99 ex coupe
built ls/vtec motor (n/a)
jeff evans tuned
obd2-obd1 step down with p28 hondata s300 ran perfect for months..

Now having these problems

1. speedometer is going crazy and is all over the place
2. idle goes up and down
3. car wont rev past 4500rpms (sounds like a rev limit)
4. CEL comes on once in a while but when i jump to check the code the CEL shuts off and doesnt blink

I know how to check for the normal symptoms but the car runs like its fine up until 4500 rpm's.. I have another socketed p28 ecu with a b/s skunk 2 chip, but i didn't want to run the car on that unless I had to..

I'm looking for someone who has a similar problem or anyone who might have any other idea's... and yes I've searched and found some stuff but nothing like this exactly.

 

 

whata help this site is.

 

You have an s300, use the datalogging to check the error code. Based on the fact that your speedo is acting strange, I would suspect a wiring related problem.

 

possibly bad ignitor unit. it'l throw a ignition output code and make your tach jump because it is getting an erroneous signal.

 

im going to guess your 4500 rev limit is a bad chip??? or maybe your soldering on the socketing went bad

 

well I'm not familiar with hondata too much..

In response to the other posters the tach is not going crazy so I don't think its the ignitor or dizzy related.. I just hate taking on someone elses work not knowing what they did to it it makes everything harder.

I don't know how to use the datalogging cable to check for the code.. if anyone can explain that to me i'll be sure to understand I'm not a dumby but thanks for the responses

 

connect the usb cable and click the yellow lightning bolt icon in Smanager

 

It's probably just your speed sensor/wiring on top of your tranny. What number code is it throwing?