Golf IV / Jetta IV :: 2002 VW 2.0 - Loss Of Power While Driving At Normal Highway Speed
Jun 25, 2014
Ok, so I was driving normal highway speeds and all of a sudden, I realize a major drop in power. I pull over and restart it and it changes nothing. Now when I floor it, it takes 20-30 seconds to get to 90K.
I checked the air filter... Nothing. Used a code reader... Nothing. Then I decided to pressure test the cylinders... Nothing, except now the check engine light is on.
The Ol Dub is still drivable, but it is extremely slow and rough at idle. I am thinking it might be a MAF or fuel filter.
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The primary electric fuel pump in the fuel tank of my 2004 W12 failed last month, shortly after I had set out on a cross-Canada trip from Vancouver Island to Toronto. The whole process of diagnosing and identifying the cause of the problem, mitigating it so that I could continue the trip, and finally replacing the fuel pump was kind of complex, so, here's the write-up.
The problem presented itself as a surging of the engine - a momentary loss of power - at normal highway operating speeds. The onset was progressive, but it didn't take very long - only about 60 miles of driving - from the first little cough of the engine until total failure of the pump. The first indication was failure of the car to maintain speed (while on cruise control) when climbing hills. That progressed to failure to maintain speed on flat surfaces, and finally led to the car coasting to a stop, engine stalled, at the side of the road.
I soon learned that if I floored the accelerator pedal and held it against the floor, the car would cough and burp for a few seconds, then take off like a rocket. So, for the next 40 miles, I coaxed the car into the next city by flooring it, accelerating to about 80 MPH, then coasting until the speed dropped to 20 MPH, and flooring it once again and accelerating to 80 MPH. Fortunately, I was on a remote road with few other cars, and no police.
I checked the fuses for the two fuel pumps - fuses 34 and 35 in panel C (above the left battery), and they were both OK.
The next day, I visited a VW dealer in the Canadian Rocky Mountains, and together with the parts manager and one of the technicians, we looked at the Self-Study Guides (SSGs) for the Phaeton, and looked at wiring diagrams. Eventually, we came to a tentative conclusion that the primary electric fuel pump in the fuel tank had failed. The SSGs stated that the primary electric fuel pump (the pump on the right side of the car) operates all the time, and the secondary electric fuel pump (the pump on the left side of the car) only operates during starting and during 'periods of high demand'. That made sense to us - the car started fine, and worked OK when the accelerator pedal was held to the floor (high demand). It just didn't work worth a darn at any other time... the engine would stall, or, the car would not accelerate at all.
Here are two illustrations taken from the SSGs that describe how the fuel delivery system works. The first image is taken from the 'Phaeton Overview' SSG, which applies to all vehicles. The second image is taken from the W12 engine SSG. I kind of suspect that all the Phaetons operate in the same way, regardless of engine, because the fuel tank in all the Phaetons has the same shape - two lower lobes, which means two pumps are required.
Descriptions from the SSGs
I think that there may be an error in the description above. My experience suggests that the right hand pump (identified as G6, above) is the primary pump, and the left hand pump (identified as G23) is the one that switches on during starting and periods of high demand. Note also how the identification of G6 and G23 in the illustration above is reversed from what is shown in the illustration below. I believe that the text and illustration below is correct, and the text and illustration above is incorrect.
The 'effects of failure' in the description above would, I believe, make sense if it was the left-hand pump that failed. In my case, the right hand pump failed, and the effects of failure that I experienced were as I set them out in the beginning paragraphs of this post - quite different from the 'effects of failure' of the left hand pump that are described in the SSG above.
After coming to the tentative diagnosis that the primary electric fuel pump (the right hand pump) had failed, we checked the parts stock status in North America. There was one pump in stock, but it was in the United States, and being that it was a Thursday, the pump could not be delivered before the following Tuesday. I didn't want to spend that much time waiting for it, so, we started thinking about other possible solutions.
If we could somehow get the secondary electric fuel pump - the pump on the left side of the car that only operated during starting and heavy demand - to operate, that just might put me back on the road again. So, I removed the plastic cover from the small relay that operates the secondary pump, and wrapped a rubber band around the relay, thus keeping the relay in the closed position. A short test drive proved that this solution worked just fine, the car once again operated normally. The only "problem" was that the last 25% of the fuel in the tank would be unusable, because that fuel would be left behind in the right-hand lobe of the tank - the lobe with the defective primary fuel pump.
Electric Fuel Pump Relays
Here is an illustration from the Phaeton wiring diagrams identifying the various relays above the left battery.
Here you can see the two relays for the electric fuel pumps. They are identical part numbers.
Here you can see the relay for the secondary electric fuel pump, with a rubber band wrapped around it to keep it continually closed.
Aside from the loss of use of the last 25% of the fuel in the fuel tank, the car worked just fine with the secondary electric fuel pump running all the time. There were no problems noted even under heavy acceleration. It was, however, necessary to physically remove the rubber-banded relay from its position in the relay panel whenever the car was shut down for more than half a hour. The power to this relay comes from Terminal 30 (battery direct) - it is not switched on and off with the ignition as Terminal 15 power is. This meant that if the rubber-banded relay was left in position overnight, the left hand battery would totally discharge, because the fuel pump would operate continuously all night. I discovered this the morning after the first night...
So, for the next 8 days, I drove across Canada, removing the relay each night and replacing it each morning. I didn't bother to remove it when I stopped for meals or fuel. The rest of the 3,000 mile trip was uneventful - except once, when I let the fuel tank run down a bit too close to the 1/4 full mark, and the car began surging again because the left hand lobe of the fuel tank (with the functional secondary pump) had emptied out. That was a close call, but I managed to get to a gas station and refuel.
After arriving in Toronto, I called the parts staff at my home VW dealer and ordered a new primary electric fuel pump. I discovered that the left and right hand pumps are slightly different (the various hoses coming out of the pumps are different), and I also discovered that a pump costs about $400. The parts staff suggested I order two seals (one for each side of the tank), because I would have to remove both the right and left fuel tank covers to change the right pump. The seals were not expensive.
Here are two pictures that illustrate where the pumps sit in each lobe of the fuel tank. Note the fuel filler port on the left side of the pictures (as we know, it is on the right side of the car) for orientation.
Phaeton Fuel Tank, showing pumps
Fuel Pump Access Panels
Below is a picture that shows where the access panels to the two fuel pumps are. It's easy to get to these access panels, just remove the carpeted panel from the floor of the trunk.
Here's a close-up of the right side (primary) electric fuel pump access panel.
The instructions (from the VW Repair Manual, or the ELSA / ErWin system) for replacing the fuel pump are quite well written. The repair manual suggests that the fuel tank be drained before replacing a pump. I didn't want to drain the tank, so, I ran the fuel level down as low as I dared (remembering that 1/4 full is effectively 'empty' with a failed primary pump). That proved to be adequate.
There are a heck of a lot of steps involved in disconnecting all the hoses and loosening the various components before the pump can be removed. I strongly suggest that anyone attempting this task have a printed set of instructions before starting disassembly.
The fuel pump has quite a few hoses and connections on it, but fortunately, each connector is unique in design, thus it is not possible to hook things up the wrong way when installing the new pump. It is possible to 'lose' a hose inside the tank... for this reason, I attached a small piece of string to each hose I disconnected from the pump.
The process goes more or less like this:
1) Remove the two 404 relays, to ensure no power is sent to either fuel pump.
2) Lift the rubber cover, and remove the electrical connections from both pumps (left and right).
3) Using a special tool, lift up the three fasteners that hold the cap over top of the access panel (these are NOT threaded fasteners!)
Here is a side view of the three fasteners that hold the plastic cap in place - they are friction fit, not threaded.
4) Now you have a clear view of the access panel. It will probably be dusty and rusty, and should be vacuumed clean before proceeding, to prevent crap from falling into the fuel tank when the cap is removed. The rust is due to condensation forming on the cold metal part whenever the car is filled with cold fuel from an underground storage tank.
5) A special VW tool is used to remove the locking ring from the access panel.
6) After removing the locking ring, I buffed it up with a wire brush to remove surface corrosion.
7) The plastic access cap can now be lifted. There are two electrical connectors on each fuel pump, but three possible fittings on the plastic cap. Fortunately, the three fittings are keyed differently.
8) This is what you see inside the tank after removing the plastic cap.
9) After following all the detailed instructions for disconnecting and stowing hoses, disconnecting the fuel measurement probe from the pump housing, etc., it is possible to lift the pump out. It will be full of fuel.
10) The old and new pumps, side by side. I was very surprised at the amount of crap that was trapped in the filter screen at the bottom of the pump. The car only has 60,000 miles on it, and I have always used premium fuel in it.
11) I was also a bit surprised at the discolouration of the pump components. Below you can see the old and new pumps side by side.
12) It is necessary to get access to the opposite side (in this case, the left side) fuel pump, because hoses from each pump travel horizontally across the tank and connect to the other pump.
13) Here you can see a new hose from the right side pump connecting into a T fitting above the left side pump. It is easy to thread this hose across the top of the inside of the tank.
14) As mentioned earlier, there are three possible fittings on the base of each plastic cap, but only two connectors within the fuel tank. Everything is keyed, thus improper assembly is not possible.
Once the new pump has been installed, the hoses connected, and the fuel measuring probe reset into the side of the new pump, re-assembly of everything is quite straightforward. I replaced the rubber ring around the access panel opening on each side of the tank, and I also buffed up the locking rings using a wire brush (to remove corrosion) on each side.
It was not a pleasant job - your hands get covered in fuel, and there are some hazards associated with working on an open fuel tank with vapour escaping, but it is not a particularly difficult job. It is time-consuming, though.
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I have a mk4 TDI. Running 18" 225/40 and coil overs. My car began to have a loose steering wheel and was unstable at high speed so i did alignment and it was bad. when they fixed it next day it broke again. My front wheels end up being too open. If front left is straight than the front right is too much open, like i am turning right. i did alignment again in the shop, they made them straight and it broke again next day. What can cause that my allignment breaks every day? Shop doesn't know.
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I want to start by saying I'm new and don't really fully know how to search vortex, I'm sure there's probably a bunch of things about this. I have an 04.5 gli, my temp gauge reads 190 all of the time but according to vag com I'm running at about 220 some times higher. I've heard my fan kick in once in the year I've owned it. Also I get a decent amount of power loss after driving for about 20 to 30 minutes. Idk if that's related, but just hard wire the fan with a switch? I don't have a lot of money so I'm not really trying to play a guessing game replacing stuff.
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I've been experiencing power loss at random times while driving, idling, With almost always flickering headlights on my mkiv 1.8t gti. Also on what always seems like the exact same spot on the freeway I'm losing all power to the wheels and it feels as if my plugs aren't firing for about 10 seconds Which causes me to bog down. At which point I down shift and play the throttle until my motor then begins running normally again.
I've semi recently replaced my battery and terminals, due to corroded terminals and worn out battery. Is is possible a ecu reset could solve this problem?
Also when the power surges during driving my traction control and hand-brake lights on the tachometer will flash and the car will beep three or four times (same as when the hand-brake on beep).
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On my '03 Santa Fe 2.7, this has happened twice, with 500 or so uneventful miles in between. At highway speed, it just all of a sudden loses power and will only go about 50 mph with accelerator to the floor. When you stop & put in neutral, it only revs to about 3000 rpm, with pedal to the floor -yet idles fine. Then when you shut it down, wait a few minutes & start it back up, it's fine. Is this a fuel problem or what?
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My 2006 Sonata V6 (88k miles) has an occasional power steering loss. It has only been noticed right after slowing down from highway speed. Total loss for a few seconds then comes back. No dash lights or noises, just cant steer - then can. Did all required maint. until 60k then just oil changes by me. Have read other forums about fluid flush, but that was for noise and I don't have any noise. This has happened with and without the Electronic Stability Control turned on. Other than that, runs great. MPG is about 25 or so (wish was 30 or so).
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I've been driving my V10 for 3 years now without a problem. The other day, while I was on the Highway in Italy driving at around 140KM/H, I suddenly had a loss of power. I could continue to drive the car, but I had no more tork... I stopped at the next gas station, turn the engine off, turned it on again, and the car drove normally again as before. About 200KM later the same happened again...
I went to check with the dealer - he hooked up the car to the computer - and told me that they had to change both turbos... What I find weird is that when I turn the car off and on again it works again. If the turbos would be defective, they wouldn't work again just by turning the car on and off. I think that it is more a problem with the turbo controller and if that's the case why change both turbo.
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I am using a Hyundai Santa Fe (Petrol, 2011 Model) here in Saudi Arabia. On July 17 (11:30 pm), I was driving in a highway at about 80-90 kms/hr when suddenly my vehicle lost power (steering wheel, brake, etc).
Baed on the diagnosis of our company mechanic, it was an alternator problem. He said the alternator bearing got stuck up.
Prior to this incident, on July 7, the same vehicle got stalled twice while it's parked. In the first case, I was able to use it after jumpstarting. In the second case in the same day (4 hours after the first case), jump starting didn't work so they have to replace it with a temporary used battery. I noticed that I had a hard start (the engine responds only after 3-4 key ignition). After replacing the battery with new one, I was able to drive normally from July 9 to Jul 17, and then the incident happened as I described in the first paragraph.
Question: Is there a way to detect the alternator bearing problem before it actually breaks down? If there is, what procedure or predictive test is normally followed to identify potential problems in an alternator?
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I was driving to work last night and too many things went wrong simultaneously leaving my MK4 stranded.
2000 Jetta 2.0
185,000
Automatic
No check engine lights or warnings
-The engine sounded like there was a hole in the exhaust at highway speed. There wasn't because it's a new system
-Low coolant light came on. The flange connector at the firewall was torn off resulting in a stream of coolant pouring out
-It was dark but the engine almost seemed cockeyed by a degree or two
-Upon parking, the motor. sounded "clunky". Driving forward seemed OK. When shifting into reverse there was a pronounced clunk and the drivetrain wasn't happy.
-I turned the ignition off and that was the last time the car started. It turns over now but will not fire up. The video I attached is my last attempt at starting it before giving up.
My car is my job and I'm at a total loss on how to proceed???
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My 2002 VW Jetta GLS 1.8T 5-Speed is over heating
Car is still over heating after replacing the following:
- Head gasket
- Coolant fan module
- Geba Metal Prop Water pump
- Full timing belt kit
- coolant fan switch in Radiator
- Bleed the system of all air blow hot air
So Driving the car around town is ok, doesn't over heat, but as soon as I take it on a highway it over heats. I drove it 50 kms out of the city and it over heated, let it cool down and added water. got it back home. Oil light flashed on as I pulled into driveway, turned it off right away. no external oil leaks. Checked coolant, Oil in coolant. also the coolant was boiling, the level was raising up and lowering. I have been reading the forums for a few hours and the oil in the coolant sounds like the oil cooler gasket. Ok so the fans are running and it still over heats. The old metal propeller water pump was very hard to turn so I replaced it with a Geba Metal water pump. no leaks at water pump. Could it be possible that the Oil cooler was causing air to leak into the cooling system causing the coolant to boil? And then when the oil cooler "o-ring" finally failed it dumped oil into the coolant?
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I have a 1994 F-250 that we have changed the thermostat, radiator, water pump, cap, hoses, and installed a spring fan. New heads. Hot heat in the heater. It runs normal at highway speed for around 10 or 12 miles and gets hot. pull up and idle and the temp retracts. Even the block has been blown thru. What could possibly be the problem?
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I don't own a VW, but my friend does, and she knows absolutely nothing about cars. She drove me home from a friend's house today, and I noticed her car was sitting at insanely high RPMs, even though we were only going like 60-65. The car was ranging from like 4500-5200rpms the entire way home, and the engine sounded like a lawn mower.
Don't know many details on the exact model of 2002 jetta it is (I'm a subaru guy) but it's an Auto. I was convinced she had it in 3rd the entire way instead of drive. I asked and she said it was in drive, but I was sitting in the back so I couldn't quite tell. Not sure how being in 3rd works on an automatic, but she could still come to a full stop. The car was pretty much constantly sitting at above 3k whenever it wasn't at a full stop though. Like, after letting of the brake at a stop light, and pressing the gas, it'd pretty much immediately flick up to 3k and never go below.
So, not sure if this is normal for these cars, but I thought it'd be worth asking since it would suck for her if this could have been fixed earlier. My subaru sits at 3k when I hit 60, and only hits 4k if I'm going like 80, so I just thought this seemed pretty weird.
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