'97 Passat TDI Build

[Caddylackn]

Next thing I added was front skirts, from left over pieces of the Ford hood. I mocked these up in coroplast to fit around the bumper first then traced to sheet metal, then tack welded, cut and fit, and finished.



This was glued and a couple screws to hold it, incase the glue fails



You can see the exit came out good, about 5/8". Front scoop is pretty big because of the bumper transition, I may close it in a little later. The skirt side pieces fit attach between the upper and lower bumper. Being steel, I just jammed them in there between body panels with some elastomeric type glue and a screw for security.



I then closed in the front wheel openings with coroplast and more sheet rock steel corners and added the side dam under the car to guide the flow from getting sucked under the car. It all lined up pretty good. Spray bomb matt black.



Last thing I did was some ghetto window tint for summer to keep the temps down so I could drive without air conditioning.

[Caddylackn]

With some stupid tdi tuning issues (boost creep) and codes and flashing glow plug light, my gas mileage did not appear to go up after these mods and actually went down. I did all of those aero mods in the last two posts at about the same time.

I was also going into limp mode at full throttle, which I do for short times once a day to cleanout carbon and preventing wastegate from sticking. I replaced my vacuum line to the turbo wastegate and the limp mode went away. The hose was not very stiff and I think it was collapsing.

I did notice, that after these last aero mods my coasting ability went up, higher terminal speeds on hills or longer coasts on my commute, so the aero mods worked.

I replaced my MAF and my gas mileage improved almost 10% so that was some of it. I still get mild boost creep, where holding a constant throttle will slowly build boost and increase fuel use, as seen with the Scan Gauge II. I think this may be from having almost no back pressure (straight pipe) and a mild tune designed to increase boost. So while driving, you just constantly stare at the boost gauge and try to keep it below 18 psi (absolute) when cruising up slight grades.

I still have air bubbles so I am replacing the fuel line to the injector pump. VW wants like $200 for the pre-formed 2-foot long fuel and return line from the filter to the injector pump. I found a substitute line (clear) to use. You need to have at least one section of clear so you can check for bubbles.

[freebeard]

You can see the exit came out good, about 5/8". Front scoop is pretty big because of the bumper transition, I may close it in a little later.

IIRC the ratio between the intake and exit affects the effectivness.

[Caddylackn]

Once I get the engine/tuning issue figured out I can close up the intake some with some cut foam.

Too many variables now to monitor improvements on aerodynamics.

[Caddylackn]

Still having injection pump quantity adjuster issues but running a can of Diesel Purge (running off the can, not as an additive) seemed to help the surging issues. Running the fuel return line back to the can showed there was a lot of sediment and junk in the Injection pump. I replaced all the fuel lines to the pump and back to the hardline.

IQ is still set too high at 6.0 causing shuddering at low throttle input cruising. I thought raising the IQ (less fuel per stroke) would improve mpg but I think it has the opposite effect since I have to give it more throttle input to stop shuddering in 5th below 55 mph. Now I know.

Last tank was 57.6 mpg so it is running better. Most of my commute is now at 65 mph or slightly higher, so this is the best average mpg per tank above 62 mph.

Diesel prices are still outrageous around here. Hard to find diesel below $5.50 per gallon . Washington state now has this carbon credit "tax" charge BS on fuel which raised the price about $0.50 per gallon with all the proceeds of the carbon credit "tax" going where? If the state makes $100 million of this carbon "tax", they will spend $99 million setting up the infrastructure to spend the remaining $1 million.

[Piotrsko]

Wow if that was mine, it would mean the injection pump commited suicide and is intent on taking out the upper half of the engine.

[Caddylackn]

I had ankle surgery in November, so have been unable to use a clutch. Yesterday I fired up my passat after sitting since November. and was able to move it around, but using the clutch still hurts too bad to try to drive it far. I will give my ankle a few more weeks.

I still am having fuel injection pump low voltage issues but it runs.

[Caddylackn]

I started driving the TDI in May after my ankle recovered. I only made it a couple weeks before my Injection Pump crapped out on the freeway on the way home in a very bad place to be stranded on the shoulder.

I started gathering parts for repairs. I was lucky and found an Injection Pump from a newer 2002 TDI ALH engine at the U pull junkyard. There is a swap procedure on the TDI forum for swapping to the "newer" ALH injection pump.

I also did the timing belt, tensioner, fuel filter, thermo tee, fuel lines, and even replaced the third injector with the needle sensor, since I was getting codes for that as well.

All is better and it is up and running great. Now no codes, no flashing light

Drove it to work today for the first time since May and I hit 60.0 mpg on trip in. My scan gauge may need recalibrating since it was calibrated to the old messed up IP, but it runs a hell of a lot better. No surging or shudder and it finally cuts off fuel flow to 0.01 gph whenever coasting.

Now that I may be driving this again regularly, I am going to repaint it.