted my gage inside the cab on the dash, but I have the problem of fuel inside the truck with me. Not good if I get a leak (fire). I used copper gage line and slipped rubber tubing over the entire length to prevent wear on the tubing. A sending unit and electric gage would be safer and I have plans to change my set up.

 

[CTD12V]

Thanks for the info, HLEschenko. The term 'snubber' makes perfect sense, I just didn't know if it was something different than a needle valve.



Good luck with your project, KMott. I am basically in the same boat as you are, only not as far along!



CTD12V

 

[Matthug]

Can anybody post a picture of a needle valve or give a link to a pic? I would to know what to look for at the hardware store because I plan on also installing a fuel pressure gauge soon. Thanks!

 

[bmoeller]

http://www.flameengineering.com/Valves.html

 

[biggy238]

I got my OF valve from them... shipped at right around $50.





Never heard of an OF valve that was pressed together though? I thought they all had the screw in the top with the spring and check ball underneath

 

[Matthug]

http://www.flameengineering.com/Valves.html

OK so you just close it up to the point where it still reads on the gauge but doesn't let it spike? Is that right?

 

[Joe G.]

Just close it. Then open it until the gauge just barely works.

 

[Matthug]

Thank you very much!

 

[KMott]

I called precision diesel and he quoted me $40 plus shipping for the overflow valve, and he said it is set at 22psi. Isnt that kind of low? He also said that if it is losing pressure when it is off (thats when ive been measuring fuel pressure by manually priming it) it could be a valve in the transfer pump. I cant see this though, because when i blocked off my return line it held the pressure. I assume after the overflow vavle the fuel returns right back to the tank?

Thanks again

 

[Matthug]

Thats a stock replacement, 22 PSI is stock.

 

[KMott]

I got a good deal on the valve through the local diesel injection shop. After replacing it, the valve is holding until 25psi. Didnt make any difference at all as far as power though. Also tried turning up the wheel on the injection pump and that made no difference either. Thinking it may be a fuel volume problem. Will do the volume and vacuum test (from haynes shop manual) and see what comes up. Thanks for the help!

 

[Joe G.]

The first advice I have is to throw the Haynes manual in the garbage where it belongs and get a good service manual.



Then read this:

http://dieselram.com/ubb/ultimatebb.php?ubb=get_topic;f=45;t=000007



The problem is probably something cheap, but not too easy to find.

 

[KMott]

Damn, i just bought that thing! What about the manual through chrysler??

Thanks for the great info, looks like ill be busy this weekend.

 

[Joe G.]

You want the one from Chrysler. I think Geno's sells them at a good price.

 

[KMott]

OK, so i got some stuff done this weekend. I replaced the stuck open thermostat, all the rubber lines going up to the engine as well as the line between the fuel pre-heater and lift pump. I also got looking at the tank and noticed the one line was a little kinked (all the tank lines/steel lines had been replaced by a shop when i first got the truck) After doing all this the truck didnt run any better. I hooked the fuel pressure gauge on with a needle valve and got a better reading. It runs idle around 26psi, and when it revs up goes up to almost 35 or higher. I did notice that a couple times it dropped down below 20 when i was revving it up.

Because of this i did a fuel volume test by disconnecting the shutdown solenoid and cranking the engine for 30 seconds and running the fuel out of the top of the filter into a container. I dont have a tach to hook up but it was cranking pretty fast (new batteries) and i only got about 200ml of fuel in 30 seconds. Even if the motor was cranking over at 300 rpm, that means the camshaft rotated 150 times, making the pump cycle 150 times (is this right??) So i tried manually priming the pump and after about 25 pumps i was already getting more fuel than the engine had produced in 30 seconds. Does this mean the pump is bad? I havent had a chance to take it or the fuel pre-heater apart or pull the tank apart (as in Joe. G's article)

Thanks again!