Idle problem with 3.6 engine

[Chocaholic]

Be careful....I don't believe Steve has a chip for the Varioram motor. Perhaps that's changed?

[shahram]

Steve Wong or Steve Timmins?
Wong has chips for 993 Vario engines and Timmins uses Cyntex for 993 Vario as well.
Wong Chip: http://www.911chips.com/993chips.html
Timmins Cyntex Chip: http://instant-g.com/Products/36Conversion/Options.html

[mmasse]

I just sent and email to Timmins asking him to exchange the chip. Let's see if this works.

Thanks

[Lorenfb]

"I don't believe Steve has a chip for the Varioram motor"

There's NO chip for the U.S. '96-'98 993 DME ECMs.
The '96 can be Mickey Moused by soldering a "piggy-back" device,
and the '97-'98 must be flashed.

Read here: http://forums.rennlist.com/rennforums/showthread.php?t=326609

"If still not working after that then start in with the brake cleaner to look for intake leaks."

If the engine runs smoothly at the high idle, then the air leak is around the
throttle body and NOT directly into the intake manifold. An intake air leak
into the intake ports, i.e. manifold leak, will usually cause an idle misfire.

[shahram]

According to his homepage he has one:
96-98 Euro Version 993
$350
Euro Version V-Ram
with 55-pin DME connector
includes Bosch DME #0.261.203.678
My DME is a 96 European version with 55-pin connector, so this should work.

[Lorenfb]

"My DME is a 96 European version with 55-pin connector, so this should work."

Must be located somewhere other than the U.S. or in some state where no emissions
testing exists. A late 993 engine requires OBDII testing!

[shahram]

Yes, I am located in Germany and OBDII was not required for Europe.

[mmasse]

Below is a picture of the back of my engine. Could anyone point me to where the throttle switch is?

Thanks a lot

[Bill Verburg]

MM,
993 does not have a throttle microswitch as used on 964.

993 uses a Throttle potentiometer
Here is what is used on Motroic 5.2(US OBD2)




RoW vram uses M2.1 which is in many respects the same

[mmasse]

Thanks Bill.

Now, I understand why I was not able to find it :-)

I guess my last chance is that the problem is the chip. I already contacted Timmins and he will exchange the one that I have. Hope this solves the idling problem.

[Bill Verburg]

I'm in the process of t/p ing my RoW 55 pin RS engine into my 55 pin US '95.

Not done yet but so far it appears that the Cyntex chip was the issue.

But as I said it's not a done deal.

[Bill Verburg]

Another possibility is the adaptive nature of the 993 idle system.

The throttle potientiometer on the throttle shaft determines the angular position of the throttle shaft. The 0 position(idle) is determined in an adaptive process by the DME control unit.

If the battery is disconectedor the control unit has been separated from the system, the engine must be restarted w/ the throttle valve fully closed.

A self adaptive system always selects the smallest opening angle of the throttle as the idle position. If the throttle moves, the engine idle settings are swithed off, at ~66&deg the full load menu is activated,

Having a Hammer or PST2 lets you read the actual vallues that the DME is seeing from this process. Soemtimes the thrttle cable is the issue.

W/ the cable adjusted to 0 at idle, it will read 84&deg &#1773&deg at wot

Another (remotely) possible issue is the coding of the DME, there is a 2pin connector branched off from the DME wire harness, near the connector.

for RoW regulated engines this open, for RoW unregulated this is bridged w/ a 1kW, US cars have a harness to ground

[bigchillcar]

bill, do you have a similar diagram by chance for the 964? having moved up from a cis 2.7 i'm trying to learn this new engine when i get time. also trying to chase down an intake leak, confirmed by spraying brake cleaner around the manifold 'area' that's giving me an idle hunt.
if you can, thanks!
ryan

[ToddM]

I had these kinds of problems with high idle and surging idle after a service

Turns out that the motronic computer loses its brain after the battery is disconnected and you need to throw the hammer back on and have the car re-adapted. Hopefully your motronic diagnistic port is available.

I would start there.

[mmasse]

If the battery is disconectedor the control unit has been separated from the system, the engine must be restarted w/ the throttle valve fully closed.

Bill, How do I do this? Is it just a matter of not depressing the throttle the first time I start the engine after disconnecting the battery?...because I did disconnected it several times and never took any specific action when starting the car again



Unfortunately, I don't have acces to a Hammer. Nevertheless, I am in the process of building a DYI code reader for OBD1 993 engine.

Bill, I think you are also working on this on Rennlist, right?

Do you know if this reader will allow me to read the info that you are refering to.

I already connected an OBDII port to my DME, following instruction on this forum. Hopefully, once i get the reader I will be able to crack this issue.

[Bill Verburg]

Bill, How do I do this? Is it just a matter of not depressing the throttle the first time I start the engine after disconnecting the battery?...because I did disconnected it several times and never took any specific action when starting the car again

Just start w/o touching the throttle, you are supposed to let it sit that way for up to 10min.

Do you know if this reader will allow me to read the info that you are refering to.

yes, it will perform all or at least most of the functions of a hammer.

[Bill Verburg]

Originally posted by bigchillcar
bill, do you have a similar diagram by chance for the 964? having moved up from a cis 2.7 i'm trying to learn this new engine when i get time. also trying to chase down an intake leak, confirmed by spraying brake cleaner around the manifold 'area' that's giving me an idle hunt.
if you can, thanks!
ryan

The closest I have on hand is a '95 993

the 964 is somewhat different in a few respects but mostly the same

One of the differences is that a 964 does have a microswitch

[mede8er]

I had these idle probs...Steve Weiner at Rennsport hooked me up with a new box and my troubles were over....

Wasn't cheap but nothing is when you live on the edge.....

[ToddM]

Steve is THE man. Always will be in my book.

[bigchillcar]

The closest I have on hand is a '95 993

thanks for remembering me, bill..knew you'd come around! i'll save the images.