Home Technical Discussions Volkswagen Vanagon: 1980-1991 (T3)

Volkswagen Vanagon: 1980-1991 (T3) 1982 Vanagon engine cutting out


Permlink Replies: 6 - Pages: 1
Last Post: May 22, 2007 2:59 PM Last Post By: holmsy
holmsy

Posts: 12
Registered: 10/14/06
1982 Vanagon engine cutting out
Posted: May 6, 2007 1:04 PM
  Click to reply to this thread Reply
My '82 air-cooled engine is cutting out on acceleration, but if I back the throttle up a bit it still runs. If I push the throttle down again, it hesitates then usually cuts out and bucks. The engine has been rebuilt, a new gas tank and fuel hoses fitted and a new fuel pump. 3 other AFMs have been tried, 1ECU ,a different distributor with points [mine has electronic ignition],the ignition switch works fine, and I have cleaned every ground connection I can find. The engine work ok for a while since my last posting 14Oct06 [Holmsy]. I am not a mechanic, it is being worked on by a VW mechanic /service manager. The mix is running rich [sooty plugs] which I cleaned. I have spent alot on the van with the intention of fixing up the body, I have had the vehicle since new.Please can any knowledgable Vanagoner advise?
I notice on this site mention of the Temp 2 sender, if this were faulty would the engine not just cut out completely? I should also mention thta the problem occurs more often after traversing rougher road sections. Holmsy
wohlfarth

Posts: 1,745
Registered: 10/31/03
Re: 1982 Vanagon engine cutting out
Posted: May 11, 2007 3:01 PM   in response to: holmsy in response to: holmsy
  Click to reply to this thread Reply
The temp sensor II, commonly known as the head temp sensor could definitely be causing your problem. When they go bad the van will run like doo-doo. I had a very similar situation once in my '81 and it was the head temp sensor.

It could also cause an intermittent situation if the head temp sensor has worked loose in the head. Check to make sure it is tight and snug against the head, sometimes the engine tin can get it the way of it making a good connection.

You can also put an Ohm meter on the head temp sensor to check it (see page 24.13 in the Bentley Vanagon manual). It's important to get a steady reading at a given oil temp. If the reading is jumping all over the place or out of spec. then replace the head temp sensor. I think they cost about $20-$30, depending on who you get it from. It is one of the primary inputs for the air-cooled (AFC) Vanagon fuel injection system.

-Stan
holmsy

Posts: 12
Registered: 10/14/06
Re: 1982 Vanagon engine cutting out
Posted: May 14, 2007 12:32 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
Thanks 'wohlfarth' for your info. Unfortunetly replacing the temp sensor din't cure the problem. When I drive, if I change gear I depress the throttle pedal about a third of the way and hold it there as the revs increase which seems to indicate that the AFM wiper is not hitting any worn spots? If I depress the pedal further though the engine may start to sound like it is struggling then it cuts out until I back off the pedal a bit. Please can you or anyone suggest what may be wrong. I read something about 'safe mode', what is this?
wohlfarth

Posts: 1,745
Registered: 10/31/03
Re: 1982 Vanagon engine cutting out
Posted: May 16, 2007 10:44 AM   in response to: holmsy in response to: holmsy
  Click to reply to this thread Reply
You mention that you switched to a different distributor, with points. Did the problem exist before this switch? I'm pretty sure that the ECU (Engine Control Unit, i.e. Fuel injection "brain") is specific to the type of distributor. The distributor with points on air-cooled Vanagons was for 49 states (non-California). The electronic ignition (hall sender distributor) was for California only. However there are also aftermarket electronic ignition systems (i.e. Pertronix) that may also be what you are referring to.

Please let us know if the vehicle is a California spec. (originally sold in California). It would also be good to know where you are located. If you provide the part number on the top of your ECU I can check the parts list to see what application it is. You can use a small handheld mirror to check the part number with the ECU installed (right rear corner of engine compartment).

How about the ignition coil? Has it been checked as per the Bentley manual. Has it been replaced with the correct Bosch unit? A faulty coil could be causing the problem you are describing.

What about a fuel pressure test? It would be good to do this and see if the fuel system might be the problem.

The above suggestions are based on similar problems and solutions that I have had with my '81 non-California Vanagon.

I'm not sure what 'safe mode' is. My guess is that it may be similar to "limp home" mode in more modern cars. This is when an input sensor fails and the fuel injection system uses other working sensors and/or pre-set values to still operate the vehicle with reduced performance. I don't know if the air-cooled Vanagons have such a mode or not. There aren't too many inputs for their relatively simple fuel injections systems.

-Stan
holmsy

Posts: 12
Registered: 10/14/06
Re: 1982 Vanagon engine cutting out
Posted: May 19, 2007 2:56 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
Stan, thanks for you input. I am in Vancouver B.C.,the van is a Canadian version with no catalytic converter, and no oxygen sensor. The ECU has 2 numbers, the top one;0 280 000 178, the lower one is; 0 399 060 21B. It is I think still the original unit although another was tried from an '82 and didn't cure the problem. The distributor is original but modified with an electronic device and it runs better with it. But it cut-out before the change and after, and another distributor with points was just recently tried but still same problem. 2 different coils have been used. Yesterday the van ran ok for about 45 mins, then stumbled as I was entering the hwy. Later I limped home on very little throttle. There was a smell of gas at the intial faltering. There doesn't seem to be a pattern as to when it happens, except sometimes sharp bumps may cause it to act up. I have just rerouted the high tension wires away from other cables. I located 2 ground wires [Bentley manual 24.12] cleaned them and rerouted the ground to another clean, temporary, place. That's all I can tell you. Peter
wohlfarth

Posts: 1,745
Registered: 10/31/03
Re: 1982 Vanagon engine cutting out
Posted: May 21, 2007 10:10 AM   in response to: holmsy in response to: holmsy
  Click to reply to this thread Reply
Those part numbers on your ECU seem to be correct. My '81 air-cooled 2.0L vangaon (non-California) has the same part numbers.

A fuel pressure test would be worth trying, but if the problem is intermittent, it's more likely to be electrical or ignition related. It's possible that the fuel filter could be randomly getting clogged up with debris. The Vanagons are notorious for having fuel tanks that rust from the top. When this happens, sediment/rust can get in the fuel system. The filter will trap a lot of it, but it can get sloshed around and cause random problems with the fuel delivery. We've had other threads covering this.

I remember my '81 had a nearly broken wire at the series resistance pack which caused a random miss. The series resistance pack is the item that is screwed to the firewall on the left side of the engine bay and has 4 ceramic cylinders encased in a metal housing. Page 24.6 (fig. 7) of the Vanagon manual has a picture of it and a procedure for checking the resistance.

The tricky part of an intermittent problem like this is diagnosing it when it occurs.

I will also say that I have been trying to track down a similar problem with my '81, for about 3-4 years now. My problem seems to only happen when the van is fully warmed up (after about 30 mins. of highway driving) and it is a very random stumble and/or miss at high speeds. It's very annoying and seems like the van will briefly have no throttle response. I don't drive the van very much and have not had a chance to determine if the problem is still happening or not. The last time I drove it any distance was in Jan. However, I did not drive it on the highway, the weather was cold, and it drove just fine.

I'd say to just spend the time doing all the various diagnostic tests covered in the Bentley manual and see what you can find.

Good luck and keep us informed of your progress.

-Stan
holmsy

Posts: 12
Registered: 10/14/06
Re: 1982 Vanagon engine cutting out
Posted: May 22, 2007 2:59 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
Hello Stan, Thank you again for your suggestions. I will check the injection system as suggested, using the Bentley manual. I thought the mechanics who worked on the van would have done this, but I just found the throttle enrichment switch was not in the correct position to operate at all. I repositioned it and now have power to spare[?],going uphill. The fuel tank, lines and filter are all new, as is the series resistance pack...I have spent alot on this van! The ground wires I mentioned were really hidden, had not been cleaned in 25 years. Would not have known they were there if not for the manual.Thanks again, Peter.

Point your RSS reader here for a feed of the latest messages in all forums

Popular Discussions:
No popular dicussions.