I've made the decision to switch to a carb, and last night I took off trhe whole TPI system. I already have an offer on it, ($375 CDN) but my question is this - can I really "throw out the ECM and dance around" like it says in the 'TPI to Carb' swap article in the tech section? Will pulling out the ECM have no other effect on any of the car's electrical system? The car by the way, is an 88 IROC. The guy wants to buy it tonight (with the ECM) so all quick replies are appreciated!

 

Yup, you throw away the TPI theres no need for the computer.

 

Not so fast. Since you have an automatic transmission, I'd hold onto the computer to control the lockup.

 

I don't care too much about converter lockup, especially since the TPI system is worth so much more with the ECM - I'm going to assume that's the only thing and go ahead and sell it I guess...

 

Throw away the computer, and buy one of these from Painless Performance to retain the lock-up function on the converter. Otherwise you will burn up your 3-4 clutch pack:

http://www.painlessperformance.com/fiacc.htm

700R/4 TRANSMISSION TORQUE CONVERTER LOCK-UP KIT
#60109 - Now you can control the lockup converter on your overdrive transmission with your carbureted engine and not have to buy an expensive computer! With our easy to install Lock-Up Kit you don’t need the computer or speed sensor. A vacuum controlled 4th gear pressure switch/lock up solenoid combination controls the lockup. Comes with everything to complete the job including a pan gasket. Fits any 700R4 GM transmission.

 

I drove around for 2 years every day without a lockup switch and my trans never gave me problems ...well, until I installed the new motor and beat the crap out of it

 

No problems here either. I am running a non- lockup converter also though.

 

Me too, going on 6 months now... but I know the fluid is heating up more than it should when on the highway. The cost of the lockup kit will be less than the gas money I save with a lockup converter. Not to mention the peace of mind that I am not killing my tranny.

 

Are you changing over to vacuum/mechanical advance? If not, you'll need the ECM to control your timing.

 

When I bought my car, someone had swapped a Auto Tranny into it, th700r4, and didn't wire the lockup. The guy who I bought the car had it for a year, and he didn't do the swap, which means it was done when he had bought it. I didn't wire up the lockup until about 4 months after I bought it, so it was running without lockup for atleast a year and 4 months, and it has no problems.

Once I did wire the lockup, I didn't really see much of a difference in gas mileage, MAYBE another mile to a gallon, but nothing big at all. I was a little disappointed actually.

Back to the original topic... As long as you have a vacuum advance distributor, and don't mind loosing lockup, or plan to wire lockup with the Painless kit, you don't need the ECM. I personally would like to get rid of all of it sometimes too, I get fed up with TPI. I don't know how smog applies to that though... I'm in California, and everyone knows smog is hard enough to pass as-is stock... imagine when you start changing major things and doing major swaps like that... It can't be an easy thing, if at all legal.

 

The torque converter is basically just a fluid coupler, and you will typically have about a 10% loss through one. It's strange that you guys are noticing such a small loss in economy though, my friends sister had a tcc go bad in her cavalier, and her fuel mileage almost dropped in half on the highway Do you guys stick mostly to the city roads where you don't hold the same higher speeds in 4th for a while?

 

I drive about 40/60, the 60% being Highway/freeway miles. When I'm on the freeway, I am usually sitting steady at 70-75 MPH, in 4th, with the torque converter locked up. I took a long trip that was primarily Freeway driving both before and after I wired up the lockup.

Before I wired lockup, I got 220 Miles to 12 gallons of gas. After I wired up the torque converter I got 235 to 12 gallons of gas, about a mile and a half to a gallon increase. Not that big of a difference.

I get terrible mileage around town tho... dunno why.

I notice when I lockup my Torque Converter my RPMs drop about... 200-250 RPMs while doing the same speed.

I really don't care for the lockup all that much.