S13 Redtop engine harness questions, idle problem.

[mrzabala]

91 Sr20det redtop in a 91 240sx. Got my wiring figured out for the most part. Thanks speed racer.My idle is really funky. Heres the steps Ive done up to now

-Before I changed the Oil catch can and vacuum lines, the engine will start but than die right away with the maf on. With the maf off it will run rough (vibrates violently) randomly around 800rpm to 2500rpm with vacuum fluctuating (4-9 vac). I installed the stock Oil catch can, previously the hoses were long. I also reconfigured my vacuum lines to more stock/better. -Presently, after the reconfiguration... revs randomly from 1000rpm to 2500rpm than back to 1000 for a 2 seconds than goes up in a continuous loop. Also it will rev near 4000rpm at cold starts and after warm and once in a while past 5000rpm to were I have to turn the engine off. So far I checked, cleaned, and rechecked the MAF and IACV. I checked the ecu 3 (different scenarios) times and gives me code 55 (after it was idling funny). Right now I took off my 200amp circuit breaker on my battery, and Im trying to figure out the harness.

Any help is appreciated. Would help if you can provide pictures of what the plug goes into. Thanks.

Videos:

Start up with all connected 1st test: - both times it revved to around 3krpm was not me. I gave if throttle enough to try and keep it at 1krpm

Start up with no TPS and no MAF 2nd test:

Start up with TPS but no MAF 3rd test: - IF I try to give it gas, it will bog and will die if I keep giving it throttle.

Start up with no TPS but with MAF 4th test: - Best idle in terms of all the other test, but as you can tell it goes up and down.

Start up with all connected again 5th test:

Modified by mrzabala at 6:28 PM 7/31/2007
Modified by mrzabala at 6:32 PM 7/31/2007

[mrzabala]

Bump

[tintdude69]

those dont plug into anything. the one in the circle is tach signal for hooking up a timing light and you could have got rid of all those plugs when you did the harness

[240 GTR]

try checking the TPS

[mrzabala]

those dont plug into anything. the one in the circle is tach signal for hooking up a timing light and you could have got rid of all those plugs when you did the harness

My friend dropped of his car today for me to compare and to check my parts. There is a brown resistor that plugs into it. Seems like its for the ignition. Please don't post if your not sure...

[tintdude69]

well i knew it didnt go anywhere and usually the extra plugs have caps on them and i never bothered to read the cap so apparently it is a resistor and i just ran and double checked on it.
Modified by tintdude69 at 9:44 AM 7/30/2007

[SpeedRacer1]

Those plugs really wouldnt have anything to do with the idle. I'd know, I made that pic and purposely did not name the unused plugs. Though the EGR sensor is also not used.

[mrzabala]

RPM hunting. I believe thats what my car is doing. Im going to try the resistor from my friends and see if it will clear this up. If anything Im going to swap harnesses and sensors onto his car to see exactly whats wrong.

[mrzabala]

Have a question. My black with yellow strip wire on the gray plug on the sr harness is connected to the grey plug from the ka harness but ends up going to the brown harness on the ka side. I checked the brown plug on the ka body harness and theres the black with yellow strip wire and they all line up. Is this okay?

[mrzabala]

Alright I directly connected the black/yellow wire from the engine harness to the body harness. Im leading towards the IACV now and will take a look at it. Check for a video soon.

[mrzabala]

VIDEOS!!! Check my first post for the videos. Im thinking it could be my IACV, CAS, and o2 sensor. I'm going to recheck for codes.

[mrzabala]

BUMP

[tiger]

Did you find any codes? Jiggle the wires on your maf.... are you running rich? No vac leaks? is the iacv bad? It kinda sounds like a vac issue... like the lines are backwards or something... if you haven't already.. get rid of that carbon canister and all of those other useless vac lines and simplify it to about 3 or 4 lines or just your boost controller. Make sure you know which is pressure and which is vac.

[mrzabala]

Did you find any codes? Jiggle the wires on your maf.... are you running rich? No vac leaks? is the iacv bad? It kinda sounds like a vac issue... like the lines are backwards or something... if you haven't already.. get rid of that carbon canister and all of those other useless vac lines and simplify it to about 3 or 4 lines or just your boost controller. Make sure you know which is pressure and which is vac.

So far my ecu is reading code 12 which is the maf. Tested than reseted and tested again with the same code. It could be the wiring but the maf I have works great as I have my friends car to test my parts on.The parts that work that I tested so far:-Coilpacks-Maf

-I used my friends ecu which can run a redtop was still giving me the same idle problem so I feel sure that my ecu is fine even though its a #63.-I also reconfigured my vac lines as stock as possible minus the boost gauge and no BOV.-Ill take out the canister and plug the line on the TB.-I rechecked timing and its fine. -This will be the third CAS I will be using. This one came of a running engine that recently had a blown engine (piston rings). -Other than that I'll have check deeper into the maf wiring. I'll also try my friends maf to see whats up.

So far I'm leaning to the IACV as this is pretty much an idle problem. Theres no problem when I give it gas.

[tiger]

I know the way I always tested coil packs and the MAF works...

start the car and go unplug the maf while running.. if there is no change in idle or anything, it could be a factor.. it works well with coil packs too.. when it's running.. if you unplug one and see a difference in idle.. then which ever one you unplugged that you saw no change in idle is the culprit!

[mrzabala]

Alright as I was about to take my intake manifold off, I found that my fuel rail didnt have the insulator seals (there the big *** rubber seals that go between the intake and fuel rail). Would this cause my idle problem?

[doridori23]

Which ones? The ones that fo on the tabs of the rails of the intake OR the ones that seal around the base of the injectors and sit inside the intake runners?

If your missing the rubber ones around the injectors this could have the random RPM changes you have been describing.

If you missing the plastic rail isolators then no it wont effect RPM however you should use something(layer of vinyl tape perhaps) to help limit the vibration that reaches the injectors.

[mrzabala]

Which ones? The ones that fo on the tabs of the rails of the intake OR the ones that seal around the base of the injectors and sit inside the intake runners?

If your missing the rubber ones around the injectors this could have the random RPM changes you have been describing.

If you missing the plastic rail isolators then no it wont effect RPM however you should use something(layer of vinyl tape perhaps) to help limit the vibration that reaches the injectors.

the ones that seal around the base of the injectors and sit inside the intake runners. When I used my friends. I started it up and bam smooth idle. I just have to adjust my tps and it should be fine. RPM right now is around 2000rpm. I burned my self from the coolant. IT hurts.

[tiger]

Hey those big donut rings are spacers and yes you do need those...you can get them at auto zone or whatever commercial parts store is nearby. I believe you can source them from a SR20de or a KA24DE. Yeah, get those put in, they are there for a reason!!! ;-)

[mrzabala]

YEah they keep your engine from leaking air.