Loss of Power

[dieselVinceOH]

I have owned my Rabbit for 6 years now. I decided to have my 300,000 mile 1.6 n/a engine rebuilt by Jack earlier this year. Everything is all in, and runs great but I'm having a couple issues and I don't really know where else to look. I have about 1400 miles on the new engine, and I did a valve adjustment 450 miles ago. It starts on the second rotation every single time. If it makes any difference, I have the 3+E 4-speed manual transmission (4A code) and a new clutch assembly as well.

I have a problem with loss of power. Now, I know that these aren't exactly race cars, but this is worse than what I've experienced. Even my worn out, low compression engine had more power. Climbing any kind of hill is a daunting task, and I usually end up doing it in 2nd gear at 15-20mph. The freeway is also an issue; if I'm going 60 and there is any kind of elevation, I quickly loose speed. Sometimes I can get it to maintain a speed if I go close to WOT or completely WOT, but not always. And if I have another person in the car with me, I can't go on the freeway, it's too dangerous.

I have no air in my fuel lines (My fuel filter was changed in the past 500 miles), the injectors are brand new rebuilds and the injection pump was rebuilt when I had the engine done. Jack timed the injection pump to 1.01mm. My exhaust isn't smoking, just a light gray haze when I shift and a little black puff when I start it. I can only see the gray haze at night when someone is traveling behind me.

I decided to try advancing the fuel screw 1/4 of a turn to see if that made a difference. It seemed to make a difference in my power, but holy smokes! Tons of black exhaust smoke whenever I was accelerating and/or going above 45. I turned the fuel screw back down to where it was before.

I have no idea where else to look. Does anyone have suggestions?

[TylerDurden]

Everything sounds in order, but since you have a problem, everything is suspect.

I'd start by advancing the timing - see if it helps. I know, >1mm sounds like a lot, but could be the injector pops are high and delaying injection.

[dieselVinceOH]

Everything sounds in order, but since you have a problem, everything is suspect.

I'd start by advancing the timing - see if it helps. I know, >1mm sounds like a lot, but could be the injector pops are high and delaying injection.

How high do you think I should go? Should I try 1.02, 1.03, etc? I don't want to advance it too much and blow the top end off.

[TylerDurden]

I'd do a hillbilly timing: turn the IP until the cusp of clatter (engine warm), tighten it down and relax the hardlines.

Not much risk of blowing the top... If it always clatters, back off a hair.

This is just a test. If it runs well, you can just keep that setting. If no difference, I'd set IP back to the original position and test compression.

[Fatmobile]

Mark where the pump is now and move the top toward the head, "a pencil line worth" try it again.
The numbers mean nothing it gets adjusted to where it runs best.

Do you have clear line coming from the pump, going toward the tank and between the injectors?
Cam/crank timing checked?

[dieselVinceOH]

I do have the clear line going from the filter to the injection pump.

I advanced the pump last night and took it for a drive. Advancing the pump actually made the power problem worse and it caused black smoked really bad. Power was okay on the low end, but after 45 I had almost nothing. I ran 3rd gear to 55mph and could barely get on to the freeway even though the ramp is flat. Normally I can shift at 45-50 and have no issue gaining speed on that ramp.

Tonight I'm going to check my cam to crank timing and make sure everything is lined up. I don't know why I didn't think of that before.

I think I'm going to dig out my dial gauge and set the timing that way. I honestly have no clue what a healthy diesel VW engine sounds like, so I'm not as comfortable doing it by ear.

Thanks for the suggestions everyone, I'll let you know my results.

[greg lousy]

I've messed with IP timing a lot on 3 vehicles. It definitely effects power but not to the extent you seem to describe here. If its in a runnable range I wouldn't expect that kind of performance.
My first thought would be to crack the injector lines one at a time and listen for loss of power. if youve got one cylinder that doesn't sound like its doing much, swap the injector and see if thats it... that way if it is an injector issue you can adress it without getting into compression.

your posts also make me wonder, was the re- torque was done after 1k miles... maybe losing compression through gasket, if everything else is rebuilt

[Fatmobile]

If advancing it made it worse, retard it a little.
Get a clear line from the pump back toward the tank.

[dieselVinceOH]

So yesterday I dug out my dial gauge and timed it with that. My problem was two things; when I hillbilly tuned it, I put it at 1.40mm, and the timing was off. It was 1° after top dead center.

I set the pump to .95mm and all seems to be well again! I have good power and no smoke. Thanks for the help everyone!

[dieselVinceOH]

your posts also make me wonder, was the re- torque was done after 1k miles... maybe losing compression through gasket, if everything else is rebuilt

I turned the head bolts 1/4 of a turn at 1,000 miles.