99 Accord EX 4Cyl vtec (f23a1)
New oil and filter, new vtec solenoid, still no luck:/
Cleared the cel, drove the car easy for about 5 miles before entering the highway, rpms stay under 4k when the cel turned on around 60mph then wouldn't rev past 4k (limp mode because of p1259). cleared the code, no cel but car wont rev past 5k under full throttle or shift to next gear, let go of gas, transmission shifts. Also had misfire codes for cylinders 1, 2, and 3 before.
Thanks in advance for any input or thoughts, iv ran out of ideas :/

 

UPDATE:
So I figured out if I clear the cel, and let the car sit for a while (overnight usually). I can drive the car, even taking it past 4k for about 20 minutes before the cel turns on for p1259. After which I will clear it and it comes back within a couple minutes.
Also, does anyone know how I could trip the MIL codes (OBDI diagnostic) on this model accord, I cant find the plug anywhere, and couldn't find any help online.

 

Code P1259 (obd1 22) is a fault in the pressure switch circuit, not the Vtec solenoid.

You can check pressure switch for continuity between 2 terminals w/ connector removed. If no continuity (short on VOM), then replace pressure switch.

If continuity is found on pressure switch, there is a fault elsewhere that will require more diagnostics. Download shop manual (94-97 Accord manual from Online Manuals post in DIY forum) and investigate code 22 fault tree.

good luck

 

The "plug" should be on the left drivers side.

Can we assume the oil level has been checked?

 

Thanks for replying,
Yes the oil level is good, I'v been researching this problem for a while now:/
Ill look for the "plug" once I get a chance (Friday probably)
Also could i use a DX ecu (non vtec) if i cant fix the problem? I need to pass CA emissions inspection (smog test) and a cel is an automatic fail.

 

Doubtful a non-vtec ECU will work. Check ebay and car-part.com for a used unit.

Note, check the pressure switch before replacing ECU.

good luck

 

I tried looking for the MIL "plug" but couldn't find it :/
Also, how would I check the pressure switch?
I did some research and a DX ecu will fit (reprogramming required), which seems to be my only option as of now.

 

The MIL plug is the 16-pin obd2 connector. If your car is drivable, then you can stop by a parts store to get the codes scanned and post the current list of codes. Or post the codes read if you have a code reader.

There is a way to get codes by shorting two of the pins to check for codes the OBD1 way. I know there are posts on here about that by me and others.

 

I have a good OBDII scanner, that's how I know what codes It's throwing. I wanted to do it the OBDI way because maybe it would narrow down my search. I know how to short it on civics but couldn't find it on the Accord.
UPDATE:
I just spent all day diagnosing the misfire and vtec codes, still no luck.
Misfire: different plugs, different ignition coil, different plug wires. Still idles rough and lacks top end power. still getting misfire code in cylinders 1,2.
Vtec: check connection between the plugs at the solenoid and the plugs at the ECM and it was good, pressure switch test failed, but already replaced whole vtec solenoid so im thinking it might be a bad ECM. Any thoughts???

 

The Vtec solenoid and the pressure switch are two different components. Both are necessary for proper operation of Vtec.

Despite that, I don't think a non-functioning vtec will cause cylinder 1-2 miss.

Any chance spark plug wires are possibly crossed?

Check distributor tower or rotor for cracks.

good luck