need pump advice

[ilikevwdiesel]

hello fellow dieselers. I live in Maine in the US. This past summer I picked up a 97 AAZ motor in Montreal. It was in a 92 Jetta, someone had put it in there and used the T3 turbo, the AAZ intake, and added an adjustable wastegate. The AAZ pump looked stock except for the boost pin which was from a 1.6TD. The motor started right up and ran good, but it leaked fuel from the throttle shaft. I took it back to the US and started tinkering with it. The first thing I did was take the pump to the nearest authorized bosch dealer to get the the leak fixed. They told me the throttle shaft was worn and needed replacing. We talked about options, I told them I had a 1.6 TD pump from an 85 Jetta, could we take the cover and throttle shaft off it and use it on the AAZ pump? They told me they could do that, and that got rid of the cluster%$) of linkage on the back of the pump. So they finished, and the pump sat for the rest of the summer while I found a nice ride to put the motor into. On one of my journeys to California I found a nice 82 Caddy which I bought and brought back. I ordered a TT Tuning 2.25 exhaust and gathered up all the other things needed for the swap. So I get the thing installed and start it up, it runs good but idles high, I turn down the throttle screw and it calms down. Now here's the problem: When I drive it at slow speeds in first and second gear with light throttle, it starts to buck like crazy, I have to let off the pedal or it will throw me out the window. This pump has the solenoid on the bottom front also. Anyone?

[blkboostedtruck]

do you have a wire from the solenoid jumped to the main one so it turns off and on with the ignition switch? if you don't do that it may help?
Duane

[ilikevwdiesel]

do you have a wire from the solenoid jumped to the main one so it turns off and on with the ignition switch? if you don't do that it may help?
Duane

I did that and it made it ping bad, like the timing was way advanced or something, not sure but didn't sound good. I'm stumped.

[burn_your_money]

What screw did you turn exactly? Pictures?

[ilikevwdiesel]

My guess is that it is an improper adjustment of the "residual pressure" screw.  The residual pressure screw is the screw that the accelerator lever comes to stop on at idle.  Someone might have used that screw to adjust the idle previously.  The idle on the later pumps should instead be adjusted at the stop screw for the "fast idle" lever at the back of the pump that goes to the cold start.  

Andrew

all that linkage on the back of the pump is gone, there's only the cold start lever there now. The cover on the pump is from an 85 so there's no fast idle provision on the cold start. I'll have to post some pics, would have when I did the OP but my camera is falling apart and it's a pain.

[arb]

On one of my journeys to California I found a nice 82 Caddy which I bought and brought back.

WOW !! Now that's a long distance body search. How did you get it back w/o spending more for shipping that you paid for the car ?

[ilikevwdiesel]

On one of my journeys to California I found a nice 82 Caddy which I bought and brought back.

WOW !! Now that's a long distance body search. How did you get it back w/o spending more for shipping that you paid for the car ?

HEY! DO NOT DERAIL MY THREAD!!!  :evil:

I towed it back with an 86 F250 diesel I bought out there too  

Seriously I need to figure this out I am jonzin to drive this thing

[ilikevwdiesel]

all that linkage on the back of the pump is gone, there's only the cold start lever there now. The cover on the pump is from an 85 so there's no fast idle provision on the cold start. I'll have to post some pics, would have when I did the OP but my camera is falling apart and it's a pain.

Did you swap out the governor spring capsule at the same time as you swapped on the older pump top?  

Andrew

I didn't do the work the bosch shop did. Basically they took the AAZ pump with the two piece pulley and mounted the cover on it from an 85 1.6 TD pump, the kind with no fast idle setup, just a cold start lever.

[ilikevwdiesel]

ok here's some pics of the thing:

[zukgod1]

ok here's some pics of the thing:
[/img]http://farm4.static.flickr.com/3044/3010623918_0366d05a8a.jpg?v=0http://farm4.static.flickr.com/3145/3010624294_4e45265cb6.jpg?v=0http://farm4.static.flickr.com/3015/3009788135_66411941f0.jpg?v=0http://farm4.static.flickr.com/3060/3010624880_53bbae47e7.jpg?v=0

http://farm4.static.flickr.com/3044/3010623918_0366d05a8a.jpg?v=0

http://farm4.static.flickr.com/3145/3010624294_4e45265cb6.jpg?v=0

http://farm4.static.flickr.com/3015/3009788135_66411941f0.jpg?v=0

http://farm4.static.flickr.com/3060/3010624880_53bbae47e7.jpg?v=0

Looks like a reg pump to me.

Your symptoms seem to be exactly like mine originally,

Turned out the return springs in the pump on the head it's self were wrong and the plunger wasn't returning fully.
New springs and the problem was gone.
The only time I experienced the bucking was in traffic when I was trying to go slow, once past that point it would run fine but dayum it was hard to drive when it was bucking.

[ilikevwdiesel]

thanks Dan I have some learning to do... :oops:

[ilikevwdiesel]

It has the '85 throttle shaft?

Andrew

yes it does the 85 cover, and throttle shaft

[zukgod1]

The only issue I can see with my theory is it doesn't sound like the changed the pump head?

If they did that me be your problem, one would think however that a Bosch rebuild center would know better.
I didn't, it was my first pump. It sure didn't take long to figure out something wasn't right in there though.

[ilikevwdiesel]

[qoute]Looks like a reg pump to me.

Your symptoms seem to be exactly like mine originally,

Turned out the return springs in the pump on the head it's self were wrong and the plunger wasn't returning fully.
New springs and the problem was gone.
The only time I experienced the bucking was in traffic when I was trying to go slow, once past that point it would run fine but dayum it was hard to drive when it was bucking.[/quote]

I'm starting to wonder about the springs, I got a 10mm head from a TDI and had them install it during the rebuild. I wonder?

[zukgod1]

There is a difference in the springs.

On my 9mm pump I didn't need the different springs but on the 10mm pump I did.

Not saying yours is the same but on mine there is a recess where the springs sit on the head. Only on the 10mm head the 9mm head there was no recesses it was flush so there was less pressure applied to return the plunger with the 10mm pump. The new springs were just that much taller to solve the problem.

Really hard to explain.

Anyone have a pic of a couple pump heads?