INTERSTATE ECM EDI

[Tnerbo1]

So here is what my problem is. I have a 97 Tourer that ran great until I changed the ecm, edi, black box etc, from my stock tourer  to a used interstate one. It now pops on deceleration alot more then before. idle is lower now. And on the low end it kinda chugs along (in a bad way) tell it gets to higher rpm's and speed then it runs fine. All I did is unplug the oem  one and pluged the interstate in. Is the more to it then that? Did I need to unhook the battery to reset something, or resync the carbs and reset the idle speed? I changed to interstate slide springs about a year ago if that needs to be done with it. Thanks for any info.

[Jims99]

I’m not an expert on this subject, and wanting to do it myself. But from what I understand it advances the timing more at lower end, so idle would need adjustment. It will also affect the popping more that sounds to me like a vacuum leak. Do you have stock or aftermarket pipe? Have you desmogged? I’m sure someone with more knowledge will chime in. I’m interested in what the outcome will be.

[Tnerbo1]

yep desmoged about a year ago. new intake o rings, the high temp ones vteck or something like that from red eyes and the rubber boots for the intakes from the carbs about 2 months ago. Addded 6 to 6 cobras  mabey year and half ago changed all the diaphrams- slides  two or three months ago.( thats a whole different story there ). cleaned and reoiled  k n air fillter with there red spray on oil.( month ago) She ran great, took over a 500 miles 2 day ride to the DRU ride no prob at all a month ago. just trying to milk here for a little more juice. Also synced my carbs with the digisync 6 carb version and set idle using it a week or so before the ride.

[Willow]

I am not an expert either but by experimentation I learned that Interstate ICM and Standard/Tourer ICM are not interchangeable.

[98valk]

yep desmoged about a year ago. new intake o rings, the high temp ones vteck or something like that from red eyes and the rubber boots for the intakes from the carbs about 2 months ago. Addded 6 to 6 cobras  mabey year and half ago changed all the diaphrams- slides  two or three months ago.( thats a whole different story there ). cleaned and reoiled  k n air fillter with there red spray on oil.( month ago) She ran great, took over a 500 miles 2 day ride to the DRU ride no prob at all a month ago. just trying to milk here for a little more juice. Also synced my carbs with the digisync 6 carb version and set idle using it a week or so before the ride.

IMHO,
It's not the I/S ignition control module (ICM) causing the problem which is fully compatible with all models. Unless one of the I/S ICM connection pins is corroded/dirty, something to check.
The Std ICM has a very slow advance curve 1500 rpms to 4200 rpms where is flattens out at 21 degrees advanced to 5200 rpms.
The I/S ICM has a faster steeper advance curve at 1500 rpms to 3k rpms where it flattens out at 21 degrees advanced to 5200 rpms.
Both have the same curve from 5200 rpms to redline.

 the pilot jets could be clogged. did it sit for awhile without sta-bil?
or vacuum leak somewhere.
set your idle at 900 rpms.
see checks here for idle circuit. http://www.factorypro.com/tech/tech_tuning_procedures/tuning_carbtune,CV,lower_rpm_engines.html
 check tightness of intake boots. check all idle screws are set the same turns out.
check all the new de-smog connections, could be leaks there esp the vacuum caps on the intake manifolds. I replaced mine with bolts.
6x6 exhaust looses HP dyno runs prove that. using the needle kit which is really rich picks up the lower midrange bottom end torque so people think they didn't lose hp, but have on the top end and lose mpg. sound great though.
k&n lets in a ton of dirt. see test results here
https://www.dieselplace.com/threads/aftermarket-air-intakes-filters-do-they-work.117009/

 OEM filter supports a lot of HP, my last dyno run about 116 HP.

[Willow]

IMHO,
It's not the I/S ignition control module (ICM) causing the problem which is fully compatible with all models. ...

98valk is correct.  I mistakenly remembered an issue that didn't involve the OEM ICM. The Interstate ICM is compatible with the Standard/Tourer ignitions.

[John Schmidt]

Yes, I agree...the I/S ICM is compatible with the other two models. I've been running one for at least 20 yrs. in my '98 Tourer that's going to my son-in-law in Louisiana some time in November.

[3W-lonerider]

Hello John, Willow and Tnerbo.

Before you tear the bike apart.....

This swap-out worked for John as he installed a good module.  It is possible the Interstate unit Mr. Tnerbo1 installed is defective.  After all, these things are only available as used parts.  Reinstalling the Tourer module would tell us that.

another thing to keep in mind is, did someone install a 6 degree trigger wheel. interstate ecm can only handle a 4 degree wheel. if the wheel is stock then it shouldn't be an issue.

[98valk]

Hello John, Willow and Tnerbo.

Before you tear the bike apart.....

This swap-out worked for John as he installed a good module.  It is possible the Interstate unit Mr. Tnerbo1 installed is defective.  After all, these things are only available as used parts.  Reinstalling the Tourer module would tell us that.

another thing to keep in mind is, did someone install a 6 degree trigger wheel. interstate ecm can only handle a 4 degree wheel. if the wheel is stock then it shouldn't be an issue.

actually it's the engine that doesn't like all of that initial advance of a 6 degree TW and I/S ICM. might work with premium fuel.
the engine likes all of that extra advance at cruise rpms for better mpg, and doesn't like it for max rpms at redline.
a 6 degree TW doesn't affect the operation of the I/S ICM.

[Tnerbo1]

Thanks for the input everyone. Have been busy with kids home for fall break so havent got back to it yet. I will pull the icm  and put the old tourer one back in to see if it fixes the problems I am having. I am guess it will. Then check the Interstate connecters for corrosion or bad connection, then reinstall it and check again how it runs. Turn the idle up to the proper idle speed then try higher grade gas just to mark it off the list as a mabey fix. What I still have not heard anyone say is if you have to resync the carbs with a swap of the icm? I had synced it not to long ago so would not thanks so but not sure? I am pretty sure it has the stock Triger wheel in it. The last owner was very meticulous about documenting everything he did or changed to the bike. And he always took it to the shop for any maintence needing done. He  said he was not very mechanical. So I would say it is oem. I also have a set of cobra jets coming but they will have to wait till I get rid of this bug before I add a new one to the mix. Thanks all for the info and thoughts and will take anymore input on the subject that may be useful.

[John Schmidt]

I need to add...I also have a 4 degree TW installed with the I/S ECM plus I/S carb springs. All have been in place close to 20 yrs. and given good trouble free service. Open highway mpg running right at 70 usually got me mpg of 34-38, depending on load and topography.

[Tnerbo1]

So today I took it off and cleaned both icm,s and the plug with small brushes and electra cleaner, then blowed out with compressor air. Then installed the oem tourer icm and took her out for a spin. She worked great just as before I changed her. Rode till I had her up to temp and  then changed it out for the Interstate icm. She started right up and sounded good and revved up good. Turned the idle up just a bit and went out for a cruise. She took off great, I can tell a difference in the low end take off grunt and pulls good mid range also. I think the rpms for cruising speed might be a little lower now which would be great. Stopped and started it multi time to make sure it wasn't a fluke. She runs great now for the 15 miles or so that I just put on it. as long as it stays this way I would say its a success. Will try cold starting her next to see how that goes. I guess it was a dirty connection. Thanks for all the input everyone, VRCC is a awesome group. will work on my cobra  adjustable needles next then mabey a 4 degree TW as John Schmidt said. Thanks.