Sorry, I searched but couldn’t find what I needed. If I were to switch to an auto tuning EFI system can I keep my digital dash functional? 87 383cu in

 

Your need to ask the supplier of the auto-tuning ECM if this can be done. As for your post here, you didn't even mention who they are. Let along whether anyone here would even know.

RBob.

 

I don't understand why people think the ECM is so involved with the functions of the dash. The oil pressure and engine temp are from sensors that can be transferred from your existing engine, or perhaps they don't change at all. Speedometer in these cars is direct to the transmission, there is no ECM interface. That only leaves the tach, I can't imagine ANY engine control isn't going to have a tach output, or you can hook to the negative side of coil 1 to pick up a tach signal if it is C.O.P.

 

Pretty sure that depends... There are a few different setups. Some thirdgens, the signal is generated at the physical speedometer, then gets processed by the VSS buffer, then goes to the ECM and cruise. Some the signal goes from the transmission to the ECM that makes the calculation, which is then sent to the cluster and cruise control. In some cases you may be able to take the ECM out of the circuit, but you might need to add the VSS buffer or lose cruise.

Best bet is to refer to your trusty Helm epic novella about the young boy named El Servico Manuel. And find the diagram for your car/engine, and see.

 

Well, pretty much since OBD2 dash's have been run off the PCM, and that was in the mid/late 90's. So its been a fair few years.

But yes, I agree that in our cars, the ECM has nothing to do with the dash for the most part. In my GTA the speedo is driven by the LT1 PCM, though I need a SGI-5, its off by a few MPH since 93 T56 had a funky signal compared to 94+

 

Thanks all for the quick responses.. RBob, I didn't think the manufacture I was looking at was relevant, which is why I didn't mention.

 

I intentionally left all that out, if they don't know how the speedo works, then they aren't going to know about the buffer or drive cable or not.