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Discussion Starter · #1 ·
Hi Passat Owners.

I'm hoping someone out there might have some ideas on my Passat Problems as of late. I own a 2002 1.8t with Aprox 86k miles on it.

Recently after about 15 Min of driving the car will hiccup (RPM drop, Power Loss, EPC Light Comes on). If I'm not in motion it stalls and It have some difficulty restarting (check engine light comes on as well) but only when the cars warmed up.

This happens almost every day for about a week. I don't have a vag-com so unfortunately I don't have codes. I've tried cleaning the MAF and The Throttle body but no luck. Any other Ideas?

Also probably unrelated when I was cleaning the maf and the throttle body I noticed some oil in the air intake hose. What could be causing that?
 

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Do an ECU reset... vag-com meas. block 60, or the "po-boy" key-on-with-engine-off-for-two-minutes method.

Basic three troubleshooting steps...
1) check for vacuum leaks ($15 vac tester from any auto shop)
2) check all fuses (yes, really)
3) clean the throttle body (already done!) and check the airbox & prefilter for debris.

If none of this works, some other items to consider are the the coolant temp sensor and the EVAP purge valve. ...I'm guessing your coolant temp sensor is slow to respond & when the thermostat first opens after 15 mins of driving the brief "dip" in coolant temp is enough to stall the engine.

Does it only stall while you are idling? What if you keep the revs up at 1200-1500 rpm or so?

Do you have access to a vag-com? The EPC and CEL lights indicate that there are some error codes logged (they'll stay logged for a while, even after the lights turn off).

Some oil in the intake hose is normal... think of the intake system as a "garbage disposal" for fuel vapors and oil vapors.
 

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Lisa Simpson
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Plenty of VAG-COMs in your area. Get on the registry (hit google) and email a few ppl requesting help.

The EPC light along with everything else signals a rail power loss. The fact that the timing is consistent indicates that it is thermal. This lends to a bad ground or major power wire being loose or corroded to the point that it can't flow the right amount of electricity. The face that you lose rpms points to fuel pump.

There is a funky problem with the coolant temp senders that sometimes produces difficult hot starts. It's a $15/10minute fix, but it won't correct the stalling problem, only the hot restart problem (if it is indeed the source). You will need to get the codes. Even AutoZone (and most other chain stores) will pull your codes for you - we can work with those in a pinch.
 

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Discussion Starter · #8 ·
Still working on the problem

Still working on the problem. Haven't gotten around to hooking up a vag-com or Vac tester.... haven't gotten there yet. I'm trying to study for my CTP Exam really killen my free time to work on the car.

"Po-boy" rest ECU - no change
Checked all fuses. All look good.
Air Box is clear.
I replaced Coolant temperate sensor about 6 Months ago so I don't think thats it.

My gut is telling me the problem is a valve getting stuck closed, or electric module sending the wrong signals.

Now to answer some questions:

1. Car only stalls while idling, when I keep Revs up at 1500 the RPMS will drop to about 500 for a second and then go back to normal (EPC light on).

2. Timing isn't completely consitant. Usually happens 10-20 Mins after starting to drive.

3. I'm almost 100 % certain the hot restart and the Stalling (RPM Drop are related).
 

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Lots of good advice, getting the codes read at Autozone or finding a vagcom would really help, but you know that by now. I don't think it's your problem, but if you want to rule out your maf, you can disconnect the electrical connector from the maf in the top of the airbox. If it's a bad maf, the problem will go away. You'll be running off data from the boost sensor and "safe" maps. The maf would need to be replaced, but at least you'd know where your problem was and you could drive until you replace it.

Another longshot that would definitely throw a specific code is the G28, engine speed sensor, in the side of the block. Your description matches the symptoms when it's bad.
 

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Discussion Starter · #12 ·
Engine Speed Sensor or Impulse Sensor

ONE8T you are a saint. I think I owe you a 6 pack!

Thanks everyone who responded to my plight. (A special Thank You to the NJ State Trooper who stopped to see if I was ok.)


It wasn't a longshot; it defiantly was the engine speed sensor, in the side of the block. All indicators are green, no warning lights are on. Warm Start with no problems.

So the story goes I drove the car to the local VW dealer about 10 Miles from my home. Car died on RT 80. I wouldn't start for about a half hour till the engine cooled. When I get to the dealer they don't have the part! (Your f-ing kidding me!) I call two other dealers, ones closed the other doesn't have the part either. Finally I call a third dealer and they have it. Do I risk driving my Passat 20 miles to get the part? Hell no, I swing by my lady’s work pick up her truck and get the part (078 906 433A) $88.17 USD.

Get the part home. Took me about an hour and a half to put the new one in. Hardest part was running the wire (makes me wish I had smaller hands) and finding the Engine Speed Sensor.
 

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EPC on, engiine dies

Hi. I have the amost identical problem as incubus474, except mine only stalls at idle afte 15-20 min. of run time. Restarts hard then the epc light is on. If I turn the engine oof & restart, it runs ok with no epc warning. The check engine light is on too, and has a code p0171 (has had that code for several months before the epc warning/stalling issue began). P0171 is a lean code, so is it possible the maf sensor has deteriorated in operation to the point of stalling? I hadn't replaced the maf before since I was ruling out all the other options 1st (vaccum lines, etc.)

Thanks
 

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p0171 is the standard OBD-II "lean" code... I'm betting on a vac leak; however, vag-com scan data could tell us more about the lean code: lean additive trim usually indicated a vac leak, lean multiplicative trim usually indicates a bad maf. (of course, there are other possible causes, too)

you may have more than one issue... get the vac leak fixed first, then troubleshoot the more-expensive stuff. :thumbup:
 

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Great info, guys, thanks! I tried unplugging the maf to see if it was related to the stalling problem; no luck still stalls at times like before, but DAMN!! this engine hasn't run this strongly in years! Unbelievable! Feels like it's been chipped. Trans shifts are a little firmer and faster, too. Will I hurt anything to continue to drive with the maf unplugged until I can get a new one? Also, is this increase in performane due to the crappy maf being out of the system, or
is the engine running on some other temporary base settings in the ecu?
 

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Discussion Starter · #16 ·
newpassatt How many miles on your car?

Since unpluging the maf does it still stall?

Why not try to clean your maf instead of leave it unpluged? they sell maf cleaners in automotive stores. you spray the sensor with the cleaner but what ever you do don't touch the sensor with your hand. when replaceing the maf don't forget you need a tamper proof screw driver head to get the sensor out of its casing.

Or you may want to look on ebay for a new or used sensor.
 

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If you are still getting the stalling with the maf unplugged, it is very likely one or more vac leaks, possibly in conjunction with a failing maf. If it was just the maf, the car would run better in all conditions with the maf unplugged. Eliminate any vac leaks first, then you'll know better if the maf is a problem. Takes a little work, but check/replace all the standard vac lines, there are a few writeups in info section. Also, check the larger diameter L shaped hose between the intake manifold and the coolant reservoir. If there is some dark spray on that corner of the intake manifold it's a good sign of a leak.
 

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newpassatt How many miles on your car?

Since unpluging the maf does it still stall?

Why not try to clean your maf instead of leave it unpluged? they sell maf cleaners in automotive stores. you spray the sensor with the cleaner but what ever you do don't touch the sensor with your hand. when replaceing the maf don't forget you need a tamper proof screw driver head to get the sensor out of its casing.

Or you may want to look on ebay for a new or used sensor.
83,000 miles 1.8 tip. Yes it still stalls, but runs MUCH stronger since the maf was unplugged.
 
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