MAF conversion question

[Abbadon]

Thanks to every one that replied to my problem yesterday. I did a MAF conversion yesterday afternoon and it fixed my 3500 rpm idle. I have a question about the vss though. I added the vss and ran the wires to the ecm, but my speedo cable doesn't work with it and I went to napa and looked at one for a 1990 and it was the same. Does anyone know if it affects the vss to not have a speedo cable plugged to it, and what cable I would need to find?

Thanks

 

[Mustang5L5]

You'd need a speedo cable for a mustang with cruise control. The cable for cars without cruise, looks different, but after 1988, all mustangs had a VSS so they should have the cruise control cable. The end just has the square cable sticking out and looks like a small nipple

VSS sensor will leak ATF without the cable in place

 

[f8tlfiveo]

I just replaced my vss.16.00 at Autozone.

 

[stykthyn]

I never changed my vss to a cruise vss when I did my swap, is this something that has to be done?

 

[f8tlfiveo]

It's the same thing. Nothing different. Vss was put on for cruise control up to 89 I think, then all cars came with it because of the mass air in 89

 

[Mustang5L5]

Correct

86-88 cars without cruise control didn't come with them. 86-88 cars did come with them.

in 1989, ford used the vss and part of idle strategy for the mass air cars, so Ford put the vss on every car.

so during the MAF conversion, you must add the vss if not present and wire it into the EEC. On 86-87 cars, the plug is not present, so you must run 2 wire from EEC to VSS. On 1988 cars, the plug is present and secured to the x-member. simply plug it into the VSS and then tap into the wiring in the kick panel to the EEC.

Not tapping the VSS in during a MAF conversion can result in hunting idle or stalling when you press clutch in when coming to a stop.

 

[stykthyn]

That would explain a lot. I used a harness from an 89 car so I didn't re pin anything. I will have to look at that.

 

[Abbadon]

Stupid question but even an '87 5-speed car needs a vss correct?
Thanks

 

[Mustang5L5]

If it has either cruise or a mass air conversion....yes

 

[jrichker]

Note: All 89-93 cars have a VSS sensor even if they do not have cruse control. The 87-88 only have a VSS sensor if the have cruse control.

Speedo cable housing assembly without cruse control:
View attachment 194402

The VSS equipped cars have a speedo cable with a different fitting on the transmission end of the cable. It is the fitting on the LH side of the following picture.

Speedo cable housing assembly with cruse control
View attachment 194403