Five Mistakes Foxbody Builders Make, or What is Wrong with my Mustang?

[@rad5.8fox7]

This channel is pure gold.

[@tecmotiondyno]

Thanks for watching!

[@jesseworkman4418]

I'm glad I found your channel because you really get down to the nitty gritty on the actual technical side that truly helps those that don't understand or haven't heard about on these cars. Keep up the great work Sir.

[@tecmotiondyno]

In a world of infotainment, I try to be more info and less tainment. Thanks for watching!

[@nedaCFilms]

Great point on covering spark plugs!!!

[@Scrapla1]

Had tapered seat plugs installed in my aluminum heads thank God only one of them gave me a slight problem. I now have the proper plugs installed.

[@tecmotiondyno]

You can usually recover from it, but I always cringe when I see it. One way or another, plugs that are made for E7’s never work right in aluminum aftermarket heads. There is a whole video on spark plugs on this channel too if you want more information.

[@123bozyb]

4 years chasing ghosts... my fox had the wrong plugs in it !!! thank you!!!

[@tecmotiondyno]

Glad to be of help. Thanks for watching!

[@sstjacques]

Very informative, thank you. Still have my fox since new... and had done some mistakes you mentioned over the years, but older and smarter now.

[@tecmotiondyno]

It’s awesome to run into an original owner! Thanks for watching.

[@arturozarate1752]

In almost 25 years I cant tell you how many times I've had to bill someone or a shop for a simple timing error. It never fails that I get told, "Well hell yes I used a light!" "Timing is perfect Mr. I done it myself. 25° initial and 40° all in at 3k rpm." Hurts me real bad inside knowing I'm about to ruin this guys day when I ask about the "SPOUT". CRICKETS every time.....and the occasional deer in headlights lost in space gaze. All great info, and very much needed! With the LS , OBD-II fuel injection, and millenials the EEC-IV of the Fox is as dead as Latin to most owners and "mechanics". As a Senior Master Technician with FoMoCo I can appreciate the knowledge your spreading. No wonder at all you have one of the FASTEST Fox bodies ever!

[@tecmotiondyno]

Thanks for your supportive feedback! The things in this video are literally all every day problems that show up on cars that are billed as “ready for a dyno tune”, and bad timing is right at the top of the list. There are lots of Fox Mustangs that are quicker than my coupe these days, though still not many naturally aspirated ones, but 15 years ago when we were running it hard it was almost unheard of, and the only reason most guys in the US never heard of it is that I live in Alberta and the distance between Tecmotion and say Englishtown NJ is 2400 miles, so we just never crossed paths!

[@kevin_nagle]

@4:48 Also the lines. People think just because they have a 450lph pump & 80# injectors that their fuel system is up to the task of supporting 600hp... then they find out really quick that the factory fuel lines are limiting fuel flow. For a typical bolt on 302 with a power adder I recommend the SVE ⅜" high performance fuel line kit. It's nice direct bolt on pre-bent ⅜ feed - 5/16 return stainless steel lines that mount to the factory points including the factory connectors. I use them on a 550 rwhp Fox with a 340 DW pump & 60# siemens deka injectors. Anything more than that I recommend ½" or -8AN feed and 3/8" or -6AN return lines & an aftermarket fuel rail with a good pressure regulator.

[@tecmotiondyno]

Completely fair. I used -10 AN feed on my 9 second Foxbody with a -8 AN return. Usually by the time I feel like I need new lines, I go with custom AN lines. I even have a video on this channel about making up custom fuel lines if any of you guys need help with it: kzbin.info/www/bejne/a4eriKaNlL6IgZY

[@kevin_nagle]

@@tecmotiondyno I use the same on my 1300hp turbo car... 10.0 GPM brushless Aeromotive pump & 160# Holley injectors. Car has been 7.70 @ 178 mph. Im liking your videos so far!

[@tecmotiondyno]

Thanks! I appreciate your feedback. I've raced and built and Dynoed a lot of Mustangs so it seemed like a good idea to share some of my experiences with others. I'm guessing a guy who is running 7.70 in a Foxbody is just watching for entertainment, but I appreciate your comments which I think should be helpful to others as well.

[@_moes_garage_]

Phenomenal video! Thanks for putting this together!

[@tecmotiondyno]

Glad to be of help. Thanks for watching!

[@bobfisher9452]

I have that exact same car, bought it in 06. Thanks for the tips!

[@tecmotiondyno]

The one in this video is a customer car, but I have a stock 93 hatch on top of my wild 90 coupe and an 88 hatch project car. Thanks for watching!

[@hartmatterhorn]

Really great video. Thanks!

[@tecmotiondyno]

Thanks for watching!

[@MP-pz9oe]

Forgot to mention the Damper, after many miles the front seal leaks, the Damper's rubber gets soaked with oil, dry rotting it. Eventualy develops a vibration that is hard to detect that also causes hesitation and misfire

[@tecmotiondyno]

All the things in video are everyday things in cars that show up for dyno. I have a whole video just released that focuses on the damper and replacing it, and I am working on another video of more serious things that are often broken on these cars, one of which is the harmonic balancer. So, I totally agree with you!

[@MP-pz9oe]

@@tecmotiondyno thanks !

[@eurocarpleurocarpl2057]

Mistakes: 1. changing headlights to ugly custom 2. Changing tailights to ugly custom/Cobra style 3. Changing front bumper to Cobra style. GT is pretty as is!!!!

[@89Whitehorse]

Thanks for the tips own a 61,000km fox all original that I drive it is an AOD but I have all 4r70w internals..

[@baldeaglegarage]

Man I wish I would've seen this video before I started taking apart my Foxbody. Great Info!

[@tecmotiondyno]

Thanks for watching!

[@ariajefferson5846]

89 fox 5.0 first fired up shorty headers turned cherry red within a minute. No cats b303 cam gt40 intake/geads bored .30 over off road x-pipe 2.5 exhaust dumped 40series flow masters. Ive had and done work myself on my foxbodies for over 15 years. Ive had 6 never had this issue

[@tecmotiondyno]

Virtually every time I see this it is because the timing is retarded. Set it with a light. If it still does it, confirm that your balancer is not spun which would give you a bad setup. Also watch for balancers with multiple sets of timing marks and make sure you are timing it on the right side of marks.

[@jennymann3704]

I threw away my stock IAC valve over an upper intake leak but we're good "mistake" new IAC installed thanks for your information happy new year to you Sir

[@tecmotiondyno]

Happy new year to you too, and thanks for watching!

[@olliej914]

Thought you be talking about re-welded floors and electrical problems perhaps leaks.. loved the video! The spark plugs was very informative.. have been rebuilding/rewiring and finally driving an 82 frankenstein gt..

[@tecmotiondyno]

There are so many things that can be wrong with these cars that it is hard to know where to stop. The ones in this video are common on cars that show up supposedly ready for Dyno. Look for a follow up video with some more things that you should look for ...

[@olliej914]

@@tecmotiondyno great I love how active you are with the channel. Just saw some drag videos from 10+ years. Im loving my car. Far from factory but who cares lol

[@tecmotiondyno]

I’ve had this channel practically since the beginning of KZbin. I used to use it mainly to post racing videos so there is some great stuff there if you look through my back catalog. The technical videos are more intrusive and harder to edit into something coherent, but they are generally more popular and I think they are useful in an era where people turn to KZbin for how-to advice. I am trying to release new content every Sunday morning right now. Thanks for your positive feedback!

[@magnumcipher4971]

Good stuff my man. Nice video.

[@tecmotiondyno]

Thanks for your feedback and thanks for watching!

[@jucedcustoms2274]

This is GOLD! Thank you for sharing your valuable experience and knowledge. What type plug is best for gt40p heads?

[@tecmotiondyno]

Probably NGK TR55. Those heads have a tapered seat.

[@jeffreymrrs150]

I got tired of dealing with the crap computer and harness and put the terminator x in. Being a cammed car it runs so much better now.

[@tecmotiondyno]

Terminator X and Megasquirt are both good ways to go, and it is quite true that Foxbodies are typically FULL of wiring problems because the harnesses have been so cut up over the years.

[@HawgKeeper]

I really enjoy your channel and the many things to learn more about our Mustangs. Now after watching this episode, I too have a issue with my new rebuild that you mention. My 93 5.0 is stock, except for GT40P heads with upgraded Trickflow springs and a Crower 15511 cam. The car idles, starts fine, but it cuts out and loses power at full throttle about 4000-4500rpm. I'm beginning to think I need more fuel as the new stock pump is not enough. The injectors are new, stock 19lb. It never occurred to me that the mods I had done couldn't be handled by it. So what are your thoughts Matt? Question two, would I need to run a hotter/colder plug with this, as I'm using NGK TR5's gapped at .045. This engine is fresh, with less than 100 miles, but just doesn't feel as strong as it once was when it was completely stock. With 4.10's behind a AOD, you could punch it from a slow roll and she would want to go sideways!

[@tecmotiondyno]

I just did a similar car with GT40P heads, Explorer intake, 1.7 rockers, shorties and off-road exhaust. It was about 35-40% over stock depending on exactly where it would have tested stock. It used 30# injectors and a 30# calibrated MAF plus a 255 fuel pump. It was definitely beyond what could safely be run with 19# injectors at my 3500 ft elevation, and real fuel demand at sea level would typically be about 14% more again. Whatever the Facebook pundits say, you need injectors and a fuel pump upgrade for your changes. 24# probably work, but I always suggest you go bigger than you truly need to give you a little headroom for the next round of mods, especially if you are going to tune it.

[@HawgKeeper]

@@tecmotiondyno Thank you sir for your advice, I will first try the bigger pump. The bigger injectors are out of my budget for now, I always heard that 19lb injectors would be fine up to 300hp, not so? Would the NGK TR5 be ok for this combo?

[@seanm5282]

Great video! Thank you!

[@Bacongrease00]

331 with AFR185 and a vortech v3 with 60LB injectors. What size pump? Right now on a 255 with a boost a pump module that gives me more voltage after 5 psi.

[@tecmotiondyno]

Most of the time I would say that a 255 with upgraded wiring would cover that. I’m not a fan of pump boosters, but that will help with your deliverability and pump boosters with mechanical regulators generally don’t produce the pressure spikes that you get with returnless systems. I use a 340 in tank pump pretty commonly on applications like this too.

[@survivethrive2468]

Your videos are great!! And have helped me out tremendously and learning alot. I own a 1988 lx 5.0. Cheers 🍻 from the states... 🤝

[@tecmotiondyno]

Thanks for watching! I’m glad it’s helping you out.

[@surfofsinify]

Don't forget to check your torque boxs

[@tecmotiondyno]

I think I have that in another video. Thanks for watching!

[@richlong4119]

What plugs go in gt 40 p heads on my 85

[@tecmotiondyno]

NGK TR5 should be a good choice. I'd gap them .045". You might like this video too: kzbin.info/www/bejne/qIWzaWCCetl1nZIsi=vARq1LgmsLWBoWcA

[@theodoredorward6245]

need to put a new bung On my older set of H pipes And I don’t like where the sensors sitting it’s right up there Crammed by the starter can I move it four or 6 inches down without having any complications

[@tecmotiondyno]

I’d be surprised if you had any trouble with that. Orient it so that the sensor head won’t get condensation on it. Guys run long tubes with headers in the collector all the time with minimal or no problems.

[@rolandrodriguez7145]

You just taught me what I did not know about my 5'0 subscribing to learn more

[@tecmotiondyno]

Glad to help!

[@robertfox8855]

Great video. Thanks

[@tecmotiondyno]

Thanks for watching!

[@tecmotiondyno]

Thanks for watching!

[@DakhilB]

I need an engine, clutch And exhaust installed all the way in Ontario Canada, Can't find anyone...

[@sneakingfox5887]

Will a alternator upgrade be needed for my Hci swap?

[@tecmotiondyno]

Heads cam and intake by themselves wouldn’t necessitate it, but the supporting parts often do. Big fuel pumps, more powerful ignitions, electric fans, stereos, and anything else that increases the electrical load will require an alternator upgrade. A real problem with the electrical system on these cars is that the factory alternator is really barely enough to run the stock car, so when you start adding anything electrical you need to upgrade it. A weak electrical system can generate all kinds of problems that are hard to put your finger on. I have a video on here regarding the 3G upgrade which goes into a little more detail too.

[@peanutbutterisfu]

Big mistake people make when doing heads is putting the one head gasket on backwards causing the engine to run hot.

[@tecmotiondyno]

It can happen for sure. There is a video out there with a LOT of KZbin views that concerns installing heads on one of these engines and the entire procedure that is shown is wrong wrong wrong, so I see that as a source of quite a few common head install problems too.

[@tonykearney4369]

Great info

[@tecmotiondyno]

Thanks. There are lots more things that can be wrong, but I catch these ones all the time!

[@bertcody88]

@Tecmotion Are you running an egr valve? If not what what are you doing about the open connection?

[@tecmotiondyno]

The car in this video has a megasquirt engine management system and deletes EGR. There is a block off plate in place of the valve.

[@michaelmoon7128]

What’s your thoughts on the motorcraft plugs ?

[@tecmotiondyno]

There’s nothing wrong with them. Some of the Lincoln guys would sooner walk through fire than use a non-Ford part on their cars, but i personally prefer and always use NGK on pushrod Ford motors. A standard inexpensive copper core plug is the best option for most of these Ford performance applications if you ask me. If you use the Motorcraft plugs that are made for the heads you have, or Autolite for that matter, it will run fine.

[@Shakerhood69]

Yep, l always found these cars like the regular copper plugs.

[@bonezshakergarage]

Which spark plugs go in GT40P heads?

[@tecmotiondyno]

NGK TR55 series plugs should work for those heads.

[@bonezshakergarage]

@@tecmotiondyno thanks

[@brandonknight7240]

Who tried to copy who ? Edlebrock or holley systemax?

[@tecmotiondyno]

I’m not sure whether the RPM II or the Systemax came out first, but Holley only really ever had one design and Edelbrock had several when the EFI pushrod 302 was contemporary. The Pro Products Typhoon is a famous direct copy of the original Edelbrock Performer RPM EFI manifold.

[@ajcates9136]

I have the same car just in vert

[@tecmotiondyno]

Honestly, I think the convertibles and the automatics are starting to come into their own in the Foxbody world as you enter an era of nostalgia cruising and older guys owning the cars. Thanks for watching!

[@ajcates9136]

Thanks

[@Melissa-dh6py]

Love the channel very informational

[@tecmotiondyno]

Glad you enjoy it!

[@vtecbanger3180]

Nice video

[@tecmotiondyno]

Thanks for watching!

[@melvinholcer4756]

That’s good info.

[@tecmotiondyno]

Hope it helps! Thanks for watching.

[@mike4fo]

Can you ground the fuel injector strap to the firewall?

[@tecmotiondyno]

It needs a block ground. The normal configuration is to attach the fuel injector harness ground and the braided firewall ground to the back of the driver’s side head with the same bolt.

[@mike4fo]

@@tecmotiondyno thank you for your quick reply 💪🏼

[@blangist]

@@mike4fo can you attach it to the back of a aluminum head and still get a good ground?

[@k9trucking]

Where are you.located

[@tecmotiondyno]

Calgary, Alberta.

[@theregoesmiller389]

i randomly just stumbled across this channel and i am thankful i did. i have a 95 gt stock bottom end 306 f303 ported p heads bbk LT trickflow upper n lower 75mm TB pro-m maf with a ted jenkins chip (tune) with a 7k rpm limiter. the car does NOT want to rev past 4k. starts to pop n bang etc. i have a aftermarket fuel pressure regulator i havent gotten around to installing , but i am also curious if my dizzy / wires / plugs are assisting in this issue. car is stabbed/ timed correctly. car is hard to start as well... takes 3-5 tries and when she does finally kick over it takes 2-3 more tries to keep her running. also if i even BREATHE on the go peddle she stalls. going to dig into your videos some more. but would love your 2cents if you have the time. thank you ! subbed !

[@tecmotiondyno]

There are a ton of things that can be wrong. My current project "The Fridge", which is a garage find 93 GT felt really gutless, and was kind of hard starting. When I got it on the dyno it was clearly lean and way off in terms of power, so I put a fuel pressure gauge on it and it was idling around 25 psi. This turned out to be because the feeder line inside the tank was cracked and fuel was bleeding back into the tank after it had gone through the pump. Sometimes a break up like you are getting is a bad coil, bad TFI module, bad or wrong plugs, bad tuning, or any of a bunch of other issues. Check the fuel pressure for starters. If it has a factory coil, a spec replacement with something like an MSD Blaster is inexpensive and probably a good idea anyway. Check for all the stuff in this video, and here's another one that might give you some ideas: kzbin.info/www/bejne/i2nYc3iXdpVqfbs Thanks for watching!

[@theregoesmiller389]

@@tecmotiondyno i was NOT expecting such a quick response.. i really appreciate your input and the link to the correct video ! cheers !

[@jimbeckert7946]

Good info. The Fox 85A alternator is pathetic. LOL.

[@tecmotiondyno]

Yes, that alternator is barely enough for the stock car!

[@jimbeckert7946]

@@tecmotiondyno I'd say it's inadequate even for that.

[@tecmotiondyno]

I’m kind of with you on that, though if you have a bone stock car and everything is in good condition it usually just works.

[@jimbeckert7946]

@@tecmotiondyno Hmm...Idk...when I used to drive my mildly modded 92 as a daily driver, I found myself on the highway in a snow storm at night. I was running my wipers, headlights, defogger and rear defogger and everything was kinda dragging. The lights on the dash were dim, the headlights were dim, the blower wasn't turning as fast as it should. I was not driving a normal highway speed due to conditions, but it wasn't a low RPM or idle engine either. Upgrading the alternator was a life changer. Of course, I no longer drive it in the snow. Haha.

[@Turbo4Joe363]

Great tips! I have a carbureted '85 GT and just bought a Holley Sniper Stealth EFI. What has your experience been with this type system?

[@tecmotiondyno]

Generally, I have liked the Sniper, and usually the problems you get with it can be solved. I have a 67 Coupe with a 347 in the shop right now that uses it, and I have had a few unusual issues that I have managed to solve so I am thinking of doing a little video on some of the gotchas that you might run into with that system. Compared to other budget throttle body injection systems, I much prefer sniper because its learn mode is better than most, and most importantly, if it doesn't work right, you CAN do a comprehensive program on it with a laptop and usually get it to work fine. With some of the other "handheld only" type systems, when they don't work right, your only real choice is to pull them out and start over.

[@Turbo4Joe363]

@@tecmotiondyno Thanks for the reply. Were the issues front mount distributor - EMI interference?

[@tecmotiondyno]

@@Turbo4Joe363 there can be a lot of issues and the proximity of the distributor (and coil on the early cars) gets blamed a lot. If any of the key wiring is run in close proximity to other wiring that is noisy, especially ignition wiring, you will have problems. If you tap the tps wiring for an automatic transmission controller or fuel pump controller or whatever, you can introduce noise that interferes with closed loop operation. If you get a poor o2 sensor install it can cause problems. If you don’t pay attention to the fuel plumbing it can cause issues. There’s really a whole video worth of stuff to consider, so I have put that on my list for a future video on this channel.

[@Turbo4Joe363]

@@tecmotiondyno Looking forward to that video! You mentioned another concern that I have with my Sniper Stealth install... O2 sensor problems. I have ARH headers with slip-on collectors and O2 bungs welded into each collector (2 o'clock position on the collector). Even though the slip on collectors fit very snugly and have 2 bolt together tabs, I'm worried about air/oxygen leaking into the collectors and screwing up the O2 sensor's reading. I won't be installing the Sniper system until July-August when my 363 build is finished.

[@tecmotiondyno]

It's probably not that big of a deal. I don't like the clamp on O2 bung that Holley sends out, but they do it so they can claim there is no welding required. In most cases a weld on bung will work better. I have used slip collectors in lots of EFI applications and have never had a serious problem with them with respect to the O2 sensors.

[@Brutalford]

Or you can convert it to carburetor and ignore all that pesky wiring..lol...but I agree grounds are very important and timing is super important as well....

[@MikeSmith-ey7ku]

Yeah and just what throw away my supercharger and giant fuel system and then make way less power. Nah I’m good

[@houseofno]

@Brutalford Drivability? Gas mileage? POWER? Who needs that, right? Or just get an '85 GT and let the rest of us enjoy our FI goodness.

[@crabbypapa3862]

My solution to the fuel injector clips breaking is the late model Panther ones, squeeze sides, their 19 pounds also have 4 holes versus single.Unless there is a tool, needle or safety pins will allow swapping over without splicing wires.

[@tecmotiondyno]

Good tip.

[@dukenukem5753]

I had the wrong plugs

[@tecmotiondyno]

It happens A LOT! Even my garage find 93 project had two wrong plugs in it!

[@fmerkl]

You the Man!

[@MrBlackbutang]

WoT?

[@mrphiscal]

The biggest mistake is putting a Ls engine😡 in your fox body!!😂

[@tecmotiondyno]

Yeah, I’m not a fan of that either, though I can understand some of the reasons behind it, and the GM LS series are good engines. I never had to resort to the General to show guys my taillights on the drag strip either.

[@black88coupe]

How many people even know what the “10-minute tune-up” is?

[@tecmotiondyno]

It used to be common knowledge. More of them will know if they watch this channel.

[@houseofno]

I think I lost my lunch seeing those horrible aftermarket headlight assemblies on that car.

[@patduggan3421]

First mistake people make is calling them fox body , they are fox platform or fox mustang not fox body .why does nobody know this

[@tecmotiondyno]

You are right, they are technically fox platform cars as are many others including the Lincoln Mark VII, but they are widely colloquially known as Foxbodys just like facial tissues are widely known as Kleenex even if they aren’t made by Kimberly-Clark.

[@jesselopez126]

They sir do you have direct email or number to contact you ? I need some work done on my foxbody

[@tecmotiondyno]

I have all of that. Contact information is all on the web site at www.tecmotion.ca. Phone or one of the messenger services is best.

[@dr.curious5136]

Biggest mistake is those absolute garbage one piece headlights. All good tips, but lets be real if some don’t know these basic rules, then they shouldn’t really be wrenching on cars

[@tecmotiondyno]

Well, these are problems that show up on cars that come to the shop for dyno every day, so I’d call them very common mistakes. In fact, almost NO Foxbody Mustang ever shows up for a dyno at Tecmotion that doesn’t have SOME physical problem like these.