VTEC sporadically engages

[Jimmy50941]

92 Integra
P28 ECU
B20B Block, GSR head

I have been having an issue with my VTEC not working most of the time, the datalog shows VTEC spool turns on, but VTEC is definitely not engaging. once in a while VTEC engages, but most of the time it doesn't. a few minutes into this datalog it actually engaged but only for like 1 second, and then it went back to no VTEC. I have checked the VTEC solenoid and it has 18.1 ohm resistance between ground and the solenoid wire. is there anything else i can check for this? VTEC solenoids are hard to find for cheap, and I'm hoping its something simple that I'm missing. Thanks for your help, and if there is any more information you need to help me figure this out, let me know!

[Jimmy50941]

Here is another datalog. VTEC never engaged once during this datalog, even though VTS was on. Is the VTP (VTEC Pressure) supposed to be on or off when the VTEC spool is on? it seems to not ever go on. I wonder if it doesnt have enough oil pressure?

[Jimmy50941]

Oh and 1 more thing, i believe i was getting CEL Code 21 for VTEC Spool a while back, but i ended up disabling the spool error check like a month ago. It would throw the code just by turning the key to the on position, without starting it. I also checked the VTEC solenoid and it opens when i apply +12v to it. I just cleaned it up, and there was a small amount of debris in the filter, but not much. VTEC still does not engage. :-(

[Spunkster]

It sounds like either a mechanical issue, or an intermittent wiring problem. Try the ECU in a known working vehicle.

[Jimmy50941]

I dont have any other honda's anymore :-/ some of my family do, but they are all OBD2's. I will check all the wires for VTEC again right now to see if i can find anything loose.

[Jimmy50941]

So, I added more oil, about a half quart over the full mark, and VTEC engages almost consistently. it cuts out a little bit still, but it engages and stays on way more than before. so maybe I need a thicker oil. I have been using cheap oil because i had some oil leaks, but i fixed them yesterday, and looks like I may need to use some better oil, or keep it half quart or more over. I haven't been running this car in several years, bought the s300 6 years ago, and have about 8k miles on it. I dont remember what dipstick i used in this, it is either the LS one or the CRV one i think, unless i got them mixed up and used one of my D series ones lol. I have no clue honestly which one i have in here. so maybe I need a little more than full on the dipstick to get enough pressure for VTEC? either that or some thicker oil. I have 5w30 Valvoline NexGen in there right now, i will be putting synthetic in next oil change, but was planning on keeping cheap oil in until 10k miles on this motor.

[Jimmy50941]

Hmm, its back to not working again...

[Johnny_9]

Hmm, its back to not working again...

does your head have a VTEC oil dowel/orifice?

[Jimmy50941]

i fixed it. it has been about 6 years since i got the hondata in that ecu, and havent had much of any time to work on that car in a long time. the ECU isnt actually a p28, its a p06 with the vtec circuit added, and the transistor at IC14 had 2 of its leads broken, not sure if it was from sitting outside for 5 years and vibration after all that time or what, but i went to the junk yard and bought a auto p06 ecu and took one of the transistors for the transmission's solenoid out of it and put in my p06 and that fixed it. sorry for the miscommunication on what ECU i have, its just been such a long time since i have done anything with this car.

edit: I have S/N: S300-1040 and its still working after being left outside for almost 6 years lol