Phaeton :: Engine Surging / Missing - Car Seemed To Shudder
May 15, 2010
Yesterday I filled my V10 with diesel and as soon as I started the engine to leave the petrol station the car seemed to shudder.
I joined the traffic and passed it off intially as poor road surface. But as I joined a queue to enter the motorway I realised it was the engine!
It was sort of surging, or perhaps it's better explained by saying it was dropping, shuddering down from say 800 RPM to around 400 then picking back up again. I revved it to 1000 RPM and it seemed fine, but if I let it drop to idle is carried on leaping and jerking for about another 3 or 4 minutes.
I then entered the motorway and it responded fine and the problem has not come back so far.
What could it be? Missing on one cylinder? Is this going to be problem? Hope not
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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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On my 05 V8 with only 39K miles, I've been experience a very slight engine shudder while the car is at idle. No fluctuations in the RPMs and performance seems normal. I use Shell premium gas and there are no indicators that anything mechanical is wrong. It has been doing this since I purchased the car in Jan 2013.
I had my VW dealer check the car out and they replaced the spark plugs and some other part which can't remember at this particular moment (3:31am can't sleep) but the engine still shudders.
I took it to another VW dealer and the service adviser who is experienced with Phaetons told me to find some Ethanol Free gas and give that a try. I found a place which sales 91 Octane Ethanol free and I put in 3/4 of a take because I was pretty much already full. The shudder is still there.
Do I need to run a few full takes of the 91 Octane Ethanol free before something changes.
I would like to try and get my Phaeton idling smoothly because this slight shuddering kind of bugs me. I've read some post which stated that on some Phaetons this is normal but there has to be something I can do especially since I have a bumper to bumper VW warranty. I just feel that a 86K dollar car should idle as smoothly as my Wife's Toyota Avalon.
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What the fault codes below could be indicating. Let me quickly bring you up to speed. I was experiencing and issue with my car running rough (engine miss/hesitation) between 1200 and 2800 rpm. My ESP and CEL lights both came on. Eventually, my car stalled on me while driving. After attempting to restart the car a few times, the engine finally started. I took the car to two dealerships and was told the Mass Air Flow sensors and Intake Manifold Runner were faulty and needed replacing. After reading some of the post on the forum, I deduced the intake manifold runner would not cause the car to stall. That said, I purchased two new MAF sensors and replaced them myself to no avail. I still had the problem. I took the car to an independent mechanic (who has experience with phaetons). He hasn't been able to identify the issue. He provided me with the fault codes below:
Address 01: Engine Labels: 4D0-907-560-BGH.lbl
Part No SW: 4DO 907 560 CS HW:
Component: 4.2L V8/5VG 0030
Coding: 0007873
Shop # WSC 01065 000 00000
VCID: 79F21F7E33C272C
6 Faults Found:
[Code] ....
What I should do next. My car starts fine and idles smoothly. After driving the car for a few minutes, the engine miss/hesitation shows up.
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When I first bought my 2001 f150 a few mos ago there were no problems but I did notice once in a while it would give one little shudder when id accelerate. now all the sudden it shudders after around 20 mph all the way up to whatever the speed limit is. Then it smooths right out until I have to accelerate again. if I punch the gas and kick it down it will clear up but then it feels more like a surging going on.
I had the cruise set at 70 the other day and I had to slow down to merge to around 50 and when I hit resume it really started shaking bad and the service engine soon light flashed on and off for a few minutes then went off and hasn't came back on again. I took it to advance auto and no codes showed up. they said its probably the torque converter but after reading multiple forums I am not so sure now.
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I just acquired a 01 wolfsburg jetta 1.8t and first time vw owner.
I just got the car and found that all the pcv ventilation hoses were crumbling and broken down. I replaced everything under the intake up to the y at the valve cover. All was in stock at the dealer was the oil cooler elbow, tee and pcv valve. From there, i made my own hoses using 3/4 hose and couplers.
Before this, it ran fine but sometimes at idle the idle would jump up and down but not die. I also had a couple codes, can't remember what the number was. One was O2 bank 1 sensor 1 lean and i think the other was O2 related.
Now, after trying to fix the leaks. CE light went out but idle still does the same but my boost improved from like 5psi to like 9psi wot. That's not an issue but coming home tonight when i went to second, it felt like it was dragging or not wanting to accelerate or accelerate and like stall for a second. If you blip the throttle it back fires while in second when its doing this.
Only mod on the car i know of is it has a forge DV/blowoff i guess is the correct name. It can be used as a dv or both.
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I live in Kansas and was home in Georgia for the last 2 weeks. The truck drove great there after a fuel up started missing and surging at 50 to 70 thought it might have been bad fuel. waited till it was low added Lucas fuel treatment and premium gas still was doing it. no check engine light. went to Advance and fuse for light was blown they checked and was getting mass air flow code. unplugged it and seemed to be better, not perfect but better. plugged it back in and went to do it again. Changed mass air flow night before the drive back to Kansas. Ran well from Savannah to north Georgia then started doing it again the rest of the way home. Going to have advance check code again.
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I have a 2004 v8 Phaeton and on my drive today I noticed that when I accelerate with moderate (or above) gas the car starts to surge, rev-ing up and down. If I accelerate slowly (Driving Ms. Daisy slowly) the car is fine. When I'm idle (at a stop light) the car is fine, no sputtering or any other strangeness but as soon as I try to accelerate past a small amount the car starts to surge again. Made through a 3 hour trip and the MIL light came on. The car has about 198K kilometers on it but has been very rock solid, this kind of just started happening.
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Currently on a 1 week mini break, and the P has decided to play up. I have had 6 months of worry free driving before this new issue. I have posted before that the 6 speed in my P has never been the best behaved in auto, a bit slippy and jerky, at times, but also perfect shifts 60+% of the time, but I know others share this issue so not unusual - its usually ok when manually going through the gears.
Upto 110k miles now and on this journey had been about 10miles in on the motorway so fully warmed up. Had cruise on doing about 70 mph. Bascially started being very erratic and surging then dropping quite uncomfortably.
I knocked cruise off and observed that under full acceleration no issue. Under no acceleration (foot off gas) no issue. Only when keeping up with traffic, so partial gas, did the issue occur. I waiting for the next exit and pulled off, and it initially carried on even at low speeds around 30mph, then went away. Parked up. Started it up about 2 hours later fearing the worse, but had no issue since. Kicking myself as I have the laptop but forgot the VAGcom lead.
Rang my VW specialist and he said as there were no MIL lights, the only way to know whats going on is to scan the car, and if it does it again get it recovered, which will mean the end of my break. I will scan the car as soon as I get back, but concerned I could do more damage.
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I got a phaeton v8, I feel a big shudder in the whole car while I have an amount of pressure on the brakes. for example: when approaching a red traffic light soft braking: no shudder, half braking: shudder and when hard braking the shudder is gone again. what could be the problem?
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I have a Phaeton W12. When I brake there is a slight shudder at most speeds unless I brake fairly hard, except when traveling at 120 km/h and 85km/h, at these speeds the shudder is severe uless I brake hard, but this could be that the car slows out of these 'bad speeds' quickly. The shudder is unnerving and severe enough to expect that it will cause damage. I did have the disks/rotors skimmed on a lathe, I thought this had fixed the problem, I can't be sure it didn't. All seemded fine initially, but I don't remember the speeds I was doing when I tested the skimmed disks for the first time.
To add to the fun, I brought with me when I moved countries and VW won't work on it before its registered locally and I need the brakes to be working to do so. Chicken and egg sort of problem. Parst are also not freely available here.
There is a rubber suspension bush in front which I noticed needs to be replaced, which I will order today, but it's likely to take a few weeks to get here unless it's used on an Audi or another car sold here, but it's the opposite front wheel which appears to have uneven wear on the disk.
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My mechanic tells me I need the intake manifold gasket replaced (check engine light on, engine surging, running very rough). How much damage can I do to the car by doing this repair myself and screwing it up? I've done lots of repairs on my car before -- brake pads, rotors, replace oil pan. I also have a copy of the manufacturer's shop manual.
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I have a 99 Grand Am GT 3400. Just starting doing this, when you start the engine, it starts surging rhythmically as if you are pushing on the accelerator and letting off. When I put it in gear, I have to have the brake firmly pushed down as it lurches forward severely. I haven't driven it far, but it seems once you get going it runs fine.
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While I'm in the engine troubleshooting the AC system, I figured I may as well get into a few other issues I've noticed.
I have a stock 1.8T and my turbo feels like it's surging occasionally. A few months ago my diverter valve started making the "blow off sound" when I shifted (manual transmission).
Is it possible for a faulty diverter valve to dump the boost overboard and cause the turbo, and engine hp, to surge? It almost feels like I let my foot off the gas for a second or two (i.e., engine power is very peaky).
A second thing that comes to mind is a clogged fuel filter. I know VW does not recommend ever changing it so it's never been done. Is this a possibility as well?
Air filter is clean, by the way. There's a K&N washable one in the stock air box and I can see daylight through it so it's not too dirty.
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So, I was just driving home from work in my 2005 Prius (~78k miles) when the engine started surging erratically and uncontrollably. I don't know if this is the cause, but I hit a bump right as I was hitting the gas and so I wasn't surprised when it revved up at first. But, then I backed off and it kept revving. Then I took my foot off the gas and it was still revving and accelerating so I had to start braking to keep going the same speed.
It kept erratically surging and then letting off as I basically kept braking at different levels to maintain speed or slow down when I could as we were coming to an intersection. The light turned red and I managed to get to a stop even though it was still revving, so I hit the P button and the engine calmed down. So, when traffic started again I slowly put it back in D and it surged again. We didn't move much before we had to stop again so I put it in P again. I noticed the battery icon was down to a few pink bars so I turned off the radio and air. Traffic started again and I put it in D and this time it seemed ok. I detected a faint smell that I think was probably from the brakes/tires being overheated, but it could've been something else maybe. It drove normally the rest of the way home.
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I have a 2000 Toyota SR5 with a 6-cylinder engine. When I first start the car (cold start) in the morning it will run at high idle (1500-1800 rpm) for about 3-4 minutes. At this point, the idle will begin to drop, but then the engine starts to surge. It's a noticeable surge that bounces from around 900-1100 rpm. It almost seems like an electrical surge, but I don't believe that's the problem. After running the car for a while and it's fully warmed up to operating temperature, the surge goes away. My thoughts automatically went to the IAC (idle air control) or maybe a temp sensor?
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