Bad Coil?

[gadget73]

you really don't need or want it. It seldom comes on, and when it does it usually will just blink randomly and irk you. The one in the Mark VII was taped over when I got it. I had to find and replace the leaky EGR valve that would trigger it randomly because it pissed me off. Ran absolutely no different.

The idiot light you can wire up by connecting it to the self test output line on the connector. I think all they did was repurpose the old "alarm" lamp to a check engine lamp in late 88.

[pantera77]

Quaterhorse is neat but it'd be a waste on a stock engine. You need to make sure you have an ECM it supports (not any lopo).

https://youtu.be/pgiHVo5-WXY

[BigT]

Cool. What I like about GM computers from the same vintage is that our Snap-On MT2500 scanner allows us to "see" what all the sensors are doing and has tips how to manually test them. Ford and their "Advanced EEC-IV" doesn't. Hooking a scanner up to it is useless other than for finding codes. I can force the thing into some self test where sensors and relays click, idle increases but that doesn't really do anything.. On the GMC it's how I found out the IAC valve is wonky, figured that anyway but the scanner showed me it's pretty far off target.

Speaking of IAC, does anyone know the difference between a Grand Marquis IAC and a Mustang IAC? Other than the 90 degree connector end? Does allow more air for HO setup than the lopo setup?

Mustang GT http://www.oreillyauto.com/site/c/de...ve%21s%21motor

Grand Marquis

http://www.oreillyauto.com/site/c/detail/BWD0/21760/02169.oap?year=1986&make=Mercury&model=Grand%2BMarquis&vi=5011239&ck=Search_idle+air+control+valve%21s%21motor_5011239_1152&keyword=idle+air+control+valve%21s%21motor

[DerekTheGreat]

IAC valve is the same. I have Motorcraft 'stang IAC on my LoPo right now.

Gadget,
You're right but all of the idiot lights are one of the reasons I want a Mark VII.. Plus I can see Check Engine in that pod, if all I gotta do is move a wire to the self test thing I'm all for it. The pods between 88 and 89 are the same. My car was built in September of 87, I'm guessing that is a mid 88 run but is the earliest 88 I've come across and it has a CEL in the pod, in the same space as Ashley's 89 and the other 89 pod I harvested for comparison. The 87 pod and lower is indeed different. I kinda like that cluster style though, looks more elegant or what have you, wonder how good the backlighting is though. Anyway, I wonder if it is already wired and that if making that jumper permanent will make the light come on, as there is a bulb in the CEL socket and my connector has all of the same wires the harvested 89 connector+pod has...

[DerekTheGreat]

Quaterhorse is neat but it'd be a waste on a stock engine. You need to make sure you have an ECM it supports (not any lopo).

https://youtu.be/pgiHVo5-WXY

Ah.

[turbo2256b]

i RAN A Tweecer on Creamy for a while but the fuel system woulnd support the 30# injectors the engine required. Alao the factory computer needed a faster processor as rpm was reaching over 7000 rpm.

[gadget73]

Have to plug the Mustang IAC in before you bolt it up. Otherwise it works exactly the same.

[BigT]

I think it was the IAC. I just put on a new one. I can't drive long because my lights are still screwy, but it didn't hesitate or stall. I'll give it more of a drive tomorrow.

I forgot to say which IAC I went with. I picked the Mustang GT one. For the most part they looked the same, but the GT had a numeral II stamped on the bottom and the Marquis had a numeral I stamped on it. On the parts they happened to have the GT's bores were much smoother than the Marquis' part. It looked like the end of life of the cutting bit used.