[permag]

Hey folks. Just thought I would share some beetle drama. Ive had this car about 3 years. 203kmiles. Engine will just turn off. Under load usually. So I started way back with a fuel pump and relay. Put a napa relay. Sets a code but works well at first but a week later, same thing. Put the vw relay back in, have 3 of them and tried them all. Still dies. So I did the lazy thing and put new sensors. Both had already been replaced by someone. Still new. A week goes by and it starts again. I replaces the shady autozone cam sensor with a napa one which was bosch if i remember...anyhow. Same. Same same. So then I noticed something. I had the idea that the ecu was having a bad ground or lost power. If I coast down from 40mph or so with the key on the engine seems to spring back to life. Once I had to pull over and restart. It happens almost every day, seemingly about the same time it would go into closed loop. Rarely rarely with a fully warmed engine. Once it does it and I restart it it will drive fine all day long. So I thought...hmm..02 heaters..air pump, closed loop..maybe 02 heaters and the air pump are pulling too much current for 203000 mile wiring. Maybe the ecu is dropping voltage when these high current draw is happening. I have an obd11 (not really a fan though) and Torque as well which seems to do just as well on this car anyhow. And its easier and faster..both have Something the other doesnt do.
Anyhow. I noticed the HO2S's heater circuits all run through the coil side of the airpump relay. Probably because the air pump will only turn on when the a/f sensors are warming. So. I took the "100" Air pump relay out and had a spare german one. The one I pulled out was a portugues AE relay (black cap). It wasn't corroded at all but I measured the coil terminals for resistance and it was 62ohms where the german "100" relay was 72 ohms. I had another AE100 relay and it was also 62ohms. So today I cleaned the terminals, cleaned the points inside the relay and put the german one (I say german but I don't remember the name, just the audi logo) with a grey cap in the panel (next to the brake fluid reservior for those who don't know where it is). And now I wait for my morning slow drive to the parts store to buy a strut bushing kit because my pass side collapsed going over the RR crossing today. Lol. These are the crankiest neediest little cars. "Please daddy...put your wrenches on me?"...
Ill keep you posted. I am really hoping it will go away. I guess the next thing would be to verify ECU power and ground voltage drops. Check and clean grounds. Oh...another detail. Sometimes if Im under load when it quits Ill get a charge sensor code. Only if it quits under load though. I also need to see if the DLC (obd2) is losing power or data. I haven't had either scanner on when it happens. But the tach goes dead..Im using torque to monitor A/F and engine temp. I dont think I can poll the cam and crank sensors with the obd11 but Ill look at that again too. If anyone had any other ideas I would be happy to hear them. Oh..I redid the ground cabling and starter cable last summer. Fatter cables and cast soldered and hex crimped cable ends...new battery.. Ive thought about adding a ground strap too.

 

[billymade]

The fuel pump relays, have given, many people a long history of problems and then, they get a aftermarket replacement , which compounds the problem. Through, many years and troubleshooting discussions; we have found, that aftermarket fuel pump relays cause starting and running problems. Through all of this, we have found ONLY: oem Stribel or Genuine VW (again, made by Stribel), seem to work correctly. If you are running a aftermarket fuel pump relay; get a genuine VW/Stribel part and see, if that helps.

Through, this troubleshooting process; have you scanned for trouble codes? When, the fuel pump relay fails or has a intermittent problem; it causes, a long list of "short to ground" codes to be thrown. This happens, as power is cut; to all the various parts, that are connected to the 409 relay (fuel system: injectors, evap purge valve, fuel pump, etc.).

P0261 – Cylinder 1 Injector Circuit Low
P0267 – Cylinder 3 Injector Circuit Low
P0270 – Cylinder 4 Injector Circuit Low
P0264 – Cylinder 2 Injector Circuit Low
P0443 – Evaporative Emission Control System Purge Control Valve Circuit
P0037 – H02S Heater Control Circuit Low (Bank 1 Sensor 2)
P0418 – Secondary Air Injection System Relay “A” Circuit Malfunction

Here is a thread; discussing, the typical 409 fuel pump relay symptoms and info, about cleaning, replacement.

Fuel Pump Relay Madness

I have a 2000 Beetle 1.8T and scanned for codes,. The scan came back with 12 codes varying from cylinder 1-4 fuel injectors, Oxygen sensor and a few other weird codes. All the codes was short to ground,. I didn't have any codes before the event happened but what I notice is my car wouldn't...

www.newbeetle.org

I see, you have replaced a number of sensors; it is crucial, that you use, oem Bosch brand sensors, as cheaper aftermarket brands, are typically poor quality and can cause more problems, complicate your troubleshooting process.

Please, post any trouble codes; that you are currently getting and not just the descriptions. Start with a full "autoscan"; using your OBDEleven, which is a VW specific, factory level scanner, compared to your ELM327 and Torque App. Thanks.

 

[permag]

Thanks for the reply.

The fuel pump relays, have given, many people a long history of problems and then, they get a aftermarket replacement , which compounds the problem. Through, many years and troubleshooting discussions; we have found, that aftermarket fuel pump relays cause starting and running problems. Through all of this, we have found ONLY: oem Stribel or Genuine VW (again, made by Stribel), seem to work correctly. If you are running a aftermarket fuel pump relay; get a genuine VW/Stribel part and see, if that helps.

Through, this troubleshooting process; have you scanned for trouble codes? When, the fuel pump relay fails or has a intermittent problem; it causes, a long list of "short to ground" codes to be thrown. This happens, as power is cut; to all the various parts, that are connected to the 409 relay (fuel system: injectors, evap purge valve, fuel pump, etc.).

P0261 – Cylinder 1 Injector Circuit Low
P0267 – Cylinder 3 Injector Circuit Low
P0270 – Cylinder 4 Injector Circuit Low
P0264 – Cylinder 2 Injector Circuit Low
P0443 – Evaporative Emission Control System Purge Control Valve Circuit
P0037 – H02S Heater Control Circuit Low (Bank 1 Sensor 2)
P0418 – Secondary Air Injection System Relay “A” Circuit Malfunction

Here is a thread; discussing, the typical 409 fuel pump relay symptoms and info, about cleaning, replacement.

Fuel Pump Relay Madness

I have a 2000 Beetle 1.8T and scanned for codes,. The scan came back with 12 codes varying from cylinder 1-4 fuel injectors, Oxygen sensor and a few other weird codes. All the codes was short to ground,. I didn't have any codes before the event happened but what I notice is my car wouldn't...

www.newbeetle.org

I see, you have replaced a number of sensors; it is crucial, that you use, oem Bosch brand sensors, as cheaper aftermarket brands, are typically poor quality and can cause more problems, complicate your troubleshooting process.

Please, post any trouble codes; that you are currently getting and not just the descriptions. Start with a full "autoscan"; using your OBDEleven, which is a VW specific, factory level scanner, compared to your ELM327 and Torque App. Thanks.

I don't get any of those codes you mentioned. Just one for the relay p1541 when I keep the napa relay in. Sometimes if it shuts off during boost it will set a charge pressure code which hasn't set for weeks since the last time it shut down under boost, I erased it about three weeks ago and don't remember the specific code as it hasnt come back or shut off under boost. It acts no differently with the aftermarket or factory fp relay. Torque and obd11 both show the same codes so far. I always use both for scanning. The engine will almost always die when the air pump starts. I hate to throw more parts at this car but so far nothing I have done replacing sensors has made any difference whatsoever. It acts exactly the same after each time I try something different. I will imake a rough assumption that the FP relay isnt the issue in this case. I have never seen any of those codes you mentioned with either scanner. Today I have a collapsed strut bushing to replace but will get back to this problem soon enough. Are there any other possibilities that could be considered? Thank you for the reply. I have been through many discussions online about this and it seems that it goes unresolved occasionally. I believe there is another issue at hand here.

 

[billymade]

P1541 Volkswagen Code - Fuel Pump Relay Circuit Open

How to repair P1541 Volkswagen code Fuel Pump Relay Circuit Open

www.engine-codes.com

If the NAPA 109 relay; is giving you the code, it is obviously not working correctly, i would return it for a refund and get a genuine vw or Stribel version.

For more “clues” to your problem; you might check under “pending codes”, to see if any are there.

These cars can go into “limp mode”; if a major problem occurs, this mode is a predetermined map, to protect the engine from damage.

 

[billymade]

For intermittent issues like this, using a scan tool; to view live data, can help you find some clues as to the stalling, dying issues. Data like fuel trims, can be a indicator of a fuel pressure, maf or vacuum/boost leak issue.

Fuel trim: + or - 10% is considered in the “normal” range:

Fuel Trim Info - Ross-Tech Wiki

wiki.ross-tech.com

Maf testing:

http://www.ross-tech.net/vag-com/advertising/DiagnosingA_MAF_TechTip.pdf

From what we have seen, a number of possible causes of problems like this; end up being, fuel delievery and/or ignition related issues.

Seeing how many parts have been replaced; i would confirm the brands of what has been replaced and tell us what each one is. A new aftermarket poor quality part; have been known to cause problems or be defective, right out of the box.

Aftermarket fuel pumps, mafs, crank sensors, etc; have all been a cause of drivability problems.

I installed a cheap “new” aftermarket maf one time; the readings were erratic, the engine died during a test drive and wouldn’t restart. Luckily, i still had my original VW Bosch maf with me; i swapped it back in, my 1.8T restarted and went back, to running normally.

Give us more info about your car and we can give you service manual links; to some testing procedures you can try.

Year, model, engine and trans, etc.

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[permag]

Thank you for the replies. I forgot to mention this is a 2001 AWV 1.8T 5 speed. I changed out the air pump relay last week as i noticed the stumble usually happens during warmup and often happens when the air pump runs, they share the "100" relay under the hood. I have had 2 minor stumbles in a week which didnt last long enough to do anything..no codes set, but overall a marked improvement after changing the airpump relay...it may just be coincidence that it has improved. I can't poll the cam or crank sensor (unless its in the unmarked live data?) with the obdeleven so I have been watching the tach like a hawk. Today I finally got a hard stumble and for the first time it happened after a long drive and it surprised me as I don't remember this ever happening hot. The tach stayed with engine rpm so cam sensor seems ok I guess. Today's long stumble (about 3 seconds) did not make the tach drop. I was on level road in a light throttle. The throttle was still working, as I can see my boost/vac gauge move from vac to atmosphere if I pump the accelerator during the event while deceling the dying engine in gear so my thought about the ecu losing ground or power may be bunk. My short term trims have not been more than 2-4% off and LT trims seem solid, never more than 1% off. but I haven't captured them during an event. I would like to be able to read the charge pressure sensor but it at least is not clearly IDed in the live data. I don't see a logging function on the obdeleven...does it have one? I think I remember seeing injector duty cycle in the live data on one of the 255ish screens of data. I will watch that for next time. I wish the scanner was faster connecting. It would be nice to be able to see rail pressure or the fuel pump circuit. Then I suppose I can watch timing advance as I don't know if the coil pack return signal can be polled. It isnt listed in any of the Live data screens that Im aware of. I get zero misfire counts, even in a long stumble that makes me have to pull over and restart. I had one 2 second stumble under boost that set a charge pressure code. As I stated earlier though, that code will only set if its under boost when it cuts out. I can always set my fluke up and monitor the fp and ign feeds the old fashioned way. It was a nice drive today though, I went through the front end last week. New strut and antisway bushings. It is so much better to drive and the floorboard knock is gone. So. ...yay.. I have 034 engine mounts and timing chain/tensioner coming from fcp euro tomorrow. I'm excited about that.
Thanks all

 

[billymade]

What testing have you done at this point? Did you get the fuel pump relay issue resolved?

If you are noting a rough idle and hesitation; on a cold startup, a bad coolant temp sensor, can typically cause that.

I’m not that familiar withe OBDEleven but it seems to be similar to VCDS.

For advanced readings; these mark iv vw 1.8T engines, may not provide things you are used to seeing in live data on more current vehicles (e.g.: fuel rail pressure).


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[billymade]

We haven’t discussed brands on the many parts you have replaced; i’m wondering, in particular the brand of the maf and if you have tested it live data readings, at idle, then max at wide open throttle in 2nd gear. Also, i would view live data; while doing a “wiggle test” of the maf plug, noting if the reading jumps around or is erratic, which might be a sign of loose terminals or a plug that is damaged.

http://www.ross-tech.net/vag-com/advertising/DiagnosingA_MAF_TechTip.pdf

 

[billymade]

Other tests, like fuel pressure; would be good to do, to rule that out and requires rhe use of a traditional fuel pressure tester with a “t” adapter inline before the fuel rail.


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[permag]

What testing have you done at this point? Did you get the fuel pump relay issue resolved?

If you are noting a rough idle and hesitation; on a cold startup, a bad coolant temp sensor, can typically cause that.

I’m not that familiar withe OBDEleven but it seems to be similar to VCDS.

For advanced readings; these mark iv vw 1.8T engines, may not provide things you are used to seeing in live data on more current vehicles.


Sent from my iPhone using Tapatalk

The car cold starts and idles beautifully. The full cut is usually 3 to 5 minutes after driving. It has never stalled idling in that time. The stumble is always while moving and anything from an almost unnoticable stumble to a hard cut usually not lasting more than 2 or 3 seconds then it springs back to life and will not repeat until another warmup cycle. It is never just one or more cylinders. The power is on or off. I thought at first the ecu was losing power or ground when it had to operate the heavy loads of the 02 heaters and air pump as the events seem to coincide but the throttle and tach still work as it decels in gear. Only once or twice have I had to pull over and it always restarts. I don't have to recrank the engine usually, if its in gear it wil spring right back to life like the ign or fuel was cut. I have not replaced the fp relay with a new one but swapped the one from my junk 2.0 beetle that I saved that never gave me trouble. Napa relay, oem relay, behavior is the same except the fuel pump curcuit code the napa relay causes because the coil is much higher resistance. Still same behavior. It doesn't make amy sense that a relay would stumble once during a deive cycle and then never again until it is restarted. 99% of the time its 3 to 5 minutes in the drive cycle amd then not again until I shut it off. Now that I know the ecu is still working the throttle, showing data and running the tach during the stumble, Ill put my meter on the fp relay and watch to see if it drops out during the event and next I think Ill do the same for some part of the ign feeds for the coils. Thats as far as Ive thought through it for now. Any other ideas? I like to diag a bad part before I replace it. For now I'll keep the 2.0fp relay in until I confirm if the pump is shutting off when it occurs.

 

[billymade]

Volkswagen Workshop Manuals > New Beetle GLS L4-1.8L Turbo (AWV) (2001) > Maintenance > Tune-up and Engine Performance Checks > Fuel Pressure > System Information > Specifications > Pressure, Vacuum and Temperature Specifications

New Beetle GLS L4-1.8L Turbo (AWV) (2001) > Volkswagen Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Fuel Pressure > System Information > Specifications > Pressure, Vacuum and Temperature Specifications

workshop-manuals.com

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[permag]

Other tests, like fuel pressure; would be good to do, to rule that out and requires rhe use of a traditional fuel pressure tester with a “t” adapter inline before the fuel rail.


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I have swapped the maf with the 2.0 and its the same. I suppose the wiring is worth checking. Wiggle test...I just hadn't gotten that far yet. Edit- just wiggled like hell....no stumble..knocked on it pulled the connector hard in all directions. Wiggled the harness as far as I could reach.

 

[billymade]

I believe the maf is different, on the 1.8T vs the 2.0L; what readings were you seeing at idle and max, wot in 2nd gear? What brand maf is installed currently?


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[permag]

I believe the maf is different; on the 1.8T vs the 2.0L; what readings were you seeing at idle and max, wot in 2nd gear? What brand maf is installed currently?


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They were both factory maf and the part number is the same. I can watch the maf with obdeleven, so Ill have that running to try and catch the next stumble. Im about to connect and take it for a ride to get those numbers.

 

[permag]

They were both factory maf and the part number is the same. I can watch the maf with obdeleven, so Ill have that running to try and catch the next stumble. Im about to connect and take it for a ride to get those numbers.

Ok. About .33-.4 lbs at idle and 12-13 at 8ish psi boost in the 5500-6500 rpm range it did not stumble that whole ride. Oh..forgot to mention the 2.0 maf was swapped recently as a "lets try this" to fix the stumble ...no difference at all.. Edit..Also watched air temp as I wiggled the maf wires. It reads about 10-15 deg warmer than ambient at idle but does not jump when reading air temp or flow

 

[billymade]

Here is a recent thread; where we discussed maf testing.

Loading…

www.newbeetle.org

 

[billymade]

A 1.8T rated @ 150 hp x .80 = 120 grams per second or 15.8733 pounds per minute for the max reading the engine is capable of. This reading should be in second gear @ WOT.


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[billymade]

As to the MAFs; the Bosch parts site, indicates these are for the two engines:

2.0L:

Mass Air Flow Sensors (0280218060)

1.8T:

BOSCH -0280218063

I believe differences in the mafs primarily is: on the 2.0L the air temp sensor is integrated into the maf and it is separate on the 1.8T.

I don’t know; if swapping it in would cause a problem or not for testing purposes?