Ford Mustang Forums banner
161 - 180 of 214 Posts

·
Registered
Joined
·
83 Posts
Discussion Starter · #161 ·
Make sure you don’t have any broken or severed wires and make sure all wires are tight in the plastic connectors. Every time I’ve disconnected a harness plug in the past 5 years some of the wires literally fall out the plastic connectors. I’ve had to remedy this the best I can and make it a habit to thoroughly clean every single pin, every time I unplug a harness connector. I’ve pretty much covered them all by now and mine starts and runs like new. It has taken a long time, years really and my car has been down weeks and even months at a time.
Patience is key if you are going to be your cars technician, which can be hard when you just want to enjoy the car. It can be maddening!
Seems like your trying to devour all this very quickly almost like taking a mini session college course which has its obvious pros and cons.
Sometimes a sabbatical can help as well. There have been times I’ve brought it to the shop, other times I have grinded it out, other times taken extended breaks and played more golf haha.
I’ve learned you are pretty much forced to learn if you want to own one of these cars cause they are just simply getting old.

Hang in there man!
I appreciate it. I checked all the wires, connectors, vacuum lines, basically everything visible and cannot find anything that looks out of place. The plastic connectors are brittle for sure so I've been extremely careful not to break anything there.

It's a tough issue for sure, and I'm doing my best. I appreciate everyone who's taken time to try to help me diagnose this. Seems like no one really has any solid theories on what might cause this issue. I can't seem to find anything in old posts on any forums with this exact issue, so it's definitely a head scratcher
 

·
Registered
Joined
·
83 Posts
Discussion Starter · #162 ·
Shop will charge $120 and give a wrong diagnosis 50% of the time though. I've complained also, but let the person learn. Personally, I'd have turned the idle screw enough to allow it to idle and then diagnose from there, but I am a person that loses my mind when an engine won't stay running!
I might try that. My only guess is that if the set screw needed adjustment, wouldn't it just idle really low and barely stay alive? It seems to idle fine until it dies.
 

·
Registered
Joined
·
83 Posts
Discussion Starter · #163 ·
the very first thing I would do is crawl under the car and make sure both hegos are getting a good 12 volts. Then I would check the ground on the back of the engine (#19). Then check the Salt and Pepper connectors (#14 and #15).



View attachment 1075221
I'm going to look into this. Not sure how to test for 12 volts but I'll see if I can find anything
 

·
Registered
87 Gt 400hp Holley Terminator, Systemax 2, TW 170cc, N41, 6psi Powerdyne, 3:73
Joined
·
391 Posts
Oh wow you got me, I posted on a different forum to try to get as much advice as possible. Lmao asking questions is wasting people's time? Feel free to move on if you have nothing to add, boss man. Sounds like you don't have any theories on what it is either.
You’re right because diagnosing a car that is not in front of me in impossible. If I was as green as you and trying to diag my car for over a week with no results I wouldn’t hesitate to get a real diagnostic. Nothing wrong with being over we have all been there. My point is why waste your money on tools you don’t have and parts that you don’t need? Your time and aggregation is not worth $100? Mine sure. No different then when I paid a mustang shop to do my ring and pinion and subframe connectors. Why would I buy a welder or put a ring and pinion in on my back? Can it be done hell yes but not in a day like it was when dropped it off. I applaud your eagerness to learn but if you were really with out a car like you previously stated I’m sure you also wasted a lot of money on Uber’s. I’m just trying to read through the lines of what is the truth and what is bullshit from your posts is all.
 

·
Registered
'87 20th Anniversary Cougar7.0 427W
Joined
·
5,405 Posts
No different then when I paid a mustang shop to do my ring and pinion and subframe connectors.
Disagree. Read WAY too many accounts of noisy gears after a shop did 'em. I did my own and spent the extra time to get everything shimmed exactly right. Quiet as a mouse. Once you buy a welder, suddenly the mounts on your lawn tractor deck will break and you'll be thanking your lucky stars that you "have a welder and know how to use it". Granted, I have an auto pit that makes doing these jobs easier, though I wish I had a lift.
 

·
Registered
Joined
·
83 Posts
Discussion Starter · #166 · (Edited)
You’re right because diagnosing a car that is not in front of me in impossible. If I was as green as you and trying to diag my car for over a week with no results I wouldn’t hesitate to get a real diagnostic. Nothing wrong with being over we have all been there. My point is why waste your money on tools you don’t have and parts that you don’t need? Your time and aggregation is not worth $100? Mine sure. No different then when I paid a mustang shop to do my ring and pinion and subframe connectors. Why would I buy a welder or put a ring and pinion in on my back? Can it be done hell yes but not in a day like it was when dropped it off. I applaud your eagerness to learn but if you were really with out a car like you previously stated I’m sure you also wasted a lot of money on Uber’s. I’m just trying to read through the lines of what is the truth and what is bullshit from your posts is all.
You've raised a few questions so here goes.

My point is why waste your money on tools you don’t have and parts that you don’t need?
I plan on keeping this car for a long time, so buying tools, manuals, etc. for this car are an investment and it's stuff I should have anyway for basic diagnostics for stuff that will inevitably go wrong in the future. I've bought a code reader and I'm ordering a voltmeter and wiring diagrams. I already have a Haynes manual. As far as parts, all I've bought is an IAC and I have no plans to buy any other parts until I have a better idea of what's going on.

I'm in touch with two shops and I have a call in to a third shop that I've gone to before. The two shops I've spoken to (BBR and Steeda) are both booked up until at least August 12th, but the people I'm talking to are looking into it to see if they can offer any advice beforehand. I did make an appointment for the 12th. And, like I mentioned, I also had my mechanic friend, who has been a Ford tech for a long time and has built several of these cars, come to try and do a basic diagnosis or at least to try to find any glaring issues.

I applaud your eagerness to learn but if you were really with out a car like you previously stated I’m sure you also wasted a lot of money on Uber’s. I’m just trying to read through the lines of what is the truth and what is bullshit from your posts is all.
If you want to know the full history of me not having a car, not like I owe you an explanation as it's not relevant but here you go since you've accused me of being full of ****:

The foxbody started having this issue when I was driving home from the gym in the middle of May. I parked the car and did not drive it after that (it's not my "true" daily, but I drive it mostly every day to the gym and just locally). On May 24th, I broke my foot, and could not drive for approximately 6 weeks, and couldn't do much to try to work on the car as I was non-weightbearing for 4 of those weeks which made things difficult.

On Friday, July 16th, my Corvette's alternator failed, so I parked that car and made plans to have it repaired by a dealership as I have an aftermarket warranty on that car. Since then, I have been working from home (I can work remotely), and have been getting grocery deliveries via Instacart. Otherwise, my girlfriend has helped me out getting places when I really need to get somewhere. It's been a huge pain in the ass not having a car, but that's what I've been doing. I've had to postpone a couple meetings with clients due to not having an operable vehicle, and I have also had to postpone physical therapy appointments for my foot due to not having a car.. The dealership anticipates that the Corvette will be done today or tomorrow. There is only one guy there that is allowed to work on "specialty" cars like mine, and he has been backlogged by several very big projects.

Since the Corvette was out of commission, I wanted to see if I could get the fox body drivable so I could at least go to the office and go to the gym and stuff like that. I also don't like not having a car in case I have some kind of emergency, for obvious reasons.

Hope that clears it up for you. I'm not sure why it's relevant to anything, or why I owe you an explanation, or what you're hoping to accomplish by accusing me of posting "bullshit" in my posts. Do I really need to have an explanation for why I want to get my car fixed?
 

·
Registered
Joined
·
25,617 Posts
. Personally, I'd have turned the idle screw enough to allow it to idle and then diagnose from there, but I am a person that loses my mind when an engine won't stay running!

wasn’t that done to get engine running codes?
 

·
Registered
Joined
·
83 Posts
Discussion Starter · #168 ·
wasn’t that done to get engine running codes?
From what we had discussed before, my intention was to try to keep the car running with the foot on the throttle to get the KOER codes (someone said this was a good idea).

But when the code reader started doing its thing, the engine jumped to 1600ish RPM and held there, and the car kept itself running through the entire test, so I didn't need to do that.
 

·
Registered
Joined
·
25,617 Posts
I figured that, and i asked, to point out that the IAC is clearly being controlled by the ECM

Now, you can try to adjust stop as temp fix for diagnostic purposes

mark the stop in its present location, so you can return it to the exact position

turn it clockwise 1/2 a turn at a time, and see the change in idle control

with engine off and batt disconnected, adjust it, and disconnect batt after each adjustment

do it at operating temp,, keep track of adjustment
 

·
Registered
Joined
·
83 Posts
Discussion Starter · #170 ·
I figured that, and i asked, to point out that the IAC is clearly being controlled by the ECM

Now, you can try to adjust stop as temp fix for diagnostic purposes

mark the stop in its present location, so you can return it to the exact position

turn it clockwise 1/2 a turn at a time, and see the change in idle control

with engine off and batt disconnected, adjust it, and disconnect batt after each adjustment

do it at operating temp,, keep track of adjustment
Oohhhh that makes a lot of sense. Alright sounds good, I will give it a try.

Some folks on the other forum have suggested that it may be the TPS that's causing the issue. I'm working on getting a multimeter and I found some videos on how to test that so I'm going to give that a try in the next day or two and report back.
 

·
Registered
Joined
·
25,617 Posts
you can check TPS voltage if you like

unless you got a TPS out of range code, i wouldn’t bother, but its a good exercise
 

·
Registered
Joined
·
2,281 Posts
It would not have taken that long on a carb application. Welcome to the 21st Century...
It would have taken anyone with any efi experience 30 minutes to diagnose this. Dude has 0 experiences and doesn't seem extremely mechanically inclined, carb wouldn't make any difference.
 

·
Registered
'87 20th Anniversary Cougar7.0 427W
Joined
·
5,405 Posts
But it would help to rule out a clogged PCV valve, however unlikely that is. Also, being able to drive the car will allow for you to get a further feel how the engine is running and where (if) you notice issues. It could be helpful in diagnosing the issue. Also, Indy has approved of doing so as a temporary analysis tool in 2 different posts.
 

·
Registered
Joined
·
83 Posts
Discussion Starter · #179 ·
But it would help to rule out a clogged PCV valve, however unlikely that is. Also, being able to drive the car will allow for you to get a further feel how the engine is running and where (if) you notice issues. It could be helpful in diagnosing the issue. Also, Indy has approved of doing so as a temporary analysis tool in 2 different posts.
Turning the screw was something you recommended. Indy approved of it to keep the engine running to run KOER codes, which I was able to do without messing with the throttle stop. The last time I drove the car before parking it (on the way home when it started having this issue) it drove fine with no symptoms aside from dying at idle.
 

·
Registered
'87 20th Anniversary Cougar7.0 427W
Joined
·
5,405 Posts
I think you're being a little too cautious. OK, perhaps almost neurotically too cautious. :p
 
161 - 180 of 214 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top