Overflow valve fix (cheap+easy)

[Archive]

Thanks to someone who knows and is willing to share his knowledge I was able to fix my low fuel pressure problem and hopefully my power loss also. The overflow valve can be disassembled and cleaned, the spring stretched and it works great. When you remove it from the pump you can see the bolt head on top, remove that and there is a spring, cup,and check ball in there. The spring should measure . 500 and you can stretch it to . 550 and reassemble. My spring was . 425 and my pressure went from 5lbs at idle to 25lb and from 10lb at 2000rpm to 35lbs after the fix. watch how it comes apart as there are 1-2 other little parts in there but real easy to figure out It took me about 15 minutes overall to do it, beats paying D/C $80. 00 for the same thing parts only.

------------------
96 SLT Laramie CC 5spd, 3. 54, no muff, no cat 80gal fuel capacity.
Member NRA/USPSA

 

[Archive]

You just answered a question I was thinking about the other day. I wasn't sure if the valves were failing because the seats were bad or the spring was weak. Now I'm wondering if the spring will retain the new length or has weakened to the point it will soon compress again. I can see a need for a source of these springs. Thanks for the info.

Bob

 

[Archive]

Deezul 1, Thanks for posting this most valueble information, will check mine today #ad


[This message has been edited by Rebel (edited 09-10-2000). ]

 

[Archive]

RA Dreher
I think the springs are the weak link in these valves. They are coils and wound in a taper so they are kinda special. the rest of the valve looks pretty well made.

 

[Archive]

Thanks Deezel 1, great post.

As stretched springs tend to return to thier collapsed state eventually, does it look like it could be shimmed with a washer of the right thickenss?

Thanks, Duke

------------------
95 2500,std cab,4x4,auto by Dunrite,TST #4,AFC spring kit,Pier's gov spring kit, timing @ 15*, 215 injectors, Walker muff, 3. 54,Diprocol gauges in cupholder slot, K&N,Optima reds, Valentine One radar deflector,Diamond utility bed, custom 52 gal aux tank under bed.

 

[Archive]

duke
My spring already had a washer under it but its a special made washer not the garden variety flat washer as it was thicker height wise than a standard washer is much thinner from ID to OD than normal.

 

[Archive]

I took out the banjo bolt between the pump and the head near the #1 delievery valve today to try this. I think my truck has been "rigged. " I noticed the treads in the pump had a heli coil. I first thought someone just cross threaded a new overflow valve in the past. But now I doubt that. I didn't find ANY spring/cup/ball setup like you have described. Everything on my pump is inside the banjo bolt itself. A small ball and spring is inside the banjo bolt. I can't find any way to get the spring out. Is something different on the '94 models or do I have a one of a kind?

 

[Archive]

Strick-9,

They valve we're referring to is the banjo bolt you're talking about. The whole setup is actually a bolt threaded into a hollow bolt. There should be a 9/16 bolt head on top of the 3/4"wrench flats you used to take the valve out. Hold the body of the valve with the 3/4" wrench (or chuck it in a vise) and remove the upper "bolt" with a 9/16. Everything is contained under that bolt. And now that you mention it, mine also had a helicoil in it.

Deezul 1-

I do have one flat washer on mine. This is on the bolt that threads into the valve. The tapered end goes inside the spring, and the spring rests on a small flat washer. It looks like there is enough room to add a washer around 0. 1" thicker than the original. It might be enough to do the trick but would probably take some trial and error to get the pressure right.

BTW, the spring in my old valve measured 0. 445"

Bob

 

[Archive]

Stick-9,
There were a couple of different type return valves used on the earlier Dodge/Cummins trucks. You may have one that can not be adusted, as it is one complete unit. I had one of these on my truck when I first took delivery. Dodge dealer replaced it about six months after I bought the truck due to poor performance. The one they installed can be taken apart and adjusted, and I have done this procedure since.

Wayne
amsoilman

------------------
94'SLT 4X4 AT/White in color. Factory Tow Hooks & Running Boards. Amsoil By-Pass filter, Amsoil Air cleaner,and all fluids are Amsoil. Optima "Red Top" batteries.
BD exhaust Brake, BD Torque Lock, BD Torque Converter, Dr. Performance Stage II Injection Pump. Mag-Hytec Diff Cover,Mag-Hytec Transmission Pan, Isspro Pyro, Boost,Oil temp Gauges mounted in 3 Gauge post mount. One gauge monitors Engine Oil, Trans, Diff. Temps.

 

[Archive]

Good point Amsoilman,

My OE 94 overflow valve was one piece. Has a ball bearing pressed into the top. Probably tough to take apart. The revised ones have the bolt that can be loosened and the vavle rebuilt.

 

[Archive]

Thanks for the response. I apparently have the tamperproof type. Where DA Dreher says there should be a 9/16" head, I have an embedded round ball. The ball looks like it is pressed into the banjo bolt.

I have taken off a lot of tamperproof covers and screws and such from my truck, but this one I couldn't figure out. I guess I have to bit the bullet and buy a new one.

Thanks everyone,
Chris

 

[Archive]

The overflow valves for the '94's were not only troublesome, they were made to not touch. There have been a couple part number changes, if memory serves, with the latest being the best. If you have the early ones, spend the money and get the latest.

Although you may temporarily regain the pressure you need, it's very likely your valve won't last long - not beyond a few thousand miles. We tested these on the test stand, and they'd get intermittent... the valve would seat sometimes, but not others. Then again, you might luck out #ad


They would commonly hold up to almost the spec, and then after they opened, the pressure would drop way off to almost nothing. A few taps, or a large surge of fuel through it would reset it temporarily and then it would fall again. It's probably more to do with the ball/seat being bad than the spring being weak.

There are other applications that have different opening pressures, and some of them cost less from Bosch. Beware, experimenting is on your own dime, and your milage may vary. #ad

 

[Archive]

Power Wagon,

Since you brought it up, what might be the "some of them cost less from Bosch"? I stretched the spring in mine a little. That helped but I know that it is just a temporary fix. Mine doesn't start as well as it did and complains a bit before settleing down and running smoothly. So before I cough up the bucks to replace it I would sure appreciate knowing my alternatives.

------------------
Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

[Archive]

I was glad to be able to do this to the valve as it allowed me to trouble shoot a power loss problem at no cost and in the future when it happens again and Im sure it will I will know I am not throwing money away on a maybe fix. I hope this has helped out those who have been suffering the power loss problems as I have. Is there a source for new springs?
Good Luck
John

 

[Archive]

I had a chance to open it up today and it pulled strong all the way till the governor said stop. We wont talk about how fast but before the spring stretch it would just kinda lolly gag up to that speed and now it squats and gits.

 

[Archive]

Originally posted by Joe G. :
Power Wagon,

Since you brought it up, what might be the "some of them cost less from Bosch"? I stretched the spring in mine a little. That helped but I know that it is just a temporary fix. Mine doesn't start as well as it did and complains a bit before settleing down and running smoothly. So before I cough up the bucks to replace it I would sure appreciate knowing my alternatives.

For those of you who know HTML: &lt/cryptic postings&gt

Let me be, as I failed to be in the other post, clear #ad


Overflow valves on Bosch pumps are not generic. They come in a variety of part numbers. Some are quite similiar, some very different. And, along with that, comes an inexplicable variety of prices. I'm sure it takes just about the same amount of resources to create them, but the prices wander all over, depending on the part number.

So, before someone either tells you, or posts here, that they got, saw, or heard of someone else getting a pressurizing valve that may/may not have fit a Cummins engine that was only $35 (or some other low price), be warned that thier size, shape, opening pressure, flow characteristics, and other details can vary considerably. Although thier purpose is pretty much the same, the results of using some other part than the one called for is unknown to me.

Being of the wild-eyed reckless rebel type, I'd be tempted to find and try them out... but, as I said before, if you try it, your results might not be as you hoped.

&ltcryptic postings&gt


[This message has been edited by Power Wagon (edited 09-12-2000). ]

 

[Archive]

Should the overflow valve be airtight when closed? The ball looks to be seated, but I can easily blow through it (with my mouth). I thought maybe the flow of fuel through the small orifice would provide restriction and therefore pressure, but I have never seen a new one so I don't know.

Chris

 

[Archive]

If not air-tight, then at least quite restrictive to airflow. On the test bench, they pass little to no fuel until opening pressure is reached. That is one of the requirements. If it blows through without restriction, how's it going to stop fuel?

My guess is, that your valve really is bad, and you need another one.

 

[Archive]

I dont mean to be to naive, but I was looking for this dvice on my 95 and in the DC service manual. Could I some coordinates on device?
Thanks

 

[Archive]

A-bomb,

On the top of the pump there is a row of six delivery valves with the injector lines. Even with the front delivery valve and on the side of the injector pump toward the engine you will see a banjo type fitting with a line going down toward the rear. That fitting is the overflow valve.