Tach cutting in and out

[1993 F200]

Hello I am new to this forum and I have a 1993 idi NA that I have swapped over to 1/2 ton running gear and have lowered 6” it is having issues with the tach cutting in and out and it is not consistent when it cuts in and out besides it seems to happen after the truck is warmed up. I have had the gauge cluster rebuilt, TPS replaced, Cam sensor replaced wires at plug on harness look good, speed sensor on rear pumpkin replaced and I am at a loss now.
Any advice would be welcomed.

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[Clb]

Check the wires on the tach sensor wires on the timing chest by the filler...

 

[DirtyWood]

Is the signal cutting out and causing shifting problems with the E4OD?

 

[1993 F200]

I have checked the wires and replaced the tach sensor the wires from the harness look good.
Yes whenever the Tach cuts out and it will bounce up and down the trans freaks out and doesn’t know what gear to be in so it will start shifting up and down

 

[DirtyWood]

When the tach goes wonky do any other gauges fluctuate?

 

[1993 F200]

No all other gauges are acting fine

 

[Black dawg]

From what I remember, the tach goes to the ecm before it goes to the cluster. If the computer is in the stock location, water runs down, and if the connector isnt tight or sealed , water can get in. Also check the relay for the computer.

 

[1993 F200]

I replaced the TCM already also sorry I forgot to mention that in the original post it was about five years ago now but the truck has only been driven maybe 5,000 miles in that time the connection appears to be tight on the firewall.
That is the only computer I know of on this truck.

 

[Olds64]

You mentioned that you had the gauges rebuilt. Who rebuilt them, did you remove the entire instrument cluster and send it in for a rebuild?

 

[1993 F200]

It was speedometer NW in Tacoma WA and yes I sent the entire cluster to them and they went through it rebuilt everything they said and checked all components.
I also got a cluster from a junk yard and put it in and had the same issues

 

[1993 F200]

Is the signal cutting out and causing shifting problems with the E4OD?

Yes when the tach starts cutting in and out the transmission starts to shift up and down sporadically than if the tach resumes proper operation the transmission will shift perfectly

 

[rreegg]

Im not familiar with the auto trans but from other threads the trans control module may be worth looking at. (Think that’s the TCM?)

https://www.oilburners.net/threads/is-this-the-cause-of-my-intermittent-tachometer-issues.94564/#post-1159683

Tach issue help

Okay to cut to the chase. I have used 2 different tach sensors, my old one and a brand new one, and get the same results. Description of the problem, when cold, my tach does not work. The transmission (E4OD) stays in "what the hell" mode and I have to manually shift it down to 1st every time I...

www.oilburners.net

 

[DirtyWood]

Yes when the tach starts cutting in and out the transmission starts to shift up and down sporadically than if the tach resumes proper operation the transmission will shift perfectly

I think a lot of signs are pointing towards the TCM as the next point to examine.

 

[asmith]

I know a lot of guys like the after market transmission controllers for the e4od. Not sure if you can get one that will work with the IDI, but they seem to work a lot better and give you more control over the trans. If it is the TCM it might be worth looking into.

 

[1993 F200]

I know a lot of guys like the after market transmission controllers for the e4od. Not sure if you can get one that will work with the IDI, but they seem to work a lot better and give you more control over the trans. If it is the TCM it might be worth looking into.

Do you know where I could start looking at those? Like a website that is reputable