is your VSS working properly?

 

whats a socketed P28? and how do you have that light wired? is it to the solenoide wire? cos if that light is coming on it means that the solenoid is getting power, wich means your wireing and computer are OK, anything else would be a mechanical problem in the head or the solenoid. did you do a head swap? did the Vtec work before? how did it mess up? what was done to the engine before it messed up?

 

I had the exact same problem and symptoms on a customers car. Light would come on after it reached a little over 4k rpm's. Vtec would fall in and out. Ended up being the connection in the ecu plug. It looked perfectly fine but the female section of the terminal was a little tweeked and under higher rpm's it would get a weak connection from the vibrations of the car. We did all the same things, switched out VTEC Pressure switches, solenoids, ecu's ect ect. We removed the clip from the harness and replaced it with another and the problem was cured. Good Luck!

 

have a friend rev the engine to just under the vtec crossover point, then connect 12v to the vtec pressure switch, if it doesnt engage vtec (youll here it) than its either the solonoid or a clog somewhere. if it does work than its a wiring or ecu problem.

 

Testing while Not moving VSS wont affect the results....

I believe the only ECM that does the 25mph check the P72 and H22A1's Correct me if Im wring but its tge only two I know of that do it. And is easily moved around. Check Tempature of the car as well. Make sure your at operating temp.

Remove the ENTIRE assy off the head. Clean in the Head Port with Brake Cleaner it drys fast and will dislodge most debry. Then Get a GOOD Known working Valve Body and Assy and Replace it. If it still does it rewire the VTEC wires VCM wire I believe it is. Its late Im tipsy and prolly garbing up tghoughts !

 

have you tried using a stock p28? I'm assuming that since you said you had it tuned that you are running ( currently ) a socketed and chipped p28 with crome or uberdata.....

 

ok lemmie try and reply to all of these.

I've already checked oil pressure and came out fine.
Yes my VSS is working properly
I don't have a vtec light, I'm talking about the check engine light coming on.
I just swapped in a good known vtec solenoid so I'm ruling that out.

I did just rebuild the engine, and did my turbo set up, but my vtec wasn't working properly before as far as i know, but it never threw a CEL for anything to do with vtec.

and yes I am running a socketed and chipped p28 with crome.

that why i'd like to toss in a stock p28 or a socketed p28 so i can try a diff program and see if that has anything to do with it.

I'm gonna check all my connection points and wiring and pins and what not again tonight.

I'm most likely gona run all new wire for the switch and the solenoid to the ECM and see what that does.
if not the only other thing i can think of is splicing d6 into a4 and bypassing the switch entirely or maybe that's a4 into d6 i forget don't have the service manual in front of me at the moment.

 

unplug the ecu connector and the vtec pressure connectors. take a ohm meter and put one lead on ground and the other on one of the pins on the pressure sensor connector. test both pins. one pin sould be a solid ground and the other pin should be open if you have the ecu connectors unplugged as well. if you have no ground check the ground location on the thermostat houseing and make sure it good. if that is ok i'd suggest running a ground wire from that connector to the thermostat houseing. if you have both that are grounded then you have a shorted wire. undo the ground on the thermostat housing and retest the connector to figure out wich one is now open circuit. the one that is still shorted is the wire that you will to trace and find the short. once you have found it and repaired the short remember to bolt the grounds back to the thermostat houseing and plug everything back in and you should be good to go.

 

Thats all good and well but Im gonna say He has an ECM issue.

 

read his first post, he clearly states that he has tried a known good ecu.