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Discussion Starter #1
I recently purchased a 87 Lx 5.0. It seems to have had a rough life previously :)

The car idles at about 1200 RPMS. This seems high to me. Opinions?

The 1st problem I need help with is "just off idle- for a split second the engine just dies when the accelerator is pressed. Afterward the engine will pick up and run fine." If I press the accelerator very very slowly this does not happen, but it makes the car no fun to drive.

2nd problem is the previous owner did some ":mad:repairs:mad:" I want to undo and fix correctly. Any help is appreciated. the questons are in the text in the pictures.





I have read the forum using searches all day and have picked up some great data. There seems to be a great bunch of guys willing to help on this forum
 

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well in your 1st picture there, there should be a spout connector plugged in (about a half inch plug) I can't tell from the pic if it is in or not..if it is missing (you should be able to just pull the plug out the end) then your motor will run like POOP! go to ford and get one before you drive it again..better yet, it looks like they are spliced together, not good..just cut that off just before where it's spliced and go to a junkyard and find one that isn't rigged up, then connect the wires..also make sure the spout conn. is in it!

As for the masking paper plug, get it off now..that could catch fire..it goes to your exhaust, and gets real hot..I would get some other cap from a hardware store/auto store..at least plug it with JB-weld or something for now..


I also noticed your IAB is upside down..just take the two bolts out and flip it..I bet that's making your idle/just off idle run like poop also..your IAB is the thing just under the black hose in pic #2..its about 8 inches long, and has that red and yellow wire plugged into it..see the bolt directley under where that bolt that someone used for a cap? thats one of the bolts that holds the IAB on then there is another bolt just under that one..the thing should come off and turn it around so the wire's are on the down and left side of the pic, instead of upper right side..

I dont know if this makes any sence, maybe someone else can exlpain better, good luck
 

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Discussion Starter #3
Thanks Natural. I appreciate your response. I take it there is no need to reconnect the part with the masking tape? Just put a better plug on it?

The "spout connector" is empty and was shorted on purpose by what I can tell. I will fix that next.

I have only driven the car a few times since the purchase. I have already replaced all the brake pads/shoes/drums and put new tires on the car. I thought it would be safe but now I have to look to more fire hazards cased by the old owner :rolleyes:
 

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hey no prob..be sure to turn the IAB (Idle air bypass) around..it's backwards upside down whatever..it's just on wrong! and I think it would cause some serious idle/low rpm problems.. check out this pic of my motor, and you should be able to tell what I'm talking about:
 

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dude look like you have a long road ahead of you!!
I got mine in about the same condition and now it looks like naturals with the same intake!! I can proball help with almost anything just drop me a line!!!

DG
 

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Discussion Starter #6
More info

I rotated the IAB thingy as suggested. That seemed to help a little. Then based on the info from this forum I checked my TPS. It measures +5volts all the time on the green wire. I am going to get another one today for replacement. Has anyone ever seen a TPS show that failure mode before?

Thanks
 

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The line that is capped on your throttle body, above the IAB, should have a hose running to the oil filler neck. Do you have aftermarket valve covers? What kind of mods have been done?

Oh yeah, does the car have cats?
 

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To check you TPS, + to the green wire and - to somewhere on the engine. It should read between .90-.95, can't remember if you have the engine off or not though.
 

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If you take 2 pins and pierce the green wire on the TPS (+) and the black wire on the TPS (-) then clip the voltmeter to these you should get around .9 vdc. If you don't then you have to loosen up the 2 screw (slightly) on the top of the TPS and rotate it around to try to get to that setting. This is done with key on ,engine off. If you can get it close but run into problems then you'll have to take and make the holes slightly larger where the screws hold it down to get it there. If you always get +5vdc then there is definitely a problem.

Hope that helps with your TPS settings


Bill
 

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Discussion Starter #11
More and More info

1. It does have aftermarket valve covers. Both Oil fill hole are plugged with little rubber plugs. That can't be good.

2. No cats that I can find :rolleyes:

3. TPS is definitely @ +5 volts. I have the new one now and will install it later today.

4. I do not know what mods are in the engine. The car was bought at auction for me by a wholesaler friend of mine on the cheap. It's eventual end game is a factory five cobra replica in about 2006. Until then I am going to enjoy the Mustang. I sold my 1968(302) Mustang about 6 years ago after driving it everyday for 11 years. I did not realize how much I missed the V8 until I drove this one home.


Again thanks for all the help.
 

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Re: More and More info

Bobasaurus said:
3. TPS is definitely @ +5 volts. I have the new one now and will install it later today.
Another thing to check is that the voltage on the black wire (ground) is less that .1vdc. There's a ground strap that goes on one of the back intake bolts that people like to forget about. This affects the TPS and EVP for sure and I think the ECT also. You usually find that the return signal volatge will be close to the reference signal voltage in this situation.
 

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Discussion Starter #13
Wow!

TPS set at 0.96v seems to have fixed it. Idles great @ 900 RPM. I also cleaned what someone on here called the 10 connector. I don't know if it helped, but it did not hurt.


I appreciate all the help. I am formulating question for another post later tonight. This place is a gold mine.
 

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All right! Glad you got it fixed, also good that you took pictures so that others could see that the IAB was upside down. Whoever had that car before you knew as much about Mustang's as I do about Brain surgery!!

Hope your next problem can be resolved as fast as this one was . :D


Bill
 
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