No speedometer
August 2nd, 2015, 7:16 PM
#1
CF Beginner
Thread Starter
Join Date: Aug 2015
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
No speedometer
Hello everyone I'm trying to get my speedometer fixed after 6 years of not having one it quit working when I removed the ecm when I put the carb on it is there anyway I can get it to work without putting a computer back into it?? Any help or insight would be greatly appreciated
August 2nd, 2015, 10:37 PM
#2
No speedometer
It has to have the ecm. Why did you pull it just to put a carb on? Are you running manual guages for temp and oil pressure?
Last edited by burnhedge; August 2nd, 2015 at 10:46 PM.
August 2nd, 2015, 10:51 PM
#3
CF Beginner
Thread Starter
Join Date: Aug 2015
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Never had a problem with the temp and the oil pressure I pulled the ecm when I put the carb on because at the time that was the third ecm the truck had eaten so I pulled it and tossed it in the trash..the oil pressure and temp senders I had to rewire to work without the ecm I was wondering if I could do the same with the speedo
August 2nd, 2015, 11:39 PM
#4
No speedometer
Well hopefully someone will post some better info for you. I've only done the carb swap with the ecm intact. I don't see why the vss couldn't bypass the ecm.
All my trucks are 4x4 so I'm not sure if the vss on a 4l60 could be swapped with a mechanical system off a old 700r4 with a mechanical speedo. Might be something to look into as well.
All my trucks are 4x4 so I'm not sure if the vss on a 4l60 could be swapped with a mechanical system off a old 700r4 with a mechanical speedo. Might be something to look into as well.
August 3rd, 2015, 9:02 AM
#5
CF Beginner
Join Date: Aug 2015
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Thats a toughie. The ECM computes the speedometer pulses and translates it into the dash. As a certified mechanic since 1970, I am puzzled why your ECM's supposedly went bad. Fairly rare for a ECM to actually fail. Most in the field are returned to repair facilities where they don't find anything wrong with just the ECM. Ecm's have battery+ voltage inputs and grounds that should be tested before determining that the ECM failed. A engine lasts much longer and runs much better with an ECM than a carburetor. Better gas mileage and etc. However for the novice, carbs are a lot easier to deal with. A good wiring diagram is critical to troubleshooting why an ecm doesn't function.
August 5th, 2015, 9:05 PM
#6
CF Beginner
Join Date: Aug 2015
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
BTW, the vss sends an ac frequency signal to the ECM. The signal coming out of the ECM is a digital pulse signal that the ECM sends to the Speedometer display. I believe that the ECM signal is different than the signal it receives from the VSS, but don't know the exact form.
Thread
Thread Starter
Forum
Replies
Last Post