Fox T-Bird/Cougar Forums

Since I finished my T-Bird Drag Car, I thought it was important to have the correct tow vehicle to get me to the track. I decided to set some limits because it's as easy as buying a new truck and going into debt by a whole lot.
#1- it needs to be from the same era as my car (look period correct). That limited me to OBS F series or E series van as well as a nice Crown Vic or Grand Marquis. A wagon would be awesome!
#2- cannot have a 460, let's face it I could not afford to race after gassing this pig up for a day at the track. 10mpg is no go in my book since this would be a second vehicle and I would be using it on a daily basis going to and from work. It must be economical in today's sense.
#3- it had to be Windsor powered! I have a whole garage of squirreled away parts from over the years and I could make an awesome EFI Windsor something.....

My buddy offered me this beautiful 1988 F250 XLT lariat that his dad willed him when he died....it has a 460 and C6. That was against rule 2.... So we started talking. There were hundreds and thousands of these trucks built with a 460. Many were for sale cheap! That was because of the fuel consumption. Can a truck like this be revised to today's standards of economical by using Junk Yard stuff for the fraction of the cost of something new. The cost of replacing everything cannot even be close to the cost of buying a new truck.

These thoughts stewed for a few months and became all but forgotten and then it happened! I found a 1988 f250 XL model with a gacked 351 and a 5 speed on Craig's List just down the street in Chula Vista. I went and checked it out. The owner would not come down 1 cent! I looked the truck over and was as giddy as a school girl. It had a complete set of unrashed real deal ALCOA wheels and the desireable ZF 5 Speed and not the Mazda turd.

After getting it home courtesy of AAA, my neighbor and I tore into the truck. Motor and tranny out, drive shaft, motor mounts, tranny crossmember, pedal bucket and steering column, wheels off and viola the frame was bent behind the passengers front tire....well that's ok. Call the Spers, instant $200!

Over the course of the past year I had the ZF rebuilt by a racing buddy for the cost of a 351w block and $300 in rebuild kit. The 351 required a complete rebuild, so an over bore of .030, hot tank, cam bearings and a lot of elbow grease! My friend with the nice 1988 f250 and I discussed the possibility of a gas mileage 393.... Was it a possibility? My old tbird would get 24-26 mpg with stock ford stuff with the exception of 3.55 gears and an HO intake. I did not see why a 393 would get less than 20. Maybe I was dreaming! But either way I thought a lot of it had to do with port velocity and air flow being high at low engine speeds and the cam in the tbird, so I started by planning the goals.
#1- must get 20 mpg! While Towing this was never going to happen and was unrealistic but daily driving, that's real!
#2- it must go 500 miles on a tank of fuel when towing. If it ended up getting 10 while towing, it needed to carry some fuel. The truck spends a majority of its life not towing, but when loaded it had to have some range.
#3- it must have some flair and charisma. Low engine speed means larger cubic inch generally for good low grunt and it can be complimented with longer rods for more grunt below the curve and in normal operating range.

Love love love my "OBS". I literally just do not like any Ford trucks made after these. The styling just doesn't even hold a candle to it for me. Kinda goes against my policy of no ABS but you can't win them all right?

Good luck with the build! MPG may be a tough one, though if you spring for a really nice high-flowing top end setup you might get what you're looking for.

Ok, well the reason the post has so much info is for the back story, but to cut to the chase.....I have already started and am almost done with phase 1. I bought a much more used truck that was much newer but was closer to what I wanted. I found a 1994 F250 2wd reg cab long bed. It was sporting a 351 that did not run and a "fresh rebuilt" E4OD. Well I pulled the motor out after finding 5 quarts of water/ antifreeze in the pan and did a cheap spray can rebuild, re-ring and bearing job to get it up and running. Found 1 bad rod that apparently got hot and was deformed on the big end. The crank was junk, but I had the crank from the beater 88 with the ZF 5 speed. Swapped the crank, used an 88 f250 rod and bought 1 piston. The best part was the F4TE block in the 1994 truck. Roller 351! I can use most of the parts stashed from the tbird and 23 years of 5.0 parts ding. I used the stock SO 5.0 cam from my tbird, a lightning lower intake, some cobra roller rockers and a set of AFR 165 cylinder heads with 60cc chambers. I had scored an awesome set of doing Thorley try-y headers for a bronco at the annual swap meet that were stainless for $65 that were almost $700 new. Thought they might fit, and they do....awesomely! I has a few race parts left over from a blown up 302, timing chain, t bird valve covers and a New NOS ford timing cover I bought almost 15 years ago.
So things I learned.....the low end on this 351 is awesome, I don't know if I need a 393. That may be overkill. The Trucks are all batch Fire efi and not sequential. Therefore the 302 cam would work well in the truck temperairally until I finish the 393 and swap over. A fuel rail from the 88 F250 is a direct bolt on and will accept a 5.0 mustang adjustable fuel pressure regulator. Speed density batch fire is very acceptable to upgrades as long as the cam remains very factory. The 351 pulls 23" of vacuum at idle and really idles smooth. I swapped the mechanical fan for an electric flex-a-lite and added a dual battery setup from a powerstroke diesel. I added a 33 gallon bronco tank in the rear.

I have been focused on my interior and the towing capability recently. The fresh rebuilt tranny was slipping like mad and did not enjoy shifting promptly. I could not tell if it was the programming of the PCM or just poor rebuild. After flushing and shift kit, I decided to ZF 5 speed the truck. bought a clutch from center force, new flywheel and master/ slave cylinders with throw out bearing. I hit the junkyard and found a 1992 f150 with a manual and got a 92-96 pedal bucket and the wiring harness from a manual and the computer from a f350 box truck. I need the front wiring harness that has brake controller and relays in the fuse box anyway. I also scored a slider back window and a set of seat brackets to mount a pair of lightning seats.

Id go with a 302 and highway gears. The zf had a super low almost granny 1st gear and with a manual while towing, staying in 4th isnt a big deal for hills. For every 1k in rpms, you use about 4x the fuel.

I am a fan of the OBS ford trucks as well. Have 4 of them. Two with 7.3 autos, one 7.3 5 speed, and one with a 460 5 speed. I agree with the notion that you can rebuild one for a fraction of the cost of a new one as long as you can turn the wrenches yourself.

20 mpg's does sound a bit ambitious from an OBS F250 gasser, but hope you can pull it off. Most F250's got 4.10's, but some 3.55 gears, synthetic fluids, non aggressive tread tires, front air dam, and a light touch on the throttle couldn't hurt. In stock form for a gas engine the closest Ford came to what you are trying to do was the 300 6cyl 5 speed. They pulled great and could do mid teens out on the highway.

Goal #3 was flair and charisma, made me think of this. Someone that pulls a 4 eye bird or stang to the track needs this.

http://ottumwa.craigslist.org/cto/5906984549.html

(http://i1060.photobucket.com/albums/t456/bodymann/dually%20van_zpsvv16w3io.jpg) (http://s1060.photobucket.com/user/bodymann/media/dually%20van_zpsvv16w3io.jpg.html)

This van is the best! Too bad I already spent my cash on this truck. This thing is perfect! Just that stripe......it needs a purple one too before I commit to buy!

This weekend I will finish the ZF install and button up the column. I got a box of carpet, not for munching, but to put on the truck floor and make some exhaust. I should then be finished with phase 1 and can check some mileage as well as the charisma/cool factor!

Exhaust, I got a 4 inch diesel mandrel bent exhaust. It was half the price of most dual kits and will likely out flow them by a bunch. Just need to fab a Y pipe from the headers. I'll try and grab a bunch of pictures so anyone who wants to see this thing can check it out.

I have been throwing around the idea of putting a 8KC t-bird computer in the truck, use a car injector harness and move a few pins in the truck harness and viola, SFI speed density. No more batch fire. I think it may be worth a few MPG. I also have the A9P computer from when my tbird used stock ford 5.0 302 parts to make it down the track. I also have a 93 Cobra computer and MAF I could use, just requires to change the cam. Maybe use the custom 393 Schneider hyd roller cam I got made for low end? Your thoughts....anyone.

Don't get your hopes up, SEFI mostly addresses emissions... If it would have increased MPG I'd think Ford would have used it in trucks sooner than the early '90s... The converted to mass air Stang I had lost .2 ET at track but did pick up approx 1mpg... I wound up converting it back to SD...

Thanks Tom, I was wondering if it would make a difference. Looks like it may be worth trying it before dropping $750 for a tune on the truck. I have found the fueling limitations of the stock computer. Maybe the 393 would be better because the RPM band may be better suited for towing vice this smaller 351 motor that easily turns up to 5K. I may try playing with fuel press before all. Seems like its running rich at idle surprisingly, 24# injectors may be too much. I used thin rings 1.5/1.5/4mm package with the napier setup and the H series Clevite bearings that had less bearing surface. It may not need so much fuel at an idle. After putting it together it only took 15 in/lbs to turn the motor over with no plugs. It may be fueling too much at idle.

Tom, this is what I was looking at that seemed to make a lot of sense.

http://www.fordmuscle.com/archives/2005/10/MassAirConversion/index.phphttp://www.fordmuscle.com/archives/2005/10/MassAirConversion/index.php (http://"http://www.fordmuscle.com/archives/2005/10/MassAirConversion/index.php")

Ok, so ZF 5 speed conversion has not gone so well. First off, I had to make a harness for the transmission, not all that bad. Then I swapped the column that I got from the junkyard, it had a bad ignition switch that took 2 days to troubleshoot and narrow down the switch itself. That was difficult because I had messed with so many things making the harness I truely thought it was the harness but turned out to be the switch. That was most likely the cause of the junkyard truck being in the junkyard. Lastly was the transmission leaking tranny fluid out of the input shaft. I thought the front seal did not end up sealing. After taking the tranny back out, I found that the pilot bearing was too sloppy in the crank allowing the input shaft to work the bearing loose. This was a problem! Usually the crank is junk at that point or can be used for an automatic, but I bought the old school bushing for a SBF and dimpled it with a punch to swedge the bushing into place. I know this is a work around, but easier than the crank being changed or manufacturing a custom bushing, so thought I would try that first. I have not got the tranny back in yet as I had to take it out to replace the seal and verify all was good internally. Had to replace a synchro on 3-4 shift to correct damage from input shaft wobble. It should be back together soon and I can test it out.

Its been over a month so just wanted to check and see if you had made any more progress.

A few things have come up, tranny rebuild X3 until I finally got the ZF right. What a bear! My father died unexpectedly. Really slowed things up quite a bit. I do have some more updates and a few pics to throw out there. Just been stupid busy!

Oh man, sorry to hear about your pops...that really sucks.

Sounds like the trans was an unholy battle.  Anything in particular kicking your butt or just one of those Pandora's box slash Murphy's Law deals?  No rush on the replies as we know you have a plate full.

If you look a few posts back, I thought the pilot bearing was toast....turned out that the input shaft had been slightly bent or warped. This took me forever to find and fix. I ended up dropping a few grand into the tranny at a shop to figure it out. I was not so happy about it....but what do you do? I had the tranny in and out about 5 times. What a bear! This thing ain't a T-5, it has some gerth to it!

Super clean man!!

How are the highway Roma and mpg? Cool setup so far.

Haystack, assuming Roma is road manners? Quite well! Rides very smooth after a new set of shocks and 55lbsof air in the tires. Mileage.....not quite sure. I have been chasing a weird CEL since getting it running. I'm beginning to think that I may be too far out of the tune on the factory computer. I cannot find a single thing wrong with any sensor. Engine codes change every time. First the tps, then the IAC, then the ECT. It runs smooth and well but always smells rich. I'm gonna tear the upper intake off this weekend and maybe find something in the vacuum lines, like holes. That the only other way I can explain this issue. Then it will be time to hit the open road. It cruises well at 70 MPH turning 1900 RPM and sounding smooth and quiet. I'm assuming that may be the sweet spot, but I bet it's more likely 62-67 MPH for mileage. I have owned 3 of these trucks and all had the best mileage including the diesel at that speed range. We will have to see.

Found the intake manifold gasket settled and compressed more than I thought it would. I retrocede all bolts and viola. Vacuum leak, found and conquered, at the exact same time. Adjusted timing, TPS and idle quality. Found it needed quite a bit more fuel and obliged with 50 lbs of fuel pressure on the 19# injectors. I think its time to throw the 24# back at her again and see what happens.

Towed my racer to the Drags in Barona California and its up some serious grades of 4-6% or more at a couple points. The 351W just does not have the beans I thought it would. It needs to be over 2500 RPM to really gain some steam. I was underwhelmed actually which just lit a fire under my a$$ to finish up the 393W and get it swapped in with a conversion to MAF. I have a computer and MAF from a 1993 Cobra that would work well here and should add quite a bit of adjustability to the equation.

Thoughts?

Trying to run a 351W on 19lb injectors is like feeding a quarter horse Cheerios...yeah its got oats but not what the horse needs.  I would say that the truck needs to go to a tuner and put it on a dyno with a wide band O2.  I only say this as my little 306 ran out of steam on 24 lb/hr injectors at about the 280ish rwhp / 290ish ftlb mark on a Mustang Dyno.  Popped in the 42 lb/hr injectors with a slight retune and it hit 300ish rwhp / 320ish ftlb and the idle was 100% better as I was not up on 100% duty of the injectors.

19's are just a no go on this thing. I had to run the fuel pressure close to 85#s to get it to run correctly. I have a set of 24#, but I'm wondering if that is futile. May need more! A tune would be great, but I do not have that kind of cash at this point. Looks like for a truck it costs quite a bit more than a car. I was quoted $750 from JBA and that includes Dyno time. Not really what I'm looking for. I wonder if 24# and mass air might correct the issue. Should I start looking for a set of 30's? Butt Dyno is all I can afford at this point.

BTW, I noticed that with my fuel press gauge installed on the schrader it was jumping around and that when the key was turned off, the fuel press went immediately to 0. I thought the rail maintained pressure. Not sure if the jumping on the gauge is the bank to bank vs the SFI I am used to. That is 4 injectors firing at once and not 1.

What fuel pump do you have? I would call Pro-M and talk to them about a calibrated MAF. They can help you with injector sizing. That will avoid a tune but in the long run that is what you need. I would go with an SCT tuner as they are usually $500 for the chip and initial tune.

Sell your 19's and matching MAF. Sell the Cobra ECU, MAF, and 24's. That should get you close to paying for the Pro-M MAF. Whatever size injector you need you should be able to source used online.

My stock fuel pump had a check valve and held pressure, even when the pump was only pushing 12psi. The new pump didn't and immediately went to 0 when the car was shut off.

I think the newer pumps just don't use them.

My stock fuel pump had a check valve and held pressure, even when the pump was only pushing 12psi. The new pump didn't and immediately went to 0 when the car was shut off.

I think the newer pumps just don't use them.

I think I found the problem. The regulator is not working well. Under load the fuel pressure drops off. Not sure if it's the regulator seat or plunger. Appears the diaphragm is still fine but something else is not working correctly. I have a stock fuel rail and regulator and I'm gonna try that with the 24# injectors.

Hope that is part of the problem but dips in pressure also indicate lack of enough volume.

I agree, but feel some of the volume is being limited possibly by the regulator returning needed fuel. I will cross that bridge once I determine if replacing the regulator makes a difference. There may not be an issue after that. After all, these pumps also fed 460 powered trucks, they should be enough for a 351 with heads and a lightning intake.

The key to this one as Aerocoupe said, the fuel pressure is fluctuating all over the gauge as well as the rail did not hold pressure after the key was off. These trucks have issues with the 1 way check valve on the fuel supply side that normally causes issues. This was not the case for me as it was not filling from tank to tank, which is the usual characteristic.

So I did find the issue. The regulator was hanging open. I pulled the rails and 19# injectors out and blew through the inlet and air was coming out the return. That should not happen until the adjusted pressure is reached. Since I did this by mouth, I doubt I reached 40ish lbs.

I replaced the rails with a stock 1994 set with a factory regulator as well as I crawled underneath to look at the fuel filter. It had a cheap Chinese duralast filter, so pitched it in the trash and installed a Motorcraft. Bang! Easy 30 hp and 100 foot lbs of tq. Now it's impressive! I'm excited to tow with it again!

Finally got a code! 38, Idle tracking switch.... Assuming the IAC is taking a dump. Gonna try to clean it and see what happens.

OK, so I've had enough of this Speed Density system. Its impossible to tune out the issues since I changed the heads and cam. It's gonna get real for the truck cause I'm going 1993 Cobra X3Z computer and Mass Air. I am sick of the erroneous computer codes and Full rich check engine lights. There is nothing left to replace or eliminate.

I'll post pictures and a write up as to why some things are the way they are! I am not using a 302 HO  or 351 camshaft, so gonna have to move some injectors in the harness and consolidate the placement of the O2's.

BTW, using a Painless harness I had left from another project, so I'm gonna have to make it work.

OK, so I was screwing this up. The truck has 3 digit codes and that would make it another test on the scanner. Codes 33, 25, 38 turned out to be 332 and 538. EGR and rack the throttle open. That turned into 332....which is no issue since EGR is not installed. Then I pulled the memory codes. Appears that 128 is an issue (Not sure of the code but think that was it), damaged or inoperable MAP sensor hose.....That's telling me that the computer is not getting the correct vacuum signal and is outside of calibration.

I'm going Mass Air this weekend! 1993 Cobra X3Z computer and factory MAF. Will work well with 5 speed and 24# injectors. I'm in the process of cutting up a harness and making a few things to make this work. Decided to go with a "Layover" harness, that lays on top of the existing one to get the job done now. I just need it to work correctly and be able to tow my race car. I'll take some pics of the harnesses and install. I have already pulled the required harness pieces out of my gacked 88 Bird harness to get what I need.

Ok, I suck. I did not get any pictures of the harness and the install this far. I will go snap a few tomorrow morning, but I'm almost done. I did fire it up today. Here is the list of stuff I did.
1. Made an injector harness from an old 88 bird harness, pinned out each injector and moved the 7,3 and 5,4 injectors to work with my Tbird SO camshaft firing order.
2. Made an O2 harness from the same old bird harness. Placed both O2 sensors in the same place on the 4" exhaust since the injectors are shuffled around. The computer may have been confused if I left them for each bank and it would be controlling the wrong injectors. This made them read all of the O2 total but would see changes.
3. Removed upper intake and cutout injector harness from truck existing harness.
4. Placed the "layover" injector harness in the truck and moved pin 8 to 19 and 11 to 32 and 51 to 38 to start. I then pulled all the original truck pins cooresponding to the new harness and plugged in each pin.
5. Placed the O2 harness in the truck and the sensors, plugged in the pins and ran a chassis ground as well as a +12 volt to the O2 heaters. The +12 can only be hot when the key is on or it will burn up the heater leaving it on all the time.
Lastly, I dropped in the MAF and harness, plugging in the pins 50 and 9 and piggybacking 37 and 40 to get the MAF up. I then had to cobble together an air intake using some of the existing piping and the factory elbow.
I was so excited to hit the key, kind of expected it not to start, but it fired right up. Adjusted the idle and tps in the ball park and drove around the block.
I did notice the motor revs so quick now, timing and fueling must be way different on the MAF computer vs the truck speed density. The idle is so nice and smooth as well as the drivability is way better.

I need to install the computer in the holder and cut back some of the removed pins as well as clean up some of the wiring tomorrow. I'll shoot some pics, I promise, and upload them. I'm also gonna drive it on the road tomorrow and see how it goes.