Author Topic: TDI Baja Racer (Read 10024 times)

Greasecar · « **on:** October 20, 2008, 07:28:17 am »

Greasecar is working with an established desert racing team on a buggy for this years Baja 1000. The car is pretty cool and will be running a water/air intercooler system, the details of the build can be found at www.greasecarmotorsports.com .

We were out in San Diego all last week trying to get the car up and running and though we got a lot done we didn't get our ECU until the night before we left and found some last minute wiring issues. The ECU and harness are out of a '98 Beetle with no cluster, ECU has all of the necissary deletes performed by Rocketchip. We were able to get the engine running but the accelerator is not functioning and we got codes "implausable signal" codes for the throttle positioner and MAP circuits. We did continuity and pinout tests between the acc pedal, MAP sensor and ECU and could not find any problems so we suspect that we may have one of the ECU grounds or power connections mixed up. Does anyone out there with engine swap experience have any ideas?

autoholic · « **Reply #1 on:** October 20, 2008, 12:57:19 pm »

Are you sure you have a good engine to chassis ground loop? How is the engine mounted, on rubber mounts? Does the bat - go to engine and frame?
That is one sick Baja, I'm in love with that thing!

RabbitGTDguy · « **Reply #2 on:** October 20, 2008, 01:19:55 pm »

Oh Justin....the fun you must have now!

That looks awesome. Can't comment much now...but more later

Joe

autoholic · « **Reply #3 on:** October 20, 2008, 01:49:36 pm »

How is the throttle pedal set up? did you use a Tdi pedal or adapt the pot to some other pedal?

zukgod1 · « **Reply #4 on:** October 20, 2008, 02:07:17 pm »

This is way to cool..

I REALLY want one of these kits for my car...

I cant find a damn oil source though.

I have a cousin that goes down on one of the teams as well.

I'll be watching the race so good luck man.

Greasecar · « **Reply #5 on:** October 22, 2008, 08:24:53 am »

The transaxle is bolted directly to the chassis, metal to metal and the engine bolted to the trans. with only a couple of rubber mounts where the engine hangs into the rear of the chassis. We are using the stock acc pedal but did have to lengthen the wires due to the rear engine configuration. We checked continuity between the ECM pins and the pedal assembly which were good. The MAP and Acc pedal share a common ground circuit out of the ECM so we are going to try and trace that. I just hope it doesn't have anything to do with resistance changes from lengthening wires.

The harness and ECM are being shipped back out to us today so we can tear into them tomorrow.

autoholic · « **Reply #6 on:** October 22, 2008, 01:32:56 pm »

I cannot imagine that would significantly increase resistance, but who knows. Maybe you can measure resistance with the stock wires, and go larger with new wires to achieve the same?

Is the adaptor plate painted? I just keep going back to some wierd ground problem, I'd still be tempted to bring all grounds to battery just to see (which you probably did already)
Does the Ecu case need to be grounded - or isolated from ground?

I'm only guessing here, i am no TDI transplant expert.

Maybe try giving Mike or Don at National a call?

the caveman · « **Reply #7 on:** October 23, 2008, 03:44:09 pm »

The only thing that would be affected by possibly making the wires too long would be the MAF since it developes such small voltages. I agree with all that are mentioning the grounds. I spent at least 2 seasons at the dealer i was at just renewing grounds on brand new cars and up to those that where 2 & 4 years old. I just did some on a golf 3 weeks ago that had already been fixed once already. Also be wary of the pins that are at the ECM. They are not really supposed to be removed too often and can get loose. Very hard to see visually and you may have to replace some with the upgraded gold ones .

autoholic · « **Reply #8 on:** October 23, 2008, 04:35:07 pm »

Quote from: "Greasecar"

The transaxle is bolted directly to the chassis, metal to metal and the engine bolted to the trans. with only a couple of rubber mounts where the engine hangs into the rear of the chassis. We are using the stock acc pedal but did have to lengthen the wires due to the rear engine configuration. We checked continuity between the ECM pins and the pedal assembly which were good. The MAP and Acc pedal share a common ground circuit out of the ECM so we are going to try and trace that. I just hope it doesn't have anything to do with resistance changes from lengthening wires.

The harness and ECM are being shipped back out to us today so we can tear into them tomorrow.

So the transaxle is bolted directly to the frame? and the engine has some rubber mounts? seems like that would put alot of stress on the trans mounts. I'm sure they know what there doing, but I find this interesting.

Tintin · « **Reply #9 on:** October 23, 2008, 07:02:23 pm »

Quote from: "Greasecar"

....... I just hope it doesn't have anything to do with resistance changes from lengthening wires.

I did TDI swap in a westfalia with the ECU at the rear and the wiring for the accel pedal at the front without any problem in 2000KM, our pedal wiring are probably more long than yours.

You do not have a spare ECU?

Greasecar · « **Reply #10 on:** October 24, 2008, 05:30:38 am »

Tintin, glad you chimed in. We have a spare ecu and it has the same problem. The modified ecu was tested in a spare car and seems to be good. The problem is in the harness. Did you connect any of the chassis or cluster wiring in your vanagon conversion? We are wondering if the throttle circuit makes ground or power through the cluster wiring.

Tintin · « **Reply #11 on:** October 24, 2008, 09:21:15 am »

No need to connect the culster, the pedal wiring goes directly to the ecu (6 wire)

T/6 on pedal harness is a ground (chassis ground or battery ground) at your choice.

Greasecar · « **Reply #12 on:** October 24, 2008, 02:11:09 pm »

#6 tests out to ground and to T80/25 and shows continuity. Do you know the function of #1-#5? what circuit supplies power through to the pedal?

This is what VAG Com says. The data was taken with the harness out of the car which is why there are so many open circuits.

Any ideaAddress 01: Engine
Part No: ROC KET AFN
Component: AFN s6e 3br EDC G40SG 1629
Coding: 00002
Shop #: WSC 00066

7 Faults Found:
01268 - Quantity Adjuster (N146)
27-10 - Implausible Signal - Intermittent
00765 - Modulating Piston Movement Sensor (G149)
35-10 - - - Intermittent
00777 - Accelerator Position Sensor (G79)
27-10 - Implausible Signal - Intermittent
00539 - Fuel Temperature Sensor (G81)
30-10 - Open or Short to Plus - Intermittent
00519 - Intake Manifold Pressure Sensor (G71)
31-10 - Open or Short to Ground - Intermittent
01262 - Solenoid Valve for Boost Pressure Control (N75)
31-10 - Open or Short to Ground - Intermittent
00542 - Needle lift Sensor (G80)
30-10 - Open or Short to Plus - Intermittent
Readiness: N/A
s on why the pedal may not be responsive?

Tintin · « **Reply #13 on:** October 24, 2008, 03:20:27 pm »

Dont know exactly for 1 and 5.

F8: Kick down switch.
F60: Closed throttle position (CTP) switch.
G79: Throttle position (TP) sensor.

autoholic · « **Reply #14 on:** October 24, 2008, 07:50:54 pm »

what a bad ass baja bug, I was just checking out the updates on the GC motorsport site. Whats the plan with testing? how many miles do you guys want to put on it, etc. Hey, that tensioner looks good, as does everything else, really nice work on all of it. Any details on the veg kit? running two tank right?
what a kick ass project man, you and Ethan will probably drive that thing at some point too!

good luck!

Author Topic: TDI Baja Racer (Read 10024 times)

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