E40D, no tach or OD light, 2nd&3rd&R only - Diesel Forum

hydrant71 · 01-25-2008, 03:46 PM

94' idi turbo E40d auto- started when cold, put in drive, lugged off the line then noticed tach and OD light were inop. seems i have only 2nd, 3rd, and rev... must manually shift
and shifts hard. i believe it is in second when starting out, no shift when shifted
from 1st to 2nd????? replaced the tach sensor with no change, tach still inop.

wondering if i should attempt to repair tach problem as this might rectify other problems?????? is the tach sensor signal recieved by the tach then passed to the shift module or from module then to the tach?

where is the trans module by the way?

researced this trans on this forum for several hours, seems to be common problem, but not all of the symptoms seem the be exactly what i am experiencing.

going to go out and check all the connections- on the trans i can find including
trans right side under tin cover, make sure fluid is topped off, and check fuses.

really cold outside, any help would be appreciated

jason

cdnsarguy · 01-25-2008, 10:41 PM

Tach and speedo are vital to correct ops of the trans........ DO NOT drive in Limp Mode 2nd and reverse only.

A dead tach sender should/would send the automatic trans into a "failure management mode" (limp mode) with harsh engagements and firm shift feel and an abnormal shift schedule. It has no effect on a manual trans only the Tach readings.
Check the wires where they exit the big nut on the oil filler housing , known to short out due to bare wire.....
Replace the tach sender on the oil fill housing a big 1" nut with 2 wires. Ford only part Engine RPM sensor E5TZ-17B384-A about $50. You can remove and clean it but usually changed later too.
You can test it too, 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.

hydrant71 · 01-25-2008, 11:52 PM

thanks for your reply, for an update i replaced the tach sender this afternoon with no change in the problem. i did find maxi fuse #13 (20A) blown in the engine compartment fuse box. replaced the fuse and the tach worked again, trans shifted well and OD was also working, no longer in limp mode...............until
i drove it about a mile, maxi fuse #13 blew again, back to square one

at least i feel i'm getting somewhere

i don't have a owners manual or wiring diagram so i have no idea what curcuit #13 is protecting. went to buy a haynes manual at the parts store but the
manuals for the f350.s only covered gas engines. do the wire diagrams in the gas manuals cross over to diesels????????????????? i didn't think they would so i didn't buy one.

does anyone with a diagram know what maxi #13 protects and if there is a associated relay? it would be of great help

94' f350 7.3 idi factory turbo diesel, E40D auto.

thanks,

jason

hydrant71 · 01-26-2008, 12:59 AM

after looking at the top of my engine compartment fuse box again i believe i was reading the fuse location backwards, it looks like it's #22 which looks like it's
in the curcuit of the pcm relay and the fuel line heater according to a diagram on autozone.com, also a diode in the curcuit as well. i heard that the fuel line heater
can short out, will check that tomorrow as well as the pcm relay. may be on to something.

jason

cdnsarguy · 01-26-2008, 01:06 AM

How did you determine #13 all the engine fuse box info/pics I have shows ABCDE etc....... for the year truck you have.

PM me your email addy and I will forward what I have..........

hydrant71 · 01-26-2008, 01:51 AM

i think it's actually #22, read it upsidedown

cdnsarguy · 01-26-2008, 07:40 AM

Relay #1 is trans control and fuse 22 and the #12 diode . You can unplug the heater, black connector on the filter header.

hydrant71 · 01-26-2008, 06:43 PM

unplugged the heater and installed a new maxifuse, drove for about 20 miles without a problem. seems to be the fix. i don't know if i'm going to replace the fuel heater, seems to me that it really cant do that much considering it's size as far as heat output. thanks for the help cdnsarguy, and taking the time. this forum is a great resource and the info available with a little research gives me a lot of
confidence to tackle what this truck will trow at me. the electronic trans system
seemed complicated at first but is really pretty simple when you get down to it.
thanks again,

jason

ncjeeper76 · 02-06-2008, 11:11 PM

Im having the same problems with my 89 F 250 I have been all over the truck. Replaced the tach senser. if checked to see that I had current going to the ECM I have both battery and switched power going to it. I hooked a OBD tester to it and got NO codes at all. For a short time. it would start up and have the normal problem then after a few minutes the tach would work and the truck would shift fine.Now it has gone back to the old problem. the only time the tach moves is when the truck is cranking it will bounce a round 500 rpm then die as soon as the truck is running. could the ECM be fryed ? anyway to test it to make sure? Ford lists a replacement for $330
thanks
Jason

cdnsarguy · 02-06-2008, 11:17 PM

Do you have a dim TCIL light when on..........

ncjeeper76 · 02-06-2008, 11:54 PM

if you are talking about the OD light right now no

MendoJim94 · 02-09-2008, 06:39 PM

Sounds pretty familiar. Have you had the codes checked? 1994 is OBD-I
with EEC IV. A code 62 could mean your PCM is toast. There was a TSB from
Ford on this back in the 90's. I don't know what pin is tied into the tach and
TCIL light, but it kind of sounds like your PCM might be going belly up. Been there, done that, got the scars and bills to prove it. Good luck.