'98 AHU Limp Mode Help

[JungleMan]

Hello to all,

First and foremost, this site is absolutely amazing with all the professional, intermediate, and newbie advice that is available to anyone.

I am on my fourth vw, and second Diesel ('93 AAZ, and currently '98 AHU)

I havn't posted too much, but have read countless posts on the infamous limp mode.

Here is what I have done so far,

- New N75 (TDIPARTS.COM)
- New N18 (WORLDIMPEX.COM)
- New Vacuum lines everywhere (Including inside ECU)
- Cleaned Intake W/EGR, Intercooler, and all hoses
- New Fuel Filter (TDIPARTS.COM)
- New Relay 109 (TDIPARTS.COM)

I have narrowed it down to the Last item, removing and cleaning out the Turbo and possibly replacing the actuator.

My car is a '93 Golf for Canadian Market with Original AAZ TD Engine, which was swapped out for a '98 AHU TDI on June/'06.
The swap took over two months to complete. I beleive that the soot inside the Turbo has caked up and is preventing the Vanes from operating.

When I cleaned out my intake, I was not able to move the actuator rod freely, I had to use a pry bar to get it to move 1/8".

So, My question is....

How difficult is it to remove, clean and replace the turbo on a '98 AHU TDI?

OR

Can anyone recommend a mechanic or fellow TDIClub member In Toronto who can do this procedure for me. I Live in North York (Keele & Sheppard)

Any help is appreciated.

Sorry to hear about your accident Doc OC, But am glad to know you are well and relatively unharmed.

Here are some pics of my intake before cleaning.
I dont have any after pics, (too excited to snap photos, thought it would fix the limp mode)

What are my options of Turbo upgrades, without too many modifications to my existing setup? I am aware of BleachedBora's hybrid K03/K04, Are there any other options..

PS, TDIPARTS.com Is my Favourite TDI parts supplier, He is professional, Curteous, and has THE BEST Shipping times.
Thanks again to Peter...

 

[paramedick]

Remember that the vanes don't move in your turbo. Chances are, removing it for cleaning is a waste of time.

Replacing your wastegate actuator is definitely desirable if you can't free it up. Spray the pivot well with a good penetrant (NOT WD40) and let it sit for a bit. Then try to move it for more range of motion. If you can free it up, lube it with a good synthetic spray lube.

You can check the diaphragm by using a bicycle pump to put pressure on the actuator.

 

[Canadian_Grizzly]

Ditto Paramedicks advice...

 

[Bookerdog]

It is possible that the diaphragm on the wastegate actuator itself is torn or the mechanism is otherwise unsalvageable but it can be replaced separately from purchasing a whole turbo. I believe these have been sourced somewhere in Canada, but Bleached Bora can probably help you track one down.

You've gone over all of your intake plumbing post turbo with a fine toothed comb, correct? Those rubber boost hoses can split on the path to and from the intercooler.

 

[Canadian_Grizzly]

Try Brian at http://www3.ns.sympatico.ca/roseland/index.htm

 

[JungleMan]

Thanks to all who replied,
I will be tinkering with it this weekend as I have been working nights this week and it is hell to adjust to.
Can anyone recommend a good penetrating product to use?
I'm glad to hear that the turbo need not be replaced. hopefully this will end my limp mode problem and I can enjoy my new suspension (Bilstein TC, and H&R OE Sport springs, New tie rods, ball joints, sway bar links, bearings, and control arms. She handles great!!)

Bookerdog, When I removed the intake and intercooler, I checked all the hoses to make sure there was no rips or holes.

 

[Bookerdog]

Can anyone recommend a good penetrating product to use?

Power Blaster, aka PB. Great stuff and available at most auto parts chains.

Just be sure that if you get it freed up using a penetrant of some sort that you follow up with a lubricant before delaring yourself done. Lots of penetrants, like WD40 are hydrophillic so while they'll free you up now, you'll actually rust more later. You don't know how many chains I saw like this while working as a bike mechanic.

A shot of spray lithium grease would be what I use, but I'm sure the chemical engineers on the boards will say that's wrong too.

Good luck to you. Once you get the power back to that bad boy it's gonna be big grins with that suspension kit on it.

 

[paramedick]

A shot of spray lithium grease would be what I use, but I'm sure the chemical engineers on the boards will say that's wrong too.

Nahhhh, white lith works fine. I don't use it because it remains "wet" and attracts dirt. The synthetic spray lubes I use have a wet carrier that evaporates leaving behind the lube in the pivot.

Superlube and breakfree are two that I like very well.

 

[MicroRacer]

Maybe I missed it, but the limp mode will not just disappear, whatever code is causing the limp mode has to be cleared with a vagcom.

I also have a 98 TDI that had a clogged intake. Mine looked worse than yours. Even after cleaning my intake I would go into limp mode and I would have to clear the codes again. This happened the better part of last summer then winter came on and I never went into limp mode again. Over a year later and the TDI still hasn’t gone into limp mode. I do remember taking it out and running the heck out of it and it was definitely better after that. If it's immediately going into limp mode after clearing then it has to be either in the pressure lines or the turbo.

Once in limp mode I don't believe that the turbo works at least it never seemed like it to me.

 

[The Ripster]

Paramedic, I may have figured out my elusive, intermittant 00575 manifold pressure on my 98 Jetta. Seems the bicycle pump and spraying with penetrant has worked now for over two weeks. Had the Emergency cables replaced at a VW shop and they have a mechanic there with a 98 and he sprays his up every 5000, seems as they age they like to stick, and at some point they may have to be replaced. So all the parts are new, and the final answer was probably a sticky actuator rod, and most times not on hills, but just easy cruising. Emergency cables they had to drill out of the body, rusted fairly well in there. This sounds pretty much like mine, spray up that rod and use the bike pump and watch.

 

[MicroRacer]

A code does not cause limp mode. A code that is stored will not cause a limp mode. Limp modes cause codes to be stored.

Limp mode is a self protection circuit that is triggered when the ECU detects differences across a variety of sensors. The ECU responds by limiting FUEL to the injectors. Further, limp mode has nothing to do with the turbo or boost directly. The ECU limits fueling and in doing so, a limit is placed on how much boost is generated. That's why a car in limp mode can seem ok on the flat, but seems so powerless when going uphill. The lack of fuel...which limits boost which is designed to protect the engine.

A CEL may or may not be triggered but usually the ECU will store a code. That is why it usually is best to be able to log the various sensors using vag com software to determine just why the ECU wants to limit fueling.

Frequently, you can reset the ECU by turning the engine off and letting it sit for a few minutes and restarting.

In this gentleman's case, he is probably unable to attach a vagcom or any scan tool to the ecu as it is a transplant into an older A2 vehicle.

I guess that's the way it's supposed to work (probably the way it works), but my car would go into limp mode (run like crap) and my wife would gripe at me for a day or two (or three) and I would go out and clear the 00575 code with my vagcom then every thing was better for a week or two then it would start running like crap again. The car wouldn't run right until I cleared the 00575 code with my vagcom.

 

[JungleMan]

Would it be wrong to spray some penetrant down the Hose that leads to the actuator? Can this method harm the internals in anyway?

 

[GoFaster]

I don't think you want to do that. Spraying into that hose just sprays into a sealed diaphragm chamber. The linkage is all outside that chamber.

 

[The Ripster]

I could not imagine that a good spraying would fix it either, but there was no other reason, I logged it and sent it to someone who could interrupt the graphs, and that person felt that I was low boost when I let off the fuel, and suggested that I needed to spray the linkage. I had been spraying the linkage with several types of fluid, then I hit it with a good penetrant and so far we have several weeks with no codes. I have replaced EVERYTHING else so my next move was a turbo and intake cleaning while I was at it. So for now I am going to spray it up every oil change while I am under there and see if it stays away.

As far as a shield, mine is always dry when I look at it, it could be a design issue with age or something. Would be interesting to note that those who have replaced the turbo with a hybrid or later model, if this problem never returns.

 

[JungleMan]

So here's the update, It's good for a laugh....

I bought some PB penetrant, went home and I tried to pump some air into the hose going to actuator. I could hear the actuator mechanics working, and something that sounded like an air leak, but I was not losing any pressure on the bicycle pump. Then I had my girlfriend start the car and rev a couple of times while I check the vacuum hoses coming from the turbo to see which had pressure. I looked up the hose routing on ETKA, and found that they were routed incorrectly. (Haven't took the cap off the PB penetrant yet)
I had a lousy diagram and little knowledge of my TDI when I replaced the N75 and hoses 3 months ago, which were all black in color before I replaced them, and still are. (No red or blue hose to and from turbo to N75). I properly routed the hoses and went for a test drive. Holy Crap, what a difference.
I was able to get great pull right up to 4000-4200 RPM, between the first three gears, it was like a whole new car.
So I decided to take it on the highway and try some taller gear runs, my car went back to limp mode in fifth at around 3200 RPM.

Any explanations why it performs better on low gears, but not on taller ones, even with actuator rod poosibly seized? (newb question)

Keep in mind I haven't sprayed anything on the acuatator yet.

So I got off the highway and did some WOT 2nd and 3rd gear runs to enjoy my new found power and torque, when, without warning my rear right engine mount fails and I can hear a deep, amplified, engine vibration in the cabin. But on the exterior of the car it is unnoticeable. When I accelerate, the noise is gone (Load off engine mount) until I de-accelerate. Awesome Torque.

Now I'll be replacing all three engine mounts and while I'm there, can spray and lubricate the actuator rod.

It's a good sign of the torque and power to come.
Maybe a good time to start saving for the clutch upgrade too...then the nozzles, then chipping, then exhaust, it never ends...in a good way of course.

 

[JungleMan]

BigAndy,
I will be tackling the Actuator with PB and bicycle pump when I replace the rear engine mount on Monday. With some perseverance, it should free up. P2B has offered to help me with VAG-COM and interpreting the graphs, as he is a seasoned user.

Also, I do have the OBDII connections to the right of the ashtray. It seems to work well, I have had no problems connecting to it using VAG-COM shareware, and an OBDII cable I bought on eBay.

 

[The Ripster]

P2B also diagnosed my graphs for me also. Like looking at a heart monitor, I can tell when it stops, but the little things requires some understanding of the graphs, and what should be happening.

 

[JungleMan]

I have not applied the PB penetrant to the actuator yet. On Monday, I had a friend take off lightly and noticed the engine front raise about 8", so I bought a new front engine mount I thought was defective. I went to install the mount and noticed that the front engine mounting bracket had sheard and was resting on it's broken piece.

I replaced the bracket and mount and now notice much less cabin vibration. I will be replacing the other two very soon.

I will be troubleshooting the actuator rod this weekend. I borrowed my brother's car ramps for better access.

I am still getting MIL light and limp mode on higer gears, but I have been driving mostly in the city and am enjoying my new found power and torque. (see attached pics of torn engine mount bracket.)