[91justforfun]

I have a 91 XLT5.8 litter and it has issues a-- lot of issues I bought it from a mother and daughter that just got tired of fixing it. My issues are running super rich lack of power and high idle I originally changed the egr from top to bottom the idle control valve map pcv some of the vacuum lines managed to get all codes fixed no more check engine light but it's just going to foul Everything again if I can't get air fuel mix to optimum not to mention$6.75 a gallon for gas! And then I had to swap rear end due to catastrophic failure I thought I got lucky when I checked the door tag they should have matched but they seemed to be off just a hair ..so now I need to find a way to make my rear drive shaft longer or possibly swap the flanged yoke on the transfer case to a slip in cause that's what came with the rear end from the diner truck my flanged shaft is too short it's trying to pull the seals from both sides out . Help if you have ideas or know of a way to get the only vehicle I have I can use for work and my kids!

 

[slimpartywagon]

Wow lots of issues… The truck axle… is it an 8.8 from an F-150? The driveshaft length shouldn’t have changed from swapping axles. Driveshaft length changes with either lift or transmission swaps. You need to swap the axle yoke from the truck axle back to the bronco axle side yoke if they are different. The axle doesn’t care if the transfer case is a slip yoke or fixed yoke… fixed yokes are stronger than slip yokes, so I would stay fixed yoke.

High Idle:
Have you reset the ECU after replacing/repairing the IAC, EGR, and vacuum lines? Is the Throttle Position Sensor working correctly? Battery at proper voltage (12.5-13 Volts Resting)? Alternator charging at 14.5+ Volts? Battery Cables good? What is your Fuel Pressure? Timing? Is the Engine Coolant Temp Sensor working correctly?

 

[JScatt]

One thing that can cause a rich condition like you describe is the coolant temp sensor(ECT sensor), not the sender for the gauge but the sensor that tells the computer what the coolant temp is then the air/fuel mixture is adjusted by the computer. It can be tested with a multi-meter.

 

[Kingfish999]

the driveshaft has a slipyoke in it. you probably had to compress it some to disconnect it. just extend it again. the driveshaft should be long enough for most people even up to 6" of lift.

unless it is seized. in that case you might need a new driveshaft. but even then you can usually bang the slip yoke off, clean and grease it

 

[MS88Bronc]

If you were/are running super rich, caused by things mentioned above, you may have fouled your O2 sensors too. You may try cleaning the soot off of them or replacing them, since they aren't too expensive.

 

[91justforfun]

Wow lots of issues… The truck axle… is it an 8.8 from an F-150? The driveshaft length shouldn’t have changed from swapping axles. Driveshaft length changes with either lift or transmission swaps. You need to swap the axle yoke from the truck axle back to the bronco axle side yoke if they are different. The axle doesn’t care if the transfer case is a slip yoke or fixed yoke… fixed yokes are stronger than slip yokes, so I would stay fixed yoke.

High Idle:
Have you reset the ECU after replacing/repairing the IAC, EGR, and vacuum lines? Is the Throttle Position Sensor working correctly? Battery at proper voltage (12.5-13 Volts Resting)? Alternator charging at 14.5+ Volts? Battery Cables good? What is your Fuel Pressure? Timing? Is the Engine Coolant Temp Sensor working correctly?

• I'm not sure about the coolant sensor, the radiator hoses are always hot and seems like high pressure, radiator always erupts when I attempt to remove cap but the gauge never reads hot and it never seems to overheat? I've flushed it with just water and a store bought kit but it's still seems pressurized.

 

[MS88Bronc]

• I'm not sure about the coolant sensor, the radiator hoses are always hot and seems like high pressure, radiator always erupts when I attempt to remove cap but the gauge never reads hot and it never seems to overheat? I've flushed it with just water and a store bought kit but it's still seems pressurized.

The ECT sensor is separate from the coolant temp sender that runs the dash gauge. The ECT sensor tells the PCM what the operating temp is so that it can adjust timing, idle speed, and meter fuel correctly based on temperature. A faulty ECT sensor can and will cause incorrect fuel mixture.

 

[91justforfun]

As far as rear end yes F150 but the diff I believe is a 9" the one I used to have I believe was an 8.8 which I think is where I ran into the issue with drive line the rear shaft is much longer and original to . short I believe if I remove the yoke from front of shaft and replace with slip how much trouble. is it to remove flanged yoke from the diff ,and will the slip yoke then work with the diff or will it pull out when suspension is at its most extended ? That's why I thought the flanged shaft has the expansion so it could stretch when necessary and not pull out due to being bolted at both ends? I'm not sure how far it will go before it pops out of diff or if it will work both ways because of the joint in the middle can compress and slip can slide out without going too far?

 

[91justforfun]

The ECT sensor is separate from the coolant temp sender that runs the dash gauge. The ECT sensor tells the PCM what the operating temp is so that it can adjust timing, idle speed, and meter fuel correctly based on temperature. A faulty ECT sensor can and will cause incorrect fuel mixture.

Thanks I'll check and replace sensor if needed .

 

[91justforfun]

Thanks I'll check and replace sensor if needed .

Also I've changed the thermostat and even just removed it the temp never changes as far as the gauge says and it doesn't change the outcome of the pressure in system so I just replaced the thermostat and left it without seeing any difference in the system? I can only imagine a partial block somewhere internally.the core is clear heater works great ,with thermostat in or out no different can't figure out if block is the issue or some internal blockage? Like I said it has issues. But as I only paid $200.00 for the truck I can't find the heart to sell it. Desperate to solve it's problems it's a perfectly straight body interior is in great shape only issues with appearance is bent gas flap and a few small surface rust spots on hood and cowling that I'm pretty sure I caused removing the flaking clear coat with some rubbing compound and scotch Brite? I had expected to re paint the silver and leave the charcoal part as is I'm not real fond of the two tone anyway.but haven't had time or money to do everything at once .like I said I have 4 kids living at home still from 19-10 yrs old and doing it myself for 12 yrs. Which means I have no savings account and live basically payday to payday and as I'm self employed they aren't always consistent or the same amount. So when I have some extra cash I try to get the things I need most or can afford.otherwise it just sits waiting to be reborn . It's getting to the point where I may have to sell her cause it's to hard to work without a truck to haul tools and or materials.

 

[91justforfun]

The ECT sensor is separate from the coolant temp sender that runs the dash gauge. The ECT sensor tells the PCM what the operating temp is so that it can adjust timing, idle speed, and meter fuel correctly based on temperature. A faulty ECT sensor can and will cause incorrect fuel mixture.

Thanks I'll check it.i really appreciate any and all help.

 

[91justforfun]

I have to apologize for my ranting I've never used a forum before so I'm having a bit of trouble following but I'm hoping to get the hang of it soon? It's a bit different than just sending a message I have to figure out how to scroll through the replies to keep on tract with the conversation I'm not real computer savvy or anything like it ie phone, tablet so please bare with me I really do need the advice. Thanks

 

[jermil01]

No worries..you can use the mult-quote function rather then responding to each post individually...

with regards to the rear end, you're '91 had an 8.8 that probably has the VSS (vehicle speed sensor) in the rear diff..the 9 inch does not have a provision for that.would have been easier to source another 8.8..

If your temp never changes,it's likely your temp sender is bad..the temp sender can be found on the lower intake near the front on the drivers side..It has a press on fitting that goes onto the temp sender post. If you ground the post out and the gauge still doesn't move that's your problem..

 

[slimpartywagon]

As far as rear end yes F150 but the diff I believe is a 9" the one I used to have I believe was an 8.8 which I think is where I ran into the issue with drive line the rear shaft is much longer and original to . short I believe if I remove the yoke from front of shaft and replace with slip how much trouble. is it to remove flanged yoke from the diff ,and will the slip yoke then work with the diff or will it pull out when suspension is at its most extended ? That's why I thought the flanged shaft has the expansion so it could stretch when necessary and not pull out due to being bolted at both ends? I'm not sure how far it will go before it pops out of diff or if it will work both ways because of the joint in the middle can compress and slip can slide out without going too far?

It would be cheaper and easier to get a new OEM style driveshaft built to the correct length than swapping to a slip yoke t-case.

As for your idle as we keep saying check the engine coolant temp sensor voltage readings… you should have a reference voltage of 5 volts, and a fluctuating voltage for different engine operating temps.

 

[Kingfish999]

you dont want to convert to a slip-yoke t-case. thats alot of work, money and you will introduce a vibration. also then your driveshaft would have 2 slips and thats not good. you wouldstill need a new driveshaft made. you would have to find a slipyoke t-case as you cannot easilly convert from fixed to slip without a donor t-case and full disassembly. in short your idea will not work

i myself havent done an 8.8" to 9" swap but they are suppose to be pretty direct swap. i usually swap to 10.25" which require a shorter driveshaft post a pic of the axle so we can see if it is an 8.8" or 9"

maybe post a pic of what your driveshaft currently looks like? then maybe we can judge what the best approach is. or what the issue is

1990 and newer trucks use flanges while 89 and older use yokes. not to mention you probably have an E4OD trans. so finding a stock driveshaft from the donor 9" truck (1986 or older) which probably had C6, different t-case, and uses yokes. so the donor driveshaft is not an option

having a local shop build you a new driveshaft is an option. but i would save that for last resort if your driveshaft is really not going to work

because you have a flange a the t-case, they do make small 3/4" spacer to extend the driveshaft alittle bit if needed. again thats would be more a last resort option if yours will not work

Aluminum Driveshaft Spacer-Broncograveyard.com

This is an OEM driveshaft u-joint.br Don't settle for anything other than the best, go with a Dana/Spicer u-joint.br Comes with clips and zerk fitting.br br Greasable 1350 U-joint.br 5-178xbr

shop.broncograveyard.com

the stock driveshaft can extend a decent bit before it becomes an issue of poping out. this is why i would take a pic so we can see it

a new driveshaft is normally like 250-350 bucks to get made. any cheaper than that will probably fail quickly. then again most aftermarket driveshafts seem to fail quickly. i would not be surprized if a good shaop charges alot more than that.

 

[slimpartywagon]

you dont want to convert to a slip-yoke t-case. thats alot of work, money and you will introduce a vibration. also then your driveshaft would have 2 slips and thats not good. you wouldstill need a new driveshaft made. you would have to find a slipyoke t-case as you cannot easilly convert from fixed to slip without a donor t-case and full disassembly. in short your idea will not work

i myself havent done an 8.8" to 9" swap but they are suppose to be pretty direct swap. i usually swap to 10.25" which require a shorter driveshaft post a pic of the axle so we can see if it is an 8.8" or 9"

maybe post a pic of what your driveshaft currently looks like? then maybe we can judge what the best approach is. or what the issue is

1990 and newer trucks use flanges while 89 and older use yokes. not to mention you probably have an E4OD trans. so finding a stock driveshaft from the donor 9" truck (1986 or older) which probably had C6, different t-case, and uses yokes. so the donor driveshaft is not an option

having a local shop build you a new driveshaft is an option. but i would save that for last resort if your driveshaft is really not going to work

because you have a flange a the t-case, they do make small 3/4" spacer to extend the driveshaft alittle bit if needed. again thats would be more a last resort option if yours will not work

Aluminum Driveshaft Spacer-Broncograveyard.com

This is an OEM driveshaft u-joint.br Don't settle for anything other than the best, go with a Dana/Spicer u-joint.br Comes with clips and zerk fitting.br br Greasable 1350 U-joint.br 5-178xbr

shop.broncograveyard.com

the stock driveshaft can extend a decent bit before it becomes an issue of poping out. this is why i would take a pic so we can see it

a new driveshaft is normally like 250-350 bucks to get made. any cheaper than that will probably fail quickly. then again most aftermarket driveshafts seem to fail quickly. i would not be surprized if a good shaop charges alot more than that.

I just had a shop build me two shafts (front and rear) for $500.00

 

[Gunfixr]

For the rear end, if the truck has had a 9" rear put in it, your simplest solution is to go back to an 8.8". Your driveshaft fits, you can plug the sensor back in. Plus, i've never checked this, but if the u-joint sizes are not the same, your custom made driveshaft will use different sized u-joints at each end. Both sizes will be available, you'd just have to remember which end you're dealing with when buying, to get the right ones.
I'd source the 8.8" from a junkyard, then sell the 9" to get your money back. You may find a junkyard willing to swap, as there's probably more 8.8s floating around junkyards now than 9s.

 

[Kingfish999]

the speed sensor on a 91 would only be for ABS so thats not really much of an issue

generally speaking, if the u-joint uses u-bolts to hold it in, it will use a 1330 'Big Cap' (sometimes called a 1330F). If it uses a flange like his original axle, it will use a standard 1330 u-joint. since they started using the flange in 90, his truck originally used a 1330 standard u-joint, the 9" uses a 1330BC, the earlier 8.8" also used the 1330BC.

the 1330BC was fords idea that it will use slightly larger caps for 2 of them so the u-bolts have less chance of crushing them. the front driveshafts use 1330BC for both ends

he also hasn't confirmed he has a 9", he said he thinks its a 9"

easy way to tell a 9" is there is no removeable differential cover in the back. the center of the axle bolts in from the front

an 8.8" axle does have removeable diff cover in back. the center does not bolt in

 

[Caddylackn]

I would be your rich condition and poor idling is caused by a faulty throttle position sensor (TPS).
These are easy to test with an ohmmeter.

 

[Gunfixr]

the speed sensor on a 91 would only be for ABS so thats not really much of an issue

generally speaking, if the u-joint uses u-bolts to hold it in, it will use a 1330 'Big Cap' (sometimes called a 1330F). If it uses a flange like his original axle, it will use a standard 1330 u-joint. since they started using the flange in 90, his truck originally used a 1330 standard u-joint, the 9" uses a 1330BC, the earlier 8.8" also used the 1330BC.

the 1330BC was fords idea that it will use slightly larger caps for 2 of them so the u-bolts have less chance of crushing them. the front driveshafts use 1330BC for both ends

he also hasn't confirmed he has a 9", he said he thinks its a 9"

easy way to tell a 9" is there is no removeable differential cover in the back. the center of the axle bolts in from the front
View attachment 197865
View attachment 197867


an 8.8" axle does have removeable diff cover in back. the center does not bolt in
View attachment 197870

View attachment 197869

I said "if" as I know he has not confirmed yet......
Good to know on the u-joints, I had never researched it, or compared, as it had never become necessary.