Help! At a loss with ‘91 running rich

[Backfromthedead2]

Hi all,

Long time lurker, first time poster.. hope I get this right.

I have a ‘91 T3 2.1L MV with 300,000km on the clock. Has never run right. On start it would idle like a bag of spanners for 15 seconds, then die, no matter how much throttle. There are two yellow plugs above the thermostat housing in the engine bay. I unplugged one, engine revved up to 2000 rpm and hummed beautifully. Turned the screw down on the throttle body to lower rpm to 1600 min. Fine to get around town, but annoyed me that something wasn’t right.

Tried to track down what the yellow plug did, thought it was the Idle control unit (behind rear tail light).. so replaced that. Started, idled great for 5 minutes (about 900rpm) drove around sweet, then loss of power, bucking and felt like running on 3 cylinders/misfiring. Black smoke.. Turn engine off and back on again, drove round fine (bit of black smoke), then loss of power, bogging and die. Turn it off and repeat to get home..

Proceeded to replace:
>O2 sensor
>Temp II sensor
>Fuel pump + filter
>Spark plugs
>cleaned everything!
>new earths and cleaned all contacts..

Started her up..

What a sh*t show. Now more black smoke, white and blue smoke!
Idles is rough as guts and no power.. stalls. Basically all over the place.

I noticed some coolant dripping from the water jacket.. might be new, but was clear.. unrelated but not ideal.

I’m worried I’ve done something to the bore and head gaskets from running to rich for too long. Was chewing through the fuel so maybe washed out and now I have oil and water mixing?

At a loss of what to do. Drop the engine take apart and replace head gaskets?

Any ideas would be greatly appreciated.

Thanks

[DanHoug]

i would suggest starting with a compression test given the history of never running right. report test results and we can go from there. gotta have good compression before other things can fall in line.
_________________
-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[davideric9]

suggest testing every component that talks to the ECU as per the digifant training manual. Follow procedures in the Bentley manual for setting timing and idle, don't just start turning screws.
_________________
1987 Syncro Westfalia, stock (bought 1994)
1986 Syncro Westfalia SVX, 3 knob (bought 2008)
1987 Westfalia (bought 2010)
1988 Wolfsburg GL (bought 2012)

[dgbeatty]

While helping diagnose a chronic rich running problem David Beirel found an error in the test procedure that had lead to dead ends.
Here is an abbreviated synopsis that covers the testing why's and wherefores. Originally posted on FB.

is.gd/1nu01y
Updated address........

https://www.dropbox.com/s/84o1f88y3vattxn/David%20Beirel%20WBX%20rich.docx?dl=0

It may save hours of tail chasing and would be over looked by a less than master diagnostian.
_________________
Schau in das Buch

[Wildthings]

Check that the wire from the ECU plug to the plug for the O2 sensor wire DOES NOT show a ground. The test is in the Bentley, you might as well run through all the FI diagnostic tests while you are at it. Takes little time and will let you know what is right and what isn't.

[Yota-toy]

Vanagon Syndrome??? it's real, I promise.
http://www.benplace.com/vanagon_intermittent_syndrome.htm

[djkeev]

Kam has undated and corrected the digifant manual.

Find it here, print it out, slip it in your Bentley so you always have it.

http://oldbluesblog.com/files/DigifantProTrainingManual_SingleSided.pdf

Dave
_________________
Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[Wildthings]

[djkeev]