Honda / Acura K20a K24a Engine Forum banner
1 - 4 of 4 Posts

·
Registered
1992 BB2 Prelude k24A3 Swap
Joined
·
33 Posts
Discussion Starter · #1 ·
I have a weird one. I have a CSS trans in a low frequency vehicle with a kprov4. Previously I was able to get my speedo working by using B11 on my PRB ecu which provides a VSS signal and not a CSS signal when setup in the kpro accordingly. I tested several times before and after putting my floorboard back together and everything was still working. The car sat while waiting for an axle and now the speedo no longer works. Verified the ECU sees the speed correctly. Here is what I tried so far:

Scenario 1
B11 from ECU to speedo wire with CSS option selected in kpro. No speedo movement at all. Verified low frequency on output wire.

Scenario 2
B11 from ECU to speedo wire with VSS option selected in kpro. Pegs the speedo at max speed as expected.

Scenario 3
Direct from VSS wire on C101. Pegs speedo as expected.

Scenario 4
Purchased a ktuned converter. Installed per directions, verifying all connections with a meter, from VSS wire on C101. No speedo movement at all.

I am at a loss with this one. If I use the verifiable low speed frequency the speedo doesn't do anything. If I use the high speed wire its pegs the speedo. I can even connect the tach wire to the speedo and it will show RPM. It's almost like the speedo only responds to high frequency anymore.
 

·
Registered
1992 BB2 Prelude k24A3 Swap
Joined
·
33 Posts
Discussion Starter · #2 ·
I think I have found something else odd. If I measure the voltage on the stock ecu plug wire that leads back to the speedo it reads about 5v. I was under the impression that the wire shouldn't have its own voltage and should only receive the signal from the vss. Can anyone clarify if that is correct?
 

·
Registered
1992 BB2 Prelude k24A3 Swap
Joined
·
33 Posts
Discussion Starter · #3 ·
I need to bump this, sorry everyone. I cannot get my speedo to register anything other than high frequency.

If I wire from the CSS to the speedo I get a pegged speedo because it is high frequency. This is expected.

When I wire from low frequency, either a k-tuned converter or from B11 on the hondata ecu, nothing registers on the speedo but the ecu can see the speed.

I cant be the only person this has happened to.
 

·
Registered
1992 BB2 Prelude k24A3 Swap
Joined
·
33 Posts
Discussion Starter · #4 ·
I sort of resolved this issue. I ended up installing a Dakota digital box and dialing the speed correction. Not really a fix as much as a problem solved.

I am not sure what changed with one of the recent hondata updates and they claim nothing in firmware would affect the B11 speed output but it worked before I updated and stopped working after. If anyone is using that pin for speed output I would love to know if its still working for you.
 
1 - 4 of 4 Posts
Top