moto44

I have completed the build on my 95 prelude with H22 and 5spd. This is race only enduro/ circle track car. ALL the wires under the dash have been removed and there is no factory insterment cluster. Its starts and runs but will only go to about 6100 rpm. I did have to wire 12 volts to ECU pin A25 to get it started. My question is the other pins that see oil psi, oil level ,coolent temp, speed sensor etc will these need to be grounded at the ecu in order for the VTEC to work. All the guages are mechanical aftermarket. If i do need to ground certain pins which ones?

motoxxxman

the ecu doesn't need to see anything from under dash stuff.
Fuel injectors, coil, and any solenoids are all powered by the ignition switch and main relay. If you removed those, you'll need to chase some wiring and connect switches to anything that uses 12v.
all engine sensors and ecu grounds are grounded to the engine itself on the water outlet.
If it has a low rev limit, that means there's a trouble code stored. Check stored codes and diagnose as necessary

moto44

There is no original dash or ignition switch wiring it has all been rewired. How would i find a stored?

ross2004

You need to wire in a check engine light & toggle switch to flash the codes. Look up an ECU pinout and find the wire for the CEL/MIL and Service Check Signal. The ECU gives ground to the CEL, put 12v+ on the other side of you light. Then, use a toggle switch to switch ground on the service check signal ECU wire. Is your engine harness in tact or has it been done from scratch? If it's from scratch, I'd highly recommend getting an un-cut harness from a junkyard/ebay/etc. There's a few things you can cut out on a race car, but it's all pretty necessary. You really need a Helms manual to look at the wiring diagrams.

Oil psi- only switches a dash light, nothing to ECU so ok there.
Oil level- there isn't one
Coolant temp- very important, goes to ECU
VSS- same

ross2004

Race car CEL. Print out a list of the trouble codes, laminate it, and keep it in your trailer/truck.

moto44

The under hood harness is all stock and all plugged in. The ecu is a p13

motoxxxman

^this^

moto44

Coolant sencer is still in place and plugged in but no OEM guage
VSS vehicle speed sencer? Is this the speedo plug?

motoxxxman

you don't need the oem gauge. I doesn't communicate with the ecu. The gauge runs off a separate sensor that isn't necessary.

The vss is on the tranny, and runs directly to the ecu. So you don't need any of the oem gauge wiring for that either

ross2004

ross2004

moto44

The transmission is out of it rt now do to a 5th and reverse issue but when I removed it the speedo plug was not on. It will be a few days before it is fixed. I' trying to make a practice on the 31 so I what to have it fixed by then.

moto44

I don't need the VSS so could I cut the plug and connect the wires. There are three wires so which one would go together

ross2004

With a P13, you do need the VSS if you want VTEC to function.

Again, get a Helms.

motoxxxman

something tells me this car is going to have nonstop issues...

moto44

please elaborate on how to attach a CEL. I' not understanding.

ross2004

I can't elaborate too much more than what I did. You take a light that'll work with 12v (I use a Longacre warning light): give it 12v+ from a source of your choosing, and the ground side goes to the CEL/MIL wire from the ECU. Next, you need a toggle switch with ground on the input, output goes to the service check signal wire on the ECU. When this service check signal wire gets grounded by flipping the toggle switch (what you're doing when you jumper the CEL plug normally), your new CEL should start flashing any codes.

moto44

ok I'm having my friend who can understand this make me a drawing. When we do get it done will I have to drivethe car to bring up codes? And the car has a master battery switch which is turned off after use. Should I be leaving the battery switch on and only turning off the ignition.

ross2004

I'll draw it in a few minutes. I wouldn't leave the kill switch on when it's setting for long periods, you'll just have to accept that the ECU will be reset every time you turn the kill switch off (which isn't a big deal). Leaving it switched on in between heats/races probably won't cause a problem. And yes, some codes will only show up after driving for a while.

moto44

That would be very much appreciated if you could make a drawing.

moto44

Is this correct

ross2004

That's it. Here's the light I use, but use whatever you want: https://www.summitracing.com/parts/lng-41803/overview/

moto44

Ok got the CEL wired and come to find out the wiring harness in this car didn't have the pins for vtec. So I installed the proper pins to the ecu.she is running good up to about 7200 were it hits a Rev limiter or it just need a tune up.

ross2004

Rev limiter is something like 7600-7700 on a P13- maybe your tach is off?

moto44

It' an Autometer tech but I'm fine with the rpm for now. I would like some suggestions about what I Sud do to the ecm to make the engine run a little better at the low end. This is circle track/enduro racing only.don't believe it will ever get out of 2nd gear. At one track I will be shifting from 1st to 2nd two times per lap. That is a Barber pole race. Engine must be all stock