80 air cooled vanagon starts then dies, runs a few seconds

[riviera blue]

I have a 80 vanagon that starts and runs for a few seconds at idle, then dies. If you give it gas it dies. I have checked the injectors, replaced most the vacuum lines, and checked the resistor pack, auxiliary air regulator and the spark plugs. I tested everything with my multimeter and found that on the double relay 88d to the fuel pump wasn't lighting up, but all the other relays were. I am fairly certain at this point that my air flow meter is not sending signal to the fuel pump. I am wondering how the van is starting without signal to the fuel pump initially. I have replaced all the fuel lines and just about every seal. I am wondering if I can clean the contacts on the air flow meter as the flap already moves freely. Thanks and great website and forums by the way. Any suggestions would be helpful.

[Wildthings]

With the key on do you have power at 86b when you open the vane in the AFM?

Your engine is probably starting because the double relay gets a signal to run the pump from circuit #50 when the starter is cranking.

[NZer]

Unplug the AMF and the ECU will default the a stored setting, the van will run but not very well.
How do I know. I removed the air cleaner to swap out plugs and forgot to plug it back in!
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A sad looking 88 Westfalia, MT 2.1 with 150k on the clock and several issues!

[OrangeBus1973]

I was struggling with a similar problem last week. Grab your meter and check continuity from the temp2 sensor to the ecu plug. My wire popped off the crimp inside the plug. Fixed that wire and I was back to normal. Also, a faulty temp2 sensor will produce issues like that.

[riviera blue]

Unplugged the afm and the van runs at idle as long as I want, but it runs badly. I tried giving it a little gas and it kinda puttered along, but died after a minute. I took the afm off and opened it up, I'm gonna try cleaning the contacts and cleaning the brass contacts. I hope this fixes the problem or I will have to buy a new afm. Thanks for all the help,didn't realize it would run with the afm disconnected.

[OrangeBus1973]

I spent several nights blaming the AFM... do yourself a favor and check the Temp2 sensor.

[danfromsyr]

I agree, it's a cheap and often confounding part.
in fact it's as much a problem on most VW fuel injections and you should at the least carry a spare at all times.. and they're cheap.
sits towards the fire wall on the Drivers side cylinder head, single black wire.


$17 at Busdepot.
http://www.busdepot.com/details.jsp?partnumber=0280130012

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[riviera blue]

I will check my temp sensor, but why would it not idle more than a few seconds with the afm plugged in and run at idle all day with the afm unplugged. Again thanks and I will check the temp sensor.

[Wildthings]

Assuming you are correct in that your pump is not getting power, the TSII sensor doesn't have anything to do with your problem.

Since the tank is higher than the engine, sometimes the engine will get enough fuel by gravity to idle even without the pump running.

As I asked early:

[OrangeBus1973]

Well,
My case was a disconnected temp2 sensor. It would start briefly, then die. I could smell a lot of gas sometimes and I think the system would pump crazy amounts of fuel into the system which would then cause it to die. I tried everything else I could think of. Swapped AFM and ECU. ran direct power to the fuel pump. replaced vacuum lines, etc. I had 2 others help me diagnose the problem and they both montioned Temp2 as a possibility.

[riviera blue]

I fixed it. First I removed the top of the afm and looked inside. I saw where the circuit opens and closes to send a signal to the fuel pump and where the signal input comes from. Both of these had good continuity. I then checked the black resistor strip continuity between the arm, I had a short. I saw that the 2 copper half oval arms of the potentiometer where not touching the resistor strip. I removed the arm, which can be removed without removing the spring. I also removed the terminal side. I bent down the copper oval arms until they made contact with the resistor strip. I checked again for ohms and it showed as a potentiometer would. I cleaned it all up with some de-toxit, put it back in the van and the van started right up.This seems like the reason these would go bad, and when I have more time, moving at the moment, I will post pics. THANKS

[riviera blue]

I didn't check 86b because it idled with the afm unplugged,but I am sure it had no signal at 86b, so thanks for the info. Just wanted everyone to know I didn't ignore your advise. thanks again

[cegammel]

So, I was having the same problem...I unhooked the AFM, and the van purred like a kitten. I then plugged the AFM back in, and the van immediately died, just like before.

Now, here's the problem: The van will do nothing...it seems to be not getting fire, but does seem to be getting gas.

If unplugging the AFM resets the ECU, would that reset have somehow messed up the firing?

Thanks for any help.

[cegammel]

Incidentally, my problem seems to have been the double relay. I thought I had checked it all out properly, but plugging a new one in fixed the issue. This was the last ditch effort, after changing all vacuum lines, cleaning all grounds, and ohm checking everything in the middle.

[The_ders]

my van is doing the exact same thing except it is the temp sensor 2. if i leave it unplugged i can idle but as soon as i plug it in it dies. I have tried multiple sensors it seems when the sensor becomes grounded it kills my engine. i also can not rev it up with the temp sensor unplugged. i am really puzzled and have gone through about every step in the bentley so any help would be appreciated