Fail safe mode / Custom tuning
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 23
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From: Vancouver, Canada
Fail safe mode / Custom tuning
2003 Ford f150
4.6l V8
Shorty headers
Throttle body spacer
True dual exhaust (No catalytic converters) no O2 sensors, where the back of the cat was.
the truck recently went into fail safe mode.
I'm looking for a tuner that has a custom tune to get rid of the rear O2 sensors and get my truck back up an running.
any help?
4.6l V8
Shorty headers
Throttle body spacer
True dual exhaust (No catalytic converters) no O2 sensors, where the back of the cat was.
the truck recently went into fail safe mode.
I'm looking for a tuner that has a custom tune to get rid of the rear O2 sensors and get my truck back up an running.
any help?
5 Year Member
Joined: Sep 2016
Posts: 258
Likes: 31
From: California
but don’t increase the shift pressure or it will eat your transmission. You need the shift kit and the heavy duty transmission rebuilt kit If you want to use that feature with out causing major damage.
You also dont don’t need a custom tune unless change ur cam or put a supercharger. I wasted money of custom tunes and found the tune that comes in the device is better.
Reason being once you pick what octane you want to run in the truck it loads a tune specifically Set up to help boost your truck overall performance and then it has option to tweak it until you find what works best for you. I can tune mine to get horse power gains or to get better fuel economy on the highway.
Last edited by Duces2you; Jun 1, 2018 at 10:44 AM.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 23
Likes: 0
From: Vancouver, Canada
SCT makes the best one. It comes ready to go out of the box. U can delete those O2 sensors, shut off the EGR, change timing, speed limit, rev limit, fuel pressure, shift pressure, change the octane level
but don’t increase the shift pressure or it will eat your transmission. You need the shift kit and the heavy duty transmission rebuilt kit If you want to use that feature with out causing major damage.
You also dont don’t need a custom tune unless change ur cam or put a supercharger. I wasted money of custom tunes and found the tune that comes in the device is better.
Reason being once you pick what octane you want to run in the truck it loads a tune specifically Set up to help boost your truck overall performance and then it has option to tweak it until you find what works best for you. I can tune mine to get horse power gains or to get better fuel economy on the highway.
I honestly haven't heard that about shift pressure before. Mine was a little slow between gears so I bumped it 20% I think and have had no problems in the past few thousand miles. The way I heard it was that it makes the band's last longer because they are not in contact with moving parts as long.
98 F150 5.4L E40D/4R100
Joined: Nov 2006
Posts: 28,533
Likes: 7,638
From: MI
Shorty's = worthless on these engines. They are and always have been the wrong headers for performance and sound. A dyno tune can increase HP numbers way up high into the rpms. But the gain is so little and so far up, it's hardly worth mentioning. However, you won't hurt a thing running them and they look better than OEM if that's what you were going for.
Spacers are useless unless it's plumbed to run injection...100 shot. BUT but itself, - won't hurt anything if your after the look or funky sound some of them make.
TD's/no cats is borderline nuts to run w/o custom tuning. The engine will be well down on torque and power. So bad, the truck won't be able to get out of it's own way. Long term, I'm not sure how long it will stay running with the original tune. The AF's will be far from right, so far out the engine will run incredibly lean until it gives out....dangerously lean is more like it. You most definitely NEED a custom tune to run that set up, if it's not too late that is. FS mode...not a good sign.
Spacers are useless unless it's plumbed to run injection...100 shot. BUT but itself, - won't hurt anything if your after the look or funky sound some of them make.
TD's/no cats is borderline nuts to run w/o custom tuning. The engine will be well down on torque and power. So bad, the truck won't be able to get out of it's own way. Long term, I'm not sure how long it will stay running with the original tune. The AF's will be far from right, so far out the engine will run incredibly lean until it gives out....dangerously lean is more like it. You most definitely NEED a custom tune to run that set up, if it's not too late that is. FS mode...not a good sign.
I concur wholeheartedly. Take a look at franchimotorsports.com if you want to pick up a used SCT for the lowest I've seen out there. I would say wait for one to pop up on Craigslist but your situation doesn't sound like waiting is a good idea.
Senior Member
Joined: Dec 2015
Posts: 23,203
Likes: 8,625
From: Utah
TD's/no cats is borderline nuts to run w/o custom tuning. The engine will be well down on torque and power. So bad, the truck won't be able to get out of it's own way. Long term, I'm not sure how long it will stay running with the original tune. The AF's will be far from right, so far out the engine will run incredibly lean until it gives out....dangerously lean is more like it. You most definitely NEED a custom tune to run that set up, if it's not too late that is. FS mode...not a good sign.
Listen to Brew, OP.... he is telling you the 100 percent truth.
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Thread Starter
Junior Member
Joined: Oct 2017
Posts: 23
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From: Vancouver, Canada
Ok so PROBLEM SOLVED!!!
Transmission was in fail safe mode because fuse 23 was blown.. thought i checked them but missed it.
fuse 23 kept blowing.. because the wiring harness for the o2 sensors were rubbing up against something, got down to the bare metal and arced.
Heat shrinked wire and ran it a different route, no more problems.
but thanks for all the info, im gonna be ordering something this week get the engine tuned right up.
Transmission was in fail safe mode because fuse 23 was blown.. thought i checked them but missed it.
fuse 23 kept blowing.. because the wiring harness for the o2 sensors were rubbing up against something, got down to the bare metal and arced.
Heat shrinked wire and ran it a different route, no more problems.
but thanks for all the info, im gonna be ordering something this week get the engine tuned right up.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 23
Likes: 0
From: Vancouver, Canada
SCT makes the best one. It comes ready to go out of the box. U can delete those O2 sensors, shut off the EGR, change timing, speed limit, rev limit, fuel pressure, shift pressure, change the octane level
but don’t increase the shift pressure or it will eat your transmission. You need the shift kit and the heavy duty transmission rebuilt kit If you want to use that feature with out causing major damage.
You also dont don’t need a custom tune unless change ur cam or put a supercharger. I wasted money of custom tunes and found the tune that comes in the device is better.
Reason being once you pick what octane you want to run in the truck it loads a tune specifically Set up to help boost your truck overall performance and then it has option to tweak it until you find what works best for you. I can tune mine to get horse power gains or to get better fuel economy on the highway.