[JamieClay]

I have the original Fuel Pump, but I mean the original Fuel Regulator.

There is about a 10 psi increase with the old regulator. At full throttle (no vacuum to the regulator) I get 3.3 bar. Still not at 3.5 to 5 bar as the spec calls for.

 

[billymade]

Interesting, what brand was the fuel pressure regulator? I still suspect the fuel pump.

 

[JamieClay]

No I mean the original Fuel Regulator. There was a marked improvement in going back to the old regulator. 3.3 Bar at full load (no vacuum).

 

[JamieClay]

I got this regulator (not cheap) - it has a limited lifetime warranty so I'm going to go see if I can get another one and check the results.

https://www.oreillyauto.com/detail/...88p/2582985/2001/volkswagen/beetle?q=fuel+pre

 

[billymade]

Dang! Pretty expensive; you can get a oem Bosch, for half that price.


Bosch 0280160557 - Fuel Pressure Regulator; 3.0 Bar

https://www.google.com/search?q=200...ome..69i57.11446j0j9&sourceid=chrome&ie=UTF-8

 

[JamieClay]

Yeah, I'm not sure why it's so expensive. That said, they gave me a new one to try, thank you life time warranty.

So, driving with the original regulator at first seemed like everything was fine, I went at least 25 miles on the highway with no issue. Stopped at my mom's to mow the lawn (yeah, 62 and I still mow my mom's lawn) and on the way home from her place,under 30 mph driving, the engine acted up like it has been.

It comes on so suddenly too, like a switch. If I put it into neutral and rev the engine it seems to clear up but I'm not entirely sure.

When you change parts and the problem persists it tends to indicate that the parts you're futzing with are not the issue.

That said, in the morning I'll put the newest regulator in and check pressures. If I don't see a significant change, I'll dig into the ignition system and see.

If 2 and 3 are regularly misfiring, I'll swap their coils with 1 and 4 and see if the problem follows the change.

If it doesn't, I may just bite the bullet and replace the pump and regulator with Bosh parts but I really hate guessing with $200 (more or less).

Film at 11:00

 

[JamieClay]

Oh and I got that regulator because when I replaced it, it was a Sunday and I couldn't find one locally otherwise. I usually buy stuff from Amazon.

 

[JamieClay]

Bosch 0280160557 - Fuel Pressure Regulator; 3.0 Bar

So why does this say "3.0 Bar" when the spec calls for 3.5 to 5? That a curiosity.

 

[billymade]

It makes sense to me, that things clear up; putting the engine in (neutral), as you are REDUCING load by putting it neutral and there is LESS, need for fuel!

Well, I am certainly no engineer but I can only assume; there has to be a general "spec" for the fuel pressure regulator and then, the "bar/psi", will vary, depending on the load and needed volume for loaded conditions (e.g. highway, up a hill, etc.)?

 

[JamieClay]

But revving the engine demands more fuel, so it's a conundrum.

I'm sort of an shoot from the hip engineer and rocket scientist. Usually pretty good at troubleshooting, too.

I'll be digging in shortly (clearing my morning schedule). I also have a new and better designed fuel pressure testing system coming. The one I've been using works but doesn't have the correct fittings for putting the gauge at the tank or bypassing the fuel filter. It also only lists PSI not Bar. (why use Bar anyway?)

Also, I need to research what flow rate data is telling me. I'm currently using Torque to log the activities of various ECU data streams and was surprised fuel pressure wasn't available to log but flow rate was.

 

[billymade]

VW uses "Bar" as it is a european/Metic spec measurement; "psi" pounds per square (INCH), is a Imperial measurement increment, so VW being German, they stick with the Metric system(s) of measuring things.

The bar is a metric unit of pressure:

https://en.wikipedia.org/wiki/Bar_(unit)

 

[JamieClay]

Thanks, yes I know about BAR (but this car is Mexican) ;-)

Anyway, I picked up a copy of the VW Service manual for this car. (From Bentley) and it indicates a different spec.

It says

- Engine at idle 2.0 Bar (29psi) (I'm actually higher with the original regulator)
- Fuel pressure with vac hose disconnected 3.0 bar (44 psi)
- Residual pressure after 10 minutes 2.0 bar

Using these numbers, my original regulator is delivering, with maybe a little high numbers for idle.

The manual also lists a different method for testing the delivery rate that I will have to wait on my new testing gear to be able to try.

I thought I read somewhere there were separate ignition coils for each cylinder but it seems there is only the one. Maybe that's with later versions, so the only way to 'test' the coil issues would be to replace it.

Anyway I also remember NOW why I didn't get my regulator through Amazon. They won't allow the sale of this item to customers in California. (grrrrrr)

So I ordered a genuine Bosh 3 Bar off of Ebay - just because.

 

[billymade]

Yes, I have heard; CARB, is really getting ridiculous and causing some parts, not being sold/shipped to California (ridiculous!). I also heard, you cannot get your car scanned for trouble codes; at your local auto parts stores? I think CARB is basically anti combustion engine; they want everything to go electric, which they see as a new "panacea", which you still have to supply the electric power from, many times carbon based sources. Anyway, typical of the politics and culture.. of the area. Annoying.

Good on the purchase of the Bosch fuel pressure regulator; for good oem parts at good prices, here are two vendors, that are close to you in California.

BMA auto parts: (look online for discount codes):

BMA Auto Parts

Auto Haus Arizona: (typically have sales and usually competitive pricing)

http://www.autohausaz.com/

FCP EURO: (back east but they offer a lifetime warranty on ALL parts; even consumables, like oil/coolant/filters/plugs/etc.)

www.fcpeuro.com

As for the fuel pressure specs; I have had various specs shown, i have different manuals. I do know, that there are a number of different engine codes for the 2.0L and a plastic, then metal gas tank, which used different fuel pumps. Early on, the 2.0L had a return type fuel system and then later, a returnless type and the fuel pressure regulator was integrated into the fuel filter. So, I wonder, if it is possible; there are variations in fuel pressure specs, based upon the engine code and the changes VW made to the system (pump, return/returnless,etc)?

I have the paper Bentley Service Manual; that goes to 2002 and then, I bought the eBah DVD, which is more in depth for repair info and finally the I downloaded the ERWin, digital service manuals, which are used by the VW dealer techs. Lastly, I have the cheap $20 Chilton; you can get at most auto parts stores.

I link the service manuals online; because, it is easy to show people, how to fix things and do it themselves. I am assuming those manuals; are probably sourced from something like Mitchell1 or AllData?

As for the spec in my Bentley; has the same specs but idle shows different:

Keep in mind; my manual goes to 2002, shows specs for these engine codes (AEG, AVH, AZG).

fuel pressure at idle: approx. 2.0 bar (36 psi) NOTE: this seems off, if you convert bar to psi? Maybe a print error or something else?

By the way, what engine code; is your New Beetle? Maybe, there are some variations on fuel pressure specs; for the different engine codes?

On the coil pack; here is a good diy troubleshooting guide to check for cracks:

VWVortex.com - DIY/Troubleshooting - Coil pack on 2.0 AZG, AVH, BEV, or BBW

 

[JamieClay]

The manual I have is from 1998 to 2010 (it's BIG).

The Engine code is AEG

So- I JUST got my new testing gauges but I also have guests in from out of town so I'm not going to be able to get back to this until tomorrow.

Thanks again for all the help.

 

[billymade]

Cool, looking forward to your next testing results and hopefully, you can get this repair completed soon. This thread is turning into a marathon troubleshooting session!

 

[JamieClay]

I took the coil off and found cracks. Not huge ones but none the less, an indicator of age and potential problems.

The new parts (ordered new cables, too) will arrive Monday.

The new fuel pressure testing gear gives me the same data as before, that all the fuel delivery seems right on spec wise. I really like the kit I got as it will useful for not only this car but my Honda and GMC - so many adapters!

I like being to clip the gauge 'in line' using the Bosch fuel line clips.

https://www.amazon.com/gp/product/B06XG2JDH3/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

So, the testing will resume upon the arrival of the new parts on Monday.

I will be grateful to get rid of the misfire problem, even more so if the 1/4 stall is gone.

 

[billymade]

Looks like a nice fuel pressure test kit; low price, those are usually $300-$500 off the tool truck! On the coil pack/wires; go with oem, I believe the oem for VW is Eldor or Bremi? For wires, I think Bosch or Bremi; is the oem for those. Plugs, NGK or Bosch; depending on your engine code.

 

[JamieClay]

I ordered NKG Plug wires and an non OEM part because I'm trying to not keep shelling out $150 for parts I'm not certain I need, I went with a $27 coil.

I've used NKG on my other cars and have had no issues and they're a pretty blue ;-)

My logic behind the coil is more of a test. It IS a 'guess' repair. If the problem goes away, I'll know where it was and I'll either opt to replace the new one with a Bosch or just know what I'll need if the problem reemerges.

If the problem doesn't go away, I will only be out $27 - it comes with a 2 year warranty and is fulfilled by Amazon, so if I do have a problem, I'm gold.

https://www.amazon.com/gp/product/B06WRS3KJY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

 

[billymade]

Something else, while you are in there; is the VW service bulletin for the ground, for the coil. It is easy to do and that can be another possibility, to remove from the list. We have also seen bad ecu's cause the misfires; the ignition driver is known to blow in the ecu.

Coil testing:

http://workshop-manuals.com/volkswa...ion/specifications/electrical_specifications/

VW service bulletin; ground wire upgrade/update: (the bulletin shows for later models 2002-2004: engine codes: AVH, AZG, BDC, BEV, BBW, BGD).
So, it may not apply to your earlier engine/vehicle: 2001 with AEG engine code.


Volkswagen Workshop Manuals > New Beetle L4-2.0L (AZG) (2003) > Powertrain Management > Ignition System > Ignition Coil > Component Information > Technical Service Bulletins > Customer Interest for Ignition Coil: > 0108-27 > Oct > 08 > Electrical - M

 

[JamieClay]

I got the new wires yesterday and the coil came today (it was supposed to be here yesterday) - got them in and took it for a long ride.

So far (knock on wood) no misfire issues, I'm still on the fence though. I've had it go for stretches and not fail.

That said, I am now getting a regular - "16806 - Main Catalyst; Bank 1 P0422 - 35-00 - Efficiency Below Threshold"

I've cleared it a couple times and it keeps coming back however not at any regular interval and the CEL is being triggered.

Going to start testing that and drive some more. Easily I probably have been chasing a number of unrelated issues. (the 1/4 tank, the misfires, this threshold error)

It's a 16 year old car with too much plastic and way too much tech after all.