2002 Accord 2.3L ULEV VTEC w/ PO112 code (IAT) and P1259 VTEC Malfunction

[bocas0225]

I have a 2002 Honda Accord LX with a 2.3L ULEV VTEC motor w/ 5 speed manual transmission. The car is lowered 3" on 17in rims. I have been having issues with the PO112 Intake Air Temperature (IAT) sensor Low Input Circuit. I have replaced the IAT but I am still getting the same code. Im trying to get help with this situation. I am also getting a P1259 VTEC System Malfunction. When I looked up this code I found it to be a Bad VTEC Solenoid Spool Valve. So I went and bought a BRAND NEW VTEC Solenoid Spool Valve and put it on. I also read that if oil pressure gets low that it will also trigger the same code as well. I just changed my oil again last night and I am still having the same exact issue. Can anyone help me with this please!!!!

 

[james'99]

Okay, so you changed the VTEC solenoid? They don't really go bad. The thing that happens is that carbon builds up in the oil screen and the pressure switch that causes problems. Other problem would be as you stated, low oil pressure. But you seen to have ruled that out. Did you change the oil pressure switch, or move it over? If you moved it over, I'd remove it and spray some brake cleaner in there. Watch your eyes! I'm just gonna assume the gasket and screen have been replaced.

Have you cleared your codes since doing any of this maintenance? I think these are codes that don't usually go away on their own and must be manually reset.

 

[bocas0225]

James when I replaced my vtec solenoid, the new oil pressure switch was attached to the new valve. I have since changed my oil again and I am still having the same issue. The original solenoid wire had been cut so a friend of mine and I soldered the wire back together but still had the same problem. So I went out and bought a brand new vtec solenoid spool valve just to make sure there was no issues. Even after putting on the new one I'm still without vtec. I had an oil leak from my valve cover where one of the front valve cover bolts was not feeding correctly into the hole. I blew the hole out with compressed air after taking off the valve cover and covering up the engine so any that came out of the hole would not land in the engine. Sure enough a small amount of steel wool came out of the hole. No more leaking from the valve cover now.

I did notce that it looks like I'm leaking a small amount from my rear main seal. My oil pain doesn't look like it has a dent in it. I have heard that a dent in the oil pain will drop oil pressure as well. So as of right now I'm stuck in a position of idk what to do.

 

[xci.ed6]

Well, after you list of problems, the only thing...

I can diag your car with way too much intervention, photos, etc...

I think your engine is safe, We gotta start with where is this leak? Where is the port you cleaned? Lets see the oil pan?

Or, you could possibly take it to a shop for a diagnosis then post the results.

 

[james'99]

How did the wire get cut? Is it possible more wires are cut?

 

[bocas0225]

XCI.... a friend and I noticed that it looked like I may be leaking from my rear main seal.... Tonight we are going to pressure wash the engine due to the fact that there is a a lot of oil every where and we want to get the engine clean to be able to notice where it could be possibly leaking from. the port i blew out with a small can of compressed air was just from one of the front valve cover bolt holes. i am going to take some more pictures of the engine of the car tonight including pics from the bottom of the engine. I am also going to look at new oil pains to be able to compare whether or not the oil pan has a dent in it.

James... From what I could tell it looked like the wire had been cut before I bought the car. The Vehicle Speed Sensor had went out as well before I got the car from what the person I bought the car from had told me. So when I replaced the VSS that was when the P1259 code triggered. I had read on several forums including on 6th gen that there has been know to be a issue with the Vtec Spool Valve screen getting clogged. I took the whole entire valve off and completely cleaned it with brake parts cleaner, pulled the gasket with the screen on it made sure that the screen was also cleaned. Once that was done, I put the Valve back on the head and cleared the code. Once drove the car and after hitting the VTEC two or three times, the code triggered again. Even after changing my oil, I still continue to have the same problem.

 

[xci.ed6]

good strategy, gotta start with cleaning!

It sounds like you may have either oil restriction, or oil pressure.

You might need an oil pressure gauge, sometimes at the shop I use one instead of stock, so you always see that light, but you know when the pump is working from the gauge.

I have used a water pressure gauge, from the hardware store. And some extra fuel line. Don't expect the gauge to last too long from oil, but they are 100psi so safe there. The $5 price was right.

Stock gauge is BPT, you need an adapter to NPT, or you're supposed to have one. The NPT fittings *might* fit.

 

[bocas0225]

XCI..... When u say: Stock gauge is BPT, you need an adapter to NPT, or you're supposed to have one. The NPT fittings *might* fit. What do u mean? I know my way around cars pretty well but sometimes I'm not sure of the abbreviations. Now I also noticed u said oil restriction and oil pressure. When it comes to oil restriction what is the best way to figure that out??

 

[xci.ed6]

You're supposed to use an adapter. I didn't when I turbo'd Honda's. They are a bit different. I got the name of ours wrong, BSPT...

1/8" BSPT = 28 TPI (threads per inch)
1/8" NPT = 27 TPI

So they are damn close, NPT works when tightened excessively, IDK if the BSPT will go back, it might, since I used NPT tee fittings so the stock sensor went into it. I never tried to go back, though, so IDK what happens there... (I kinda blew up my engines after I turbo'd 'em, let's call that my trial & error path to success).

The stock sensor makes sure there is pressure there, but there isn't enough. So testing pressure at the bottom tells you the answer. Not enough pressure there either, that's points to pump. Enough pressure there, but not at the top, points to some kinda restriction between them.

 

[xci.ed6]

I gotta toss this in for Menards...

They're a hardware store, I worked there in highschool. That place was a supplier for most of my HMT setup (see: homemadeturbo.com, that place was awesome back in the day, started by Abaz who I knew before he did).

PVC charge pipe, and little brass fittings for oil, connected by fuel line I clamped on running DSM 450 injectors (2x stock) with a GM MAP sensor (3-BAR, half the stock signal), with a ford oil cooler stuck in a box to make it into water:air intercooler of the stock intake box turned into a tank, with a boat pump to circulate water so it was a SUPER ghetto, but it was a super functional setup.