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I have a 2000 VW Golf TDI, and I am loosing power when I am driving uphill. For example: I am in 5th gear, driving with 75 m/hour and all of a suddent am am slowing dorwn evenb though the accelerator pedal is all the way down. What may bethe cause?
 

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I have a 2000 VW Golf TDI, and I am loosing power when I am driving uphill. FOr example: I am in 5th gear, driving with 75 m/hour and all of a suddent am am slowing dorwn evenb though the accelerator pedal is all the way down. What may bethe cause?
http://www.myturbodiesel.com/1000q/multi/limp-mode-TDI-fix.htm

Read this article. It's impossible to tell you over the internet exactly what is causing your problem so here are possible causes and troubleshooting steps to narrow it down. If you're stuck, please report back.

Also, post moved to it's own thread.
 

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Discussion Starter #3
Similar problem

I have a 2000 Golf Diesel, 127.000 miles. I have the same problem. Not enough power. When I drive uphill 75-80 miles per hour all os a sudden I feel I am slowing down loosing speed even though my accelerator pedal is all the way down. I have the same problem on flat road with the AC running for a long time. I feel all o a sudden I am loosing speed and I need to shft in lower gear.
I took it to Autozone to put the scanner on. The only code that pops out is P1163 regarding fuel temperature senosr. I bought a new one and replaced it. Same problem,same code showing up still no power. What should I do?
 

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I have a 2000 Golf Diesel, 127.000 miles. I have the same problem. Not enough power. When I drive uphill 75-80 miles per hour all os a sudden I feel I am slowing down loosing speed even though my accelerator pedal is all the way down. I have the same problem on flat road with the AC running for a long time. I feel all o a sudden I am loosing speed and I need to shft in lower gear.
I took it to Autozone to put the scanner on. The only code that pops out is P1163 regarding fuel temperature senosr. I bought a new one and replaced it. Same problem,same code showing up still no power. What should I do?
It's not the fuel temp sensor as you already found out. You're hitting limp mode. Look through the limp mode troubleshooting article in the FAQ.
 

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Discussion Starter #5
Thank you for the info. I have just read the article. I can;t figure out what might be. I went to Autozone, and they put the scanner on. The only code that shows up is the fuel temperature sensor one. I changed it with a new one. I got the same code showing up. My check engine light is still on. No other codes. The car runs fine, unless I go uphill or I drive on flat road and with the AC on. If its really hot outside and I have the Ac on for more than 45 minutes I feel the engine is not "pulling" anymore the way it should. My foot/pedal is all the way down but it doesn't accelerate. It might be the turbo charger???
 

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What have you checked so far? Scanning for error codes is just the first step. Things like a defective MAF sensor do not throw any codes. You have to do manual testing of the sensor to determine if it's bad. However, the MAF normally doesn't cause limp mode and you say it runs well at other times.

Go through the checklist and please say where you're getting stuck. Please be descriptive in the tests and results because it's hard to mind read over the internet. The alternative is to go to a mechanic and pay them to get stuck.
 

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Discussion Starter #7
All right here is what I have done so far:
- replaced timing belt, timing is perfect, and water pump
- replaced turbo charger and actuator;
- checked hoses for leaks and replaced all vacum hoses; car runs the same, no power at all
- cleaned EGR valve, is opening fine now;
- checked the intake manifold and EGR valve body, they were full of carbon, and I got them cleaned, car runs the same;
Took the car to the dealership for a test and they said the MAF sensor reads low numbers and the conector looks bad and the hoses were old (this was before I changed the hoses). They wanted to charge me $700+ for the MAF and replacing the hoses. I bought from NAPA a MAF sensor made by BOSH and also hoses and replaced them myself. Car runs the same.
I checked the intercooler sensor aka MAP sensor, the pipes/tubes coneccted to the intercooler had oil in them. CI took them off, and cleaned them. Bought a new sensor, car runs the same.
Today I finally changed the N75 and no difference.
We put the scanner on the car and the new MAF sensor reads the same as the old one: when the engine is on at 900rpm reads 270 and if i RAV the engine to 3000 rpm the MAF don't read more than 450. If I RAV the engine to red line it doesn't go all the way to the red line.I disconnected the MAF, and the scanner shows a 550 by default, and if I RAV the engine, it passes the red line.
Bought a compression test. I got 350 per cylinder.
Car runs the same, no power no boost.
I am stuck and have no clue what to do!
HEEELP!!!
 

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Have you done a boost leak test? You said you checked the hoses but do an actual boost leak just incase you're missing something.

Reference your vacuum line diagram under the hood. Triple check that all lines are going where they need to be going. You've replaced a bunch of stuff so it's possible something has been misplaced.

Datalog the boost - you've already replaced the sensor so you just now need to figure out if the turbo is putting out correctly. Also datalog the MAF - saving a chart may give you some clues.

The compression is not great but it's not horrible. A healthy engine should be in the 400-500 range but as long as it's consistent it shouldn't be causing your problem.

Also check the EGR solenoid and function - maybe the EGR gasses are displacing the intake air which is lowering the MAF reading. More likely is that there's a turbo control problem which is causing low boost but you havent' said that you datalogged the boost values.
 

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Discussion Starter #9
We routed the vacum lines by the sticker under the hood and by now we now them by heart. It was done at least 3 times.
EGR solenoid measured, when checked with an ohmmetter 17.3 ohm. The books said it should be between 14-20 ohm.. SO it should be good.
When we hooked up the scanner at 900rpm the boost is 816 and if we rev it up to 3000rpm it shows aprox. 1155 actual which is the same with the specified value, give or take 5-20.
 

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Have you done a boost leak test? You said you checked the hoses but do an actual boost leak just incase you're missing something.

Reference your vacuum line diagram under the hood. Triple check that all lines are going where they need to be going. You've replaced a bunch of stuff so it's possible something has been misplaced.

Datalog the boost - you've already replaced the sensor so you just now need to figure out if the turbo is putting out correctly. Also datalog the MAF - saving a chart may give you some clues.

The compression is not great but it's not horrible. A healthy engine should be in the 400-500 range but as long as it's consistent it shouldn't be causing your problem.

Also check the EGR solenoid and function - maybe the EGR gasses are displacing the intake air which is lowering the MAF reading. More likely is that there's a turbo control problem which is causing low boost but you havent' said that you datalogged the boost values.
Another day working on the car and no success. I checked for power the conector that goes in the N75 solenoid and the ground is really really really really week. I traced the wire and goes into the computer in the middle of the car, under the windshield.
I checked it many times while checking other plugs and sometimes it does show a little more power but still not good enough as the other ones do. Is that normal? That wire comes from the computer. Can that be a problem for my power loss????
I also changed the MAF again with a different one and I have the same values as the other 2 MAF sensors. Don;t know what to do anymore.
 

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Not sure about the weak ground. I don't see why it would be. Have you swapped the N75 with the EGR?
Have you datalogged the injection pump quantity? Maybe there's an IQ problem - no fuel=no power = no turbo boost and air. Maybe block off the EGR with a block off gasket and see if that makes any difference?
 

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What was the solution????

Going through the same thing, just not replaceing everything if I can help it. There seems to be to many quirks about these cars, so unless you get lucky or it just happens to be the most common ones good luck.
 

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This is an old thread but for the benefit of DIY'ers, there is one thing that gym_flo has not mentioned and that is the amount of vacuum. Like him, I changed my timing belt and started having performance problems and bad fuel economy. With a mityvac, I was able to pinpoint the vacuum pump as the problem. Vacuum at the small nipple at the first junction from vacuum pump was 15 mm Hg. It needs to be >25 mmhg. It turns out that the vacuum nipple was loose (can be turned) and was leaking at the border of the housing and the nipple. I patched this with epoxy (had to remove pump).

A good place to check vacuum is at the top nipple of the N75. It should also read >25 mmhg
 

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MVB 11 will show the percentage it is at (45-95%), when it goes into limp mode (mine) maintains a fixed 92.4% ... also if your multimeter can measure duty cycle you can see what its operating at.
 

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This is an old thread but for the benefit of DIY'ers, there is one thing that gym_flo has not mentioned and that is the amount of vacuum. Like him, I changed my timing belt and started having performance problems and bad fuel economy. With a mityvac, I was able to pinpoint the vacuum pump as the problem. Vacuum at the small nipple at the first junction from vacuum pump was 15 mm Hg. It needs to be >25 mmhg. It turns out that the vacuum nipple was loose (can be turned) and was leaking at the border of the housing and the nipple. I patched this with epoxy (had to remove pump).

A good place to check vacuum is at the top nipple of the N75. It should also read >25 mmhg
Do you mean inches of Hg(mercury), or do you intend to say millimeters? 25mm seems quite low, ~10", mine currently is ~22"Hg. I had not seen anywhere a specification for the vacuum pump and how much it should produce.

Currently I have 22"Hg supplied to N75, engine at idle im seeing 11"Hg on the line to the VNT acuator.
 
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