87 5.0 coupe with issues

873Stang

New Member
Jun 19, 2006
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:shrug: sooooo lol, well i have a 1987 stang 5.0 ho 5speed ex chp car.

and so first issue is my blinkers don't work, they work when they want to which is hardly what could cause this?

also my heater is hooked up and i dont get hot air im thinking heater control valve??

my check engine light comes on with key on engine off but key on engine on it doesn't and i had my o2's disconnected and i would think it would of came on? disconnected the iac still didnt come on? its running rich too?

and i was also wondering if any one knew the speaker size
for the coupe?

rear
door
and dash?

all help and ideas are greatly apreciated thx
 
If the blinkers started going haywire after doing the heatercore (I'm not sure if you did it recently), get with Sgarlic. He chased an issue like that and found one wire that had been disturbed during the heatercore R/R that was the culprit, IIRC.

Good luck.
 
FWIW, I have an 87 Gt and I was losing about a quart of oil every 2-3 weeks. Turns out when I replaced the intake, the gasket in the middle on the backside of the lower had almost completely fallen inward and was losing it all back there. Kind hard to see with everything assembled but I noted a bunch of grime all over the top of the bellhousing. I'm glad I was upgrading the intake cuz it would have been aweful depressing to go to all the work of pulling it to fix that stupid leak and still wind up with my ****ty old intake when it all was done.

No heat issue maybe the damper door that allows heat to pass from the core into the hvac system. Maybe a bad acuator or disconnected vac. line. If the heater core is in the coolant circuit, there is no valve so thats about all it could be unless its all stopped up with crud. If the engine is getting hot, check the two hoses in and out of the core. If they are both hot then you got flow. If one is hot and one isnt, then its not flowing...
 
6X8's and 5X7's for the rear speakers, 5 1/4 in the doors and 3.5 in the dash.

Blinkers could be in the multifunction switch as mentioned. They also funnel thru the hazard switch up by the gauges above the rear defroster switch. The wires like to pull out of the harness so if anyone had the dash housing off and pulled too hard on the plugs taking them apart, that could be what is up there....
 
FWIW, I have an 87 Gt and I was losing about a quart of oil every 2-3 weeks. Turns out when I replaced the intake, the gasket in the middle on the backside of the lower had almost completely fallen inward and was losing it all back there. Kind hard to see with everything assembled but I noted a bunch of grime all over the top of the bellhousing. I'm glad I was upgrading the intake cuz it would have been aweful depressing to go to all the work of pulling it to fix that stupid leak and still wind up with my ****ty old intake when it all was done.

No heat issue maybe the damper door that allows heat to pass from the core into the hvac system. Maybe a bad acuator or disconnected vac. line. If the heater core is in the coolant circuit, there is no valve so thats about all it could be unless its all stopped up with crud. If the engine is getting hot, check the two hoses in and out of the core. If they are both hot then you got flow. If one is hot and one isnt, then its not flowing...


dude i love you man! lol you were right about the oil! and im 99.9% sure your right about the switch! you rock! the heater im still trying to figure out! both hoses are hot and when its on the a/c compressor will cycle it turns on the off then on and so forth.
 
As far as your heater, it's likely the HVAC blend door not opening. Either you've got a vacuum line going to it that's split, cracked, disconnected, or otherwise leaking. With the car running, crawl around the passenger foot area under the dash and listen carefully for a hissing sound, and see if you can trace it to its source. If not there, do the same under the hood and listen close for a hissing. Only other things I can think it would be is a bad vacuum actuator (but those hardly ever just fail outright, really) or the HVAC controls are broken or otherwise unhooked somehow (maybe if someone was installing/removing a stereo and got sloppy about it, might've damaged something).
 
Try this for your heater control problems.

Diagram courtesy of Tmoss & Stang&2birds
Mustang_AC_heat_vacuum_controls.gif


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
 

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  • Mustang_AC_heat_vacuum_controls.gif
    Mustang_AC_heat_vacuum_controls.gif
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Glad it helped out some. As far as the compressor cycling on and off while you control is set for heat, the compressor should only run when in mix and defrost....I think. I know it runs in defrost but not sure about mix. I know its not supposed to run in heat tho. Regardless, you should still be able to get hot air no matter where you have the controls set. It sounds like the damper isnt opening for some reason. That is a very good diagram for the vacuum routing as I just learned something from it myself. According to it, there is no actuator for the heater core bypass door. Its cable driven and not opened or closed by vacuum. Damn, thats good to know. I havent had mine apart yet but will soon cuz my heater core is a leaker and coming out soon. That makes things easier for you then. Just track down the cable running to the door and make sure its working. If thats all good and the door is opening and closing, you are having an issue with the core itself.

Guud Luck......:)