b16a1 ecu/vtec solenoid problem

we got the b16 in, but the ecu (pw0) is throwin code 21, which is the vtec solenoid (right?). anyway, we checked the setup, and everything seems fine. we troubleshooted using the helms manual and it seems to point to the ecu, does that seem right? we gave the solenoid 12v and it made the engine scream, so its working and we checked the resistance and things were fine except from the ecu side. I guess I have to go hunting for another ecu. anyone else had this problem, or know of another check?

Well if the solonoid is working, then the problem is either in the ECU, or its in the wiring to the ECU.

But also remember that the ECU will not activate the solonoid if it finds other problems.

It needs a good signal from the oil pressure sensor, the engine temp sensor, and the Vechile speed sensor.
So the car has to be moving, and the engine upto temp and with good oil pressure before it will activate.
It might be an idea to check those sensors as well before you worry about replacing the ECU.

damn I got the same problem but its with the vtec oil pressure code 22 and 15 which is ignition output signal whatever the hell that is. code 21 is the vtec solenoid. Since you checked everything after the solenoid and jumped the solenoid with 12v's then make sure the wire to it is okay and make sure YOU HAVE THE WIRE GOING TO THE RIGHT PIN IN THE ECU! As I recall it was pin "A8". Honda ecu connectors read left to right even numbers on top odds on bottom. Also make sure the ECU pin is okay. The ecu is rarely ever the problem in fuel injected vehicles. try rechecking wiring and all. Did it work before then just go out? or did you just finish the swap and fixing bugs? my vtec hasn't been working ever since I did the swap which was about 3 months ago. Clutch slips too on hole shots. Really gay.... Hope that helps buddy!

well, I was figuring that the other sensors were working soince I didnt get any codes from them, only 21 (so wouldnt that mean they are ok?). but since you mentioned the vss, maybe it makes a difference that I'm using the mechanical vss from my old tranny? I believe the wiring is right, I'll check it myself. And yes, the swap is just done, and the vtec has yet to work, the only problem we're still having. Let me know on that vss...thanks guys for your input. The only reason we're using the old one is to keep my cluster working until the SiR cluster is installed.

If the mechanical one dosnt have a signal going to the ECU then no the VTEC shouldn't work. :)

If it does, and its sending a signal the ECU can understand then it should be fine.

As 5 liter said the ECU is very rarely the problem, and its most likely in the wiring, if its not the VSS

hmm...that may be it then - anyone know if the mechanical speed sensors from the old d-series tranny's send a signal to the ecu? Thanks for the help again moppie.

I am using the old mechanical speed sensor off a dseries motor and y Vtec is activating. I believe the signal is sent to the cluster and converted to an electrical signal before the ecu reads it.:)

Originally posted by 91zc
I am using the old mechanical speed sensor off a dseries motor and y Vtec is activating. I believe the signal is sent to the cluster and converted to an electrical signal before the ecu reads it.:)

yep, that seems like the verdict. I'm gonna check the wiring again, but it looks like my ecu may be faltering. This sucks, too many stupid things. I hope this motor is ready to scream at 8k when vtec is working. Thanks fellas.

Yeah, I've got the same problem. B16 into 3 gen civic and can't get VTEC. I tried fitting the speedo from the integra but still no VTEC. Is there a way of fooling the computer?

It needs to read a square wave signal from the sensor. Can this wave be simulate electronically?

Need help......Need VTEC.

well I just looked into my Vtec yesterday. WEIRD!!! okay well first I was gonna jump the vtec oil pressure switch with a 12v signal to bypass my wiring. I took a wire hooked it up to a safety pin and hooked it up to the wire that goes the the ECU and to the vtec oil pressure switch. that pin got so f**king Red HOTT!! I should have check to see if it had power or ground first :rolleyes: anyways I check my ground to it and it was good. But listen to this. one side goes the the ecu other side to ground... my ground is good. the wire that goes to the ecu has a ground when plugged into the vtec pressure switch, When I unplug it NO MORE GROUND!? I check to see if it has ground to the pins on the switch and it doesnt!? so weird. no ground when its unplugged and there is when it is plugged in. The pins to the switch aren't grounded... you think this might mean I got a shorted pressure switch? anyone know how much thery go for? this is stupid. I think I am gonna go check my wiring to the ECu from thwe switch.

I need help too... I NEED VTEC!!!!!!!

ohh yeah... how much faster do you think it will be with the vtec? I mean the car still hauls without it but I dunno.... b16a in a CRX with all bolt ons... anyone know what I will run? THANKS

try putting 12v to the vtec solenoid and check it for function. you can hear it clicking when it is activating, or play with the throttle while toggling. We are all gonna be so happy when our vtec works. I'm in the process of getting another ecu...

It seems that most b16 powered crx's are in the high 14s in the 1/4...

Yeah, It'll be a pizza night that night for sure :D

Does a V-AFC need the same inputs before it'll actuate VTEC? I want to get one anyway and if it'll work without the stupid @#$% VSS, I'll make it a priority.

WAAAAAA!!! So I'm sitting at work in my garage nothing to do and decided to go on the computer and shoot up some Wiring diagrams to check my VTec. I tell my boss whats going on ( KNOWS A HELLA LOAD OF SHEITZ ) and goes ohh its a pressure switch eh? so I go outside mess with the wiring, jump the solenoid and it sounded pretty kool but it was at idle and sorta did some weird stuff. Anyways I know the switch is good cuz I check for continuity and decided to check my wiring backto the ecu. I want to bring my car in and I couldn't because we are about to leave. I grab some tool go home and cut the electrical tape I wrapped the wires in. start it up 2 times and check engne light still come on. Go back side take a nap and go over to a buddies. I get to the entrance of my sub... no check engine light..... I say hmmm to myself.... behind a tracker and I floor it down the street. HOLY SH*T!!! I got right on the ass of that tracker like no other, see that no one is coming and swing around him. I felt like an ass. I go over to my buds tell him my Vtec works and he goes yeah okay Big Al.... take him for a spin all you see him do is grab that damn "Ohh Shit!" handle and my arm yelling at me to slow my ass down! LMAO! I HAVE VTEC!!! I AM AN ADDICT!!!!! Thankyou to all of you who motivated me to look into the Vtec problem..... I am a lazy man and I still would be sitting here without Vtec. You guys are great!!!!

I NEED VTEC!!!!! Correction.... NEEDED!!! MUHAHAHAHA!!!

Originally posted by 5_LiTeR_EaTeR
[B]i take him for a spin all you see him do is grab that damn "Ohh Shit!" handle and my arm yelling at me to slow my ass down! B]hahaha i get that everytime i drive with a friend in the car :D

5_liter - what do you think the problem was then? ..and congrats on getting it to work.

okay take these steps... First off you jumped the vtec solenoid so you know it works for sure. make sure your vtec oil pressure switch is in working order. Run the car to operating temperature then check for continuity between the 2 pins in the oil pressure switch. If it reads anything you are good if not replace it but usually it will throw a code. Also Make sure you are getting code 21.... lol, may sound dumb sorry, it may seem offensive but we all make mistakes... Then check the wiring back to the ECU. Pull the carpet over and undo the 4 bolts to the shield covering the computer... Now is a good time to redrill a hole in it so you can see the LED and check for codes without taking the cover off for a PR3 Computer. Now make sure you got it in the right pin to the ECU its pin "A8". Honda computer pins read right to left odd numbers on top and even on bottom. so it should be on the 4th one from the right on the bottom. Now Make sure you have a good connection to the ecu. tug on the wire a lil bit see if it pulls out. usually if you Cooterized it like mine the pin I used was too short and didn't reach the pin on the ecu therfore not making a connection. undo that white clip inside of the plug and pull the wire out. make sure you have no breaks in the wire and recheck all of your splices if you made any. That should cover everything! All there is to that circuit is the vtec solenoid Vtec sol. ground and the wire going to the ecu. OHH YEAH CHECK THAT GROUND!!! I grounded my vtec sol to my clutch cable bracket but you can ground it to the head or something. It just made mine easier to work with cuz it was a longer wire. Let me know how things go and I hope you get that working!!!! GOOD LUCK!!! VTEC IS ADDICTING!!!

~Alex~

or you can do what I did. Sick of trying to please the @#%$#@ computer I bought a Autometer shift light module. Fitted to car and wired to relay to actuate VTEC. Unit has replacable "pills" that can engage VTEC at (In my case) 5000, 5200, 5400, 5600 or 5800.
Now my VTEC "kick in" point is UP TO ME!!!!!!!!
Module can handle loads up to 1 amp. Only takes about 30 to 50 milliamps to actuate relay so there shouldn't be any problems.

Your actualy missing out setting the change over to one point.
(keep it at 5,000rpm)
The ECU varys the change point between 4,800 and 5,200 depending on gear, engine load, and road speed.
Means less chance of getting a flat spot coming out of a corner, and better economy when driving fast.




And 5_LiTeR_EaTeR that is an awsome bit of trouble shooting!

I don't think PR3 computers take that into consideration (but I could be wrong)

How would the computer know what gear I'm in???

yeah, 5_liter's steps were almost exactly what we did a few times, still with no good result...the helms manual pretty much outlines it the same, and the end verdict was the ecu is faulty.

Thanks Moppie! I think if your ecu was faulty it would be throwing codes like crazy. Usually a faulty ecu won't throw just one code but numerous ones. I think its sorta crazy and weird that if you popped the ecu it would only make the vtec not work. Funny but it is a possibility. What you want to go and do now is take the ecu out and find someone with with a CRX or Civic with a b16a or a integra maybe and see if that will throw codes and vtec not work. Don't put theirs in yours because you could end up blowing theirs if there is a short somewhere. I say FUGG it get a really big tach and hook the vtec solenoid to a toggle switch :D lol j/k... don't go and do that but it would be cool and still work!!!

I understand your concern but the ecu isnt even throwing a code for the second 02 sensor which isnt even hooked up. I dont know anyone around here that has a pr3 or pw0, so I just bought another. if both ecus are good, I'll just throw one on ebay, no big deal. we'll see