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Sun Apr 13, 2014 7:56 pm

87 Westy.
So I seem to have the dreaded poor mpg problem. Been reading up on it here.

Burned a whole tank in 3 hours appx 160miles. It's also had an unstable idle for a while(2 weeks?) but hadntt driven it long enough to notice the mpg drop. At idle the rpms bounce up to 1800/2000 and back down to 1100. Seems like it used to sit at 800/900 before.

So, ideas ?
Tps? Which is what by the way?
O2 sensor, which has 3 wires, none of which SEEMS to be coax.
Air flow meter?
Ts2 ?
I'm mid trip right now. Any help would be great!

Happy travels.
Jimi

Sun Apr 13, 2014 9:20 pm

good recent thread:
http://www.thesamba.com/vw/forum/viewtopic.php?t=583813

a bit extreme regarding the rpm jump for this, but check your timing at 5° ATDC? Is it 5° for an '87??
if you have a timing light during the trip.

TPS is throttle position switches.

edit:From the Haynes manual ignition timing:
2.1engine codes "DJ" = 10° ATDC, for 98 octane fuel,vacuum disconnected.
"DJ" for 95 octane fuel 5°ATDC, vacuum disconnected.
"MV", "SR", "SS" engine codes = 5°ATDC

Mon Apr 14, 2014 3:07 am

Steve M. wrote: good recent thread:
http://www.thesamba.com/vw/forum/viewtopic.php?t=583813

a bit extreme regarding the rpm jump for this, but check your timing at 5° ATDC? Is it 5° for an '87??
if you have a timing light during the trip.

TPS is throttle position switches.

edit:From the Haynes manual ignition timing:
2.1engine codes "DJ" = 10° ATDC, for 98 octane fuel,vacuum disconnected.
"DJ" for 95 octane fuel 5°ATDC, vacuum disconnected.
"MV", "SR", "SS" engine codes = 5°ATDC

A US spec '87 van will have the Digifant control system and the distributor will not have any kind of vacuum advance. The timing is best set via Tencentlife's method.

To the OP. You need to check that the center wire of coax for the O2 sensor is not shorted out to the shield. Yes you have coax.

Your idle problem is likely a vacuum leak.

Mon Apr 14, 2014 3:15 am

Steve M. wrote: good recent thread:
http://www.thesamba.com/vw/forum/viewtopic.php?t=583813

a bit extreme regarding the rpm jump for this, but check your timing at 5° ATDC? Is it 5° for an '87??
if you have a timing light during the trip.

TPS is throttle position switches.

edit:From the Haynes manual ignition timing:
2.1engine codes "DJ" = 10° ATDC, for 98 octane fuel,vacuum disconnected.
"DJ" for 95 octane fuel 5°ATDC, vacuum disconnected.
"MV", "SR", "SS" engine codes = 5°ATDC

A US spec '87 van will have the Digifant control system and the distributor will not have any kind of vacuum advance. The book timing for an MV engine is 5° BTDC, but the timing is best set via Tencentlife's method.

To the OP. You need to check that the center wire of the coax for the O2 sensor is not shorted out to the shield. Yes you have coax.

Your idle problem is likely a vacuum leak.

Mon Apr 14, 2014 4:36 am

Wildthings wrote: Steve M. wrote: good recent thread:
http://www.thesamba.com/vw/forum/viewtopic.php?t=583813

a bit extreme regarding the rpm jump for this, but check your timing at 5° ATDC? Is it 5° for an '87??
if you have a timing light during the trip.

TPS is throttle position switches.

edit:From the Haynes manual ignition timing:
2.1engine codes "DJ" = 10° ATDC, for 98 octane fuel,vacuum disconnected.
"DJ" for 95 octane fuel 5°ATDC, vacuum disconnected.
"MV", "SR", "SS" engine codes = 5°ATDC

A US spec '87 van will have the Digifant control system and the distributor will not have any kind of vacuum advance. The book timing for an MV engine is 5° BTDC, but the timing is best set via Tencentlife's method.

To the OP. You need to check that the center wire of the coax for the O2 sensor is not shorted out to the shield. Yes you have coax.

Your idle problem is likely a vacuum leak.

So much for the Haynes manual!
Do you have a link to Tencentlife's method?

Mon Apr 14, 2014 5:10 am

http://www.thesamba.com/vw/forum/viewtopic.php?t=252560&postdays=0&postorder=asc&start=0

Third post down.....

And if you haven't had a timing light in the back of the bus much,
I use the alternator main stud as a pickup for 12 V. Saves trying to
go to the battery.

Mon Apr 14, 2014 5:59 am

Steve,
I read all four pages of that recent post before posting. I think the consensus became his tps?

Or should I try unplugging the o2 sensor to see if it helps?

I don't have a timing light, and haven't done timing before.

I THINK it's running rich, but I'm not very sure.

My o2 sensor has two white and one green wire on it, they all look small, not at all like coax. If there's a short unplugging it will tell me right ?

Wow, I'm all over the place typing this on my cell phone.
I'm headed to Santa Fe/Taos in a few days, can anybody recommend a good mechanic?

Thanks again gang.

Mon Apr 14, 2014 7:10 am

If your in the Albuquerque area PM me, I would be glad to take a look.

Phil

Mon Apr 14, 2014 7:46 am

Thanks Phil!

I'll also be in OKC soon and Amarillo.

Jimi

Mon Apr 14, 2014 7:48 am

jimimeg wrote: S
My o2 sensor has two white and one green wire on it, they all look small, not at all like coax. If there's a short unplugging it will tell me right ?

The wire going from your ECU to where the wire on the O2 sensor plugs in is a small diameter coax.

Mon Apr 14, 2014 8:23 am

Wildthings wrote: jimimeg wrote: S
My o2 sensor has two white and one green wire on it, they all look small, not at all like coax. If there's a short unplugging it will tell me right ?

The wire going from your ECU to where the wire on the O2 sensor plugs in is a small diameter coax.

So unplug it for a test, see how the mpg is ?

Mon Apr 14, 2014 9:19 am

Any help in little rock ?
Just burned a tank in an hour and a half?

Mon Apr 14, 2014 9:41 am

Forget about the timing, it isn't going to change itself and it ran fine before. So something who're out or came loose. Did you unplug the o2 sensor and see how it does? Did you check tho see if you have loose intake hoses out clamps? I doubt you went from 160 miles to the tank to 90 so you need to take better measurements of gas mileage while you try things. It seems like two different problems, air leak for the high idle and over fueling for the bad gas mileage. Too much gas could be fuel pressure regulator, maybe o2 sensor, bad plug wires out plugs. Easy to look at the plugs and see if they all look ok which would probably rule that out. Or gas leak from an old hose? Those are ideas off the tip off my head.

Mon Apr 14, 2014 9:56 am

jimimeg wrote: Wildthings wrote: jimimeg wrote: S
My o2 sensor has two white and one green wire on it, they all look small, not at all like coax. If there's a short unplugging it will tell me right ?

The wire going from your ECU to where the wire on the O2 sensor plugs in is a small diameter coax.

So unplug it for a test, see how the mpg is ?

You need to use an ohm meter to check that the center conductor isn't grounded to the sheath. This is best done from the plug for the ECU as described in the Bentley. If grounded, unplugging the sensor will make no difference in how the engine runs or what your gas mileage is.

Mon Apr 14, 2014 9:58 am

I didn't see anyone mention it, but vacuum leaks can (or in my case did) cause a cycling idle.

Mon Apr 14, 2014 10:33 am

Ok so the problem seems to be intermittent . Watched the gas gauge drop to half a tank in half an hour, then it sat at half for 40 minutes.

When I pulled into a parking lot to start checking it it was idling at about 900.

Of course my odo is broken so mileages are approximate. Gonna limp it into camp at hot springs natl park and do checking for loose wires bad grounds etc.

So I can check for continuity at the Ecu plug in the engine compartment? I don't have to under the bench seat? Which setting on the multimeter do I use for that ?

Man, this is getting frustrating, thanks for everyone's help!

Mon Apr 14, 2014 10:55 am

jimimeg wrote: Wildthings wrote: jimimeg wrote: S
My o2 sensor has two white and one green wire on it, they all look small, not at all like coax. If there's a short unplugging it will tell me right ?

The wire going from your ECU to where the wire on the O2 sensor plugs in is a small diameter coax.

So unplug it for a test, see how the mpg is ?

If the center lead is grounded between the ECU and where the O2 sensor plugs in, it will do no good at all to unplug the O2 sensor.

You need to get out your meter and check the center wire as directed in the Bentley.

Mon Apr 14, 2014 12:54 pm

Ok wildthing, I gotcha. I'll do my best, I'm not a wiz with the MM.

BUT, I was lead to believe If you unplug it and the ecu gets no signal, it goes into a default mode. If your mpg goes up then, you know for sure it's the o2 sensor or the wire. No ?

Jimi

Mon Apr 14, 2014 1:40 pm

you might find someone along the way using the "Rescue Squad" through here:
http://www.vanagonauts.com//index.phtml?catid=74

Mon Apr 14, 2014 2:52 pm

So I ran all the checks on fuel injection in the Bentley. Halfway through i found a vacuum hose off right by the idle stabilizer valve. Finished all the checks anyways. Everything checked out ok. I'll post after a long drive tomorrow and see if that was it!

Not sure i checked the o2 correctly tho. It said to unplug it and ground the green, which I had to use a jumper to do, because the green (coax?) was a female with a boot over it. Does that sound right ?

Thanks again.
Jimi