Hey H-T,
Having this weird issue, not driving the car until its fixed, dont want to hurt anything, but would
like to get my daily back on the road so i can stop driving the weekend EG track car

Car is a Stock EBP 99 EM1 with the original B16a2 and Tranny and P2T ECU

Car does not have the FITV(does not come with one stock)

The rpms were staying constant at 2k rpms

replaced with another IACV and it brought the RPMS down to 1500

turned the Idle Adjustment screw in all the way, car idles at 1055 rpms now

CEL code is p1399, which is random misfire.

Timing Belt is installed correctly(gates)

has new Dizzy cap, rotor, ignition coil, spark plugs(gapped .44)

Checked TPS sensor, sits at .5volts throttle closed 4.5 WOT

Vtec still engages good

Checked timing with Timing light, its good

checked for vac leaks with carb cleaner

Any Ideas? Thanks

 

If you reset the ECU, does the same code return?

Have you cleaned the TB and adjusted the throttle cable to have some slack?

Have you adjusted the idle speed as per the service manual?

 

Compression test and i'd also recommend a pulse test just to rule out the fuel system as an issue.

 

is there an actual issue beyond the idle and the cel being on?

 

This, is it actually misfiring? Do as Ronj said above and check/adjust your throttle cable tension as well. Did the high idle just suddenly come out of no where or were any other repair/mods done?

 

Yes i took the throttle cable off to rule that out

i adjusted the butterfly valve to make sure it closed all the way

reset the ecu as well

yes i cleared the codes with a ODB scanner

the issue reappeared as p1399

the cel will flash after i let it idle for 2-3 mins. when driving it stays solid, back at idle it flashes

 

the only thing i havent done is a compression check, but to my knowledge it should not idle high due to lower compression

before i cleared the codes it said all cylinders were misfiring, now its just p1399

 

You adjusted the throttle stop screw? If so, this should never be done.

This^ is not the proper procedure for adjusting the idle speed.


Misfire: Why didn't you also replace the plug wires and fuel filter? Has AutoZone tested the ICM?

 

i had adjusted the throttle stop screw because originally it had been messed with by the previous owner and it was sitting slightly open

I did the entire process for adjusting the idle but in the end it was still very high and i has to resort to setting the screw all the way in to lower it even more.

the wires are only a month old, ngk wires.

i have not had the icm tested. ill have autozone test it today

 

Messing with the throttle stop screw is the kiss of death for getting the idle set correctly.

 

ill redo the idle setting again via the book and let you know how it goes. thanks again