Idle surge 86GT

[bigmd]

Ok guys i have a stock 86 GT i bought a few months ago. It’s been converted to MAF but I’m not sure why. It looks like it was dealer installed judging by the A9L. It also has a Motorsport vac gauge . The guy I bought from bought it that way. He had the IAC unplugged because it idled better . Said it prob just needs a new one. I’m on the 2nd IAC and today it surged to 2500 at idle while driving. After doing some research i read about the diode on the 86s. Should I be running an 87-93 IAC because of the MAF conversion. Or at least be bypassing the diode? Thanks in advance .

[306gt]

Had that problem on my sons 86 after I converted it to mass air. The diode was in the harness and also had one in the replacment iac valve. Swapped back on his original iac valve with no diode and it cured the idle surge.

[bigmd]

Thanks . I have to check the IAC . The car is currently at body shop.

[bigmd]

Ok so I have been researching this and it seems that All remanufactured IAC valves come with the diode internal. Most articles i have read said this is indicated by a “D” on the valve. I checked both new valves I have and see no D anywhere . However when I check the part number it states 87-93 . So I’m a little confused to say the least. Being that my stock harness plug is broke and has no tab to lock it in I may buy the 87-93 plug because it’s the only one I could find . I’ll splice it in and delete the external resistor to see if that helps .

[bigmd]

Now I stand corrected , after further investigation I found a “1D” on my remanufactured unit that has a Ford part number. The one on car now Doesn’t have indicator on it but when I run part number it says 87-93 and the picture shows a “D” on it . I’m going to assume the one on car now is internal as well.

[306gt]

Best bet for you is to eliminate the diode in your harness and use the 87-93 IAC. That way in the future it will never be an issue. The 86 IAC seems to be a 1 year deal. The aftermarket will never make that. But they will make the 87-93 unit because it is more popular.

[bigmd]

306 GT thanks . That’s my plan . Also, being That the clip broke off the factory plug, I bought a new aftermarket plug that was listed for 87-93. I just received it and it fits great . However both wires are white. Any idea how I solder these?

[Tigger]

I am not sure I follow 100% but I would think you should be able to unclip the pins from the original connector housing and plug them into the new connector housing? Then you do not need to solder anything.

[bigmd]

I’d have to look at factory connector . This connector fits but is not an exact factory piece. I guess i can just hook them up before i solder and see if it works .

[bigmd]

I’d have to look at factory connector . This connector fits but is not an exact factory piece. I guess i can just hook them up before i solder and see if it works .