Just Got My First Fox.

Welcome to Stangnet...

Not all of us know how to fix everything, but some of us know how to fix some things
with excellence!

Places to check out here on Stangnet:
http://www.stangnet.com/mustang-forums/threads/technical-thread-how-to-index.808661/ How to do it tips for some of the most common problems and upgrades for 5.0 Fox body Mustangs.
http://www.stangnet.com/mustang-forums/threads/the-official-progress-threads-thread.761371/ the collection of build/progress threads from Stangnet members. You get to find ideas and clues to what works well and what doesn’t.
http://www.stangnet.com/mustang-forums/resources/ Has tech tips for common problems on Mustangs.

If you are in California or some other state with strict emissions laws, part of the deal should be that the owner takes the car and has it emissions tested. If it passes, you buy the car and pay for the emissions test cost, if any. If it does not pass, walk away from the deal. For a mechanically inexperienced owner, emissions related problems can be difficult and expensive to fix. Avoid any car that was originally EFI and has been converted to carb like the plague. That's often a clue to the fact the previous owner had problems and the resulting hack job has MORE problems.

Keep in mind that states with strict emissions laws may make the go faster goals more difficult to reach. Some parts are OK to replace with aftermarket parts and others aren't. Check carefully before you get out your wallet and buy something you can't use in the area where you live.


If you want to do the fix up & power up thing, make sure that you have some other form of reliable daily driver. That way the stang can sit while your wallet and hands take a rest from the last project that didn't quite get finished on that 3 day weekend. Things always cost more and take longer the first time you do them. Having some other working vehicle makes life easier since it isn't the big crush to get it running for the Monday morning drive to work or class.

Plan on spending some money on tools it you don't already have them. The stang has both metric and American fasteners, so you really need two sets of wrenches. A timing light, digital voltmeter, vacuum gauge, compression tester, fuel pressure test gauge and fuel line coupler tools are some of the test & tuning tools you'll need. Visit the pawn shops and sometimes you can find a deal on tools & test equipment if you stick to well known name brands.

A sheltered work area is almost a must, someplace that you can leave the car in pieces without upsetting anyone. Some guys here have changed a transmission in the parking lot of their apartment in a rainstorm, but they will tell you it wasn't fun. Depending on where you live, a warm dry garage is a nice place to do the winter projects that stangs tend to become.

EFI (Electronic Fuel Injection) Computer - every stang after 85 has or had one: don't let it intimidate you. The computer based EFI systems are not hard to fix and most of the time they tell you what's wrong with the engine. Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst: ISBN 0-8376-0301-3.

It's about $35-$45 from Borders.com see http://www.amazon.com/ . Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search

Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.

For lots of great ideas and tech notes on upgrades and repairs, be sure to check
out http://forums.stangnet.com/showthread.php?t=643651 “Useful Technical Thread Index” sticky at the top of the 5.0 Tech forum.

Things that break often:
T5 5 speed manual transmission (syncros go bad, mostly 3rd gear)
TFI Module (Thin Film Ignition module - mounts on the distributor)
Electric door locks (see the link in my sig for a cheap & easy fix)
O2 sensors(oxygen sensors) They are good for about 60,000 miles and start to go down hill after that.
TPS Sensor (Throttle Position Sensor) causes flaky problems with idle & acceleration.
Fog lights They overheat the wiring and cause the headlights to flicker. The fix is cheap and simple if you can do electrical stuff.
Harmonic Balancer – they separate between the hub and outer ring. A harmonic balancer puller is a must have to change it. You can rent or borrow a puller from most of the larger auto parts stores.

Things that are very durable: Engine - as long as it hasn't been abused, it will run good for 150,000-200,000 miles without an overhaul
Rear axle - other than an occasional case of worn clutches in the traction lock, they almost never have problems.
Computer - believe it or not, the computers seldom have problems of their own. Most of the problems are with the sensors and the wiring.
Suspension – the front and rear suspension has very few problems if the car hasn’t been wrecked or seen a lot of drag strip runs. The drag strip runs tend to distort and tear the mount points for the rear axle control arms. Revving the engine up to 4000 RPM and dumping the clutch with slicks or drag radials tends to break things.

Things that don’t break often but are hard to fix:
Water pump mount bolts – they corrode and shear off when you try to change the water pump.
Rear oil seal on the engine – lots of parts to remove to get to a $20 seal.
Power steering pump – the pumps are noisy and the pulley requires some special tools to remove and install. If you have the tools, they are easy to do. Again, the larger auto parts stores will rent or loan the tools for the pulley.
Power Steering rack - it is hard to get the toe in set so that you can drive the car to the shop to get it properly aligned.
Starter – the top bolt is hard to get a socket on if you don’t have the right combination of socket, universal joint and extensions.

Everything considered, 5.0 Mustangs are not hard to work on. They just require some patience and though before you get started.

The leaning condition is the first thing I'd be looking at. Get it on a lift and check it real good for accident damage. Look for buckling evidence where the frame connects to the body in the area behind the front tires. It doesn't take much to total one of these things. Hopefully you wont find anything, but a good idea to check it. Do all the doors, fenders, hood gaps mostly equal and line up?

Rear bushings / control arms:

Maximum Motorsport is at the top of list for many folks, if nothing else peruse their site a ton of great info on suspension etc

Springs/ lower stance: eibach pros work well and give a good rake appearance, kyb shocks mate nicely

Puff of smoke: keep an eye on your oil level,, Also check/replace the PCV filter, its hidden at back of intake

First5.001 said:

Thanks for the reply, have a 2 bay garage that's packed full of 1971 International crew cab pickup. Doing a full ground up restoration on that. Also have a 1991F350 I swapped a inline 6 cylinder diesel in from a IH school bus. I've restored several international and ford trucks. IH is my first love, but I've always liked ford trucks. Been a huge 60s mustang fan since I was a kid, just too rich for my blood.

Funny you said about the door locks, they're both inop, need to pull out the power probe and do some electrical testing, I'll check out your post. Also the fog lights are completely gone. Planning on LED upgrading those. I'm in northeast Pennsylvania so we're pretty lenient in the emissions area. Already has an EGR delete throttle body spacer. Need to find a diagram to clean up some of the emissions wiring under the hood. Lots of extra stuff I don't need. I completely rewired my engine bay on my ford doing electric fans and headlight relays to save the switch overheating issues.

I'll do some reading on the links you posted.

Sent from my SM-G920V using Tapatalk

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Power door locks....
Follow this link to fix your door lock actuator problems

You will need the Adobe Acrobat viewer which is also a free download – http://get.adobe.com/reader/

http://www.stangnet.com/mustang-forums/attachments/door-lock-actuator-fix-pdf.88290/

Stuck with door lock actuators that don't work and don't want to pay the $50+ for a new one? Tried the junkyard ones and found that they last six months and freeze up?

A new actuator for less than $7. Fix one side for $20, do both sides for only $28. I don't sell parts, I don’t make any money off of the upgrade, I just tell you how to do it cheaply and easily.

By the way, i am still using the same $4 actuators I bought in 2002 and this is the second Mustang I have installed them in! Beat that with your fancy replacements!


The following is a must have reference link for 5.0 Fox Mustangs...
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/ Everyone should bookmark this site.

94-95 Mustang wiring diagrams
http://www.veryuseful.com/mustang/tech/engine/#95-95Diagrams

Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/91-93_5.0_EEC_Wiring_Diagram.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

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

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

O2 sensor wiring harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangO2Harness.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pin out
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Mustang 5.0 Lights and Radio schematic, by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxLights-Radio_diag.gif

87-92 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang87-92 PowerWindowWiring.gif

93 power window wiring
http://www.veryuseful.com/mustang/tech/engine/images/mustang93PowerWindows.gif

T5 Cutaway showing T5 internal parts
http://www.veryuseful.com/mustang/tech/engine/images/5_Speed_Cutaway_Illustrated.jpg

Visual comparison of the Ford Fuel Injectors, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/Ford_Injector_Guide.jpg

Convertible top motor wiring http://www.veryuseful.com/mustang/tech/engine/images/mustang88VertTopMotorCkt.gif

Engine mounted fuel injector harness
http://www.veryuseful.com/mustang/tech/engine/images/mustangEngineHarness.gif

Location of the TPS, IAB, and the 10-pin connectors on a 5.0, picture by TMoss:
http://www.veryuseful.com/mustang/tech/engine/images/TPS_IAB_Pic.jpg

Starter circuit
http://forums.stangnet.com/attachment.php?attachmentid=21328&d=1080916057

First5.001 said:

Thanks. I ordered a new pcv valve so I can toss that in when I have it all apart. Also I forgot to mention I scored 1" lowering eibach springs for $40 with no miles on them. Still hunting for the coil overs.

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PCV valve, Screen (birds nest), And Grommet. ALL 3

PVC some aftermarket dont fit very well, Valve is easy, Screen gets oil soaked (its under the valve and grommet and is just a party to get out -lol, and Grommet -they get hard and leak air around them - grommet also has aftermarket fitment issues....