'98 Jetta. No revs.

[shagin'wagen]

Hi all,

I'm looking at buying a '98 Jetta TDI for a decent price. It has 387 000Km on it. So it's a bit high, but not too bad. However the car does not rev above 1300 RPM. There's just no power. Not much for smoke either when driving, a bit of white smoke. It starts ok in the cold, however there's lots of white and black smoke for a few seconds. Then it idles pretty clean. You can tell there was lots of black smoke in the past because the whole trunk/bumper area is covered in soot.

I'm thinking there is some sort of fuel issue here. Not sure exactly what, but I'm thinking that there may be a plugged fuel pickup (says the fuel filter was replaced not too long ago) or the injector pump. The MAF and N75 valve was replaced, so it's not that.

Any ideas on this? The owner says he's on here too, so he may chime in.

If it is the IP, would a 10mm one from a ALH fit, or are they different? I think they are, but want to make sure since I got a spare sitting on the shelf.

-Martin

 

[thebigarniedog]

Hi all,

I'm looking at buying a '98 Jetta TDI for a decent price. It has 387 000Km on it. So it's a bit high, but not too bad. However the car does not rev above 1300 RPM. There's just no power. Not much for smoke either when driving, a bit of white smoke. It starts ok in the cold, however there's lots of white and black smoke for a few seconds. Then it idles pretty clean. You can tell there was lots of black smoke in the past because the whole trunk/bumper area is covered in soot.

I'm thinking there is some sort of fuel issue here. Not sure exactly what, but I'm thinking that there may be a plugged fuel pickup (says the fuel filter was replaced not too long ago) or the injector pump. The MAF and N75 valve was replaced, so it's not that.

Any ideas on this? The owner says he's on here too, so he may chime in.

If it is the IP, would a 10mm one from a ALH fit, or are they different? I think they are, but want to make sure since I got a spare sitting on the shelf.

-Martin

Moderator GoFaster has an excellent low power thread in the A3 section. My car, had similar problems ..... see Muffy in my signature ..... Before doing anything else, I would change every vacuum hose including the one in the ecu. Note, I said change, not inspect. The injection pump is different but per Growler can be made to work with the AHU.

 

[shagin'wagen]

Thanks. I think he was changing vac hoses, but I'll let him speak for himself.

 

[OldSchoolFresh]

Yup that's my car some of you may remember a thread I made a while ago, http://forums.tdiclub.com/showthread.php?t=270915
I did check the hose inside the ECU and replaced the one leading to it and still no change, replaced the N75 and MAF no change, and am currently in the process of changing the vacuum lines, albeit slowly since I don't have as much free time as I used to. Other than changing the lines I'm out of ideas.

 

[shagin'wagen]

Did you ever change out that small hose in the ECU?

 

[Vince Waldon]

Been there done that on an ALH Martin... pulled the connector off the MAF as a test and all of a sudden the car knew what 5000 RPM could be. Dunno if an AHU pays as much attention to the MAF, mind you?

.

 

[OldSchoolFresh]

Did you ever change out that small hose in the ECU?

Sure did, no change.

 

[shagin'wagen]

Had the MAF in my '99 go bad. Was like driving the IDI all over again. Unplugged it till I got a new one.

The MAF in this car was replaced, so I don't know what's bothering it. Hopefully it is something simple and easy.

Hopefully going to head to Edmonton next weekend with tools and ramps to try to get to the bottom of this. You should come by too Vince. The car isn't too far from your place. 15 minutes tops. 2 heads are better than 1.

 

[OldSchoolFresh]

The more the merrier!

 

[sullyTDI]

Had the MAF in my '99 go bad. Was like driving the IDI all over again. Unplugged it till I got a new one.

The MAF in this car was replaced, so I don't know what's bothering it. Hopefully it is something simple and easy.

Hopefully going to head to Edmonton next weekend with tools and ramps to try to get to the bottom of this. You should come by too Vince. The car isn't too far from your place. 15 minutes tops. 2 heads are better than 1.

MAF's Can be bad right out the box, if you haven't tried it unplug it and give it a try. The ecu will use the default value. Wouldnt hurt....

 

[shagin'wagen]

Any more insight on this? What could be causing the misfiring?

 

[thebigarniedog]

Any more insight on this? What could be causing the misfiring?

Again, all the vacuum hoses must be replaced. The owner has not yet done this per his post in this thread. I would also note that the ALH is a different animal then the AHU when it comes to these vacuum lines ---- I think I discuss this in some detail in my referenced thread. Good luck ......

 

[OldSchoolFresh]

Props to shagin'wagen for coming by again and taking a look, we tried connecting a post on the injector pump to the postive terminal on the battery and we measured a amperage going though. The car definately revved quicker but sounded like crap and still didn't rev over 2000. We tried it again and connecting the pump to the negative terminal and the car sounded better but revved slower. Injection pump failure? shagin'wagen has some pics and he can help clarify.

 

[shagin'wagen]

Alright. What I did was unplug the connector in the pic here:

The one wire goes to the fuel solenoid and the other 2 go to a sensor of some sort near the bottom of the pump as pictured here:

All I did was run my multimeter from the + side of the battery to the solenoid to give it power in the amperage setting. That data was pretty useless since all I wanted to do was give the solenoid power and that is all that I had with me. However the engine did rev higher, but sounded like ass still.

Then I tried grounding the pump directly to the battery in case there was a bad connection. Again, it did rev higher and was smoother, but still not as it should.

All the while when we did rev it up there is LOTS of white smoke.

I'm out of ideas. All the vac lines are good now, and I'm thinking it is the injection pump that is messed. Yay or Nay?

 

[OldSchoolFresh]

It definitely is a puzzling problem! Anyone with any ideas?

 

[shagin'wagen]

Nobody? Really?