Code 67 on my 86 vert

[Kenandtj]

Ok guys,
Please help! I pulled my codes today and found a code 67, with that said the reason I pulled them was because the idle was surging. Now I'm reading how this code will cause a surge. History of my car, 86 gt with I think the original tranny and no major mods done...HELP, what am I looking for and how can I make this stop, it's driving me crazy. I also on occasion get a real high idle at start up, it random and revs to like 3k then come right back to the surging, and yup I checked the tps sensor it was within range..thanks in advanced...ken

[FM2NOTCH]

some code info here

http://dfwmustangs.net/forums/showthread.php?t=7908

on my 92 I was having idle problems, I tried almost everything, try turning the idle screw out to lower the rpms and then recheck the tps voltage, may as well clean the IAC also(it's bolted to the throttle body)

[Kenandtj]

I was just doing that, I checked and rechecked it several times, I was reading for hours ( thanks four eyed pride) did it exactly how it was recommended. Got perfect voltage, I also cleaned the hell out of the intake etc etc...frustrating as hell having my pride and joy surging like a kid with asthma. Ken

[FM2NOTCH]

actually there is no perfect voltage, the computer will read the tps and adjust accordingly at every startup, most people shoot for 1 volt or less tho. you are running to lean or too rich, lean- check for vacuum leaks, rich- fuel pressure, forget the names but it may be air inlet temp sensor(on the intake) or water temp sensor (on the water tube)

pull some vacuum on the egr, if it's' working the engine should die, do you have vacuum hooked to the map sensor?(on the firewall)

[Kenandtj]

Sorry I guess I should have said the egr valve is new, and I did recheck it, works fine and hold a vacuum. New tps sensor and new map sensor. I just bought the car a month ago so all this was done by the previous owner. I think he was searching for the same surging problem. It wasn't enough of an issue for me not to buy the car. It's like a woman eventually I'll figure out the problem..lol

[Kenandtj]

Few more tid bits, the smog crap has been removed by the previous owner. I sprayed every inch of every thing looking for vac leaks, I found zippo. It's getting time to put her in storage for the winter so help sooner rather than later would be appreciated, if not it can wait till next year. Again, thanks in advanced...ken

[FM2NOTCH]

I know what you're going thru, I still don't have mine fixed, computer is my next install

[Kenandtj]

Funny, I just found an old computer in the box I got when I bought the car, so I can assume it was changed...I think I might just lose my mind! The good thing is it still run fine, just a bit annoying.

[FM2NOTCH]

Funny, I just found an old computer in the box I got when I bought the car, so I can assume it was changed...I think I might just lose my mind! The good thing is it still run fine, just a bit annoying.

I even pulled my upper intake and actually replaced some leaky vacuum lines, no help tho, mine runs perfect at anything but idle, idle is fair after a month long session but it's a little too low at 500 rpm and I still have a CEL on

[grabbergreen84]

Is there an exhaust leak between the header and H-pipe? Make sure your EEC ground (runs to the negative battery terminal) is making a good connection. I've seen bad battery terminals/cables cause a surge, too.

Check timing and fuel pressure.

A newer computer in an '86 would throw a 67 if the '86s don't have neutral switches.

[Kenandtj]

Brand new exhaust, thanks to the previous owner. I will check the ground and the timing was spot on. Fuel pressure tho hasn't been checked yet. And I'm pretty sure mine has that switch......I just want to thank you for all your help. Ken

[Kenandtj]

This is going to sound like I'm an idiot, but where is the cel light. For some reason mine doesn't have one. I used the test light method to check codes...I might be losing my mind but I pulled the dash panel off and see no CEL indicator.

[moelll]

Your car does not have a CEL (check engine light) they weren't mandated til 1989 (1988 in California).

Sent from my XT897 using Tapatalk

[Kenandtj]

Oh thank god, I was thinking I was stooped. Lol, thanks guys

[qtrracer]

Did you clean the IAC? A sticking one is the typical cause of a surging idle. Lots of YouTube videos on the subject.

[OldManRiver]

http://sbftech.com/index.php/topic,7333.0.html

Something else to look into.

OMR

[Kenandtj]

So guys, the IAC is brandy new, another buy from the previous owner. ( yup he was chasing the same demon) now as far as the neutral switch goes, I've seen that video, but have yet to get it up on a lift to check it. Unfortunant for me time has run out, the old girl is in storage for the winter. This will have to await until spring, DAMN YOU Mother Nature! Thanks to all that gave input, I'll readdress it in the spring. Hope to talk to ya all in the spring! Ken

[Kenandtj]

Hey guys,
Well spring is here and I had the old girl out and about. As posted above I still have the surging idle problem, I also forgot to mention at really random times when I go to start it up the idle goes up to like 2k then falls right back down, but then starts hunting. A quick question, I noticed my temp gauge never ever reaches the mid way point...can a issue with either a too hot or too cold stat cause this? I still have a code 67...... I'm at my wits end and it's only been out of storage for a week... Thanks guys! ken

[mustangxtreme]

Ken, do you have access to a digital thermometer? Check to make sure the car is able to get up to operating temperature. The PO may have put a colder thermostat.

[Kenandtj]

I do have one, an infrared one I can borrow from my service van. What should the temp be at normal op temp? Would that cause all my drama? Thanks for your help. Ken

[Kenandtj]

Tested the temp today got around 190ish. But like I said the gauge reads barely over hot. Do I have a bad gauge and it means nothing?

[mustangxtreme]

190 is fine. You may have a bad sender or a bad ground for your sender. A PO may have used teflon tape to seal the sender so it may not get a good ground.
Is your car manual or automatic?

[Kenandtj]

Manual, so more to add as of this morning. I go out to start it on a cold damp morning and get just the engine cranking and no firing. So I pull the cap off and don't hear the pump running. This has happened in the past, so I go run my errands and come home and veroom, she starts right up. After of course I stopped at auto zone and grabbed a new fuel pump. My problem is I don't want to just throw parts at it, I did chance the fuel filter this morning. I was late for an appointment when it first didn't start but I couldn't check the relay. I guess my only other option is wait until it happens again.... Oh boy is it frustrating, I drove it all day today with out a problem...weird! Ken