Advance or Retard Injection Pump Timing * now with results *

Post by **Fatmobile** » Thu Dec 13, 2007 4:53 pm

Cleaning the injectors doesn't mean much.
You should have them tested for spray pattern and breaking pressure.

82vdub · Post by **82vdub** » Thu Dec 13, 2007 5:02 pm

I think the point was missed. A few weeks back I fixed my cold starting problem (was glow plugs). After that, I pulled the engine to do motor mounts and a bunch of other things. Of course, the timing belt and IP were removed, which makes any previous running condition/timing condition pretty much unknown since you have to re-time the system. Because the top of the injectors were exposed and the lines removed, this allows dirt to get in the lines and cause one to not operate correctly. Remember, it operated correctly before this work was done and I have one cylinder that now runs 20 degrees colder than the others. From before this happened, this cylinder was not touched, except for the removal of the injector lines etc. Since I have a problem with one injector (when it's started from cold and for the first couple minutes running when it's cold), I don't suspect that anything is wrong with the physical injector, since this did not change, and the timing was spot on according to the Bentley. I suspect dirt or something in the line causing a blockage. That's my assumption at this point since I've had this noise and issue before. When I blow out the injector tops, IP ports and injector lines and re-assemble, I will find out the next cold start I do if this was the issue and will post results after that.

82vdub · Post by **82vdub** » Mon Dec 17, 2007 9:58 am

As I get older, I'm beginning to hate this time of year more and more. It's always dark and my hands can't take the cold like they used to.

On Sat, I fired up the car, warmed it up and then took off the injector lines to blow them out to see if there was anything in one of the lines. Waited 4 hours to see how it started and sounded, and it was pretty much the same.

So, on Sunday, I fired the car up, warmed it up and proceeded to advance the IP timing. I couldn't move it far enough to get much noise, but I moved it as far as I could. It's about 1/8" advanced (as marked on the IP and IP bracket) from where it was initially set. When I run the car and pull out the cold start cable, there's more marbles dancing on a plate. I didn't really hear a noise change prior to this when pulling out the cold start cable. I let the car sit 4 hours and started it up, and I think it's better. Hard to tell though.

Tonight when I get home, I'm going to see how she fires up from sitting outside all day. This past weekend was my last daylight hours to work on the car before our trip this weekend.

vwkook · Post by **vwkook** » Mon Dec 17, 2007 10:19 am

You'll be just fine. Just don't lug it in the mountains. You'll fit right in with the semis with their hazzards on climbing passes in third gear.

82vdub · Post by **82vdub** » Mon Dec 17, 2007 10:41 am

I won't be running it in the mountains this trip. I've never lugged the car on hills either. If I'm slowing down to about 50, I'll drop down to 3rd and run it at 45-50 up the rest of the hill. I sure would like a nice 5 speed..........

JRM · Post by **JRM** » Mon Dec 17, 2007 12:46 pm

yeah but with my 5 speed 4th revs out hard at 55MPH then no guts to pull 5th, so on my commute im still pullin 7% hills at 55MPH in a 70MPH zone, its rough and dangerous in my neck of the woods. Girlfriend is really pressuring me into a Turbo Subaru WRX so I can pull these hills on my new commute where I MUST climb 4-5 18% grades that are 2-7 miles long at over 60MPH. I climb from sea level to 6,000 feet

82vdub · Post by **82vdub** » Mon Dec 17, 2007 2:40 pm

The 4th gear in your 5 speed has lower revs than 3rd gear in my 4th speed. I run it up to 55 in 3rd on occassion, but it sure sounds like it's going to grenade.

backwoods · Post by **backwoods** » Tue Dec 18, 2007 9:32 pm

This is interesting stuff, as a reference to how my NA Rabbit behaves. My pump is set by noise, somewhat clattery at idle, and the pump mark ends up lining up with the clockwise (head) side of the mount plate mark.

The cold start has resistance and snap only when the engine is idling. At any sort of road speed it has no feel at all. I'm assuming that at idle it pushes on the advance device piston, but at any normal running speed the piston has already moved out of range ... as in, the cold start raises the minimum timing but does not add to the timing in general so should have no effect once underway.

The idle timing seems to have little effect once underway. A small part of a degree advance makes the idle very clattery, but it all disappears when the engine passes maybe 1000 rpm. I'm guessing my idle is around 700, judging from how my tractor looks when the tach says around 700. Noticeable vibration at idle, but very steady even stone cold, you can feel each cylinder hit, so I'm guessing they're all behaving themselves lol.

tawney · Post by **tawney** » Tue Dec 18, 2007 9:57 pm

I'm assuming that at idle it pushes on the advance device piston, but at any normal running speed the piston has already moved out of range ... as in, the cold start raises the minimum timing but does not add to the timing in general so should have no effect once underway.

Assumption is exactly correct. Cold start mechanism advances the timing by 2.5 degrees; internal pump pressure, which is roughly proportional to rpm, activates the advance mechanism, so once the engine is running it advances farther than that rather early in the rpm range.

82vdub · Post by **82vdub** » Wed Dec 19, 2007 10:31 am

Ok, some real world data after driving the car to work for a couple days.

When I start the car when its cold out (at lunch or after work), the diesel noise (plate of marbles) is somewhat loud for about 2-3 minutes, then quiets down. The cold start cable increases the noise slightly when pulled out. After the car runs for the couple minutes and quiets down, pulling the cold start cable changes the noise, but does not make it really loud.

When cold, the car still seems to start and run on 3 cylinders, but if I partially let the clutch out for 5 seconds and put a load on the motor, it runs on all 4 cylinders.

Based on this information, I think the timing is well set, not too advanced and not too retarded. I have not input a dial gauge to see what the reading is, but may get to that later. As far as I'm concerned, she's good for this weekend's trek to Colorado.

P.S. - Just for a side note, I've been wrenching on engines and my own cars for close to 30 years now. I'm pretty good when it comes to the actual work and I can tune an old big block gas engine pretty well. When it comes to doing the fine adjusting and tuning on the diesel, this is pretty new to me, even though I've been wrenching on my VW engine for a while. I had previously left the timing belt replacement and IP adjustments to someone that had a clue, but as each year goes on, I keep pushing myself to do and learn more and more. hippiehulahooper and greenrab - you keep working on getting your cars running. It may frustrate the hell out of you for a while, but you keep going. When you're done, you will know MUCH more than you did before, and next time you find yourself with a similar situation, you will likely solve the problem much, much faster with half the work. Keep up with the learning - YOU WILL FIX IT!

surfcam · Post by **surfcam** » Wed Dec 19, 2007 12:08 pm

I just thought that I would add the point of being a pack rat and VW's go hand and hand. It is sure handy to have a few spare parts around to diagnose probems. Replace your IP with a spare. If that fixes the problem you could work on the new spare at your leisure. Last month I changed at CV joint and noticed the rotor was a little groovey. Since the car is all jacked up with the wheel off its only 10 minute job to change it. I heard they can do it faster in California but I'm semi-retired and have more coffee breaks.

Post by **Fatmobile** » Thu Dec 20, 2007 1:34 am

Turning the injection pump is much like turning the distributor on an old V8,... just like old times

. Ha, you don't even know,.. or care where it's set, it runs good so that's wher eit belongs.
I usually check to see where that pump injector combo likes it.
You said you couldn't turn it much, why was that? Hit the end or it was hard to turn?
I grabbed the pump with a pair of vice grips, like a big timing handle it was.
Remember to loosen the injector lines at the end of the head when you are done adjusting timing. The twisting stress on the injector line (that makes it hard to turn) with all the vibrations and pulses, can cause a line to crack.
I put a rag under them, loosen them all up, snug them up lightly and start it. Then tighten them until they quit leaking and no more. Clean it up, run it, check for leaks... until they stop leaking. Overtightening them can cause leaks.

82vdub · Post by **82vdub** » Thu Dec 20, 2007 9:43 am

From past work on IP/timing belt replacement, If I remember correctly, I found that by loosening up the IP bolts a little would allow the IP to rotate a little, but to fully rotate it the full slotted open area, the bolts needed to be undone more. I can't remember if it's the bolt that's behind the pully that stopped it from moving more, or if it was the one under the output side of the IP.

I didn't want to go too far with it as it was an experiment anyways. It runs great and if it needs to be rotated any further, it's probably not needed to move by much. I did clamp a vice grip on the bracket on the IP, but it didn't provide much leverage without the possibility of bending the bracket.

I did loosen the IP lines - actually completely removed them and reseated both ends to make sure nothing was stressed in any direction.

It's heading for Colorado tomorrow, so hopefully I won't need to do any wrenching on the road.

Post by **Fatmobile** » Fri Dec 21, 2007 12:11 am

Happy trails.

82vdub · Post by **82vdub** » Fri Dec 21, 2007 8:16 pm

We made 400 miles today and am sitting in a motel in central Iowa trying to figure out what to do for tomorrow's trip to avoid snow. I did find that I had a noisy injector and could hear it at about 45MPH and slower when I gave it gas (put a load on the motor). After stopping at wallymart, it wasn't as loud from there to the motel, maybe the motor cooled enough where it wasn't making a noise. I pulled one of the injectors out tonight in the parking lot and blew it out as best I could, but when I ran it, it seems to have the slight noise. So, I probably pulled the wrong injector, but I do have one that's making noise that will need to be dealt with. Think I'll damage the motor by continuing to run it?