993 conversion: relay + ISV making noises + throttle cable setup & photos

[DW SD]

Guys,
I've got the wiring completed for the 993 conversion. The oil lines aren't, yet done, yet, but soon. I turn the key, the first DME relay clicks on and I hear the Idle Stabilizer Valve humming away.

Good sign, right?

I'm hoping to confirm that the ISV should start humming at ignition on. I'm using the Patrick Motorports DME conversion harness and a '95 55-pin DME unit (no drive block).

CAN SOMEONE WHO HAS A SIMILAR CONVERSION CONFIRM THAT THE ISV COMES ON WITH THE IGNITION SWITCH??

On a side note......

Also, for those interested, I made my own throttle cable kit using some sheet metal (20 gauge), 1/8" plate and a universal throttle cable kit from a 36" Lokar universal throttle cable. $40 @ Summit.





The cable mount on the transmission started with sheet steel, which I bent into a rough L - shape. From there, I twisted the end which attaches to the cable to point directly at the bellcrank. I then added some sheet metal to triangulated and gussetted the cable mount. The bell crank is modified to change the ratios between the gas pedal and the throttle. I added about 7/8" in length from the previous stock setup. I also repositioned the larger lever on the bellcrank shaft to ensure that the cable is not offset from its housing or its pull.



as for attaching the cable on the other end: At the throttle I used a small shaft, cut down to fit into the factory throttle bracket. The cable slips through a hole in the shaft, while a bead at the end that locks in place against the hole in the shaft.



Finally, here's a few shots of the bracket I made to keep the filter housing from bouncing around. It is simple sheet metal, twisted and gussetted.





Sorry.....The flash from the camera makes the black painted pieces hard to see. If anyone wants a close up, I'll take another photo in the daylight with more ambient lighting.


Doug

[Bill Verburg]

The ISV shouldn't hum, at least none of mine have(that I have noticed)

Mechanically, you should hear the rotary valve hitting it's stops when shaken.

electrically, the center pin is battery voltage and the outer pins are for the opening and closing windings.. You can make an oscilliscope adapter for testing purposes at idle, the scope should show ~+15v for 6ms followed by ~-15v for 6ms etc. at each outer pin.

[Bill Verburg]

P.S. nice job on the rest of the install, you will be very pleased when it's done

[DW SD]

Bill,
I thank you for your response and kind words!
Mostly, I'm trying to confirm that the electronics seem to be working correctly.

Should the ISV have voltage in the ignition (1) position (IE... run, but not start, prior to cranking) ??

I'll start with that and will check out the ISV more closely. Unfortuantely, I don't have an o-scope.

The hum is very soft and it clicks upon turning the key to the on position. I would almost call the hum an audible vibration, as if it is opening and closing. I can feel it vibrating when I touch it.

Worst case, I can trouble shoot the ISV's operation, when I get it running.

Thank you,

Doug

[Bill Verburg]

Should the ISV have voltage in the ignition (1) position (IE... run, but not start, prior to cranking) ??

I would think so, but only God and Bosch know what the DME is telling it to do.

There are 2 opposing windings that keep the idle at the specified RPM. I believe that the internal contacts wear causing some of the idle issues on these cars.

One of mine idles too low the other too high, just by a few 100 rpm in both cases. One of these days i'll buy a new ISV and dissect the old one, but so far it's not that big an issue.

[DW SD]

Makes sense. If you have an opportunity, please see if your ISV vibrates before you've cranked the engine over when the key is on. Not a big deal, but confirming that things are happening properly along the way, is very helpful, especially if I encounter problems later.

Thank you very much,

Doug

[Bill Verburg]

The one in my nice warm 75&deg garage does vibrates and make a slight hum(never noticed it before) w/ key on but before engaging the starter.

The one out in the unheated garge shall remain a mystery untill it stops snowing

[DW SD]

Originally posted by Bill Verburg
The one in my nice warm 75&deg garage does vibrates and make a slight hum(never noticed it before) w/ key on but before engaging the starter.

The one out in the unheated garge shall remain a mystery untill it stops snowing

Bill,
This is indeed a good omen for me!

Thank you for taking the time to check!

Hope the weather thaws out for you soon!

Best,

Doug

[rattlsnak]

That air fliter bracket looks like an exact replica of the one I made for my conversion!

Throttle cable setup looks real nice. The one I got with my Timmons kit worked, but I didnt like the way it worked or hooked up.

[DW SD]

Rattlesnak-
Thanks a bunch! The conversion is turning out very nice! Hopefully, these little tidbits will help someone else down the road, too.

Doug

[beamonk]

Doug, where did you get your air filter setup. More pics of the bracket would be appreciated.
Thanks

[mjshira]

Doug

I have to second Bill's comment, that doesn't sound right. Let me know if pics or anything from my swap experience can help.

good luck

[DW SD]

Originally posted by Bill Verburg
The one in my nice warm 75&deg garage does vibrates and make a slight hum(never noticed it before) w/ key on but before engaging the starter.

The one out in the unheated garge shall remain a mystery untill it stops snowing

James,
I think you may have misread this comment from Bill?

I appreciate your offer of sharing some pictures.
I'll take you up on it, if I have any issues. For now, things seem to be coming together nicely.

Thank you,

Doug

[DW SD]

Beamonk,
I don't know where the filter came from, maybe from Timmons or Patrick Motorsports. It came some conversion parts, which I bought from a friend.

Here's a close up of the bracket. Note, a triangular gusset is welded to stiffen it up. That is to the right side of the M6 bolt.

Camera just ran out of batteries, so I can't take any more for a few hours.

Doug

[DW SD]

I added some shrink wrap tubing so the hose clamp wouldn't chafe the paint.
To make the bracket:
From the bolt, the sheet metal is twisted counter clockwise. Then a 90 degree foot is bent into to it to support the filter housing. The foot was radiused a bit to follow the profile of the filter housing.
I added the gusset to the right of the M6 bolt to strengthen it.

I spray with Wurth self-etching primer and then a few coats of satin black epoxy paint and let the parts dry (each coat) in the oven on the very lowest setting (150 degrees, or a bit less). The paint is then very hard, almost like powder coat.

Let me know if these pictures are enough.
Doug

[mjshira]

opps, sorry man.

that cone filter is cool!