battery light on,no tach,trans wont shift.

So for those of you who have been helping me for awhile i am once again calling fo your help... This morning i have finally gotten a chance to drive my 91 f350 and ive noticed several issue that it now has that it didnt have before. first off i jump in started it up and noticed hey bettery lights on thats weird but guage shows its charging (havent gotten a meter on them yet) figure eh it will probably go away or something's just loose on the stsrter realy.. Second issue noticed the tach isnt working. it just sits at 0 the entire time. and finally when i started to drive i quiclly realized soemthing isnt right. the trans feels like its starting out in 3rd as it takes a little bit to get going from a stop unless i manually shift too mnl 1st and then i went up to two and didnt feel a diffrence and thenback to drive and it shifts and you are in third.. i dorve it work just down the road less than a mile and i noticed the overdrive light on my switch was indicating the overdrive was off which is true it will not shift out of third this trans is an e4od so im missing those last two gears.. would these be all related somehow? i looked over all the conectors I would have had contact with or could have messed with and couldnt not find anything out of place.

Someone with more experience will chime in.
If I remember correctly, your auto trans goes into "limp mode" when it looses signal from the tach.
That combined with battery light ... I'm not sure, I'd be looking for a damaged wire in your tach / trans circuit.

No tach could be caused by no power/ground to the TECA, check your fuses.

Kizer said:

Someone with more experience will chime in.
If I remember correctly, your auto trans goes into "limp mode" when it looses signal from the tach.
That combined with battery light ... I'm not sure, I'd be looking for a damaged wire in your tach / trans circuit.

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Ill check it out on my linc

Thewespaul said:

No tach could be caused by no power/ground to the TECA, check your fuses.

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just had a quick break from work ran out there looked around fuses were good. I did find a wire thst i forogt about when i rewired my glow plug main power its a little wire that was spliced into the old two wire glow plug wires on one big eyelet that goes to the hot side of the starter realy. stuck a eyelet on there and hooked it up. started it up and tach now works havent gotten to drive it yet butmy battery light is still on so possibly two diffrent issues?

I'd say it's very possible. As long as you are still running the original 1G style of alternator, you're gambling anyway (my opinion and others may agree). A very good, fairly inexpensive investment is a volt meter. This will tell you more than your factory gauge and the battery light will.

so it drove home fine shifted good no problems. the battery light is still on though and the huage isnt making sense it starts up and its about to the R in normal. and soon as it revs up or i drive it it goes to about between M and A in normal. before i left work i tested it and first time i looked at it my meter red 12.8... figured that the alternator was the problem and then i checked again just to be sure and it read 13.5 on both batteries on the terminals and the battery clamps.. so i drove home lights still on.. made it home and they are still reading 13.5. i tested it while its running and with my matco multimeter. I recently bought a serpantine belt setup i was going to install at some point off a 94 with the newer style alternator with the internal regulator. how difficult would it be to wire up this new style alternator ?

Nick_Rego said:

so it drove home fine shifted good no problems. the battery light is still on though and the huage isnt making sense it starts up and its about to the R in normal. and soon as it revs up or i drive it it goes to about between M and A in normal. before i left work i tested it and first time i looked at it my meter red 12.8... figured that the alternator was the problem and then i checked again just to be sure and it read 13.5 on both batteries on the terminals and the battery clamps.. so i drove home lights still on.. made it home and they are still reading 13.5. i tested it while its running and with my matco multimeter. I recently bought a serpantine belt setup i was going to install at some point off a 94 with the newer style alternator with the internal regulator. how difficult would it be to wire up this new style alternator ?

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Is it a 1 gen type alternator with this kind of connector? My RV's is weak and would wiggle loose, basically turning off the alternator. I put a small zip tie around it and forced it down in, and it holds much better and doesn't wiggle out. Maybe yours is loose or something? Just a thought.



Are also you saying your water temp gauge is wandering? Check your coolant level and see if your fan is turning. Early this summer (around May) when driving my RV in high wind with a weak fan clutch, my temp gauge was getting pretty high up at times. I've since installed an Equus mechanical water temp gauge so I know better the real temperate in degrees. It would run rougly 190-200F on fairly flat highways with the weak fan clutch. After putting on a new Motorcraft fan clutch and thermostat, it runs about 180-185F.

sorry i was referring too the voltage guage.

It may not hurt to double check your readings with another DVOM. Strange readings aside, I'd suspect either your voltage regulator or your alternator. One that I had would read only about 12.5 volts (give or take) for a while and then it would read 13.5 or higher. After I gave in and did the 3G swap last summer, it's always reading 14.2 or 14.3. These readings are by the voltmeter in my truck. While trying to diagnose this particular bad alternator, I found out that there's .1 volt difference between what this gauge reads inside the cab and putting my DVOM across the battery terminals while the engine's running. That's close enough to being accurate for me. I don't know what it takes to wire in the style of alternator that you have. Just what it took to wire in my aftermarket alternator. Didn't you say that you ended up with the whole truck? If so, you can compare the wiring between the two and that may help you with the wiring. From my experience, when a 1G alternator starts acting like yours is, it's only a matter of time until it quits completely.

IDIBRONCO said:

It may not hurt to double check your readings with another DVOM. Strange readings aside, I'd suspect either your voltage regulator or your alternator. One that I had would read only about 12.5 volts (give or take) for a while and then it would read 13.5 or higher. After I gave in and did the 3G swap last summer, it's always reading 14.2 or 14.3. These readings are by the voltmeter in my truck. While trying to diagnose this particular bad alternator, I found out that there's .1 volt difference between what this gauge reads inside the cab and putting my DVOM across the battery terminals while the engine's running. That's close enough to being accurate for me. I don't know what it takes to wire in the style of alternator that you have. Just what it took to wire in my aftermarket alternator. Didn't you say that you ended up with the whole truck? If so, you can compare the wiring between the two and that may help you with the wiring. From my experience, when a 1G alternator starts acting like yours is, it's only a matter of time until it quits completely.

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that is exactly what im affraid of. I do have the truck but we have already started gutting it i did dave the wires and avoided cutting anything as much as possible in the short time I have to get it all torn down. i also looked at the wiring diagram and looks like the early 94 7.3 wiring looks the same as a psd. i have a few wiring diagrams bit havent really done the research yet ..

im swapping to this setup with that alternator. it looks identical to the psd ones except the pulley is different.

its the internally regulated setup.. and my only hesitation is will it work how its supposed too and how long will it take.. so far every big modification ive tried to make ends up putting me further behind ...

heres what its looks like in the cab..

@Nick_Rego

Does the belt squeal when you turn the truck on or off ? Your alternator may be charging enough but the bearings that the belt system turns could be starting to fail putting resistance on the pulley. Causing the belt to slip which would be why your battery light is coming on , then you would need to swap alternators or upgrade

the tach issue can be solved by swapping out that sensor by the IP , But I would test the sensor first before throwing money at it.

does the OD light flash at you while driving down the road ?, can you manually shift the truck with ease ?

Slicknik said:

@Nick_Rego

Does the belt squeal when you turn the truck on or off ? Your alternator may be charging enough but the bearings that the belt system turns could be starting to fail putting resistance on the pulley. Causing the belt to slip which would be why your battery light is coming on , then you would need to swap alternators or upgrade

the tach issue can be solved by swapping out that sensor by the IP , But I would test the sensor first before throwing money at it.

does the OD light flash at you while driving down the road ?, can you manually shift the truck with ease ?

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I fixed the tach issue had a wire disconnected for power to the trans computer. the battery light however is still on i tried wiggling the wires on the back of the alternator. noticed two things one the ********* with orange wire i assume is the charge wire has a less than desirable looking connection.. and the other connector is pretty loose i pushed it further in hoping thst was is but the light is still on. drove home fron work and the guage is about half way on the guage. still reads 13.4...