Hello guys, this is my first post. The vehicle is a 2005 Golf TDI the engine code is BEW. The first issue the car came in with was a runaway engine. I found the crankcase full of fuel, It turned out the Vacuum pump/fuel pump was leaking into the cylinder head. The pressure from the fluid in the crankcase destroyed the windage tray and took out the #4 oil squirter. After cleaning all of the plastic out of the head and crankcase and installing a new squirter as well as new fuel pump and a crankshaft seal it started up smoked for awhile and ran well. I drained the oil dropped the pan and cleaned out the rest of the plastic then filled with fresh 505.01 oil and a new filter. The issue now which the customer states is new is that during the first start of the day when the engine is fully cold there is no throttle response for the first minuet of running. Then the revs drop from a fast idle (1000 rpm) down to around 750rpm and the throttle is again responsive. It will only happen when totally cold as in not being run for about 8 hours. I have logged the TPPS and it reads fine. I did notice the piston for the EGR was very nasty and cleaned it as best I could with no positive results. If anyone has experienced this issue please let me know or if anyone has any Ideas. I do alot of TDI work at my shop but have not encountered this issue.
PD no throttle response at first start
- Thread starter 100% Euro
- Start date
PDJetta
Top Post Dawg
- Joined
- Nov 6, 2003
- Location
- Northern Virginia
- TDI
- '04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
Welcome to the TDI Club.
Diesel engine runaways usually happen from a blown turbocharger, that allows lube oil (from the turbocharger oil line) to flow into the intake tract and the engine burns the oil as fuel in an uncontrolled manner. I suppose if the crankcase filled with fuel, the normal blowby would eventually push the fuel/oil mix through the breather and into the intake tract with the same consequences--a runaway engine.
And yes, I have read about a tandem pump failure where the pump internal seal fails and allows diesel fuel to flow into the vacuum pump half and get exhausted through the vacuum pump port into the cylinder head and into the oil. Does not happen often, but it can happen. After I dissasembled my old tandem pump I could plainly see how it could happen. The two pumps share a common driveshaft, sealed by a garter spring type seal.
When a run-away happens from a failed turbocharger, sometimes enough oil gets sucked into the engine to hydrolock it and bend the connecting rods. This may be what happened to your customer. Bent rods will lower the compression and on a cold diesel motor it may be insufficient to light off the fuel, hense the poor running and power until warm. A simple compression test will tell you if that is the case. Usually cylinders 2 and 3 bend the rods from a hydrolock before the #1 and #4 do because they have a shorter, more direct, path from the intake manifold.
Let us know what you find. This is an interesting (but unfortunate) occurrance.
--Nate
Diesel engine runaways usually happen from a blown turbocharger, that allows lube oil (from the turbocharger oil line) to flow into the intake tract and the engine burns the oil as fuel in an uncontrolled manner. I suppose if the crankcase filled with fuel, the normal blowby would eventually push the fuel/oil mix through the breather and into the intake tract with the same consequences--a runaway engine.
And yes, I have read about a tandem pump failure where the pump internal seal fails and allows diesel fuel to flow into the vacuum pump half and get exhausted through the vacuum pump port into the cylinder head and into the oil. Does not happen often, but it can happen. After I dissasembled my old tandem pump I could plainly see how it could happen. The two pumps share a common driveshaft, sealed by a garter spring type seal.
When a run-away happens from a failed turbocharger, sometimes enough oil gets sucked into the engine to hydrolock it and bend the connecting rods. This may be what happened to your customer. Bent rods will lower the compression and on a cold diesel motor it may be insufficient to light off the fuel, hense the poor running and power until warm. A simple compression test will tell you if that is the case. Usually cylinders 2 and 3 bend the rods from a hydrolock before the #1 and #4 do because they have a shorter, more direct, path from the intake manifold.
Let us know what you find. This is an interesting (but unfortunate) occurrance.
--Nate
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04SlvrJetta
Veteran Member
100%Euro, do you mean the engine doesn't respond well, or that you can repeatedly push the accelerator and it behaves as if you never touched it? I have had the latter a handful of times and have never really diagnosed it and it only happened when very cold in winter. I have read that this can be caused by a brake switch problem. Remember, TDI's are drive by wire so there is no mechanical link to the engine from accelerator.
I will certainly test compression although after the initial start the motor runs good and strong and requested boost mirrors actual. I was also suspicious of the turbo seals but when I saw the amount of fuel in the oil I decided it was either the tandem pump or injectors leaking. I pressurized the tandem pump and found the seal to be leaking (poor design for sure) so I have cured that issue. Now one more thing that may or may not be of consequence here is they are running bio fuel. I do not have much experience personally with Bio so I don't know the issues caused by it nor do I have a sufficient customer base running it. I have solved the fuel infiltration issue. Now all that is left is the cold start issue. The odd thing is that you can turn the vehicle on immediately cycle the key off and then restart and have immediate throttle response which in my mind rules out mechanical failure. What I mean by no throttle response is an Idle of 1000rpm and no matter how much throttle is applied you will never get about 1100rpm until it decides to idle down and give throttle response which is usually within 60 seconds.
PDJetta
Top Post Dawg
- Joined
- Nov 6, 2003
- Location
- Northern Virginia
- TDI
- '04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
"Now one more thing that may or may not be of consequence here is they are running bio fuel."
The PDs do not do well on biodiesel, especially the home brewed type. This may have led to the pump seal failure. There is a thread on this list with internal pictures of a PD run on biodiesel and it wrecked the motor. A lot of sludge build-up too.
"The odd thing is that you can turn the vehicle on immediately cycle the key off and then restart and have immediate throttle response which in my mind rules out mechanical failure."
I recant my statement that the rods may be bent. Maybe its a problem with the accelerator pedal (it has a potentiometer in it since there is no throttle cable, its "drive by wire").
--Nate
The PDs do not do well on biodiesel, especially the home brewed type. This may have led to the pump seal failure. There is a thread on this list with internal pictures of a PD run on biodiesel and it wrecked the motor. A lot of sludge build-up too.
"The odd thing is that you can turn the vehicle on immediately cycle the key off and then restart and have immediate throttle response which in my mind rules out mechanical failure."
I recant my statement that the rods may be bent. Maybe its a problem with the accelerator pedal (it has a potentiometer in it since there is no throttle cable, its "drive by wire").
--Nate
FlyTDI Guy
Top Post Dawg
Weird for sure. First off, I'm spitballin' and don't have a PD but... The fact that it restores itself after a key cycle definitely points to an electrical issue, IMO. This sounds similar to the issue of, with your foot on the brake, you can't accelerate beyond about 1100 rpm. In very cold weather, the idle will step up but shouldn't prevent you from taking off and driving normally. You haven't mentioned scanning for codes. I'm wondering if the MAP temp sensor is wiggy or even the brake switch is intermittent? If you're familiar with 'limp mode', it resets after a key cycle as well. You could be experiencing some kind of 'safe mode' issue. Regardless, sounds like electrical. Sorry I don't have anything more specific but it sounds like you're more than capable/resourceful and will get to the bottom of things.
04SlvrJetta
Veteran Member
When it exhibits this behavior, try tapping the brake pedal to see if the problem goes away.
FlyTDI Guy
Top Post Dawg
Bingo...not a TPS issue but possibly brake switch or MAP.
PDJetta
Top Post Dawg
- Joined
- Nov 6, 2003
- Location
- Northern Virginia
- TDI
- '04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
I would go ahead and install the latest brake light switch for the car (VW went through a bunch of versions). Its only about $7 and just snaps right in.
--Nate
--Nate
whitedog
Veteran Member
I'm not seeing how a brake light switch would cause it to idle at 1000 RPM instead of 900. Please keep us posted on what you find.
FlyTDI Guy
Top Post Dawg
My point is, the behaviors he describes are actually hardwired into the car's logic under certain conditions. They are actually two separate sets of conditions but the car seems to be demonstrating both at the same time. One is you have your foot on the brake and the second is a cold start idle step up. The fact that cycling the key fixes it is a clue. Why the car is exhibiting both at the same time, I don't know. It's at least worth verifying that the sensors involved in both behaviors are working properly.
I will check the brake light switch. It seems illogical that would be the issue since VW/Audi's logic is if the throttle is applied before the brakes you are not given throttle response. If you are implying that the ECU is seeing the brakes to be applied this would still not effect the throttle because if the brakes are applied before the throttle you are still allowed throttle input. Its only when throttle is applied before the brakes that throttle is cut.
FlyTDI Guy
Top Post Dawg
Visa-versa actually... Foot on brake, then throttle and you're limited to about 1100 rpm. Do it twice and it's overridden. It's an attempt to curtail powerbraking, I guess...
No its defiantly Throttle then Brake = no power. Its because of the unintended acceleration dilemma from the old Audi 5000's.
FlyTDI Guy
Top Post Dawg
If that's the case, then there was a change for the PD engine and it makes the scenario less probable. I do know this, the VE engine acts exactly as I described.
Addendum: Just an additional thought, I've never actually tried working the brakes and throttle against each other while underway. It could be the limiter would work the same under those conditions. If so, that is much more as you describe. In fact, it could work both ways.
OK, it's global. I just tried it and regardless of who comes first, if you brake, throttle is limited. Sorry for the tit-for-tat, just trying to help.
Addendum: Just an additional thought, I've never actually tried working the brakes and throttle against each other while underway. It could be the limiter would work the same under those conditions. If so, that is much more as you describe. In fact, it could work both ways.
OK, it's global. I just tried it and regardless of who comes first, if you brake, throttle is limited. Sorry for the tit-for-tat, just trying to help.
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Franko6
Vendor , w/Business number
I didn't read that the turbo has been replaced. Runaways are very hard on turbos. Is the turbo sticking? Also, since this is a problem that can be 'reset' by cycling the key, then it is between the MAF, MAP and turbo, with the off chance that the CAT is clogged.
Check for requested and actual boost. Also check to see if your boost is overshooting the mark. If you have the stock 2.5 MAP, a sticking VNT in the turbo could be causing your problems. Running bio creates a lot of issues for sticking; rings, injectors, turbo... you name it.
Check for requested and actual boost. Also check to see if your boost is overshooting the mark. If you have the stock 2.5 MAP, a sticking VNT in the turbo could be causing your problems. Running bio creates a lot of issues for sticking; rings, injectors, turbo... you name it.
Perhaps it is both ways, I have not tried it on an MKIV with a PD. I don't mean to argue either. I appreciate the help.
The turbo has not been replaced, I did actually state that I logged requested VS actual boost and they are on par. The MAF is reading normally. The CAT being clogged is unlikely due to the power being at normal levels.
FlyTDI Guy
Top Post Dawg
Just curious, 100% Euro... Did you get this resolved and, if so, what was the problem?
bazket_case
Active member
Sorry to bring up an old thread, but this is exactly happening to my PD. Wondering if a solution was ever found?
bazket_case
Active member
Anyone have any ideas what the solution would be to this issue? Starting to become quite annoying on each start to either wait 2-3 mins or to have to restart a couple times to get the throttle pedal to work. Any help would be greatly appreciated.
JETaah
Vendor , w/Business number
I am reviving this in case someone that found a solution has had the symptoms in the first post and has found out THE solution.
I have had two cars come in over the last couple of months that have had the exact symptoms and can not find a reason for it.
Both are PD cars and both are automatic transmission cars although they are different transmissions....Jetta with 09A and Passat with 01V.
Both exhibit the elevated idle (1100 RPM) and zero throttle response upon a cold start that clears up shortly after start-up and once the idle speed drops to a normal 890-903RPM.
I have had two cars come in over the last couple of months that have had the exact symptoms and can not find a reason for it.
Both are PD cars and both are automatic transmission cars although they are different transmissions....Jetta with 09A and Passat with 01V.
Both exhibit the elevated idle (1100 RPM) and zero throttle response upon a cold start that clears up shortly after start-up and once the idle speed drops to a normal 890-903RPM.
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JETaah
Vendor , w/Business number
Another few notes regarding similar circumstances between vehicles...
The cars both came in for camshaft work and, while in my possession, had the break-in oil which is relatively thick for the current ambient temperature. It is the 15W50 Joe Gibbs oil.
This can make it more of a challenge to cold idle in the current frigid Michigan temps.
I have an email sent to the Jetta's owner to see if anything has changed with switching to the post break-in 5W40 oil. The owner needed the car back and did not see the glitch as a reason to not use the car.
The Passat is still in my shop and still has 15W50 since the camshaft service was just performed.
The reason I am bringing this up is that I read a post by aNUT in another similar thread that said that the no-accelerator response was a feature that was intended to protect the turbo from a lack of lubrication on automatic trans equipped cars while the engine is cold starting.
I do not know how aNUT determined this as a feature. I spoke with a tuner that said that he had no knowledge of this in the programming.
The Jetta in this case is a great starting car. It hits on the first cylinder even when ice cold. The Jetta is less consistent with the accelerator drop out sequence but the temps were not as cold as they are presently.
The Passat has a little harder time starting but has an older battery and had been sitting for a while in disrepair. Power seems normal once the idle drops and you are underway.
These are not isolated incidences as there are a few threads like this and no one has posted a solution...at least not that I have not found.
The cars both came in for camshaft work and, while in my possession, had the break-in oil which is relatively thick for the current ambient temperature. It is the 15W50 Joe Gibbs oil.
This can make it more of a challenge to cold idle in the current frigid Michigan temps.
I have an email sent to the Jetta's owner to see if anything has changed with switching to the post break-in 5W40 oil. The owner needed the car back and did not see the glitch as a reason to not use the car.
The Passat is still in my shop and still has 15W50 since the camshaft service was just performed.
The reason I am bringing this up is that I read a post by aNUT in another similar thread that said that the no-accelerator response was a feature that was intended to protect the turbo from a lack of lubrication on automatic trans equipped cars while the engine is cold starting.
I do not know how aNUT determined this as a feature. I spoke with a tuner that said that he had no knowledge of this in the programming.
The Jetta in this case is a great starting car. It hits on the first cylinder even when ice cold. The Jetta is less consistent with the accelerator drop out sequence but the temps were not as cold as they are presently.
The Passat has a little harder time starting but has an older battery and had been sitting for a while in disrepair. Power seems normal once the idle drops and you are underway.
These are not isolated incidences as there are a few threads like this and no one has posted a solution...at least not that I have not found.
Dimitri16V
Top Post Dawg
Oil has nothing to do with it
pdq import repair
Veteran Member
If it looks old at all, pop in a new coolant temp sensor. We know those fail and can cause odd issues.
Probably not the problem, yet, but couldn't hurt to freshen it up.
Probably not the problem, yet, but couldn't hurt to freshen it up.
offroad2surf
Active member
I've had a similar problem on an old afn tdi. Turned out to be throttle pedal.
HiltonjaceVwTdi
Active member
Has anybody found a solution to this !!! This is a very frustrating problem and to have some one post and problem and not post a solution is very annoying,
VincenzaV
Veteran Member
Maybe or not related with my 2004 PD 09A tiptronic auto wagon.
It used to have a low power feel upon start up from cold. Meaning, when I pressed the gas once in drive from the car sitting overnight and cold engine, it wouldn't get out of its own way. It was dangerous. I could barely pull away from a stop sign without worrying I was going to get hit.
It is better now. I think 100%, haven't really experienced it. This is what I did maintenance wise, not sure what, if anything is related.
-Replaced white/black one way check valve in vac system. It failed, you could blow through it and suck through it. No longer one way.
-Replaced rusted turbo actuator and N75 solenoid (that also had rust chunks in it when blowing it out)
Car has been great since!
***NOTE*** I was under the car doing the actuator replacement, and heard what has to be a transmission solenoid, buzzing. With the key out of the ignition too. I felt a vibration while hearing it, at the bottom of the transmission. I was under the car, and it was cold. Not sure it gear one is/was sticking and maybe the car was starting out packed and that was the low power issue, or no power due to the aforementioned turbo components.
I hope this helps.
It used to have a low power feel upon start up from cold. Meaning, when I pressed the gas once in drive from the car sitting overnight and cold engine, it wouldn't get out of its own way. It was dangerous. I could barely pull away from a stop sign without worrying I was going to get hit.
It is better now. I think 100%, haven't really experienced it. This is what I did maintenance wise, not sure what, if anything is related.
-Replaced white/black one way check valve in vac system. It failed, you could blow through it and suck through it. No longer one way.
-Replaced rusted turbo actuator and N75 solenoid (that also had rust chunks in it when blowing it out)
Car has been great since!
***NOTE*** I was under the car doing the actuator replacement, and heard what has to be a transmission solenoid, buzzing. With the key out of the ignition too. I felt a vibration while hearing it, at the bottom of the transmission. I was under the car, and it was cold. Not sure it gear one is/was sticking and maybe the car was starting out packed and that was the low power issue, or no power due to the aforementioned turbo components.
I hope this helps.
JETaah
Vendor , w/Business number
No, I did not.
Both car were picked up when the winter weather had broken and the symptom had diminished. It was more pronounced in frigid cold weather. It will be interesting to see if the problem returns.
I heard back from the Passat owner saying that the issue did not resurface for him.
The Jetta owner never reported back with any complaints...or decided that it was not enough of a problem to be without the car. I had run out of ideas anyway.