Nick's Black 90 - 3B Swap: Running!

[PRY4SNO]

This is where the fun begins...

Congratulations.

[chaloux]

Needz moar boooooooooooooooooost

[85oceanic]

Thanks! BBQ is my motivation to get the next phase of the project complete I'm for sure planning on attending this year, can't wait!

Sweet dude!!! I can't wait to see it in person!

[vt10vt]

Congrats! It looks and sounds awesome, and I really like how you set up that evo intercooler.

[nsimps]

Thanks everyone! Yes, moar boooost is in definite need. Got my oil pressure gauge working and seems like I have good pressure. What's odd though is that whenever I get on boost the oil pressure warning light beeps. Any thoughts on what that could be?

Had a little meet today during lunch and Darin showed up. I should never have looked under the hood...

[Audilard]

I shouldn't take you for a ride either then.

[my2000apb]

are the high and low rpm wires on backwards?

[nsimps]

Are those separate from the tach signal wire? The problem with my harness is it's from a rhd S2 3b and some of the wires are different colors than normal. Still doing some trial and error with things.

Darin - Yes, you should take me for a ride. It just won't be good for my wanting to be happy with stock levels of boost

[nsimps]

So here's my dilema with my clutch. During the swap I separated the master cylinder from the booster because I thought it was necessary to pull the harness through. When I separated them, brake fluid came out of the booster. I didn't think much of it and bolted it back together. After the swap was done and running, I bled the brakes and gravity bled the slave cylinder. I've been having some vacuum issues with the booster and have had some vacuum noise when braking(I've had partial power brakes since). Recently the clutch pedal started acting up and would start engaging a few seconds after pressing the pedal down. If I barely pressed the pedal I could hear air and it would fall to the floor without disengaging the clutch. So to remedy this I unhooked the vacuum to the booster and the clutch was better, but not fixed. I had to pump the clutch up to get decent pressure. Last night I bled the slave by pressure (pump clutch, hold clutch to floor, release bleeder, close bleeder, pump clutch). During this process I could hear air in the booster ever pump of the clutch. Every couple bleeds it would push through a bit of air. It never did get any better and actually got worse to the point of no clutch anymore.

My first thoughts are that the brake booster itself is bad and I need a new one but what does everyone else think?

[nsimps]

Report from BBQ:

I had about a week of driving before BBQ this year on the recently completed 3b swap. Would've been more if I didn't have to replace all the front suspension pieces and get an alignment before leaving. With no temp gauge I was a bit worried about those getting too high and to reassure myself went ahead and bled the system. Ran decent all the way down to Vegas with no issues!

While in Vegas I got some help from both Dave and Brent on trying to figure out my LIMP mode issue and found out a few things:

- Diagnostics can't run without power…(temporarily hooked up to ignition switch)
- Air Temp sensor was bad (replaced, thanks Hank and Marc!)
- N75 bad (replaced, thanks Brent!)
- Knock Sensors bad (replaced, thanks Hank and burnt hand!)
- ISV wasn't working and now is

Car ran so much smoother after that but still didn't have full boost. It would give me about 10psi once during a drive and then go right back to LIMP mode. Drove it home with no issues and was very pleased with how far we got with fixing things.

At home I haven't had a ton of time to diagnose other than re-tourquing the front knock sensor.

Currently the MTFS(multi function temperature switch) is not hooked up to leave that signal open to the ECU.

On one drive yesterday I could boost into normal territory for a second through different gears but once I went past 10psi it would go LIMP mode.

Bottom line is I need to get it hooked up to VAG COM again and see what codes, if any are being thrown and fix them.

Would a bad wastegate diaphragm cause the ECU to go into LIMP mode?

Again I can't thank Brent, Dave, Hank and everyone else enough for all their help through this build!

[nsimps]

Small update:

Been driving this thing daily and aside from the limp mode issue, everything is good. Recently repainted the front bumper and installed the lower grilles again. Looks a lot better(pics will come soon enough ).

It has totally been worth all the hassle to get this project to where it is today and I can't wait to get this thing on full boost so the next phase can begin!

[nsimps]

long story short, I'm at my wits end with this thing. It's almost been a year since it fired over and still yet to get it running proper.

This is more/less a plea for help, some real troubleshooting help to get this thing to running proper in stock form.

I know there's the SJM link with the step through of what causes limp mode to occur. I'm still trying to work on getting a known working mtfs into the system and eliminate that from the equation, maybe next week this will happen. However, when it comes to reading electrical issues it just boggles my mind and a little help, whether in person, over the phone or skype (we have cool video conferencing technology now) will be tremendously appreciated.

Here's the basic run-down of the current status:
- Every time it's ran, I can get full boost once, and depending on the gear, I can get full boost to sustain through the rpm range and it feels solid. After once, maybe twice, it will revert to limp mode.
- At the moment there's a vacuum issue where it won't regulate properly and cause boost to build under vacuum. I have an ISV to swap in to try that first.
- Also, at the moment it will cut out every once in a while when going from steady throttle (vacuum) into a slight throttle. It figures itself out but does do a cut cut before smoothing out.

If it seems I'm not putting forth much effort to figure it out myself, please know I've tried and tried and tried to work out these issues and go through the steps to test the potential issues. This is absolutely a last resort to try and figure this out.

This build has happened because of the awesome community here and I am extremely grateful for the enormous amount of help I've received already and for the friendships as a result :-)

If you do wish to help (please please please) and need my number, pm me and I'll send it to you.

Thanks in Advance!

:thanks:

[Audilard]

Nick, did you ever get it to pull codes?

[nsimps]

Yes, at BBQ Brent figured out that I didn't have power to diagnostics so we hooked that up and were able to pull codes. We were able to eliminate the air temp sensor, isv and eventually knock sensors as non issues (after replacing them). This was where I took over after getting home but haven't been able to trace down the issue. I'd rather not start replacing things on whim (just don't have the cash flow for it) so any help or guidance on how to test the different parts/diagnose will be super awesome helpful.

I'd love to get a "Fix Nick's Car" tech session together but know it's really hard to schedule something like that.

[PRY4SNO]

Well I'm far from an expert, but what about that WG diaphragm you mentioned? Any vac leaks? How's your fuelling system... nothing wonky there?

[nsimps]

The only test we've done with the WG was unplug the vacuum line and do some manual (throttle) boost control. It would boost just fine to whatever psi I wanted. I stopped at 15 but it had no problems getting there. There are some vacuum issues at the moment where it will let the turbo start to spool even under vacuum. Last time this was an issue with the ISV so I'm going to try a different one to see if that's it again.

Not sure how to test the fuel system but I'll pull the vac line off to see if it's leaking and replace if it is.

Tuesday is wrench turning day pending that the knock sensors come in.

[A20V200]

How is your N75 valve....replaced with a known good one? ISV? = output test....?
have you done that yet to see if everything is getting power and working properly?
How does it run when you unplug your ISV...better...or worse...or the same?
Knock sensors properly torqued to spec...?
Double check your vacuum line that connects under your fuel pressure regulator...? corroded or in good condition..actual take it off to inspect it.
MFTS...you need a good one for sure....and a good plug as well...could be your boost cut.
Take off your WG cap and physically look at the diaphragm?

and last but not least....is the ECU you have a good one? Nothing wrong with it? Can you borrow another to see if anything changes, just to make sure?

These are all short list items...check them off after thorough inspection.

hope this helps.....

[nsimps]

So last night had some time and did the following:
- ran codes with engine off:
ISV
Knock Sensor
EVAP Canister
Speed Sensor(RPM)
- Cleared codes
- Replaced ISV with a spare one I had on the bench
- Replaced front knock sensor (blue) with one I bought from Ebay (the other one is still in Florida)
- Drove car

Car drove a lot smoother and didn't jerk around like it was. The limp mode is still present but I do still have another knock sensor to install. MFTS is still not hooked up. I might just buy a new one and install it later. Not in the mood to replace it with other used ones hoping they are good.

I'll keep posting as I try more things.

[Mcstiff]

Get that MFTS!

1991 200TQ 20V:
This MFTS sensor also provides a ground signal from Pin 2 on the sensor to PIN 36 on the Motronic ECU (J220) if the engine is running too hot (over 247F, 119C) which will reduce the amount of boost the ECU will provide.

The Waste Gate (WG) operation is not allowed when this overtemp condition occurs. The BL/G wire (2/R terminal) coming from this sensor should be tested to ensure that it is not grounded. If you remove the connector from the Multi-function temp sensor, pin 2 is the one on the lower right, with the connector end facing you and the connector notch towards the top.

If you suspect the Multi-function sensor is causing the low boost, you should remove the connector from the Multi-function switch and redo the test.

If it works with the connector removed from the Multi-function temp sensor, then the temp sensor is defective and is grounding Pin 2 which will prevent correct operation and this will limit turbo boost output. You should check the wiring between the throttle switch and the ECU as well.

[nsimps]

Getting the MFTS working properly (getting a new one) is part of the plan for sure. here's my question though, if I unplug it, then the ground signal won't be there. Does it matter if it's always been unplugged since I finished the swap? Does the ECU need the good (non ground) signal to continue to operate at full boost or will unplugging it only give me the one or two pulls at full boost and revert to limp mode like I am currently seeing?

[Mcstiff]

Getting the MFTS working properly (getting a new one) is part of the plan for sure. here's my question though, if I unplug it, then the ground signal won't be there. Does it matter if it's always been unplugged since I finished the swap? Does the ECU need the good (non ground) signal to continue to operate at full boost or will unplugging it only give me the one or two pulls at full boost and revert to limp mode like I am currently seeing?

Right, we both should read "If you suspect the Multi-function sensor is causing the low boost, you should remove the connector from the Multifunction switch and redo the test."

Does the 2 pulls to limp (there is a joke there) issue reset after a key cycle or do you need to clear the codes?

[nsimps]

It resets after a key cycle.

Not sure if this helps, but when it does go from spring pressure to full boost it's very quick and actually goes a little beyond 12psi and then comes back down to about 10, holds then goes limp. Just seems like it's a faster jump than it would have been stock.

[nsimps]

Another update:

On the way from Lehi Utah to Miller Motorsports Park in Tooele (1 hour drive) I pushed the car pretty hard and it gave me some new behavior. Every few pulls in 5th it would go to about 10psi and hold for the pull. Then try again and limp. Try a few more times and 10psi again.

On the way home there was traffic and didn't really have a chance to try this method out again. Car did run smooth there and back though and my co-worker enjoyed the fun ride there.

Good news: My knock sensor arrived in Salt Lake City this morning and hopefully will be in my mailbox tomorrow for when I get off work. Then we can eliminate that as an issue and move on.

[nsimps]

Yet another update:

Ran codes again and got the following fault codes:
- 01247 - Activated Charcoal Filter (EVAP) System Solenoid Valve 31-00 - Open or Short to Ground
- 00524 - Knock Sensor 1 (G61) 03-00 - No Signal
- 01257 - Idling Speed Stabilization Valve (N71) 31-10 Open or Short to Ground - Intermittent
- 00513 - Engine Speed Sensor(G28) 03-00 - No Signal

After clearing the codes I had good boost in 5th gear, even 4th on the highway. After getting off and into lower gears though I had boost momentarily and then limp. Wasn't able to check codes again when I got home but might be able to tomorrow.

Do I need to worry about the Engine Speed Sensor signal?

[nsimps]

Here's a quick (12 minute or so actually) of my drive to work. Had some good success with getting good boost! Still some issues though, if I jump on it in 1st or 2nd gear it will go limp right away. Doesn't like the low speed, high boost.

[youtube]http://www.youtube.com/watch?v=45JJ_O6Eh1U[/youtube]


In other news, my other knock sensor has been delivered and is waiting for me at home! I'll be installing it tonight and report back.