roosa master problem, 6.2 diesel

[chevy1500z71]

Sorry if im way out of line here but there's not a sole left on the planet that can help me with my old 86 chevy 6.2 pickup and I cant help but notice how much more knowledgeable the tractor guys on these old roosa master pumps. So if yall wouldn't mind helping out, heres what I have going on

the injection pump had the elastic ring failure in the injection pump and i rebuilt the pump using the new solid weight cage. Ever since the rebuild it will run for minutes, sometimes seconds, or even hours but eventually it will run out of power and die. during my diagnosis i have so far determined that fuel supply is good and steady, Im using a carter electric pump with a 5 micron water separating pre-filter and a 2 micron cat post filter. The post filter head is mounted to the firewall a few feet from the injection pump and has a valve to open air on the outlet side used as an air bleed or in this case to diagnose/determine fuel pressure or volume. When you pull the return line from the top of the pump it will return large amounts of fuel when its running good, and once its running poorly it immediately changes to a dribble. Sometimes the idle will surge, in this instance fuel return volume surges right along side of the rpm surge. but at all times, fuel feed is steady, air free(as best i can tell) and more then sufficient volume and pressure. My testing is based on me opening the air bleed and watching it fill a water bottle.

I have read about the return check ball being a problem, but when i remove it all together and run the motor with fuel free flowing it is still doing exactly the same thing... maybe this is a useless test as i am relieving any pressure that should stay in the injection pump? After rebuilding the injection pump the truck would hardly run on the mechanical pump(which was verified good in volume testing), swapping to the electric pump has given it a lot more power for short bursts and overall its running better and more often but still very un-derivable, leading me to believe the transfer pump in the injection pump may be to blame as i'm helping or band-aiding so to speak transfer pressure with the electric pump? just some thoughts, im completely lost here, idk if i should pull the transfer pump apart or pull the whole thing back apart.

 

[rustred]

I had a 1986 6.2 diesel I bought brand new. very good fuel mileage it gave. so when u say" I" rebuilt the pump is that you or the injection shop doing it??

 

[ptfarmer]

My uncle had one of those trucks long ago, he got rid of it after it went through 6 injector pumps in a 2 year period.

 

[chevy1500z71]

Truck gets incredible mileage and with no overdrive and 4.10 rear gears.

I did in fact rebuilt it myself. I am a mechanic and I work on heavy diesels for a living but I?m certainly not qualified to work on something I have no experience or service information for. I did the best I could and made no adjustments, just a very simple rebuild to remedy the torn flex ring.

The symptoms the truck had were extremely similar before the rebuild, I thought the flex ring was my smokin fun but I?m thinking I must have missed something.

All of the components in the pump show little to no wear, I meticulously cleaned and re assembled the pump but I never made any adjustments to the transfer pump and I don?t have the tooling to check or calibrate anything in that regard.

The pump plungers move freely, so does the metering valve. Governer and timing advance seem to function properly but I suppose it?s possible to put the timing advance piston in backwards, maybe I managed to do that,

 

[chevy1500z71]

As a side note, I must admit the truck runs on a blend of diesel and used atf. Has for several years, only with the addition of the cat 2 micron filter tho.

I personally think the pump lives longer in oil then dry modern diesel, as I said mine shows no wear and tear but that atf destroyed the flex ring.

 

[Gene Davis (Ga.)]

On the '84 6.2 GMC I had the return line got stopped up and caused problems like you describe. When you replace
the drive ring in the pump, you are not really rebuilding it. You need to get it done at a pump shop. I found out
this the stubborn hard way. Have you had the pump been checked by a shop?

 

[Dieseltech]

The pump probably also needs an oversized advance piston
installed, advance won't work right with a loose piston.
Common problem on 6.2, 6.5, 6.9, and 7.3 servo advance
pumps. Most every one I repair needs the housing machined
for a new piston..

 

[Bob]

(quoted from post at 20:35:20 11/20/19)

I guess a couple of the guys that answered never worked on a Versatile 145!

NO "hinge bushings" are used, they are Torrington "spherical plain bearings", part # 20-SBB-32.

MANY reasonable sources for those, if you GOOGLE the number.

FIAT part number is 86000739, some seventy bucks at your friendly FIAT/dba CNH dealer.

Upper hinge bolt is V100T167, lower hinge bolt is V100T168, both nla from FIAT.

Great Lakes Equipment ((800) 634-0084) shows stock on the upper bolt, don't see anything legit out there for the lower bolt.

A machine shop likely can make new pins, or possibly weld up and grind down your old ones.

 

[Bob]

SORRY, I screwed up and posted this reply to the wrong thread!!!

 

[JK-NY]

What happens to your fuel flow to the pump at your filter air
bleed when the power drops ? Could you have a fuel pick up
issue in the fuel tank? I would try blowing out the lines back to
the tank or if your fuel flow is noticeably less when you lose
power maybe you need to drop the tank. Or maybe easier to
pull off the box to access the tank. Is that tank outside of the
frame, I had a 1986 Chevy gas engine pick up with the tank
outside the frame on the left side.

 

[Mike M]

I had one in an 1982 K10. It never ran long enough to have injection pump issues ! Cyl. head gaskets leaking were an issue. I got tired of messing with it and pulled the 6.2 out and put a gas engine in.
No more GM's products for me ! I wish I would of sold it years before I did.

 

[Determined]

What pressure is the electric pump delivering to the injector pump?

Where in the system did you install the electric pump?
Any connection between pump and fuel tank is a place for it to suck air in.

Checking your volume and pressure at the filter air bleed port is not telling you what is happening at the injector pump it is only confirming the lift pump is functioning.

86 6.2 would have come from the factory with the box style filter on the firewall so I am assuming the spin on filters were added on.

If one of the filter bases was installed backwards you would be getting good flow and pressure at the bleed screw even if the filter itself was plugged solid.

 

[chevy1500z71]

I have pretty much complexly redone the fuel system. Fuel tank checks out ok, I removed the filter sock and re installed the pickup tube which checks out ok. New fuel hose from their to the water separator filter mounted low on the frame rail directly before the carter pump. From the pump it goes up the frame and to the final 2 micron filter which is directly in place of the stock box filter.

The pump is rated at 7-9psi and 70gph. Stock unit is 40gph 9-11psi

 

[Determined]

(quoted from post at 12:38:23 11/21/19) I have pretty much complexly redone the fuel system. Fuel tank checks out ok, I removed the filter sock and re installed the pickup tube which checks out ok. New fuel hose from their to the water separator filter mounted low on the frame rail directly before the carter pump. From the pump it goes up the frame and to the final 2 micron filter which is directly in place of the stock box filter.

The pump is rated at 7-9psi and 70gph. Stock unit is 40gph 9-11psi

Think about what shuts down these engines.

When the power to the solenoid on the injector pump is removed basically it blocks off the fuel return, housing pressure goes up, timing retards and engine stops.

The same thing happens when the retainer ring breaks apart, a piece of it blocks the return fuel flow, pressure goes up, timing retards and the engine stops.

People then pull off the return line/check valve fitting and are able to limp along a while longer.

Now I am not saying this is what is happening on yours but it would stand to reason that a fuel pump with 5/16 or 3/8 lines feeding the injector pump that has a much smaller return line may have trouble keeping the housing pressure where it wants to be.

Have you tried running it with the fuel cap loose to rule out a plugged tank vent issue?
You mentioned that how long it runs before it acts up varies, does it do it sooner on hot days? (like when expanding fuel may already have built up pressure in the tank)

Those trucks will continue to run reasonably well with a faulty electric or mechanical pump until you would go to change a fuel filter and are not able to re-prime the system.

Try disabling the power to your electric pump and see if it starts.

If it does and continues to run for 5 minutes then you can rule out the pump sucking air into the system as the problem.

If it dies shortly after starting it would suggest you are fighting air in the system.

Dual tank selector valve can also cause grief on these trucks if so equipped.

If you are certain everything is fine in the injector pump then really what is left;

air or water in the system
inadequate fuel supply
blocked fuel return system
plugged, defective or intermittent electrical issue with shut down solenoid

 

[Bob]

(quoted from post at 14:23:45 11/21/19)

(quoted from post at 12:38:23 11/21/19)

"When the power to the solenoid on the injector pump is removed basically it blocks off the fuel return"

Actually, when power is removed from the shutdown solenoid spring tension rotates the metering valve to the "no fuel" position, stopping the flow of fuel to the pumping plungers.

The other solenoid in the pump cover, the HPCA DOES affect injection timing by lifting the housing pressure regulating valve checkball off of it's seat in the fuel return fitting, decreasing housing pressure to advance timing for cold starts and cleaner burning during warmup.

 

[Dieseltech]

Solenoid does NOT block the return, but moves the metering valve to NO FUEL position for shut down as Bob said. There's an updated return valve for that pump too, that he may not have..

 

[chevy1500z71]

I have actually re done the circuit for the fuel cut solenoid as
well as replaced the solenoid. The solenoid that pinches
return fuel doesn?t work. I live in Florida and don?t notice any
real difference there.

Return line is clear, blew it back to the tank. The fuel cap is
non vented... I? leave it loose, what can I say, I was to cheap
to replace it.

I think I?ll try drilling out the return check ball and see what
happens. Does anyone have the part number for a
replacement? Idk how I feel about trashing it unless I have
another on the way.

Why are my posts all over the place, is there no order to posts
here?

 

[Tx Jim]

Yrs back I purchased a used '83 3/4 ton 6.2L diesel 4WD with granny 4 speed 4:10 gears that was a very good truck. It got 16.5 MPG empty & 11 MPG pulling GN with 11 rd bales of hay. After 80,000 more miles the block cracked in a cylinder wall. Truck came to Texas from Kentucky & had serious rust damage or I would have put another engine in it.

My guess is return line on OP's engine is clogged.

 

[Determined]

(quoted from post at 15:27:24 11/21/19) Solenoid does NOT block the return, but moves the metering valve to NO FUEL position for shut down as Bob said. There's an updated return valve for that pump too, that he may not have..

Thank you Bob and Dieseltech for providing the technical knowledge to correct my post.

I personally think he should start with a pump that has been gone through and calibrated.

With that said if he feels his pump is fine then checking long shots will only cost him his time and every now and again it can pay off.

 

[Determined]

(quoted from post at 15:27:24 11/21/19) Solenoid does NOT block the return, but moves the metering valve to NO FUEL position for shut down as Bob said. There's an updated return valve for that pump too, that he may not have..

Thank you Bob and Dieseltech for providing the technical knowledge to correct my post.

I personally think he should start with a pump that has been gone through and calibrated.

With that said if he feels his pump is fine then checking long shots will only cost him his time and every now and again it can pay off.

 

[Determined]

(quoted from post at 19:27:48 11/21/19)

(quoted from post at 15:27:24 11/21/19) Solenoid does NOT block the return, but moves the metering valve to NO FUEL position for shut down as Bob said. There's an updated return valve for that pump too, that he may not have..

Thank you Bob and Dieseltech for providing the technical knowledge to correct my post.

I personally think he should start with a pump that has been gone through and calibrated.

With that said if he feels his pump is fine then checking long shots will only cost him his time and every now and again it can pay off.

Not sure what causes these double posts and seeing as I can not edit it I will just call one a thanks to Bob and the other a thanks to Dieseltech.

 

[chevy1500z71]

I cant hardly even make any sense of this thread anymore because of the odd location of the posts but anyway.

I drilled out the return fitting and it was clear that it was jammed up with debris from the flex ring. So it runs ok and i drove it for
longer then i have since the injection pump was apart. the throttle feels too peppy and the idle hunts, has some driveability concerns to
say the least. I adjusted the governor down and it helped alot, its derivable but something isn't 100%.

Im wondering if the return line should have some level of restriction, maybe free flow is causing my abnormal idle.

I completely agree that Im wasting my time by the way, having the pump calibrated is nearly a necessity that Im desperately trying to
bypass. the truck has had blown head gaskets for several years, i put one set on and it lasted 2 months because the block and heads need
machine work. one piston is battered from glow plug ingestion, injector cups are all cracked up. this motor is a complete throw away yet i
have been daily driving it for more then 3 years on a steady diet of liquid glass for coolant, no thermostat and a fixed blade fan.

so if yall could please help me out id appreciate it, im just trying to keep her on the road. it would be a shame to give up on the truck
and it cannot be justified to spend too much on it.

 

[TGP]

You answered your questions. You know what needs to be done.

Engine rebuild, cooling system service, Injection pump
Professionally rebuilt, calibrated.

Now you can keep going until it dies or find a usable engine.
There's a lot of 6,2 engines out there from military vendors and hobbyist, willing to part.

Two things to take with a grain of salt from my experience, and
I have several K30's with 6.2 and one with 6BTA Cummins.

The 6.2 will run hot without a t-stat. 160Deg. is better than nothing.

And ATF mixed with Diesel is the worst thing you can do to the IP.

In earlier days it was common, but now with the Friction modifiers in almost all ATF other than maybe Ford, it
Destroys the pump.

If you think you need additives use quality diesel additive with
Lubricity, or two stroke oil.

Tom

 

[TGP]

One other thing,
You might try Modern View in the upper right corner.

Sounds like your on classic view which can be confusing
Sometimes.

Tom

 

[GarryinNC]

I think that I may have some new check balls in a box of parts from a garage sale. The owner rebuilt stanadyne/roosamasters.
Will check in the morning.

Garry

 

[chevy1500z71]

(quoted from post at 21:12:41 11/21/19) I think that I may have some new check balls in a box of parts from a garage sale. The owner rebuilt stanadyne/roosamasters.
Will check in the morning.

Garry

Would greatly appreciate it. Thanks, I could PayPal you money for one.

 

[chevy1500z71]

(quoted from post at 20:19:39 11/21/19) One other thing,
You might try Modern View in the upper right corner.

Sounds like your on classic view which can be confusing
Sometimes.

Tom

Thanks, all better.