01 golf turbo probs, 1st time owner prbs aft 2days

[sidlad]

Just picked up £9000 01 golf tdi. Please help i've saved for ages to get my first car over £1k!! Immediately after picked up from garage experienced power problems on motorway at higher speeds, especially on inclines. The nice garge people who sold it to me (sarcasm!) have changed the vacuum pump but i'm suspicious and only have a one month warranty. Does anyone know how i can test if they've found the real problem????

[Rustynuts]

Hi there, Sid.

What power is the engine on your car (90 bhp, 110, 115, 130, possibly even 150)? There's a choice, and knowing which one it is will be a help.

It could be a MAF problem and here's the way to check.

Under the bonnet (i'll take it that you know a thing or two about engines) at the right hand side is the airbox. The air filter is in here, and don't open it. There's a pipe which comes out of the airbox and disappears off down behind the engine towards the turbo. Just after this pipe leaves the airbox, there's an electrical plug clipped into the side of it. Unclip this connector (engine turned off here) and take it for a spin. If the power is about the same or better, then you need a new MAF.

The Mass AirFlow sensor reads how much air is being pulled into the engine so the ECU can deliver the correct amount of fuel. If the MAF is reading incorrectly, the ECU cuts fuelling accordingly, hence less power.

Try it and come back with the results.

Welcome to TSN.

[sidlad]

Unfortunately only 90 bhp, went for low mileage instead of bhp on my buget, ironically i thought i'd have less problems.

I'm working away from home at min so dont pick up (with new vacuum pump) til friday. I'll give it a good workout and if it happens some more i'll try your tip. I'll let you know outcome either way. Thanks alot

[sidlad]

Got golf back this weekend after new vacuum pump, seemed fine at first but thought a run over M62 from leeds to manc would be in order. Went into limp mode when accelerating to 85 - 90mph (i dont normally drive at these speeds but wanted to check it was fully sorted). Turbo returned as soon as ignition was turned off and back on again. Garage have it back again now.

I presume if everything is A ok, the car should never go into limp mode even if i was driving like a madman???

[Rustynuts]

Hello again, Sid.

Limp mode is a total loss of turbo rather than a general power loss. This is caused by the boost being asked for by the ECU and the actual boost from the turbo not being the same.

I noticed in your other post you asked about how the car runs without the MAF connected. The MAF detects how much air is passing into the engine by cooling an element in the air flow. The more air drawn in, the cooler the MAF reads, and the ecu calculates accordingly. When you disconnect the MAF, it defaults the airflow sensing in the ECU to a default set of values which is good enough for most situations, but not as good as it would be with a fully functional MAF. Disconnecting the MAF and giving it a good belt will probably not give as much power and you'll still get a "Limp mode" in your situation, I suspect.

You're more likely to be looking for

1. a split in a turbo hose, easy to find. Inspect all the hoses carefully and replace if any are split. You lose boost out of the hole and Limp mode is set off.

2. A faulty VNT mechanism on the turbo. The Variable Nozzle Turbine actuator moves a set of vanes inside the turbo and changes the angle of airflow over the turbine to give more boost when required. If the vanes get carboned up, they stick and you get a lack of boost at higher revs, the ECU sees a fault and Limp mode is set off.

3. The VNT is controlled by vaccumm from the now new vaccuum pump. The actuator valve for this is the N75 solenoid valve which is electrically controlled by the ECU. If the N75 sticks or fails, not enough boost is set up by the VNT and Limp mode.

You see where this is all going? Limp mode is the ECU shutting things down cos it sees a problem, it isn't the actual problem itsself.

One last thing to look for is the intake / EGR might be clogged with oil and soot. These get plugged up if the car gets chugged arround without getting enough right foot every now and then.

Get the Garage to check these things out and see what the find. They are all common on a TDI, and I'd expect a competent mechanic to know these sort of things.

Let me know what they find.

[sidlad]

Thanks rusty, that makes things clearer, i think i understand better now. The garage are meant to be contacting me today or tomorrow, so i'll find out what they're doing and let them know what i (you!!) think. I'll let you know what happens.

[sidlad]

Got golf back from main volkswagen dealers on friday, they head replaced the pressure inlet manifold (or similar). I took it across same section of M62 on saturday and experienced limp mode twice, both times when really opened it up 85-90 mph. The garage that sold it to me are being awkward now, so i am not best pleased, its going back to the main dealers this week. Meanwhile i'm paying ofr a car i dont have and driving a clapped out old fiesta. Is there a particular fault that would mean limp mode problem only occured at such high loads? Also do you think if i got a bit more weight in the car (only me, 14 stone!,in when testing at mo) i really need to be able to reproduce the fault at lower speeds. Thanks again for you advice

[Rustynuts]

If the garage hook it up to their computer, it'll give a fault code. The code will indicate what caused the limp mode, but not how to fix it. It'll be something like "Charge pressure: negative deviation" which would indicate too little boost, and "positive deviation" would be too much boost.

This would be a help if you could find out what code it's showing. If the Garage haven't got a computer, they're guessing! Every time it hits limp mode this code will be shown, and the computer will be able to access it, there is the proof that there is a fault.

The garage have a responsibility to honour the warranty, and if they can't fix it, tell them you'll get another garage to fix it for them and they can pay the bill. If they are unhappy with this, then tell them the car is "Not of merchantable quality" and you would like your money back. I suspect they won't want to shell out for someone elses time and work so be prepared to argue with them, and get things in writing.

[sidlad]

Cheers rusty

The garage are already paying for someones elses time and money cos they're sending it to a VW dealership. Will the VAGCOM show a fault code even if the car is not in limp mode? Because the fault only occurs at high speed with just me in the car the only way it could be in limp mode at the time of test is if it was driven in such a way and the ignition left on, until the test. This can't be done as no-one will drive it above 70 cos they're not insured to.

The garage a bought from (the car people) have said they will keep attempting to fix it until someone tells them its not possible.

Thanks again for all your help its much appreciated.

[Rustynuts]

Once it's been set, the fault code is stored in the ECU's memory until it's cleared by the computer. You don't need to leave the ignition on or anything like that, it'll be there all the time.

Find a long steep hill and floor the car in as high a gear as possible, that should set off limp mode without speeding. Keep trying differnt gears until you can reproduce it at will. It's a definate fault, not anything to do with your driving style, and as such, it shouldn't be happening.

[sidlad]

Thanks rusty i understand how fault codes work now.

I can reproduce fault in 5th but onlu at speeds of around 90, i've bben going up the first few inclines across M62 from leeds and this seems to be steep enough.

Would it work at lower speeds if i was in a lower gear, and if so should i be making sure i don't redline in fourth to prevent damage?!?!

[sidlad]

Garage just called to say the VW dealers dont know what it is and that it could be a number of problems, looks like i'll be getting my money back. ANy ideas where to get a decent quality Golf or bora in west yorks?!?

[Rustynuts]

Well, shame on the fact that you aren't getting the car you saved for, but then again, good enough that you haven't got a car with a fault that can't be found.

Have a trawl through "Autotrader" website, it'll come up with a load of cars for your area. Something'll catch your eye.

This time, you'll have an idea what to look for when you go shopping.

[sidlad]

Managed to get an 09/02 bora tdi sport (130) for an extra grand with only 25K on the clock. Hopefully, this will live up to the VW reliability reputation i was expecting!

Seems to drive well and had no problems with three in car accelerating to 95 up a hill (i made the garage allow me to test on the motorway this time!.

Thanks for all your help rusty, it certainly helped to get the garages @rse into gear when i knew what i was talking about!

[Rustynuts]

Nice car. Just like the one I had until last year. Got another one the same, and it's starting to get worn in a bit now.

Be aware that the sump on these (Sport versions) is very close to the ground due to the lowered suspension. If you hit something, it makes an awful mess of things, don't ask how I know.

Consider getting a sump guard if you plan on any sort of farmm tracks etc. It lowers the clearance about 3/4 of an inch, but if you do hit something, nothing's going to get damaged. Guess what? I've got one fitted now.