Idle and cruise control probs

[Paul_]

unplug the iac with the motor running. if the engine stalls the iac is good. if the motor does not stall, the iac is shot

[qazvick]

Ok I unplugged the iac and it stalled even quicker than before. I also adjusted the tps and got the voltage to read .97V and nothing changed. So I guess first I'm going to go swap out the iac with a known good one and see what happens.

[gadget73]

Could also be a stuck open EGR valve causing the idle problem. Wouldn't hurt to pull it off and make sure the "button" will push in and the passage isn't totally clogged with carbon buildup.

If you have access to one, I'd really think about using a code scanner to see what it has to say.

[qazvick]

I tried a different IAC which I was told was a known good one. Made no difference in idle or the way the engine ran at cruise speed. I'll check into the EGR valve idea.

Do you know where I can get a code scanner? Or could I just take it to the auto store where they pull codes for you?

[gadget73]

You can buy one online or at most automotive stores. Not sure if places like Autozone can do old style OBD1 diagnostics, but a scanner should only run about $30 or so.

IAC has nothing to do with cruise. You'll need to replace the VSS probably. Check the wiring first though, it might have just gotten damaged somehow and the computer isn't getting a signal from it.

[Paul_]

you really don't even have to get a code scanner. theres two plugs under the hood. one is a single plug and the other has 5 contacts in it. looks like a house roof. iirc, you take a paper clip and put one end in the top right of the house plug and the other end into the single plug. you turn the key to ignition, and the check engine light will flash at you in sequience . you do this also with the motor running. in the cfi/electrical forum theres a sticky with the codes.

figure i'd save you a trip to vato zone

[qazvick]

That sounds like the same exact way I pulled codes on my RX-7. I guess I'll look for those codes and see what happens? Where under the hood are these plugs?

[Paul_]

usually on the drivers side on the fenderwell.

my jeep was even easier. turn the key to igntion 3 times and the cel starts flashing at you. nothing to fuck with under the hood

[Paul_]

http://www.grandmarq.net/forum/viewtopic.php?t=85

heres the thread wit the codes. my bad, it was in 5.0/5.8 lol

[gadget73]

Mine lay on the fenderwell near the brake booster.

I forget about the wire/CE trick because my car doesn't have a CE light. There is supposed to be a way to wire a light onto the plug and read them that way, but I've never bothered.

[qazvick]

OK I'm not sure if these are it. They match the description of the plugs, but they're weren't near the brake booster. They were right behind the coolant overflow tank. Here's a pic tell me if these are those plugs. I DID put a jumper wire from the one plug to the top right slot in the other plug. Is this the correct way to do it? I did it that way and check engine light just stayed on solid.

Also I checked VSS (I'm assuming it's the plug on top of the speedo cable) and it looked all clean inside, I put the plug back in with some added pressure to make sure it's got a connection. No difference.

I'm going to go to AZ and see if they can pull the codes.

[Paul_]

yup, those be the ones. the paperclip should go in the top right contact point, while the other end goes right into the single plug

[qazvick]

And the car has to be ON and running? Or just the key in the ON position?

[qazvick]

Well that sucks... I went to advance auto AND autozone and both said they don't do OBD1. I did the code checking my self again to double check. With the engine off but the key in the ON position, the CE light stays on solid. With the engine running, the CE light never comes on.

[Paul_]

all depends on who you talk at vato zone. call them and inform them that if they don't check your codes, you'll be taking your business(and with an old box theres usually alot of business ) and you'll go to the competition. they're full of shit when they say they don't do odb1. obd2 is merely more convenient for them since the connector is in the same spot on every car usually.

as to the cel, mine was solid for about 1/2 a minute, probably less and then it started flashing at me. with the engine running it did the same thing. try wiggling the paper clip around. i did run into that problem. the paper clip was actually not in far enough,lol