I have been trying to swap a 1996 LT1 engine and transmission out of a Cadillac Fleetwood into my 1986 el camino. I bought a digital dash because the old engine used a cable speedometer. The speed sensor in the transmission has 2 wires, and it seems to go to the ecm. The ecm has a speed wire that I hooked up directly to my dash. The speedometer has never worked. It sits reading 0 mph all the time. I used a multimeter on the wire out of the ecm, and it did have voltage that changed with the speed of the car, and changed when I was stopped. I sent the dash in, and they verified it works. Does anyone know why my speedometer does not work? I wonder if I need a speedometer filter, but there is no info on the internet that I could find on these things. It could be a ground issue, i guess, but I have no idea where it would need one that it does not have. I did replace the speed sensor while assembling the project, and had to change the plug on the 94-95 wiring harness I got with the engine to make it plug in to the speed sensor, but I was very careful to get the plug wires from getting hooked up backwards. The reading from the multi meter seems to prove everything is working somewhat, although I don't remember what range I was getting, and if its the right range for my dash. I do remember it was not exactly what I was expecting from reading the dash manufacturer's instructions to test for signal, but not that different. I think it was higher than expected.
One solution I thought of was to tap one of the wires from the sensor and take that to the dash, but I am afraid that would rob signal going to the ecm and cause problems. If I am wrong and I will have to do it this way, would I tap wire "A" or "B"? I did plan to hook up a cruise control unit, and that would possibly need to use the wire coming out of the ecm.
The car drives fine, except it shifts into overdrive at 50mph instead of 40mph, which I thought was odd, but could be right for that car it came out of. It goes up into the mid 2000's before shifting.
Thank you.

 

Which digital dash did you purchase? If it is Dakota Digital, they have very good product support and will readily assist you. They also have a very good online catalog for various parts that can help you.

Rick

 

I wish I did buy that one, but I bought one from Intellitronix. They don't know what the problem is, and have no advice for me.

 

Thanks for the suggestion. I will try Dakota Digital.

 

So.... Any ideas, anyone, or should I give up and try a gps unit?

 

Hello,

Forget about cruise control for now, My Dakota Digital dashboard can accept speed signals between 2000 and 250,000 parts per million (PPM) coming out of the PCM and I suspect this is your problem. We need to find what the PPM rate is coming out of your LT1 is and calibrate your Intellitronix dash to that. It was quite easy doing this with my DD dash and a P01 PCM and a 4L60E transmission during my initial speed calibration drives.

Your shifting problems in the last paragraph could easily be operating tune related problems inside your PCM. Your El Camino has a different tire height and a different rear differential gear ratio than the Cadillac Fleetwood that must be accounted for in the OS tune. Otherwise, your shift points and eventually . . . . eventually this will also matter to the accuracy of your speedometer.

Can you post a link to the Intellitronix web site for a downloadable copy of their user / installation manual, please?? As a fellow El Camino owner, I'm compelled to assist you here - mine is a 1970.

Rick

Rick

 

I can't edit my previous post . . . why is that???

Rick

 

https://www.intellitronix.com/_files...72e0bd72c2.pdf
Its on pages 5-6 about installation and calibration.

 

I tried the calibration procedure described, but it said error, and can't be calibrated. According to the instructions, that means it can't receive the signal. I suspect that since it has a signal a multimeter can detect, it has some kind of thing about the signal that is unreadable by my dash. I have tried to look for information on the Cadillac system, but there is not much I could find.

 

It seems that the instructions are certainly thorough enough. Your engine is not an LS so you might need to better figure out which pin has the speedometer signal. Have you tried using the Intellitronix Speed Sending Unit?

Rick

 

https://www.lt1swap.com/pictures/100_1591.jpg
Pin 8 from the black PCM connector is your speedometer output. Hook it up to the white wire on the cluster. It's a 4k output and per your instructions, it's set to 8k so you will have to recalibrate. If the PCM is a 96, it's OBDII. 94-95 were OBDI. Here's some more info on the differences. https://www.lt1swap.com/all_lt1.htm Unfortunately, reprogramming the PCM will be difficult as you need OBD2 software, which isn't cheap. If it were OBD1 it would be a cinch. Buy a cheapie OBD2 interface similar to this and some software and you can at least see what is going on. Hope this helps brudda.

Alex

 

That is for a cable driven speedometer. It's to adapt to the old powertrain system I replaced. The inability to connect a cable to this trans is the main reason for this dash.

 

[QUOTE=CapSS92;20490812]https://www.lt1swap.com/pictures/100_1591.jpg
Pin 8 from the black PCM connector is your speedometer output. Hook it up to the white wire on the cluster. It's a 4k output and per your instructions, it's set to 8k so you will have to recalibrate. If the PCM is a 96, it's OBDII. 94-95 were OBDI. Here's some more info on the differences. https://www.lt1swap.com/all_lt1.htm Unfortunately, reprogramming the PCM will be difficult as you need OBD2 software, which isn't cheap. If it were OBD1 it would be a cinch. Buy a cheapie OBD2 interface similar to this and some software and you can at least see what is going on. Hope this helps brudda.

Alex[/QUO
That is the right pin, and the multimeter indicates it is getting some kind of reading, so I don't know why it can't see the signal. Do you happen to know if these used a filter circuit to eliminate ignition interference?

 

All I can think of is a ground issue. Make sure your intellitronix dash ground is also connected to the PCM ground and engine block ground

 

The ground is only connected to the ground the original dash had. I don't know where it goes to, but probably just the body.