80 vanagon...

[dustindavisusmc]

I am a new member and would like to have some advice.. I have worked on VW's now for about 3 years.. I am an able body mechanic, but VW's can be a hastle some times.... The short of it is that I have an 80 vanagon that hasnt ran for the last ten years.. I started by replacing the fuel system and it worked.. kinda.. The vehicle ran great for about 3 days and then acted a little funny..

It does not have aN 02 sensor.... 49 state model... when it warms up.. when it warms up... if you give it more that 1/4 throttle or if under a load it acts like it is not getting any fuel... sound is bboooooaaaa then when I let off it will continue to idle.

Here is what I have done
I got two air flow meters .. both used.. one Alpha type and one original... tore both down inspected and. both of the Air temp sensors failed, read about 1500 ohms.. terminal 6 and 27, read below recomened tollerance. I know this will be a retard question when I get done but want to check with VW MEN to make sure I am not crazy and havent failed in all other tests... so to continue, I opened both and when I diconnect the terminals and consequently reconnect when it is warm.. there is a difference in idle and performance. I can play with the potentiaometer and the throttle body ( when the temp gauge is disconnected) and get it to run like a champ, while in the driveway...

Here is the short of it ... no 02 sensor.. closed off EGR (which dosent make a difference) .. and the fact that once it gets warm.. It will not run under load or more than a quarter throttle...

Has plenty of compression, has new ignition to include electronic, petonics... I started this project with all the best.. New tank, injectors, ECU is great, no intake leaks, #2 temp sensor..Head temp sensor works, I have also greased and cleaned EVERY electrical connection..



Any suggestions would be appreciated and respected...I really will not take any lightly...

Thank you Gentlemen and Ladies in advance..

SGT Dustin Davis

P.S. I am a ASE certified Master Diesel Mechanic... I have a clue..

[Amskeptic]

more that 1/4 throttle or under a load it acts like it is not getting any fuel...

both Air temp sensors failed 1500 ohms.
once it gets warm will not run under load or more than a quarter throttle...

Any suggestions would be appreciated and respected.
I have a clue..

All right Sargeant, attenCHUP.

With a warm engine at idle, remove the AFM black plastic cover.
Using one hand to push throttle lever and increase engine rpms to problem territory, you will grasp the wiper and move it counterclockwise simultaneously in an effort to make the engine accelerate normally. If you can find the sweet spot, and the engine responds readily, it will confirm that you are not getting enough fuel.

If it still bogs, I am going to guess that a wire at the connector has gone loose in its crimp or has actually been pushed into the connector due to a misalignment between the connector and the spade on the AFM. This would give you the same symptom with two different AFMs. Look closely at the little receptacle fingers to make sure they are all aligned with each other. You will need to carefully pull back the boot to inspect the wire-to-crimps.
Report at 0900 hours 08 June.
Colin

[dustindavisusmc]

Hand Salute...

Confirmed Sir, that the VW is not getting enough fuel. When I play with the wiper and the throttle, while the van is warm, I can get the engine to rev nicely.

What do I do next? Replace AFM?

Thanks again for your help

[Westy78]

I didn't see anywhere in your post that you replaced the fuel filter? Was that part of the fuel system overhaul?

[Lanval]

Hand Salute...

Confirmed Sir, that the VW is not getting enough fuel. When I play with the wiper and the throttle, while the van is warm, I can get the engine to rev nicely.

What do I do next? Replace AFM?

Thanks again for your help

Hmmm... that sounds like the sort of answer I'd like, which makes me think Colin will tell us "not so quick!" ~ as in, "why aren't we getting enough fuel?" Several things come to mind, but I'll suggest the fuel delivery is probably not the problem. I say that, because if fuel delivery is bad, it shouldn't run too well at any point. That said, I would rule out fuel delivery as an issue. This means checking fuel pressure and volume;

According to the Bentley at 20.7:

- disconnect fuel return line at pressure regulator
- attach hose to return line fitting on pressure regulator A [refers to diagram] and place other end of hose in one quart measuring container
- turn on ignition and open air sensor (or bridge air sensor plug terminals 36 & 39). Run pump exactly 30 seconds
- delivery quantity should be at least 500 cc (approx. 1/2 quart)
- if NO, check fule filter is not blocked, ground connections are O.K. and voltage at pump is at least 11.5 volts before replacing pump

From the Bentley at 24.5

Pressure regulator controls fuel pressure depending on intake air distributor vacuum
WARNING Fire hazard. Do not smoke or have anything in area that can ignite fuel
- connect gauge US 1076 to fuel ring main
- disconnect hose between intake air distributor and pressure regulator
- start engine and run at idle
* pressure should be: 2.5bar (36psi)
- re-connect hose
* pressure (at idle) must drop to approx. 2.0 bar (29psi)
If pressure too low, check fuel pump delivery rate
If pressure too high, check return line [I assume for blockage, but it doesn't say what you should be checking for]
If readings still incorrect, replace pressure regulator

****************************

OK ~ Now if everything is cool in the fuel delivery department, and the AFM can run the engine well, but isn't, we'd be looking at information coming in. That leaves a number of pieces: sensors, etc. Auxiliary Air Regulator, Cold Start Valve, Control Unit (ECU) and wiring harness, intake air/temp sensors, oxygen sensor/wiring, Temp II sensor, etc.

I'd be looking at those (You'll need the Bentley ~ I haven't checked back to the original post to see if you've got it) for values and check points.

****************************

I replaced my wiring harness late last year, and Colin had hell's own time getting the damn engine to run after doing the heads. Turns out the PO had done some kind of work on one of the connectors, so one input wasn't entering the AFM. Fix that and the engine purred. I'm guessing it's an input issue, with one of the sensors/units above, and not a fuel supply issue. But the fuel supply is easily checked, and I know Colin did that too when working on my engine, so it might be a quick sanity check.

Mike

[dustindavisusmc]

the entire fuel system is new from the tank to the injectors.. to include fuel filter.

there is no O2 sensor and the head temp sensor checks out... the only one that is not testing at the correct ohms is intake sensor in the very front of the AFM...

the engine will run about 20 min longer doing well when the air intake sensor is unpluged in the AFM.. but eventually continues to do the same..

at about 15 min of run time when I hook up the AITS (Air intake temp sens) the idle drops and the engine stutters..
I truly think the problem is not the fuel system its self, but the computer that is telling it how much fuel. when tested though all ohms check on ECU... ECU seems to be in working order.

I do appreciate all that everyone says. The fuel flow I dont believe is my answer and I may just end up replacing every regulatory sensor and AFM.

Thank you gentlemen for the advice.. and I will double check my fuel pressure and output might be a bad fuel regulator..

PS has new fuel filter.

Very respectfully,
SGT Davis

[Lanval]

It could be the FPR, but I'll bet it's not. The sensor and electrical system is almost surely your culprit. Don't forget the simple stuff; checking/cleaning grounds (for instance, the one from the transmission to the body). Then wait for Colin to add his precision knowledge to your problem before you buy all new parts. Unless, like me, you just like having new parts.

Mike

[Amskeptic]

Hand Salute...

Confirmed Sir, that the VW is not getting enough fuel. When I play with the wiper and the throttle, while the van is warm, I can get the engine to rev nicely.

What do I do next? Replace AFM?

Thanks again for your help

Okey Doky. Engine is capable of responding when you provide additional signal for fuel at the wiper. Now, try to see the difference in wiper movement between when you do it by hand and when you ask the engine to do itself. There are lots of visual "markers" in the AFM to see how far the wiper needs to go to give a sufficient signal. If, when you do it by hand, the wiper tip lines up with one of the copper strips leading to the connector, for example, but it refuses to go that far when you ask the engine to do it by itself, then we have two possible issues:
One, the spring is too tight.
Two, the engine has a serious vacuum leak.

The first option is not likely, particularly with two AFMs at your disposal.
The second option opens up a can of worms. When I say "vacuum leak" it includes real vacuum leaks like a split hose or a brake booster line shot to hell 10 feet away underneath the car, or it can include any reason that the engine does not draw sufficient air when you hit the throttle. A worn engine, leaky valve guides, horrendously retarded timing, etc. Do you have access to a vacuum gauge?
Colin

[dustindavisusmc]

I tore apart the top end down to the heads and new gastkets and tube/whit hose clamps.. When I spray the engine with starting fluid nothing... however I will check my brake booster.. and will groom the engine a few more time to find any that are there..

It didnt even dawn on me to check the brake booster.

I have to leave for about two weeks to the field so, I will check what I can this afternoon and report back..

[dustindavisusmc]

Allright I made it back safe from the dreaded camp roberts and am now headed back to work on the westy... Last time we talked we were discussing vacuum leaks and the possibility that the spring is to tight in the AFM.

Now I continue to have the same problems.. Not a single vacuum leak in the entire intake system... (there where a couple that were small, but fixed)..

SAME PROBLEM NEW SYMPTOMS.. When attempt acceleration I get the "boooorrr" sound. Bogging down. The vehicle warm or cold (gently acelerating) will now hold a half throttle well but any more than that and she suts down... If I open it up she will rev then decelerate, rev decelerate and wide open just die... If I opperate it by peddle and not by hand all i get is burrrr... Idles great though..fuel pressure is outstanding by the way..

I wonder if both of the AFM are faulty or have been tampered on to begin with.. as one look at both of them they both had aftermarket silcon on the covers.. could both of them have a deadspot... There really is not a lot to this system after tearing it down a half dozen times..


Semper Fi
SGT Davis

[dustindavisusmc]

I will make a short video tomorrow and try to post it or I will post it on youtube and put the link on the forum..

[Kubelwagen]

*Bump* I have an 81 and am interested in learning about the troubleshooting process here. Anything new to report, soldier?

[dustindavisusmc]

http://www.youtube.com/watch?v=k948daTMp4g

that is the video link to the problems video... it took me about two days to understand how to get the damn thing to load onto a server... the quality isnt the best but if I didnt want to wait for three days then that is what I had to compromise...

If anyone has any suggestions or ideas please let me know

Semper Fi
SGT Davis

[dustindavisusmc]

If it still bogs, I am going to guess that a wire at the connector has gone loose in its crimp or has actually been pushed into the connector due to a misalignment between the connector and the spade on the AFM. This would give you the same symptom with two different AFMs. Look closely at the little receptacle fingers to make sure they are all aligned with each other. You will need to carefully pull back the boot to inspect the wire-to-crimps.
Report at 0900 hours 08 June.
Colin

I did this too Colin and the connectors are tight and in place.. I also cleaned the prongs and inspected the connections behind the boot.. I can take pictures if you would like to see..

Thanks Colin

[Amskeptic]

If it still bogs, I am going to guess that a wire at the connector has gone loose in its crimp or has actually been pushed into the connector due to a misalignment between the connector and the spade on the AFM. This would give you the same symptom with two different AFMs. Look closely at the little receptacle fingers to make sure they are all aligned with each other. You will need to carefully pull back the boot to inspect the wire-to-crimps.
Report at 0900 hours 08 June.
Colin

I did this too Colin and the connectors are tight and in place.. I also cleaned the prongs and inspected the connections behind the boot.. I can take pictures if you would like to see..

Thanks Colin

Good morning, you're back. I am out of time today here in Portland, OR. Where are you located? You have a challenging one on your hands which always gets me chomping at the bit to fix the damn thing.
Colin