# Throttle cutting out! Please Help!



## MKIVRider (Feb 20, 2008)

*Throttle cutting out! Car dying... Please Help!*

I own a 2003 VW GLI 2.8l 24V. 165,000 miles. I have owned it for about 5 years. Ever since I got it used, it has had a throttle cut out problem. It used to happen about 1 time every 6 months or so. I will be driving on the freeway and the throttle pedal would become useless and my car would slow down for a couple seconds then the throttle pedal would work again. Driving home from work this morning, the throttle cut out for a really long time on the freeway. About 8 seconds. The whole time I was pushing then letting off the pedal until it started working again. When I got off the freeway it did it again so I pulled into a parking lot and it died as soon as I pulled into the lot. I tried to start it and it had a hard time starting. Took about 5 seconds of cranking to start. Then it drove great a couple miles to my house. I am stumped. Things that have been recently changed are the fuel pump, fuel pump relay, ignition coils, 1 ignition coil connector, crankshaft position sensor. Coolant sensor and fuel filter were changed about 50k miles ago. Anyone have any ideas what is causing the throttle to cut out like it is? Any help would be appreciated. Thank you.


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## MachtSchnell (Oct 31, 2010)

The only time I've had my throttle cut out was when I was screwing around and had the gas and brake depressed at the same time and after a few seconds the throttle closed; I always thought it did that as a safety procedure. 

Have you ever had your brake light switch replaced? They were recalled and can malfunction.
Here's a thread
http://forums.tdiclub.com/showthread.php?t=77545


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## MKIVRider (Feb 20, 2008)

No I haven't checked the brake switch. One reason is because recently I had a dealer run my VIN and he said my car had two recalls and both had been already taken care of. The other reason is because one time this problem happened is when I was using cruise control. The throttle cut out for a few seconds and then it came back on and cruise was still engaged and the speed when back to what was set before the throttle cut out. I was just thinking that if I was in cruise and the brake switch engaged that cruise would not come back on by its self. From what I have seen in my car is that if I'm in cruise and hit the brakes the cruise disengages. Thank you for replying though. I appreciate it.


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## [email protected] (Sep 14, 2012)

If you have VAG-COM or know someone that does, do a throttle body alignment. May not be the exact cause but a good thing to do, especially due to the fact that your issues are throttle related. (Measuring blocks, 060).


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## MKIVRider (Feb 20, 2008)

At the moment I don't know anyone with the software to scan my car. I posted in the nor-cal forum asking for anyone that can help. One other thing I noticed is that when my car dies is that the only light illuminated on the dash is the battery light. Could this be an alternator issue? I ordered one and was planning on installing it in the morning. The voltage i'm getting from the alternator when the car is running with ac on, lights on, and radio on is 13.1 volts. About the same voltage reading when driving at freeway speeds as well. Also, I ordered an Autel VAG405 scantool about a month ago. Will be picking it up at the post office tomorrow. Is this something that can troubleshoot my issue?


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## [email protected] (Sep 14, 2012)

No. The autel won't help you with a throttle body alignment. 

It looks to be a good scan-tool but for a little more cash you could get vag-com and get some serious bang for your buck.


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## MKIVRider (Feb 20, 2008)

OK, so I got my VAG405 scan tool and scanned my car. Came up with a few codes. I feel stupid because the one code, 00526 Brake Light Switch-F Sporadic 008 Implausible signal, means my brake light switch is faulty. MachtSchnell was correct.


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## MKIVRider (Feb 20, 2008)

I replaced the stop light switch and the fuel filter yesterday. Im pretty sure the throttle cutting out issue is taken care of. I am still having the stall issue while driving. I drove it around a bit and it stalled. Started right back up no problem. Re-scanned it with the VAG405 tool and no codes are present. I did notice that one code that came up was in the airbag section saying the airbag module wasnt getting enough voltage. I cleared it and it didnt come back. I am seriously stumped on this one.


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## MKIVRider (Feb 20, 2008)

Update: I found the problem. A tube coming off the big black round thing on the drivers side firewall was cracked on the connection to it. The hose has 1J0612041FQ marked on it. I cut off the broken end. Heated up the fresh cut end with a lighter to soften up the hard plastic line and when the plastic was soft I pushed it onto the connector going to the round thing. Put a hose clamp on it for good measure. Purge valve is acting correctly now. Clicking like crazzy! No more stalls! Is that round thing the brake booster or vacuum pump??? Thanks for the help everyone! I really appreciate it! :thumbup::thumbup::thumbup:


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## MKIVRider (Feb 20, 2008)

Well it seems that I have the dreaded 1/4 tank or less stalling issue. It died on me again today.


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## Holmes741 (Feb 13, 2012)

The big black round thing is the brake booster. The hose coming off it is the vacuum hose to the intake manifold and the check valve is also in the middle if that line. I replaced mine a few weeks go bc it was cracked, but I don't think it's what is causing this issue. The 1/4 tank issue is usually a bad fuel pump, but you said you replaced that. The problem is going to be something weird because its too intermittent to be as simple as a failing sensor(but I can always be wrong). Start taking notes when the problem rears its head and that may shed more clues.


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## MKIVRider (Feb 20, 2008)

I replaced the hose that goes from the purge valve line to the breather hose because it was broken. It is idling and driving better after this and the engine doesn't bog down anymore at random times during idle. I drove it to work tonight which is 40+ miles and it has lots of power that I havent seen before. I noticed that the fuel gauge, at one point driving it tonight, did move a lot from about 3/4 to about 1/2. I went to VW this morning and they didnt have anyone that could look at it over the weekend and I made an appointment for monday morning. They said I need to be having the problem happening at the service dept. Which means I have to drive it til the fuel goes down a bit. Scary situation because I dont wanna get stranded. I might just siphon the gas out of the tank until it has the problem again and have it towed to them.


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## MKIVRider (Feb 20, 2008)

OK so I have fixed the dreaded 1/4 tank issue! VW had it for 8 hours today and couldn't get it to die. They are full of it because when I picked it up, it died on me 2 times driving it home which is about 2 miles. The solution is this. The aftermarket pump I bought had a different screen on the bottom of the pump and there was a hairline crack on the sending unit. I replaced the sending unit with the old one. The old bottom screen allows fuel to be more easily drawn into the plastic reservoir and it has a small nipple that "clicks" into the bottom of the pump. The new bottom screen has a smaller "tunnel" that doesn't allow fuel to be easily drawn into the reservoir when the fuel level gets low. And it doesnt click into the bottom of the pump. It kinda just sits inside. Put the old bottom screen onto the new plastic assembly and the stalling problem is gone! Anyone else having this problem, should do as I did to see if it remedies the problem.:thumbup::thumbup::thumbup:


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## MKIVRider (Feb 20, 2008)

Turns out that my original problem was 2 problems combined into 1 without me knowing it. The other problem is that at random times while using cruise control at freeway speeds, the car will start slowing down and the throttle pedal becomes useless. Some times it will come back to being responsive and more times lately the car will continue to slow and the car will stall. I have tried a couple times when the car starts slowing down to turn the cruise control switch off and switch it into neutral and then back into gear, but the throttle pedal with continue to be unresponsive with the cruise turned off. I just decided to order the Ross-Tech VCDS cable and use the software to find the problem. I am getting the VAG error - 00526 - Brake Light Switch (F): Implausible Signal. So im hoping it is a simple fix.


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## MKIVRider (Feb 20, 2008)

Well the 1/4 tank issue continues! Thought it was a venting / breathing issue with the tank. It even dies at 1/4 tank with the gas cap loose. VW service cant figure it out. I have also been chatting with a VW tech on the justanswer.com website and he cant figure it out yet either. All breather lines have been checked. When it dies there is still plenty of gas in the tank, about 3.5 gallons because when I go to the gas station it only takes about 9-10 gallons before the station pump automatically shuts off. I have read on another forum where this guy was having the same exact issue and he never figured it out either. I just wanna get rid of this car at this point.
BTW the pump that I used is a Beck Arnley 152-0966, dunno if that helps to know or not.


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## vora1989 (Mar 2, 2010)

dude i'm having very similar issues with my 04 Gti Vr6 24v with 88,000 miles. I'm getting just as fed up as you, i changed ALL plugs and all 6 coils with new ones last year. Cleaned my throttle body and i'm still stalling. I feel like its only after a certain time or its heat related because after my car cools down i don"t have any issues. I have been driving the car with low gas, dont know how much that would be related to this problem though.


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## MachtSchnell (Oct 31, 2010)

MKIVRider said:


> Well the 1/4 tank issue continues! Thought it was a venting / breathing issue with the tank. It even dies at 1/4 tank with the gas cap loose. VW service cant figure it out. I have also been chatting with a VW tech on the justanswer.com website and he cant figure it out yet either. All breather lines have been checked. When it dies there is still plenty of gas in the tank, about 3.5 gallons because when I go to the gas station it only takes about 9-10 gallons before the station pump automatically shuts off. I have read on another forum where this guy was having the same exact issue and he never figured it out either. I just wanna get rid of this car at this point.
> BTW the pump that I used is a Beck Arnley 152-0966, dunno if that helps to know or not.


That's a bummer man. Hope you get it sorted, and keep us posted 'till the problem gets fixed.


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## stoppre95 (Jul 15, 2012)

VORA1989 and MKIVRIDER
Ok when did you get your crankshaft positioning sensor replaced??
The car stalling out and the throttle having a mind of its own are symptoms of a faulty crankshaft pos sensor or even a cam sens.
I have a post with the same symptoms
http://forums.vwvortex.com/showthre...ttery-light-coming-on&p=78383515#post78383515


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## stoppre95 (Jul 15, 2012)

I did the same procedures, new alternator, plugs wires, cleaned out throttle body and checked for air leaks etc.

All my problems went away when i replaced my crank pos sens with a nice brand new bosch sensorumpkin:


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## stoppre95 (Jul 15, 2012)

The bosch one is about 130 bucks but I replaced it myself so i did not cost much. It is a couple hour job, a local mechanic said he would do it for around 200$$


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## MKIVRider (Feb 20, 2008)

I appreciate the responses. My problem is completely fuel related. The car runs superb when the gas is above 1/4. When it gets to exactly 1/4 the car acts like it is starved from fuel and dies. Many times when I was troubleshooting I would remove the fuel pump assembly and there is 2.5-3 inches of fuel still in the tank. When refueling at a gas station the tank only takes 9-10 gallons before the station pump shuts off automatically. Also I have found out that my gas cap is faulty. Getting a replacement tomorrow from VW. When I have the gas cap on the car runs like crap and I have to keep on the throttle more to keep up at freeway speeds and my fuel economy sucks. When I remove the cap completely my car runs much better and has a complete power gain on the freeway and I barely have to give it any throttle to maintain freeway speeds and better MPG. I did a fuel pressure test today both with the cap on and the cap off and both tests had normal results according to the bentley manual both idling pressure and residual pressure after the car is shut off. I have contacted Beck Arnley about this issue and this is the response they gave me about their pump assembly part no. 152-0966 installed on my car.

Beck Arnley Response:
I’m so sorry you are having issues with this pump. When talking with our product department they would really like to have this pump tested and back to us directly here in Smyrna, TN. They also said that there is a possibility of the replacement part having this same issue. Who did you purchase this part directly from so I can work with them on this credit and the return of this particular part to us?

After knowing what they said in their response it seems that they are maybe making fuel pump assemblies that are not compatible with my car, even though their website specifically shows that part number for my exact car. I will keep updating as I get more results. Getting Ross-Tech vag-com delivered wednesday. Maybe it will help me diagnose further even though my vag405 scanner is not showing any codes.


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## MKIVRider (Feb 20, 2008)

Decided to go with another brand. Ordered an Airtex E8424M. Will be delivered this weekend. :banghead: Will be returning both Beck Arnley brand pumps back to Amazon.com.


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## 24vGTiVR6 (Sep 14, 2010)

MKIVRider said:


> Decided to go with another brand. Ordered an Airtex E8424M. Will be delivered this weekend. :banghead: Will be returning both Beck Arnley brand pumps back to Amazon.com.


I don't get it.... with all these problems with the aftermarket pump why not bite the bullet, go with OEM, and call it a day?


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## MKIVRider (Feb 20, 2008)

I found out the problem and it is not my car. It is the pump and here is what it is doing. It is a "safety" feature that keeps the pump pumping if the supply line to the engine gets blocked. This one is defective and malfunctioning.
http://www.youtube.com/watch?v=hCYSAilgSTE


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## MKIVRider (Feb 20, 2008)

24vGTiVR6 said:


> I don't get it.... with all these problems with the aftermarket pump why not bite the bullet, go with OEM, and call it a day?


Mostly because I am stubborn...


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## MKIVRider (Feb 20, 2008)

Sorry to revive this old post but ever since my last post I went through a few more fuel pumps. One problem was that the alternator was bad and not providing enough voltage to keep the battery charged. I replaced that. More recently my car died while driving home and was a blown fuel pump fuse. I replaced the fuse and the car ran for a few more days then died again as I got home from work right as I pulled into the driveway. Another dead pump. It lasted longer than the other ones only because every time I got to half a tank of gas I would refill. This most recent one that went out was covered under a lifetime warranty and I got a replacement installed. Started the car with everything back together and I could hear the fuel tank creaking like it was becoming pressurized with nowhere for the fuel vapor to go. I did many diagnostics with vag-com and came to the conclusion that the fuel pumps had been fighting against the built up pressure by the displaced fuel in the tank as it was being used while driving. I did much research and came up with an answer. The vapor charcoal canister and the vapor purge valve were bad. I activated the purge valve and tried to blow air through it without success. I even cut apart the vapor canister and found that all the filters in it were caked up with charcoal. This was a direct result of me always topping off at the gas station. I ordered a purge valve and canister. Got them installed today. Started the car up with a DC amp clamp around the positive wire going to the pump, drove around for awhile and the max amp draw was 6.2 amps. I just wanted to let anyone who has been having this same issue that they should look toward changing out the vapor canister and purge valve. I will update soon. :thumbup::thumbup::thumbup:


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