How to tell if Injection Pump is Bad?

[Doakster]

What's  the best way to tell if your injection pump is going bad? Can you check the output pressure some how?

I've been trying to track down a mileage issue for some time now. Rebuilt injectors are going back in this week, IP timing is good just checked it tonight, fuel filter is new, turbo does have oil around it and I can't figure out where it's coming from, going to put a new air filter in and check the compression tomorrow.

[ilikevwdiesel]

hey I'm in Maine where are you at?

[maxfax]

Unless the pump is leaking, preocess of elimination is best way of checking the pump, short of pulling it and having someone check it on a test bench...

[Doakster]

hey I'm in Maine where are you at?

I'm a ways north...Lincoln area

[Doakster]

Unless the pump is leaking, preocess of elimination is best way of checking the pump, short of pulling it and having someone check it on a test bench...

So what's the process of elimination, i've tried just about every thing short of pulling the turbo and having it rebuilt.

Also checked the compression tonight...all good at around 440-450 psi

[Rabbit TD]

I've  read on here numerous times that when mileage starts dropping off and the motor seems to have no other problems that air getting in the fuel line to the pump is a good cause for this, that's where the clear fuel line from the filter to the pump comes in handy. 

[Doakster]

I've  read on here numerous times that when mileage starts dropping off and the motor seems to have no other problems that air getting in the fuel line to the pump is a good cause for this, that's where the clear fuel line from the filter to the pump comes in handy. 

Funny you say that because I do get an air bubble going from he filter to the pump every once in awhile, I just put on new rubber hoses on that line, but I'll have to check again.

Also with my new rebuilt injectors my mileage went from 30ish up to 35ish....still not the same as my 43 I was previously getting

[92EcoDiesel Jetta]

Do you have a fuel leak somewhere? How about the odometer? Have you verified that it is not slipping and counting every mile? Air can get in from bad seals in the IP. I was seeing bubbles in the clear fuel line. I also had a leak in the distributor head o-ring. I replaced that o-ring and the leak is gone as well as the bubbles.

[Doakster]

Do you have a fuel leak somewhere? How about the odometer? Have you verified that it is not slipping and counting every mile? Air can get in from bad seals in the IP. I was seeing bubbles in the clear fuel line. I also had a leak in the distributor head o-ring. I replaced that o-ring and the leak is gone as well as the bubbles.

I verified the mileage on a GPS, it's within a half a MPH.

Also false alarm on the bubbles, I had observed that just after I finished the install on the injectors, so it was working the air out, no bubble now.

I am still completely stumped. It's frustrating when I read a bunch of posts about people getting around 45mph no prob with and ECO, I had that once, but can't seem to get it back.

[Powered by Spearco]

Here's a stupid question, but does your throttle cable need adjusting?

[Doakster]

Here's a stupid question, but does your throttle cable need adjusting?

Well I don't think so...I can cruise fine 60-75 on the highway no problem....throttle works smooth. How are you relating throttle cable to a mileage issue?

[Rich_91]

What's  the best way to tell if your injection pump is going bad? Can you check the output pressure some how?

I've been trying to track down a mileage issue for some time now.

I am having exactly the same issue. I have no visible fuel leaks, and I am wondering if one of the IP seals is sucking air somehow?

Im not sure how to test this though.

My milage is around 6.7L / 100km 

Are your injectors original or quite old? I did get an increase in power and milage when I replaced mine last fall, but my fuel milage is still well below what it should be.

[Doakster]

Injectors are freshly rebuilt, just put them in a few days ago. Mileage only increased from 30 to 35 mpg, I've verified there is no fuel leaks to and from the pump, no air bubbles are visible what so ever in the clear lines.

I just inspected my turbo piping, and reinstalled with RTV sealer at the hoses...we'll see if that helps. 

[Rabbit TD]

Here's a stupid question, but does your throttle cable need adjusting?
[/quote
From what I've seen they almost always have slack in them and keep it from going to full throttle.

[Doakster]

Here's a stupid question, but does your throttle cable need adjusting?
[/quote
From what I've seen they almost always have slack in them and keep it from going to full throttle.

Just verified I can go to full throttle....with the peddle all the way down the throttle arm on the pump bottoms out on the adjustment screw before it hit the peddle stop inside the car.

I've always run this car no more than 60-70 mph freeway, and have always had more throttle to go.