Installed rebuilt injectors and problem remains or even a little worse

[78sharpshooter]

86 Jetta GL Turbo ~220K miles, 5 spd, intermittent rough idle with a lot of shaking, not much throttle response from 1/4 to 3/4, checked injectors and 2 were wet (the one near the oil drain hole had a lot of very dark fluid on the end which did not appear to be oil but diesel fuel and carbon mixed), replaced the injectors with reman 155 BAR bosch and not much changed and perhaps the rough idles happens more frequently. At stop lights I have to hold the brake and accelerator with my right foot otherwise it shakes really bad (doesn't die). No excessive smoking, the previous owner had the timing belt replaced in Jan and the receipt said the motor mounts were bad and causing the shaking. Checked the cam timing and it is dead on relative to TDC (the locking pin went in on the IP gear while at TDC). The cold start lever helps in the morning even though it is only 62 F. Boost doesn't appear until the last 1/4 throttle. I am planning on having the IP rebuilt but am new to the VW IDI and wanted to get the input from the forum here before spending $500+ (IP rebuild from vwdieselparts.com)

[Vincent Waldon]

Two thoughts in terms of things you can measure scientifically to investigate further:

- what is your injection pump set to, numerically? 
- what is your compression like?  In particular, any weak cylinders?

[78sharpshooter]

I tested compression with a chinese guage and all cylinders were 350 to 360 psi which I know is far below the bentley specs but because it starts right up and seems to run very smoothly besides idle, I'd like to think the gauge is not accurate so I trust the relative differences instead. The PO said the motor was completely rebuilt ~60K mi ago but I have to call the owner before him to confirm that.

I have the adapter and dial indicator (chinese stuff) but haven't measured IP timing.

I noticed that the rebuilt injectors were sand blasted on the outside and was going to use my marine grade corrosion spray to cover them but is there something else that is preferred for preventing rust on the injectors?

[burn_your_money]

Sounds like air or a plugged fuel filter to me.

Hook a vacuum gauge up to the fuel feed line post filter and see what the reading is when it's idling rough.

[78sharpshooter]

the fuel filter is new but maybe that does not automatically mean it is not bad. Instead of the vacuum guage could I rig up a small fuel bottle to see if the rough idle is gone while fed from the bottle?

[burn_your_money]

Yes that would work as well. Put both the feed and return into it.

It could be the intank filter as well

[78sharpshooter]

So I pulled the fuel line at the filter and stuck it into a glass jar with fuel and nothing changed. Then I pulled the return line and stuffed it into the glass jar as well and nothing changed but from the return line was a fair amount of soda sized bubbles such that after a 25 seconds or so it was looking like a freshly poored pint of boddingtons minus the head. Is this typical? I also noticed that where the return line attaches at the banjo bolt on the pump the line spins on the banjo bolt easily. They look like they are the original fuel lines with red lettering and 86 on them. There is no fuel leaking from the injector lines or anywhere on the pump. After reconnecting the lines it idled rougher but I just moved it to park it so perhaps there was still some air in the fuel filter.

[Baron VonZeppelin]

All those tiny bubbles are not normal.
Maybe that loose line/fitting you're talking about is causing them.

On your running issues, sounds like you only have 2 more hopes.
An ATF soak for a day or two
or/and
Diesel Purge treatment

After that, sounds like you might need another pump - or have yours rebuilt.

Partsplace.com in Michigan might be competitive price range.

A performance rebuild by the master in canada is running about $700-800 plus shipping both ways on a TD pump.

[78sharpshooter]

I just replaced both fuel lines (feed and return) and nothing changed. When I first got it I gave it a large dose of diesel clean in the tank but if I add 1 or 2 quarts of ATF to the tank would the increase in viscosity temporarily compensate for a worn pump? Thanks for the heads up on parts place because I'd rather do it all in one day than pull the pump and wait a few days to install it again. I think everything behind the pump has been eliminated and nothing is leaking and there's new injectors........gotta be the pump.

[78sharpshooter]

Looking harder at the pump it seems to me that someone tried increasing the idle stop screw way out and that the rocking arm at the idle link to the cold start doesn't appear to have the ability to move much. Does anything look abnormal?

[78sharpshooter]

any suggestions for what dose of ATF I should try?

[burn_your_money]

Take the feed off and stick it in a quart of ATF. Run the engine so that the pump fills right up and then let it sit.

I suspect that you have worn out driveshaft bushings. This is allowing the driveshaft to be pulled out of the sealing range of the driveshaft seal. A full overhaul would be required.

Your pump looks like it was recently rebuilt though. Any info on that?

[78sharpshooter]

Thanks for the info and I will feed it ATF tonight and let it sit overnight.

The whole engine compartment is very clean for an 86 but I still have to give the original owner a call to see if the pump was rebuilt when the motor was supposedly rebuilt.