Fox 89 Mustang Convertable Lx 5.0 Conversion Appraisal

noreaster

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Nov 7, 2014
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Good evening fellas. Recently I had a Maxima up for trade on Craig's List for a motorcycle and hadn't got any hits for a month or so. Roughly a month later a guy wanted to trade me his Mustang for my Maxima. It was his son's first year driving in the winter up here in New England so they wanted something good in the snow with airbags etc for him.

I come here looking for some help pinning down a good dollar amount/trade value to list the car with. Below I'll list everything I know about the car and post some pictures.

  • Complete conversion to 88 GT5.0 HO drive-train from 4 cylinder.
  • 8.8 gearing.
  • All new springs and front struts.
  • New brakes all around inc. new E-brake.
  • New gas tank + lines.
  • New High ratio steering rack.
  • Heady duty radiator.
  • Rear seat in good condition.
  • Front seat newly reupholstered with Black leather.
  • Carpet in good condition.
  • Dash is from 88 GT.
  • Ford racing 140mph cluster.
  • JVC KD-S38 Stereo.
  • Original exhaust from the 88GT back to the mufflers which are new and it's also new from there back.
  • 1" Drop all around
  • New rear tires, fronts are in good condition.
  • Strut towers in excellent condition.
  • Includes cold air intake, not currently installed.
  • Grant steering wheel
  • Current Massachusetts inspection.
  • Previous owner stated 90,000 on the chassis which lines up with the title, 60k drive-train.
  • Clean title
 

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Dollar amounts on 5.0 conversions are tough to nail down. Some people believe in only owning original 5.0 cars, so the conversion will stick with that car forever.

With that said, that car looks better than many of the real v8 cars we see in posts containing cars they are considering.

The one positive a 4cyl car has over a v8 is that usually they don't have the crap beat out of them.

Only things i can see that don't look right is that stripe on the hood and it has a gt exhaust instead of an lx, the real lx exhaust would seriously improve the look of it.

This is a guess, but i'm going to say $3500 or so.
 
Dollar amounts on 5.0 conversions are tough to nail down. Some people believe in only owning original 5.0 cars, so the conversion will stick with that car forever.

With that said, that car looks better than many of the real v8 cars we see in posts containing cars they are considering.

The one positive a 4cyl car has over a v8 is that usually they don't have the crap beat out of them.

Only things i can see that don't look right is that stripe on the hood and it has a gt exhaust instead of an lx, the real lx exhaust would seriously improve the look of it.

This is a guess, but i'm going to say $3500 or so.

Thanks for the guesstimate. Is the LX exhaust more of a straight shot out the rear as opposed to down and out?


Very clean, but it's a speed density efi instead of mass air. What's your mechanical aptitude?
Advanced. Not pro, but advanced. There isn't much I would be afraid to take on. I usually sit down and read up thoroughly on any given project to make sure I understand it completely before I start spinning the wrench.
 
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Whats up where the front bumper / nose meets the fender?, could be minor but could be wrecked and theres more to see... what the condition of the Maxima? I love my 89 vert!
 
Thanks for the guesstimate. Is the LX exhaust more of a straight shot out the rear as opposed to down and out?



Advanced. Not pro, but advanced. There isn't much I would be afraid to take on. I usually sit down and read up thoroughly on any given project to make sure I understand it completely before I start spinning the wrench.

The lx exhaust is straight polished tubes, completes the look. It will bolt in, kit's range from $250-$500. It's probably my favorite thing about an lx. Just look up some lx 5.0 pictures you will see.
Since you are handy i wouldn't worry too much about the car, but as hoopty said you if you plan on modding the car you will want to convert it to mass air.
 
Thanks for the input fellas. About the front fender, in person it just looks like the hood is slightly out of adjustment on that side. I'll have to see if it can adjust up or down at all.

2000xp8, I know the style your talking about I've seen a few before and they definitely look good.

Any chance someone has a breakdown of the bulbs for the Ford motorsports 140MPH cluster? Mine has no back lighting and it doesn't look like there was ever a CEL in it. Should I even put one in?

DSCF0001.JPG DSCF0002.JPG

Either way I need to find which sockets are for back lighting at least.
 
Just to further describe...

You can see in the picture that one socket is missing. I believe it is a back-lamp bulb judging by inspecting the front side under the sunlight. Could one back-light socket missing cause all the rest to not fire? As far as i can tell all the rest look to be in good condition.

The only other thing I can think of is the dimmer switch.
 
body looks straight and clean. Nice interior, top. The only things I would address are it has no fan shroud that impacts cooling and I don't like all the schoche connectors on the wiring by the wiper motor.
 
If the car has the roller dimmer switch on the lower left dash/ knee area, it could be rolled to a very low light level...

This has all the schematics, bookmark it.

http://www.veryuseful.com/mustang/tech/engine/#Diagrams
Thankyou sir.

If suspect dinner switch here.

1988 also had no functional CEL.
HA! I was out there all morning scratching my head on the CEL. Put the cluster back in with a new socket and bulb....not 5 minutes ago I thought to google the issue for the 88 instead of the 89 and came across that same information. Thank you for the heads up. I guess it's at least there now for in case the car ever has the Mass Air conversion.

I'm out there right now trying to set it up to check for codes manually. Can't find the damn test light.

It has two known issues at this point. it runs rough when parked at mid rpms, and the back-lights don't work on the cluster. The I'll have to wait until it's dark to see if the back-lights are working now with the new bulbs and sockets filled which weren't before.

The rough running at low to mid throttle has me sort of stumped. It's acting like a bad MAF, and of course...it doesn't have a MAF. Maybe the o2 sensor(s)? I took a look and I couldn't spot them from above. I'm guessing they are accessible from below.

I'll see about getting a video of what it sounds like at startup. I do think it has a crack in the right side pre-cat, but I can't see that causing it because it's downstream.

body looks straight and clean. Nice interior, top. The only things I would address are it has no fan shroud that impacts cooling and I don't like all the schoche connectors on the wiring by the wiper motor.

Thanks for the input. I forgot to get the shroud off the previous owner...he has it too. Thanks for reminding me.
 
Noted. I may wind up picking one up. Thanks.

I don't know for sure but I think I may have identified the crappy running issue. Possibly from two sources.

First I found that when I unplug the TPS the car runs and revs much better. I tested the TPS and came up with about .90 and 4.60(after adjusting). I need to reset the computer to see if that had any effect overall. If not I'll get to testing the IAC valve and see if it needs cleaning/replaced.

Then there is the seemingly rich running condition. Parked for 5-10 minutes running it leaves soot marks under the tail pipes. Yesterday I discovered the car has no coolant overflow jug. Consequently the radiator was only 80-85% full. I'm guessing that this was keeping the coolant level below the temp sensor and sending unit. Hence why the coolant temp wasn't reading at the gauge(I may have replaced the sending unit for nothing).
 
I wouldn't focus too much on the TPS issue. basically the TPS rezeros each time you start that car and any value 0.6v to 1.1v is correct. So unplugging it after the engine is running makes the car chnge it's fuel/timing curves

Ideally you would check the code and if the car doesn't like the TPS setting, you get a code.

Long story short...running the codes here would be a huge help in troubleshooting
 
I wouldn't focus too much on the TPS issue. basically the TPS rezeros each time you start that car and any value 0.6v to 1.1v is correct. So unplugging it after the engine is running makes the car chnge it's fuel/timing curves

Ideally you would check the code and if the car doesn't like the TPS setting, you get a code.

Long story short...running the codes here would be a huge help in troubleshooting

Thanks for the tips.

I have some preliminary codes here to work with. Right now the car has the battery unplugged to be tested again here shortly.

This is what I got KOEO:
  • 22 - MAP sensor out of specified range(This had a Vacuum leak which I just repaired on the tube)
  • 22 -
  • 1
  • 22
  • 63 - Throttle Position Sensor or circuit
  • 22
  • 63
It doesn't look like 1 is even a code. So I'm guessing that 1 is actually a code 122 combind with the next code down.(Throttle Position (TP) Sensor circuit below minimum voltage)

There is a chance the TPS codes are related to me running the car with it unplugged I'm guessing.

KOER:

  • 98 -
  • 22 -
  • 98 -
  • 22 -
When it was finished the engine stumbled for a brief second and then I got a steady light on the test light that just stayed on for the rest of the time. a quick WOT didn't seem to have any affect at all on the car as far as the automated self test go's.

Heading out now to go run the tests again.
 
The hesitation at mid throttle is still there when revving slowly up the RPMs, though it does seem to be getting better. Below are the codes I have now. On KOER, it still runs through the codes then gives a small hesitation before going back to regular idle and giving a solid non-stop light on the test light.

Still getting a 1 in the middle of KOEO. I don't know what's up with that. It's definitely a 1, I did it two more times to be certain.

KOEO:
  • 22
  • 22
  • 1
  • 22
  • 22
KOER:
  • 98
  • 22
  • 98
  • 22

I'm looking now for a procedure to test the MAP sensor and I'll also double check for anymore vacuum leaks on it. I'm also curious if anyone has some knowledge on the KOER test ending with a solid light on the test light and never going away and never appearing to run the self test.
 
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