Computer 101 please

stock89 · 04-01-2003, 01:20 PM

Fellow enthusiasts,
My car has had a rolling idle problem, actually it sometimes just goes to 2500 and stays there. First I cleaned the IAC, then replaced it (from Ford), the TPS, and TB. Nothing seemed to work for more than about a week or so. Then I realized that it's a complete random problem. If I disconnect the IAC it runs fine.
If I disconnect the battery for an hour, it'll run good for about a week. Then the problem comes back.

So now the dealership says I need a new computer. The problem, they say, is they aren't in the inventory any more. Is that BS?

Will any computer from the junkyard work? Do any of you have a computer sitting on a shelf you don't need anymore?

Thanks,
Rob

jruppert · 04-01-2003, 01:30 PM

Yeah it is pretty stupid. Ford only has to keep parts for so many years. I would think that they would keep the computer though. Being that your mustang is an 89, I dont think your computer is any different from a 90-93. As long as its for a mass air setup. Of course you need an eec-iv for an auto or 5 speed. I would go on ebay and get something from there. Take a look at this one, its from an 89 5-speed. http://cgi.ebay.com/ebaymotors/ws/eB...category=33596

Good luck

stock89 · 04-01-2003, 04:20 PM

Got it, thanks for pulling that link up for me. I called around and OReilly's has one for 118.99, what do you think? Does is sound like the computer? The codes it pulled up were for a clutch sensor and A/C compressor sensor. Neither one of them would cause the idle to go to 2500. So I'm thinking computer.....

Any other opinions?
Rob

Hethj7 · 04-01-2003, 09:51 PM

If you have already pulled codes up, then I would fix whatever is causing the codes before I spent the money on a new computer.

Also, the A/C compressor code may cause some weird idle problems. When the compressor is running, it is loading the engine. At idle, the computer will make adjustments to keep the engine idling high enough since their is a load on the engine caused by the compressor. It may or may not be causing the exact problem you are speaking about, but I would get those codes cleared and fixed before I bought a new computer.

jruppert · 04-01-2003, 11:04 PM

What codes do you get off your computer. I agree with what Hethj7 says. I have a Ford Fuel Injection & Electronic Engine Control book that does refer to A/C causing idle problems under certain situations.

stock89 · 04-02-2003, 01:42 PM

Thanks for your votes, I'm just going to take this one as it comes, sometimes you win and sometimes you don't. This is a "didn't win" situation. I'm just going to take it to Ford and drop it off and let them deal with it to chase it out. I hate to do that, but this problem has been plagueing me for awhile now. I'll post an update next week, it goes in on Monday. Thanks anyway though-
Rob

04-01-2003, 01:20 PM	#1
stock89 Registered Member Join Date: Oct 2001 Location: Mannheim, Germany Posts: 124	Computer 101 please Fellow enthusiasts, My car has had a rolling idle problem, actually it sometimes just goes to 2500 and stays there. First I cleaned the IAC, then replaced it (from Ford), the TPS, and TB. Nothing seemed to work for more than about a week or so. Then I realized that it's a complete random problem. If I disconnect the IAC it runs fine. If I disconnect the battery for an hour, it'll run good for about a week. Then the problem comes back. So now the dealership says I need a new computer. The problem, they say, is they aren't in the inventory any more. Is that BS? Will any computer from the junkyard work? Do any of you have a computer sitting on a shelf you don't need anymore? Thanks, Rob

04-01-2003, 01:30 PM	#2
jruppert Registered Member Join Date: Jul 2001 Location: Reed City Mi Posts: 106	Yeah it is pretty stupid. Ford only has to keep parts for so many years. I would think that they would keep the computer though. Being that your mustang is an 89, I dont think your computer is any different from a 90-93. As long as its for a mass air setup. Of course you need an eec-iv for an auto or 5 speed. I would go on ebay and get something from there. Take a look at this one, its from an 89 5-speed. http://cgi.ebay.com/ebaymotors/ws/eB...category=33596 Good luck __________________ '94 GT, 347 stroker, AFR 185's, Trick Flow stage 2 Cam, Edelbrock upper and lower, 70mm Tbody, 77mm MAF, 24lb injectors, 255 lph pump, underdrive pulleys, 1 5/8 Motorsport Headers, king cobra clutch, tremec tko, 3.73 gears, flowmasters

04-01-2003, 04:20 PM	#3
stock89 Registered Member Join Date: Oct 2001 Location: Mannheim, Germany Posts: 124	Got it, thanks for pulling that link up for me. I called around and OReilly's has one for 118.99, what do you think? Does is sound like the computer? The codes it pulled up were for a clutch sensor and A/C compressor sensor. Neither one of them would cause the idle to go to 2500. So I'm thinking computer..... Any other opinions? Rob __________________ 89 LX 5.0 Notchback, FINALLY NO LONGER STOCK!

04-01-2003, 09:51 PM	#4
Hethj7 Mizzou Tigers Join Date: Apr 1999 Location: weston, MO United States Posts: 1,455	If you have already pulled codes up, then I would fix whatever is causing the codes before I spent the money on a new computer. Also, the A/C compressor code may cause some weird idle problems. When the compressor is running, it is loading the engine. At idle, the computer will make adjustments to keep the engine idling high enough since their is a load on the engine caused by the compressor. It may or may not be causing the exact problem you are speaking about, but I would get those codes cleared and fixed before I bought a new computer. __________________ 2006 Mustang GT 1990 LX GT-40 motor 262 horsepower, 307ft-lbs (sold but forever loved) 1998 Contour SVT Rice Haters Club Member #244

04-01-2003, 11:04 PM	#5
jruppert Registered Member Join Date: Jul 2001 Location: Reed City Mi Posts: 106	What codes do you get off your computer. I agree with what Hethj7 says. I have a Ford Fuel Injection & Electronic Engine Control book that does refer to A/C causing idle problems under certain situations. __________________ '94 GT, 347 stroker, AFR 185's, Trick Flow stage 2 Cam, Edelbrock upper and lower, 70mm Tbody, 77mm MAF, 24lb injectors, 255 lph pump, underdrive pulleys, 1 5/8 Motorsport Headers, king cobra clutch, tremec tko, 3.73 gears, flowmasters

04-02-2003, 01:42 PM	#6
stock89 Registered Member Join Date: Oct 2001 Location: Mannheim, Germany Posts: 124	Thanks for your votes, I'm just going to take this one as it comes, sometimes you win and sometimes you don't. This is a "didn't win" situation. I'm just going to take it to Ford and drop it off and let them deal with it to chase it out. I hate to do that, but this problem has been plagueing me for awhile now. I'll post an update next week, it goes in on Monday. Thanks anyway though- Rob __________________ 89 LX 5.0 Notchback, FINALLY NO LONGER STOCK!

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