Horrible Mileage...STILL...after alot of work/troubleshooting

[Doakster]

Thanks, i'd greatly appreciate it, i've never had to take a VDO cluster apart before and it sounds a little hairy from the description. Any thing you can find on the repair would be appreciated.

[Rabbit TD]

I just found it.  I don't know how to do the posting links thing but if you search {VW cheap tricks} it is listed in the repairs section under broken odometer.  It shows exactly how to do it with all the pictures.  This guy has a very interesting site and it's amazing how many of his problems he lists are ones I've had.  Check out the Missing Link shifter kits he has too.  From what I remember it wasn't as complicated as it sounds and he shows how to do it step by step.

[Doakster]

I just found these two links on the subject, the second one is the write-up. Sounds like quite a process to do the repair.

http://www.4crawler.com/Diesel/CheapTricks/Odometer.shtml

http://mysite.verizon.net/janvdb/vw/Body/speedo_fix.txt

[Doakster]

Also found this one, the guy used snap rings to hold the split gear together, probably will never fail. And it seems like there is much less tear down of the cluster to get to the gear in his explanation. What exactly did you do to the cluster to get to this gear?

http://forums.vwvortex.com/zerothread?id=4181342

[Rabbit TD]

Also found this one, the guy used snap rings to hold the split gear together, probably will never fail. And it seems like there is much less tear down of the cluster to get to the gear in his explanation. What exactly did you do to the cluster to get to this gear?

http://forums.vwvortex.com/zerothread?id=4181342

It's been about 4 years since I did it but once the cluster is out the speedometer then comes out and it's pretty straight forward from there.  He does have the instructions there at his site.  I can't remember if the speedometer needle has to come off or not but if it does carefully mark it's location to the shaft somehow.  Like I said this is all for a Rabbit but it's a VDO unit regardless.  There are places on the net where you can even get replacement gears for these speedometers if need be but his drill and supeglue method works fine.  Just follow his guidlines and it's not hard at all.  From the other things you've done with your pump, injectors ect. this is just childs play

[Doakster]

Did another mileage check tonight and here are the results.

Topped of the tank and checked the following:

Odometer: 112696
Trip Meter: 0
GPS Trip:   0

Ran the car for over 2 hours on my normal trip home, here are the results:

Odometer: 112812
Trip Meter: 116.? (don't remember the tenths)
GPS Trip:   123.64

Topped off tank, total of 3.941 gallons used

Mileages:

Odometer: 116miles / 3.941 = 29.4mpg
Trip Meter: 116miles / 3.941 = 29.4mpg
GPS Trip:   123.64miles / 3.941 = 31.3mpg

So I've proved the following:

1. My odometer and trip meter are right in check with one another.
2. My odometer & trip are only slightly off from the GPS check, not nearly enough to cause such poor mileage. The odometer runs smooth, no clicking what so ever, so the odometer is not the issue.
3. The difference has to be due to my larger tires. As i said my speedo runs about 2-3mph slower, so running the car for just over 2 hours at 60-65mph more or less accounts for the 7mile difference between the GPS and the odometer/tripmeter.

Today was a new low for me and the car. It went into the 20s with the mileage, can't believe it, just keeps getting worse.

How could i have NO mileage increase while increasing the IP internal pressure?

I still think it is the IP or the turbo, maybe my wastegate is stuck open? I have to get my gauges in and see what i'm putting out for boost.

Who want to by a car?

I'm probably going to post this up on vwdieselparts forum just to get a few more thoughts on this mind numbing issue.

[Doakster]

What's the condition of the car?  My folks are in Gorham, Maine and I'm due for a visit.  My dad just had a heart attack and angioplasty...     I don't do rust, tho.... 

Actually the car is in great shape, only has a little rust on the around the gas cap and small spot on the door, has low mileage at 112k. Heck i think i've put easily $4,000k in parts into it in the last year with the new peloquin, clutch, complete new front with 11 in brakes in the front, new brakes and bearings in the rear, 2.25in exhaust, wheels, etc, etc. I have an VW original Votex console that needs to go in along with my gauges and a new radio. Bet there are not too many 1.6s with a peloquin and a Votex console floating around.

I'm so frustrated with the thing i just want to sell it, but then again i get pissed at myself because i can't figure it out. When i get that way i usually don't stop until i figure the problem out, it becomes a mission for me.

So we'll see. It's been a good car for me except chasing the mileage issue. It helps me keep the mileage off my F-350 diesel, but then again i bought the car for great mileage and I love MK2 cars, and it's not delivering.

We'll see, i probably won't end up selling it. Want to stop by and take a look at it while you're in Maine?

[Doakster]

Here's a couple of pics of the car:

Trailering it down, so i can go pull the trans:




The day i brought it home:


A little front end work:





If I keep the car it's going to get the following treatment:

- H&R sport springs
- Single Round headlight conversion, with black turn signals
- New Radio/speakers
- The Votex console with gauges
- Giles Pump or new turbo (if it needs it)

[Quantum TD]

Couple of thoughts:

1) Are you running a thermostat? Or, did you drill some holes in it? ECOdiesels are notorious for running hotish.  Not sure why. If you are running no t-stat or have drilled holes in it, or it's stuck open, you might be affecting the mileage due to lack of thermal efficiency. Others can chime in, cause I really don't know much about it. But, the bottom line is you want your diesel to run in the 190F range (87 C).If you aren't in that range, it can affect mileage.

2) Have you checked that your fuel return line is clear to the tank? One of the trouble-shooting tips is to blow the fuel back to tank and make sure it's clear. If not, that can affect mileage.

3) Compression test? Some think that off compressions can affect mileage. I'm sure it can to some degree, but I'm not sure it can account for 15 MPG worth of discrepancy. But, it could be a good idea to check and rule it out. But, given the mileage you were getting before this happened (see below), I'm not sure this is the problem. I just can't see a sudden drop in compression causing this (even if you blew the HG, which I'm sure you'd know, unless of course there's no T-stat in there.

The 40-43 you were getting with the stock AVX trans and stock injectors, is about right for an ECOdiesel. By dropping the RPMs with the 3.94 final drive, you should have improved it. That means the following:

1) Assuming your T-stat is working properly, and has no auxilary holes in it, AND, your fuel return line is not clogged, AND your compression is decent, then the only logical conclusion is that your pump needs a rebuild.  Increasing the internal pressure will address only ONE part of the equation. It will not compensate or fix other internal pump problems like worn/broken components, worn springs, sticking components, tired delivery valves, misadjustment, etc.

I'd say, have it rebuilt. Or, better yet, have a true TD pump rebuilt. The stock ECO pump has a smaller pump shaft, and lacks the LDA. Really no point in bothering with it if you want performance and power.

[Doakster]

Couple of thoughts:

1) Are you running a thermostat? Or, did you drill some holes in it? ECOdiesels are notorious for running hotish.  Not sure why. If you are running no t-stat or have drilled holes in it, or it's stuck open, you might be affecting the mileage due to lack of thermal efficiency. Others can chime in, cause I really don't know much about it. But, the bottom line is you want your diesel to run in the 190F range (87 C).If you aren't in that range, it can affect mileage.

I have not done anything with the coolant system since i bought the car. I will say that on normal driving the temp sensor in the cluster runs fine ( in know they are not absolutely accurate), it barely goes over the half mark. On a hot summer day it will creep up the 3/4 mark if i'm at idle a while. But i've checked the temps with a laser temp gun and they are never above 190-200, so i think the gauge is a little off. As far as i know the car has a T-stat, i can't say otherwise because i haven't dove into the coolant system

2) Have you checked that your fuel return line is clear to the tank? One of the trouble-shooting tips is to blow the fuel back to tank and make sure it's clear. If not, that can affect mileage.

yes i have done this, i was getting leaking on the "cap" of the injectors, blew out the return line with air, it was clogged, after doing this there was no increase in mileage, but i might check again

3) Compression test? Some think that off compressions can affect mileage. I'm sure it can to some degree, but I'm not sure it can account for 15 MPG worth of discrepancy. But, it could be a good idea to check and rule it out. But, given the mileage you were getting before this happened (see below), I'm not sure this is the problem. I just can't see a sudden drop in compression causing this (even if you blew the HG, which I'm sure you'd know, unless of course there's no T-stat in there.

yes did this, all cylinders were in spec, don't remember the spec, would have to look at my note, but they were all good number and very close to one another

The 40-43 you were getting with the stock AVX trans and stock injectors, is about right for an ECOdiesel. By dropping the RPMs with the 3.94 final drive, you should have improved it. That means the following:

1) Assuming your T-stat is working properly, and has no auxilary holes in it, AND, your fuel return line is not clogged, AND your compression is decent, then the only logical conclusion is that your pump needs a rebuild.  Increasing the internal pressure will address only ONE part of the equation. It will not compensate or fix other internal pump problems like worn/broken components, worn springs, sticking components, tired delivery valves, misadjustment, etc.

I'd say, have it rebuilt. Or, better yet, have a true TD pump rebuilt. The stock ECO pump has a smaller pump shaft, and lacks the LDA. Really no point in bothering with it if you want performance and power.

One would think the 3.94 should increase mileage, that's why i wanted it in there, but of course it didn't help in my case. If the pump goes to giles, i'm going to get one of his TD LDA built up pumps for sure, not messing with an ECO pump

[Doakster]

I also haven't seen on the list that the cam timing was checked and is bang on.

You know i thought about doing this, maybe the cam jumped a tooth? Wouldn't you notice it running rough? But when i rechecked the IP timing only about 2 months ago, my cam lock down tool slide right in like it should on the end of the cam when my timing marks came up on the flywheel, so i assumed it was good. Thoughts on that?

[Vincent Waldon]

I also haven't seen on the list that the cam timing was checked and is bang on.

You know i thought about doing this, maybe the cam jumped a tooth? Wouldn't you notice it running rough? But when i rechecked the IP timing only about 2 months ago, my cam lock down tool slide right in like it should on the end of the cam when my timing marks came up on the flywheel, so i assumed it was good. Thoughts on that?

"Checked" in this context means:  what setting did you dial the pump into, using a dial indicator?

Can't tell from your description, but you don't explicitly mention what timing setting you're using... in many cases when we see that it means the owner has eyeballed the timing marks like you do with a gasser but has forgotten/doesn't know that a dial indicator is needed to finish the job... at least from VW's perspective.

Dialing in the timing also allows you to try various settings scientifically until you find the right balance between power and economy.

[Doakster]

"Checked" in this context means:  what setting did you dial the pump into, using a dial indicator?

Can't tell from your description, but you don't explicitly mention what timing setting you're using... in many cases when we see that it means the owner has eyeballed the timing marks like you do with a gasser but has forgotten/doesn't know that a dial indicator is needed to finish the job... at least from VW's perspective.

Dialing in the timing also allows you to try various settings scientifically until you find the right balance between power and economy.

I always checked my pump timing with a dial indicator, cam lock tool, and pump lock tool (per the bentley manual), the hole nine yards.I checked the pump timing after i changed my timing belt and it was right in the middle of the Bentley spec range, (don't remember the numbers of the top of my head). After the timing belt replacement about a year ago, i still got 43 mpg. Then it dropped way off on me and i rechecked it a few months ago and it was still right in the middle of the spec. Seems like it would have to be way off, (something that would jump out at me when i check it) to affect my mileage this much.

I may try to advance/retard the timing by playing with it, but i don't think it's going to help 12-15mpg worth.

I had a long talk with Giles today and explained my situation. Basically what i need to do is get my gauges in or put in a temporary boost gauge, see where i'm at and go from there. His thoughts are that if all the things i checked are good, than it's either the turbo or the pump. That has always been my hunch as well.

[Doakster]

I found my notes(maintenance log) for when i last checked my timing. I wrote down that i was within spec, .037-.041"

.039" seem to ring a bell for some reason.

looks like i didn't write down what i actually set it to, but it was within the range.

[Quantum TD]

Sounds like your pump is toasty.