Should I kiss my IP goodbye?

[TechnoWeenie]

So, noticed on the highway, steady throttle application, that it will surge a bit at certain spots.. Thought it was air in the line...

Now, I notice a distinct lack of power....

and... now... going up a small hill, I can maintain power at low RPM, but as pedal goes farther to the floor, I lose power, and the engine sound gets... more harsh..almost like the rattle you get when it's cold....

Fuel filter has less than 3k miles on... probably less than 1k, really....

Thoughts?

Sometimes it runs great, other times it's slow. No rhyme or reason, hot or cold, rainy or sunny, running for 5 minutes or 5 hours, etc.

EDIT: 86 M1031, currently 27k miles, put about 5k on it in a little over a year.... filter was changed a couple months ago and has little use.... all other maintenance is up to date. I use TCW3 on most of my fuel fillups

 

[Chaski]

I'd put a section of clear yellow Tygon fuel hose on the return from the pump to be sure no air is getting introduced first.

Other possibilities include governor weight retainer failure. If your pump does not have a small metal tag with the letter E stamped on it it most likely has the old design that self destructs.

So, noticed on the highway, steady throttle application, that it will surge a bit at certain spots.. Thought it was air in the line...

Now, I notice a distinct lack of power....

and... now... going up a small hill, I can maintain power at low RPM, but as pedal goes farther to the floor, I lose power, and the engine sound gets... more harsh..almost like the rattle you get when it's cold....

Fuel filter has less than 3k miles on... probably less than 1k, really....

Thoughts?

Sometimes it runs great, other times it's slow. No rhyme or reason, hot or cold, rainy or sunny, running for 5 minutes or 5 hours, etc.

EDIT: 86 M1031, currently 27k miles, put about 5k on it in a little over a year.... filter was changed a couple months ago and has little use.... all other maintenance is up to date. I use TCW3 on most of my fuel fillups

 

[cucvrus]

Do NOT kiss old injection pumps good bye. Diesel fuel tastes and smells horrible. You may how ever kiss the new re-built injection pump. But at 30 years old I would say the pump has gone bad from sitting. Common issue. Easily remedied with a cost of about $350. I would change the lift pump while I was doing the injrction pump. They get full of sediment and crud also. Good Luck. No romance with injection pumps.

 

[goldneagle]

I would replace the lift pump (mechanical fuel pump) and possibly add an inline electric fuel pump. I did that on my M1008. Now when I turn the key on and WAIT for the WAIT light to go out, the electric fuel pump is circulating fuel through the system. My truck starts and runs great since the mod was done.

 

[cucvrus]

All mine run great with/out an electric fuel pump. Just saying. IMHO. The electric fuel pump is not needed in addition to a stock mechanical lift pump. Do as you wish but I would avoid the extra cost and aggravation. 30 + years in ran as designed just fix the problem not change and add more faults to the design. Peace man.

 

[goldneagle]

All mine run great with/out an electric fuel pump. Just saying. IMHO. The electric fuel pump is not needed in addition to a stock mechanical lift pump. Do as you wish but I would avoid the extra cost and aggravation. 30 + years in ran as designed just fix the problem not change and add more faults to the design. Peace man.

My IP has a minor leak through the throttle linkage seal so I would get some air in the line when it sat a few days. I do not want to spend the money to have it fixed since it is minor. Besides there is nothing wrong with redundancy. It was less than $20 for the electric fuel pump from NAPA.

 

[cucvrus]

Throttle shaft o rings/seals are less then $5. and that will quickly be recovered in the lost fuel savings alone. Yes I would not replace an injection pump for throttle shaft seals either. Back to the original inquiry that started this thread. I still think he is having an injection pump on the way out. The injection pump change with a fresh rebuilt pump resolves a lot of issues at the single cost. Hard starting,loss of power, excessive smoke just to name a few. And adding an electric pump really has a minimum of benefits. i was trying to resolve the original issue not add more parts. Peace man.

 

[goldneagle]

Throttle shaft o rings/seals are less then $5. and that will quickly be recovered in the lost fuel savings alone. Yes I would not replace an injection pump for throttle shaft seals either. Back to the original inquiry that started this thread. I still think he is having an injection pump on the way out. The injection pump change with a fresh rebuilt pump resolves a lot of issues at the single cost. Hard starting,loss of power, excessive smoke just to name a few. And adding an electric pump really has a minimum of benefits. i was trying to resolve the original issue not add more parts. Peace man.

$5 part. What about the labor. Not everyone is a mechanic. Shop cost here is $80 to $90 per hour.

 

[cucvrus]

$5 part. What about the labor. Not everyone is a mechanic. Shop cost here is $80 to $90 per hour.

Exactly. I agree that is why I would not put anymore add ons that are not needed. Just more to go wrong. And then when it don't run right and you bring it to someone like me. You pay me to get it back into reliable running order again. And the first thing I do is remove all the addons that can cause more problems. I just like plain and simple. As do the books when it comes for NON mechanics to diagnose. I am not a mechanic. That degree was never earned. I just worked on vehicles all my life. I would have to get a degree to be a true mechanic. I am a Pennsylvania Certified inspection mechanic. But that just means I know how to properly check safety related items on vehicles. I do not need to know how to fix them. I have not been in a mechanical position since 1986. The last school I went to was about the wiring circuitry of the high mount 3rd brake light. That became mandatory on all 1986 and never cars. I used some of that knowledge to mount 3rd brake lights on several M1009's. Other then that I just work on trial and error and what I learned along the way. WOW. $80.- $90. an hour. I only charge $30. I am not free but I guess too cheap. It works for me. I have lots of work most of the time. Peace man. Have a great day.