tach signal, speedo problem

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turbojeeper
Making Progress
Making Progress
Posts: 76
Joined: October 11th, 2009, 8:04 pm
Vehicle Year: 1989
Vehicle Make: jeep
Vehicle Model: comanche
Location: dyess afb texas

tach signal, speedo problem

Post by turbojeeper »

ok to start off with my jeep is running on ms. i hooked up the tach signal wire to the negative on the coil and i am getting a tach reading but it is way off. tuner studios shows idle at 750-800 and it feels like that, but the tach says 1300 rpm. my rev limiter is set at 5300 and when i feel it hit the tach show 7000+ rpm. i know the pcm supplied the tach signal and i am wondering if i just nee to buy an aftermarket tach or what?

problem 2. the speedometer. i have 8 volts running to the sensor and the sensor grounded where the cluster is grounded (on block) with it hooked up i still get no mph but the weird thing is when i free rev or drive it the speedo jumps randomly with the rpm, but only when the speedo is hooked up. i already cleaned the crap off of the solder joints on the back of the cluster and at the connector, didnt change much. any ideas?
boosted Comanche on megasquirt, 8.90"s in the 1/8th. getting faster one step at a time!!
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vashxj
I made it to triple digits!
I made it to triple digits!
Posts: 193
Joined: August 10th, 2012, 8:46 pm
Stroker Displacement: 4.6
Vehicle Year: 1999
Vehicle Make: jeep
Vehicle Model: cherokee
Location: belvidere, il

Re: tach signal, speedo problem

Post by vashxj »

Is there anyway to find the wires for the crank signal and trans output signal and just tap into them right at the pcm
turbojeeper
Making Progress
Making Progress
Posts: 76
Joined: October 11th, 2009, 8:04 pm
Vehicle Year: 1989
Vehicle Make: jeep
Vehicle Model: comanche
Location: dyess afb texas

Re: tach signal, speedo problem

Post by turbojeeper »

There is no pcm anymore. Its on megasquirt now.so alk I have is the coil negative/signal from the squirt and speed sensor signal straight from the sensor
boosted Comanche on megasquirt, 8.90"s in the 1/8th. getting faster one step at a time!!
turbojeeper
Making Progress
Making Progress
Posts: 76
Joined: October 11th, 2009, 8:04 pm
Vehicle Year: 1989
Vehicle Make: jeep
Vehicle Model: comanche
Location: dyess afb texas

Re: tach signal, speedo problem

Post by turbojeeper »

Well the speedo works again. Sensor wasn't tight in the tcase and had spun away from the gear.
boosted Comanche on megasquirt, 8.90"s in the 1/8th. getting faster one step at a time!!
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