injector pump advice

The place to discuss problems and routine maintenance questions and tips. This is for topics that are specifically diesel-related.
swamp pup
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Isuzu vehicle(s): 1981 2.2 pup dlx long bed

injector pump advice

Post by swamp pup »

After having my 81 diesel pup for a couple of weeks, never having a problem, I'm now losing my prime overnight.
At first I thought it might have been other issues, so I checked each glow plug, all cherry red at 8 seconds.
I changed the fuel filter, replaced any suspect fuel lines and finally installed a lift pump near the tank, hoping to give me time to hunt down a replacement injector pump. I've driven a Cummins for the last 30 yrs ( 600K ) and know how injector pump rebuilds are just a part of owning diesels, so I expected nothing less with my pup, I just figured I had more time.

I'm hoping that someone here can turn me onto the correct part number, or the correct part,...so I can make the swap more efficient than having the front end in pieces while I wait for a rebuild.

any help is much appreciated

Vincent
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joeshmoe44883
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Re: injector pump advice

Post by joeshmoe44883 »

Probably not the pump. Most likely a bad line or ive seen the seals go bad in the hand primer on the filter housing.

Quick way to test would be to get a cheap inline filter for a lawnmower or something and bypass the filter housing completely.
2 86 Trooper II diesels, one 4 door the other 2, both projects.
86 Jeep Cherokee Pioneer with factory 2.1L turbo diesel.
05 Jeep Liberty Limited with 2.8L diesel (totaled)
06 Chevy Silverado with duramax
2014 Jeep Grand Cherokee ecodiesel
dorf
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Re: injector pump advice

Post by dorf »

Ditto......plus?....fuel lines and clamps

I used a marine hand pump up bulb.....and fuel Gage to isolate
swamp pup
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Isuzu vehicle(s): 1981 2.2 pup dlx long bed

Re: injector pump advice

Post by swamp pup »

So,.. I've replaced hoses, had the injectors checked, and finally just broke down and had my pump rebuilt, figuring now is as good a time as any to make sure that all is good in this area and swap for a new belt.

this is a new to me vehicle and I just want to feel confident.

I see that this is a recurring theme on this forum, and I am not immune to the ensuing troubles that this pump swap might incur.

so, I have some questions.

let me preface this by saying, no, I did not chisel mark the pump prior to removal.
before any disassembly/re assembly , the crank , with belt in place, was always turned back to TDC so that every effort was made to retain alignment with the cam.

that being said, I notice a couple of things that makes me question myself.

yes, I realize there is a neutral zone at TDC where you can rotate the crank a bit, but I've never strayed much and always re aligned the pin and cog key with the mark on the block during any fudging with the belt.

I don't think I inadvertently spaced it and turned anything out of place but I notice that the cam is the only part of the equation that doesn't move much,.. but there is a cog's worth of rotation if you push it up or down. I don't think I can have it in the wrong place and still have the arrows at their nearest gap with the injector pump, but at this point things are getting blurry.

So I ask,.. how does one check to ensure that the crank and cam are in correct orientation to one another?

At TDC, what should I be seeing with valve movement?

just trying to eliminate variables here.
I have fuel coming out of #1 cracked a bit

not firing up



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Paul
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Re: injector pump advice

Post by Paul »

swamp pup wrote:
Mon Nov 21, 2022 5:22 pm
So,.. I've replaced hoses, had the injectors checked, and finally just broke down and had my pump rebuilt, figuring now is as good a time as any to make sure that all is good in this area and swap for a new belt.

this is a new to me vehicle and I just want to feel confident.

I see that this is a recurring theme on this forum, and I am not immune to the ensuing troubles that this pump swap might incur.

so, I have some questions.

let me preface this by saying, no, I did not chisel mark the pump prior to removal.
before any disassembly/re assembly , the crank , with belt in place, was always turned back to TDC so that every effort was made to retain alignment with the cam.

that being said, I notice a couple of things that makes me question myself.

yes, I realize there is a neutral zone at TDC where you can rotate the crank a bit, but I've never strayed much and always re aligned the pin and cog key with the mark on the block during any fudging with the belt.

I don't think I inadvertently spaced it and turned anything out of place but I notice that the cam is the only part of the equation that doesn't move much,.. but there is a cog's worth of rotation if you push it up or down. I don't think I can have it in the wrong place and still have the arrows at their nearest gap with the injector pump, but at this point things are getting blurry.

So I ask,.. how does one check to ensure that the crank and cam are in correct orientation to one another?

At TDC, what should I be seeing with valve movement?

just trying to eliminate variables here.
I have fuel coming out of #1 cracked a bit

not firing up

pup41 (1 of 1).jpg

Your photo shows all the right stuff. Cam and pump sprocket arrows pointing at each other with the crankshaft at TDC.

If you have the pump mounted with the bolts close to the center of the elongated holes, the timing will be close and should run OK that way. You might want to time it with a gauge later.

A new pump will be empty of fuel and can take a lot of cranking to fill it. If the hand primer on the top of the filter is working you can use it to fill the pump body. Unfortunately, most of the hand primers are no longer working. Alternatively, you can use a vacuum pump and a bottle to pull fuel through the injection pump from the fuel return fitting. Or, you can buy a hand pump to install inline to pump fuel.

Once you have filled the pump body, you should crack the injector nuts loose a bit and then crank to get the high pressure lines filled. When you see fuel exiting the high pressure lines at the injectors, you can tighten the injector nuts and hopefully start your engine.

Even though you have fuel at #1 injector, that may not be good enough to start. Need all four to be squirting fuel.

Valve movement. When a cylinder is on TDC the two valves will either be closed or they will be alternately rocking open and closed as you rotate the engine back and forth over TDC, depending on whether the cylinder is on compression stroke or not.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
swamp pup
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Re: injector pump advice

Post by swamp pup »

Hmm,..ok...yeah, that's what I'm seeing, at TDC my valves at #1 are closed.
From what you see in the photo, my cam looks to be lined up correctly I guess.
that one notch of cam movement, is there any wisdom you can share there?
is this design one where the crank can be rotated X number of times to re align everything?
I'm guessing that is not the case since there is nothing connecting them besides the belt.

will keep trying
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Paul
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Re: injector pump advice

Post by Paul »

swamp pup wrote:
Tue Nov 22, 2022 9:26 am
Hmm,..ok...yeah, that's what I'm seeing, at TDC my valves at #1 are closed.
From what you see in the photo, my cam looks to be lined up correctly I guess.
that one notch of cam movement, is there any wisdom you can share there?
is this design one where the crank can be rotated X number of times to re align everything?
I'm guessing that is not the case since there is nothing connecting them besides the belt.

will keep trying
One notch of cam movement? I have not seen this happen. But, if the timing belt is too loose I suppose it can happen. Maybe you should recheck the tension?

They do recommend that you rotate the engine at least once to be sure that everything is in place. Not sure one needs to do this if all of the arrows are right but it can't hurt.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
swamp pup
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Re: injector pump advice

Post by swamp pup »

The cam movement only comes into play with no belt in place.
it's not easy to move it and it's only maybe an 1/8'' of movement, which I imagine is just the lobe in slight rotation?
I've seen Halden? mention this in another post somewhere.
swamp pup
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Re: injector pump advice

Post by swamp pup »

So,..I just got it started,..a few times.
seems to fire up within a couple of seconds, no accelerator, no glow plugs.
I think I still had air in the line yet to come out.

I realize that until this is under load, I won't know how to fine tune by ear.
As it sits now the pump is secured in the middle of the slots
advancing is leaning toward the engine?

any suggestions before I button up the front ?

I am sooo thankful this thing is firing up!!
yeahyourite!!
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Paul
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Re: injector pump advice

Post by Paul »

swamp pup wrote:
Tue Nov 22, 2022 4:50 pm
So,..I just got it started,..a few times.
seems to fire up within a couple of seconds, no accelerator, no glow plugs.
I think I still had air in the line yet to come out.

I realize that until this is under load, I won't know how to fine tune by ear.
As it sits now the pump is secured in the middle of the slots
advancing is leaning toward the engine?

any suggestions before I button up the front ?

I am sooo thankful this thing is firing up!!
yeahyourite!!
Well, some success! But, no glow plugs? Most of these engines will not start when cold without using the glow plugs, even in the summer.

Won't keep running? Maybe you have an air leak in the fuel inlet line. An easy way to get an idea of this is to use a clear piece of plastic hose between the fuel filter and the injection pump.

Fine tuning? I would leave the pump where you have it for now. You can use a timing gauge to fine tune it later, but it may not make a noticeable difference. Leaning the top of the pump away from the engine will advance the timing.

I would not button up the front until you are happy with the way it runs.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
swamp pup
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Re: injector pump advice

Post by swamp pup »

So here's where we are...

rebuilt pump installed and belt on the marks, everything fires right up.

I haven't taken it out yet to see how it is under load but everything sounds as it should, no smoke.

I installed temporary clear Tygon lines fore and aft of the primer pump and am noticing a small periodic stream of bubbles coming into the primer, the line outbound half full.

I changed all of the soft lines at the tank and those after the hard lines as well.
Made a new gasket for the fuel cap.

as I sit here realizing that all of this losing prime seemed to happen only when I've had a half a tank or less,...

I'm thinking the line going down into the tank?
these sending units have a stem I imagine that doubtfully developed a hole, but maybe a seam or gasket at the top of the tank?

insight?

suggestions?
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puttputtinpup
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Re: injector pump advice

Post by puttputtinpup »

I have read in past posts about the pick up tube in the tank having pin holes in them, but I'm thinking that was primarily in gas trucks. I wouldn't doubt it could be a problem with the diesel also. Remember there are a couple of flexible lines at the tank. Those were replaced along with the others, I presume.
A new tube could probably be brazed onto a good section. Idk
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Paul
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Re: injector pump advice

Post by Paul »

I think the pickup tube is soft soldered into the tank. So, can be fairly easily removed and replaced. If there is a hole it probably can be repaired.

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.
swamp pup
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Re: injector pump advice

Post by swamp pup »

So, I took the bed off to check all of my leak culprits thoroughly.

Like Paul mentioned, the pick up tube is soldered in place and I can't see the tube from the fuel float opening.
Could this really be an issue?
If so, how would you suggest one remove and replace without screwing something up?

the tank looks clean but I noticed considerable surface rust on the float when I pulled it out. I imagine from 40 yrs. of condensation.
swamp pup
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Re: injector pump advice

Post by swamp pup »

I might add, at this point all of the soft lines have been replaced, and I have a clear line on the feed to the filter.

once primed and running, I am getting a slow periodic group of bubbles coming in from the tank, seemingly they lessen and eventually dissapear,..only to lose prime again overnight.
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