I don't think EBL is my problem but I need to ask here first just to be sure.

This is a 84 corvette

2 weeks ago I parked the car to do a LCD to Analog guage cluster exchange. The analog gauges I got are from Vetteaid, I also installed a digital Fuel PSI guage and digital Vac Gauge

Did the exchange and now I'm at the point where I'm calibrating the speedometer. Car idles fine, but blms dropped to 110 and if I take it out to the road all its doing is bucking like crazy...almost as if it doesn't know what gear to go into. That said I need to drive a total of 4 miles to calibrate this guage. During this process the gauge jumps to 160 for the first two miles... then for the second two miles it will read 80 mph.

Is it possible that since this gauge is reading these numbers my TCC is locking and unlocking not knowing what to do?

Typically my TCC locks in at 49mph/unlocks at 68 mph....then forced lock at 100 mph.

If this is my problem how can I get around this temporarily to calibrate the speedometer.
thanks

FYI- I did go thru my spark plugs/wires and vac lines to be sure nothing had gotten knocked off.

 

Set this value high:

TCC - Lock Enable CTS

Note that the EBL VSS input is a 2K PPM square wave.

RBob.

 

Thanks Bob, I made that change and I'm still having the "bucking" problem. I'm trying to figure out how this new gauge set up would effect the tune at all. I don't think it should

the output voltage ranges of this sender are
hall effect sender 3-wire (5-16V)
sinve wave generator 2 wire, (1.4 Vac min)
5V square wave (CMOS)

according to the instructions the ecm must meet 2 of those conditions above
Does the EBL?

As far as tach goes this is set up for a 8cyl 4 pulses.

 

Ok, here's where I'm at
I removed my analog gauges and put the LCD cluster back in. Runs back to normal.
So somehow these analog gauges do effect the .bin

Can anyone tell me or suggest which gauges could be inputs?
I'm assuming CTS,Tach, and maybe the speedo

 

Did you tap into the CTS for the ECM? Shouldn't.

RBob.

 

No, there weren't any modifications to the CTS at all, its a plug an play unit from vetteaid.com for the C4's.

I'm really curious if its the VSS signal to the ecm?
I put my orginal LCD back in and the car runs fine

 

Looked at their web site and it appears to be plug & play. I can't see how they could say that if the dash doesn't provide the proper VSS signal for the ECM. From '84 through '89 the ECMs all used the same 2K PPM digital VSS signal.

Which are the same years that the gauge kits are for.

If the manual has what you posted above:

> the output voltage ranges of this sender are
> hall effect sender 3-wire (5-16V)
> sinve wave generator 2 wire, (1.4 Vac min)
> 5V square wave (CMOS)

I'd wonder about the compatibility with the stock ECMs. The Hall Effect output sender would have the proper electrical signal for the ECM. But it also needs to be a 2-pole sender.

Pop the pin out of the ECM harness connector for the VSS: A10

Then see how it runs with the new panel. If it is OK I'd go back to VetteAid for a how-to on supplying the stock ECM with the proper VSS signal. Otherwise, their gauge panels are not plug & play.

RBob.

 

Thank you for looking into that and giving me your feedback. I'll try what you asked and report back

 

Update
Remove the VSS to ECM wire. The car ran fine... as I drove I reconnected it and it started bucking again. The problem is within the speedometer. Called vetteaid,and they are going back to autometer to try and come up with a solution.