84' Idles fine but sputters and dies with throttle

[keving]

I'm totally stumped and at my wits end. My '84 westy with 80k will idle fine but dies as soon as I give it gas.

About a month ago I replaced my fuel lines, water pump, thermostat, temp II sensor and whatever coolant hoses that were available to buy. Got it all back together, flushed the coolant and filled and bled the cooling system.

It ran great, went out and ran errands for a few hours and then filled up at the gas station. About a 1/2 mile from the gas station the van sputtered and died. At first I suspected bad gas but I tested pulling gas from and outside tank with the same result.

Then I suspected a vacuum leak so replaced all of the rubber bits for good measure.

Since then I've tested the temp II sensor, afm, o2 sensor, fuel pressure, and throttle switch. All of those are with in spec of what the Bentley says. Even tried switching out ecu's and afm's with a friend.

Tonight I pulled the throttle body and cleaned it and it seemed to be in really good shape. But still no joy.

Everything checks out. I really feel like I'm missing something obvious but I've double and triple checked almost everything I can think of.

Initially I had thought this was temperature related as it would only happen after the engine warmed up. But now since my garage temp is near 100F daily it's happening within 10-15secs of startup so I can't verify.

I'm really kicking myself for replacing so many parts at once but I was trying to save on time and shipping.

Anyone have ideas or suggestions?

[wbx]

Did you do anything to your timing/distributor or to the AFM?
I've had a frustrating intermittent problem with mine where the AFM is making sporadic contact on the inside. The copper spring arm that goes from the little connector PCB to the pivot on the AFM wiper arm, for some reason, every once in a while, loses contact. That one took me a little while to figure out. When it does, van no workey.

Now, i'm not saying that is what it is, but i am saying that an unplugged/no signal from the AFM will do exactly what you are describing - let it fire up and idle, but as soon as you hit the gas, it'll sputter and die.

So check your AFM - hopefully yours doesn't hate you as much as mine hates me...
_________________
'84 Westy (first owner).......but my daily driver has pedals
My "perspective" mantra:
A Volkswagen Vanagon is just a material thing,
As such, it is of the earth,
And if i need to, I can let my Van go.

[hdenter]

Any chance that you damaged or loosened the wire to the O2 sensor while you were swapping all those pipes and the water pump? The O2 kick's in after warm-up. A bad or missing signal might be the problem even though the sensor it's self is ok. Same with the wires and connectors to the temp II.

Good Luck!

Hans
_________________
'79 triple white convertible bug
'84 sunroof vanagon
'85 weekender

[Wildthings]

What is your fuel pressure?

[Ahwahnee]

Good news is that you have a fine collection of spare parts to take along when you do get back on the road.

I would start by confirming that you have spark at the plugs and fuel in the cylinders. Perhaps you have already done that but I didn't see it in your post.

[keving]

Hi guys, thanks for the replies. I've ran back through and tested everything you recommend as I've been trying to troubleshoot this for so long I forget what I've tested.

[keving]

[wbx]

[keving]

Just thought i should post a follow up in case it helps anyone in the future.

I had the van towed to the mechanic because I couldn't deal with any more hours in the 110F garage.

Turns out I had a few different things going on. The distributor would start to fail on 2 cylinders after it got hot. I believe this to be my initial problem or at least part of it. And I failed to find this because I assumed the distributor was good because I was checking spark when it was cold or cool.

Then later on at some point I had 2 fuel injectors go out, not sure if bad gas could cause this? This happened in the final days leading up to me getting it towed.

The shop mentioned they thought the gas was bad, saying so many additives were in it that it wouldn't burn. They drained and put in fresh gas. Now it runs like a champ.

Anyway, happy to have the van back and running again on the new vancafe steelies.

[msinabottle]

Congratulations on not giving up, and knowing when to bring in the pro's, a VERY TOUGH call for a shade-tree mechanic.

Glad the beast is back! I wonder if the AFM fix will improve things for the Digijet, I'm still toying with the idea myself.

Best!
_________________
'Winston,' '84 1.9 WBX Westy
Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence."

[Ahwahnee]

Thanks for the follow-up, so often we hear of problems, offer lots of advice and are left to wonder whatever became of the poor soul who was trying to fix things.

Thanks to the link in your post I, too, added that jumper wire to my AFM (Digijet) can't hurt I think.

For all the times I've heard someone speculate that the problem was bad gas (and it turned out to be ignition) interesting to hear of a case where it was at least partially to blame.