Trans electronics
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Trans electronics
I have been looking for the trans controller (TECA?) on my 91 F 250 diesel and can't find it. I believe it is causing some problems and may need replaced. Where is this thing at? I have a manual and it shows it's on the driver's side near the firewall but I can't find it.
The problem is I have a brand new rebuilt E4OD with all the upgrades and it's staring to "hunt." I have very few miles on it due to this. I'm also looking at the tach sensor since it doesn't read until you start to accelerate. I cleaned it but it's no better. Am I on the right track?
Thanks in advance!
The problem is I have a brand new rebuilt E4OD with all the upgrades and it's staring to "hunt." I have very few miles on it due to this. I'm also looking at the tach sensor since it doesn't read until you start to accelerate. I cleaned it but it's no better. Am I on the right track?
Thanks in advance!
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From: Pukalani, HI
Also, if it's hunting it may be due to the tach signal being lost. The tach may look like it's reading fine, but the trans is still not seeing it all the time. Change out the sensor and it should go away.
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What Doug said - tach sender failures are common for these trucks with old age and high mileage, a new one is like $50-60 and it's a dealer-only part. The sender lives on top of the IP gear cover, on the driver-side of the oil-fill neck, and it takes a 1" wrench to remove - pretty easy job.
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Guys,
Thanks!!! The tach sensor was my first instinct. What about the speed sensor?? I'm going to replace it as well. I know I'm throwing parts at it but as of now I'm keeping this truck for the long haul (no pun intended). I did remove and clean the tach snesor but it was no better afterwards. I'll start there and move on. Is it possible to test the trans control unit? I'd like to have it tested anyway. Long story short I bought this truck with a long laundry list of problems and they are rapidly going away. I've never owned a diesel before but I absolutely love this truck regardless of the price of fuel. Guys like you have really helped me out and I greatly appreciate it!!
Doug - how do you like the Baumann controller? Is it worth the extra $$
Thanks again!!
Thanks!!! The tach sensor was my first instinct. What about the speed sensor?? I'm going to replace it as well. I know I'm throwing parts at it but as of now I'm keeping this truck for the long haul (no pun intended). I did remove and clean the tach snesor but it was no better afterwards. I'll start there and move on. Is it possible to test the trans control unit? I'd like to have it tested anyway. Long story short I bought this truck with a long laundry list of problems and they are rapidly going away. I've never owned a diesel before but I absolutely love this truck regardless of the price of fuel. Guys like you have really helped me out and I greatly appreciate it!!
Doug - how do you like the Baumann controller? Is it worth the extra $$
Thanks again!!
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From: Pukalani, HI
I haven't gotten to drive it much yet, right after I got it running I had elbow surgery and it's on hold for now. BUT, I do like that it's totally adjustable for shift speed and you can have 2 programs, one for normal driving and one for towing, or whatever. There is a procedure for the tach sensor. Hold it in the air away from ferrous metal, using an ohm meter lead on each wire you need DC resistance between 2000-3000 ohms.
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My tach sender passed that test, but it was still acting up - funny thing is the trans never picked it up, as the sender was only malfunctioning for short times every now and then, and I guess I never spent enough time idling for the PSM to figure it out and throw a code. I now run a sender I yanked from a junkyard truck, and it seems to be doing great, but if it ever fails I have yet another junkyard sender, and next time I go if there's a tach-equipped diesel Ford I'll snag the sender off that one too (they are free).
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a resistance test is of no real value on the tach sensor unless it has an open coil
the only real test that ford found of real value is to use a hertz meter and check its frequency at different engine speeds
there was in the beginning of the E4OD to check the sensor for a/c voltage with the engien running but that was found to be a faulty test since a bad sensor will still generate a/c voltage
the only real test that ford found of real value is to use a hertz meter and check its frequency at different engine speeds
there was in the beginning of the E4OD to check the sensor for a/c voltage with the engien running but that was found to be a faulty test since a bad sensor will still generate a/c voltage
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Thanks again. I checked it and couldn't get it to do anything. Bought one from a junk yard and the tach worked worse and same symptoms. Called tranny shop and they said it's either that or the TPS (FIPL sensor) needing set. I've set it based on the directions I was given here and double checked it. I'm going to get a new tach sensor and be done with it. Once i get that straightened out then it's going in to have the FIPL sensor checked. It's new as well but I want it set by someone with better tools and more experience than I have. Thanks again for all the help!!
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if you still have tach issues after replacing the sensor beaware that these trucks are old enough that they do have wiring issues developing from age
the insulation becomes brittle and sometimes if the harness is disturbed the wire breaks internally
sometimes you have to overlay the harness with a new wire or two , i have many timers had to do so especially with the fipl wires , you simply cut the wire a few inches from the connector splice in a new piece all teh way to the processor and repeat the process there
also use butt connectors that are heat shrinkable or use solder and heat shrink tubing
the joints need to be water tight
on computer control systems the processor doesnt need current on a circuit just the presence of voltage so any water can short voltage into the wrong place and cause all kinds of issues
the insulation becomes brittle and sometimes if the harness is disturbed the wire breaks internally
sometimes you have to overlay the harness with a new wire or two , i have many timers had to do so especially with the fipl wires , you simply cut the wire a few inches from the connector splice in a new piece all teh way to the processor and repeat the process there
also use butt connectors that are heat shrinkable or use solder and heat shrink tubing
the joints need to be water tight
on computer control systems the processor doesnt need current on a circuit just the presence of voltage so any water can short voltage into the wrong place and cause all kinds of issues
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Thanks!!!! I was going to ask what to do if that didn't fix the problem but I didn't want to get ahead of myself before I tried the other fixes. Do you happen to know what gauge wire that is? I've been thinking about re-wiring the entire engine compartment anyway due to old wiring and the heat developed by the diesel. I have found some harnesses in junk yards that are better than mine but I believe for a 91 I need one from an 89 - 91. Is this correct? I really like the 92, I believe, harness that is all on the driver's side and doesn't wrap around the front like the 91. First things first though. Tnaks again for your help!!
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89-91 alright , 92 changed due to body change for the 92
i,m not big on rewiring it unless you have a new or a good used harness
when you start cutting and splicing that many wires it usually ends up with wiring issues
as far as the wires for the sensors 16 or 18 gauge is fine there is no current involved
and if this doenst fix the tach , you could have a bad tach or the processor is bad
the sensor feeds directly to the processor it then passes the tach signal through completely different wires to the tachometer
i,m not big on rewiring it unless you have a new or a good used harness
when you start cutting and splicing that many wires it usually ends up with wiring issues
as far as the wires for the sensors 16 or 18 gauge is fine there is no current involved
and if this doenst fix the tach , you could have a bad tach or the processor is bad
the sensor feeds directly to the processor it then passes the tach signal through completely different wires to the tachometer