I was wondering if anyone could help.
The problem basically is that my 99 prelude sh is redlining at 6900 instead of 7500. If i take the car to around 6000rpm in 4th or 5th gear , the check engine light comes on and its an air/fuel mixture problem. The car runs fine and compression is perfect in all cylinders. It's not a major mechanical problem. Im thinking it's a vtec problem. i had the vtec system checked and the silenoid is fine along with everything else. The oil pressure at 3000 rpm was 57psi. Could the head not be getting the right oil pressure or losing oil pressure in high rpms? oil pressure switch problem? I know this isnt much, but I would appreciate any help.

Thanks

 

Didn't you just say it was an air/fuel ratio problem? Have you diagnosed that?

 

i had the same problem in my 99. my problem that i figured out was i didnt have enough oil pressure in high fourth gear for vtec. but that was because i had an APEXi VAFC in my car and i had the vtec controller set at a lil too low of a level. so check into the computer codes to see if that could be the same prob with urs

 

if your engine check is on it will red line at 69000, mines did that when my cel went on for my knock sensor.

 

It would be a lot easier to solve this problem if you knew the code for your cel...
I'm betting on knock too though. Can't be sure without a cel code though. You probably need to retard your timing a little.

 

yeah the we need the devinci code

 

thanks for the reply. I'll try and get the code in a couple of days

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sirwags &raquo;</TD></TR><TR><TD CLASS="quote">my 99 prelude sh</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IHateJDM &raquo;</TD></TR><TR><TD CLASS="quote">You probably need to retard your timing a little.</TD></TR></TABLE>

 

the code is p1259 and it said something along the line of air/fuel metering. Basically, a VTEC system malfunction. I'd appreciate any help

 

P1259 = VTEC system malfunction
Check your vtec wiring.

 

But it's strange cause i had the system checked and everything is fine mechanically. Where would I start if i had to check wiring (the connections on the silenoid are solid). It seems weird since the cel only comes on when i take it to 6000rpm in 4th gear, eventhough im redlining at 6900 in all gears. Could my oil pressure be dropping in high rpm, could a sensor cause the problem or what?

thanks again

 

A4 is VTEC Solenoid
D6 is Oil Pressure Switch
A26 VTEC Pressure Switch ground &lt;-- pay attention to this one. Not all ecu's look for the ground here, but the p13 does.
Just trace the wires from the ecu to the head and make sure they are hooked up right.

 

connections seem good. What else could it be? What does the p1259 exactly mean about the VTEC system failure, cause I know that there are a view other codes that also mean the same.

 

https://honda-tech.com/zerothread?id=1171263
Its on there. Sounds like one of your vtec sensors is bad. Might be time for a trip to the junkyard.

 

do you know where the sensors are located? So im gaining that you dont think i could be losing oil pressure in high rpms right?

appreciate it

 

I doubt it, but it is possible. The sensors are on the passenger's side of the head just behind the dizzy. The one with one wire is the vtec solenoid, and the 2 wire sensor is the pressure switch.

 

try this thread https://honda-tech.com/zerothread?id=830163

your hitting the rev limiter at 6800 because thats the ecus fuel cut when all the paramaters for vtec havn't been met.

check your oil first off, make sure you have enough

 

where exactly is the 10mm bolt to test the oil pressure.

thanks


Modified by sirwags at 4:51 PM 4/29/2005

 

just some more info. I went to a honda dealership just to get some thoughts and at first the guy says the oil pressure switch, but then another guy suggests that it seems like a ECM problem because if it was an oil pressure switch problem that would set off the oil light. This sounds bogus to me, but just thought id throw out some more information.

thanks again for the help

 

it can throw 22 without your oil light going off.