HELP!!! O/D light dim and stays on, afraid in limp mode

[madvillepocket]

Ok so here we go... I've got a 1990 Ford F250 4x4 with a 7.3 idi. Only has 106k miles on and runs like a champ....sometimes lol for starters, the O/D light is always on, the tach does not work when running (does bounce like its trying to work when turning the engine over), the speedo starts on 15 mph, the battery light is on and won't hold a charge. Now on to what all I've done so far... I've replaced the tach sensor with a new one, new EEC relay, checked all fuses (all are good), cleaned both side plugs on transmission, cleaned EEC plug,cleaned tach sensor plug and put dielectric grease in all mentioned plugs to no avail. So what or where do I look next? I'm beginning to get more and more frustrated cause it has to be something simple cause the idi is a simple design, I just can't figure it out so I'm hoping that someone can please help me figure this out so I can get my truck back on the road. Thanks guys

 

[IDIoit]

if you had a ZF5, you wouldnt have an OD light
BTW welcome to the forum.
try introducing yourself

 

[bigfoot]

Is the OD light always on, or is it always flashing? Flashing means limp mode. read the tech article about the FIPL. I just bought a replacement from the dealer, about $70. but before you buy a replacement, check yours for proper voltage. Next, check your vehicle speed sensor. not sure where it is on a '90. both the VSS and the FIPL have to be working to get your tranny out of limp mode. Is your alternator charging properly? check the codes if you have a reader. there are plenty of here more knowledgeable than me, but those are starters. you'll get if figured out eventually.

 

[laserjock]

Okay, you have to have a good tach signal for the E4DOA to work. It needs inputs from the FIPL, tach and vss I believe. One of the trans gurus will chime in.

 

[madvillepocket]

Well I've already replaced the alternator with a new one and had it tested to make sure it was good prior to buying. Now as far as the FIPL, what does that stand for and can I get one at a local store? Also a location would help lol also the od light stays on, it does not flash

 

[gandalf]

Well I've already replaced the alternator with a new one and had it tested to make sure it was good prior to buying. Now as far as the FIPL, what does that stand for and can I get one at a local store? Also a location would help lol also the od light stays on, it does not flash

The FIPL is located on the driver's side of the IP. It is adjustable, done very carefully. Instructions are scattered around the forum.

Most of us are visually oriented, so I'll toss in a picture. The FIPL is the black thing, just to the right of the white hanging tag, in my picture. It has 3 wires coming out of it.

 

[Deathstar182]

I'd open up the dash and clean the connections behind the cluster. it could be as simple as that.

 

[Deathstar182]

and Gandalf, that is a gorgeous IP if it happens to be yours

 

[FORDF250HDXLT]

your issue isn't the tach sensor,vss nor the fipl(tps).

the problem is the TECA not getting power or the TECA is bad.without power to the TECA,the tach doesn't work either.there's no sense in replacing the tach sensor in hopes you make the dim od light go out.
pull the TECA harness (10 mm bolt) and test for power with the key on at pin 35 and insure you get 0 ohms between pin 60 and battery terminal - (negative).

it's imperative you resolve your battery light/charging issue first.

 

[FORDF250HDXLT]

if you had a ZF5, you wouldnt have an OD light

no,you'd have a noisy transmission instead.

 

[trackspeeder]

Did you check the voltage regulator.

Low voltage will make the TCM have a fit.

 

[sjwelds]

no,you'd have a noisy transmission instead.

Hey at least it would work!

 

[FORDF250HDXLT]

Hey at least it would work!

so did Henry's motel t's lol.all in what ya want i suppose.

 

[davlun]

I went through this recently. http://www.oilburners.net/forums/sh...40D-in-limp-mode-No-Tach-Help-Identify-Relays

Mine turned out to be relays. With the help of some experts I replaced my old relays with the newer style using newer, easy to change bosch relays.

 

[LCAM-01XA]

I went through this recently. http://www.oilburners.net/forums/sh...40D-in-limp-mode-No-Tach-Help-Identify-Relays

Mine turned out to be relays. With the help of some experts I replaced my old relays with the newer style using newer, easy to change bosch relays.

That won't help if he has no power to feed the TECA relay to begin with tho. There is a fuse link on the passenger side of the engine bay that is responsible for just that, the factory electrical manual calls it "Fuse Link P" - it's a 20-ga fuse link that powers the TECA relay and also provides constant battery power (for memory purposes among other things) to the TECA brain itself. That's actually what one of the two wires coming off that fuse link does, the other powers the DRL module (Canadian vehicles only), the work lamp if you have one, and the 15-amp fuse #1 under the dash for essentially the brake lights. It's a cheap and dirty design, the TECA really stuff should have its own dedicated power supply, but that's not what Ford came up with. To make things even more interesting there are several fuse links in that location, at least two of them 20-ga and blue in color, and the harness wires hooked up[ to them are often discolored bad enough for some yellow to turn white and some brown. Oh, and you really wanna pull the passenger=side battery if you're going to be working in that area, it's a bit on the tight side... So yeah, make sure the TECA relay is actually receiving 12V battery voltage first.