Car running rich and only on 3 cylinders

[idahotuner]

nope, i really cant understand it. everytime i think i have pin pointed the problem something else seems to be the issue. i got a new MAF and nothing seemed to change. i swapped out spark plugs because it fouled the ones i had been using. and that helped a little. but it almost seems like it is only running on 3 cylinders. i thought coil pack number 4 wasn't firing possibly so i swapped it with number 1 and that didnt do any thing. its idling right around 500 rpms and its so rich that it burns your eyes. its backfiring alot when you give it gas. and something weird. cylinder number one has like this gas smoke/steam come out of it. like when you **** match out and its has that last bit of smoke. well when i took the first spark plug out it did that steady stream of smoke for a long time. and the last couple times i cranked it the steam /smoke came out around the injector seal on the intake. i have the new tuned chips in.but i am ata lost. and i only have about 2 weeks to get it figured out before school starts. so it might end up sitting all winter until i have time to work on it.
Modified by idahotuner at 10:39 AM 9/3/2008

[boro drift]

Sorry I'm not current on your older threads. What mods do you have, and what else have you tried to remedy the problem?

[Neil]

stuck injector? if you checked compression and it's within tolerance across each cylinder, then one of your fuel injectors might be bad and stuck open.

get a long screw driver, put it on each injector and put your ear on the handle. you should hear each injector clicking.

smoke coming out of the injector seal is , each injector has 2 o-rings and then the bigger rubber isolator that you see in the manifold. Even if you had a bad valve and combustion gasses were getting out to the intake, the last place they would exit from is out from around the fuel injector. so maybe there is something wrong with that one injector and it itself is smoking. that sounds a little dangerous, being around gasoline and all.

When I first did my swap, I lengthened the O2 sensor wires and accidentally spliced a braid of shielding to the sense line, which essentialy grounded it out and made the car run open loop as if the O2 sensor was unplugged. It ran wayyy too rich in that condition, too.

[idahotuner]

well i figured out it was crappy spark plugs and an exhuast leak before the o2 sensor. so my cheep megan racing manifold is cracked. i will be swapping it out for the stock one. and leve it like that i guess. tell i can have my manifold fixed

compression was good al lthe way across

[Sphinxmunkey]

Did the car used to run with the same setup other than bolt ons? sounds almost like a timing issue but good luck with the header issue.

[boro drift]

bring that maniflold down to L-town and I'll fix it for ya.

[Neil]

NGK spark plugs are historically win.

an exhaust leak the magnitude of which that would come from a crack in the manifold wouldnt make it run that poorly.. i agree with above, may as well double check timing, also verify TPS voltage.

If you had a new O2 sensor it may have fouled by now from running abnormally rich due to other issues. If there's someone local who can bust over and let you run your car with his O2 sensor to test out that theory, i'd suggest making arrangements to do so.

really the only things that can contribute to making a stock swap run rich are O2, TPS, bad injectors, and wiring mishaps. That is given the fact that there's nothing that you're not telling us about your setup, such as an SAFC and Z32 maf for example? it's always best to troubleshoot a 100% stock rig first.
Modified by Neil at 11:20 AM 9/1/2008

[Neil]

wait, I just re-read your original post

i have the new tuned chips in.

Can you elaborate on that?

[idahotuner]

well i am pulling the manifold off. and i actually have it running all right except for it is braking up in the higher rpms.

so i am sure the leak is that last problem to fix.

wait, I just re-read your original post

Can you elaborate on that?

my reflash from scott at enthalpy. i have been emailing him about the problem too.

bring that maniflold down to L-town and I'll fix it for ya.

if i was coming down that direction i would, i have an idea for a brace.

timing was off and spark plugs being f'd up where a major part of the problem.

[boro drift]

Well, if you ever come down this way, shoot me an E-mail and let me know.

[idahotuner]

yeah dude you should check out my build thread.

i am moving to walla walla so i will be near, i am allways looking fora fabricator

[jaco]

hey did your MR mani come with a support bracket? did you have it bolted up? i keep hearing that they do but mine didnt come with one...so im counting the days untill mine cracks too.

[idahotuner]

yes it did but i discovered that the blots i used vibrated out. because i didnt use thread lock on them. lol probably my main problem causeing the leak.

[idahotuner]

well i need help now guys. i got the car running. but it is running uber rich almost like it is in a safety mode. and the car is idling around 900 rpms wich is good but when you give it gas it rev but between 3-5000 it like its stuttering really bad and back firing.

i have replaced or fixed everything possible to replace. and i switch between my old tune to my new one and it does exactly the same thing.

timing is set at 15dbtcbut the car wont run with it the tps disconnected for me to really set it correctly

oh and one really strang thing. when the car floods. i disconnect the fuel pump to clear out the fuel then it fires up. and normals once that fuel has burned off it dies. but no it idles at 3000 rpms soild wit hthe fuel pump not connected. then if i press the throttle at all it dies.but i can plug the fuel pump back in and it will drop back down to 900 rpms. weird huh?

its almost making me think that my injectors are part of the problem. but i have been chasing this problem all over the place. and its gettting old

[boro drift]

The car should not run with the fuel pump disconected PERIOD! It might stumble a bit while cranking, but it should not run. You got a strange problem bro. I mean, if the fuel pump is not connected, there is zero fuel pressure at the fuel rail and therefor when the injector opens, nothing should come out. Strange.

[idahotuner]

i know. the fp gauge is reading zero. and the car is running. which makes me think it is an injector problem.

[boro drift]

If my car wasn't tore apart I'd unplug my fuel pump and see if it runs just to see. It's almost un-diognosible just reading about it. If you get too stumped, contact Marco at SR20store.com.

[idahotuner]

i emailed scott and maybe he will have some insite for me.

[idahotuner]

iFailed detonation. When spark fails to ignite the air fuel mixture. This failed ignition is most often caused by issues with the ignition system itself, though an extreme rich condition can also cause failed or late detonation, it is usually accompanied by black exhaust smoke. What makes failed detonation so difficult to diagnose is the multitude of causes. The ignition system on the SR20DET is rather complex, there are quite a few things that can be the problem, and they will all have similar symptoms. Something like a failed coil pack will cause a dead cylinder which is easy, where as a partially failed coil pack, or a coil pack with a crack in it, or its boot will have the same symptoms as an over gapped spark plug or a loose spark plug to coil connection. All those issues cause the symptoms we are discussing, a semi random misfire, only noticed at mid to high RPM.

The reason the misfire only occurs at mid to high rpms is due to a few factors. When an over gapped spark plug is the issue, the increasing airflow or boost at higher revs blows the spark out before it can ignite an adequate flame front. If a failing coil is the issue, the higher rpms begin to put too much load on the coil itself, causing it to fall behind, either not firing enough, or not producing enough voltage for proper spark. If the coil pack or coil pack boot is cracked, as rpms increase, so does voltage, that voltage will always choose the path of least resistance. When the voltage reaches a certain point it may choose to jump though the cracks in the coil pack or its boot strait into the head itself.

[idahotuner]

the above post i found makes me think it has something ot do with my sparkplugs not being gapped correctly any more but i didnt know you could gap iridium ngks. so its not burning all the fuel off which is the reason for all the black smoke. and the fuel that isnt getting lit in the cylinders is igniting in the exhaust when i am reving it causing alot of back firing.

[Kalypso]

dont forget about next summer ben, when you get tired of the 28

[idahotuner]

yeah but i have to be able to drive it and get sick of it first lol. i am going to recheck my intake cam position and see if that will change anything up.

[idahotuner]

well scott said to check the o rings o nthe injectors, and the more research i do the more this seems to be the problem. i will pull them out at lunch and see.

[idahotuner]

well the injectors are pulled out and they seem to be the source of the problem. so i will get new o rings and see waht that does.

[Neil]

You say "FP gauge".. Are you running an aftermarket fuel pressure regulator? At the risk of being incorrect I'm going to empty my head now just to get it over with.

If you have an aftermarket fuel pressure regulator, how is it hooked up? You have to run an aftermarket regulator by itself, not in conjunction with the stock one.

If you've still got the stock fuel rail with the stock regulator in it, and then an aftermarket FPR installed after that, you're making the fuel pressure skyrocket. That would definitely make the car run too rich. Fuel pressure is there so the injectors spray- the injectors themselves are only valves, they only open and close, they don't push fuel. the fuel pressure is what pushes the fuel out. with too much fuel pressure, every time they spray they spray too much.

That would also explain why the gauge reads 0.. because there's not supposed to be any fuel pressure between the stock FPR's outlet and the gas tank. If you have the aftermarket FPR cranked down trying to get the gauge to register something then that's your problem, and you should definitely remove the aftermarket FPR.

I'd remove it not only for troubleshooting purposes, but I'd suggest permanently removing it, because they aren't even needed since we have such a wide variety of drop-in fuel injectors that are specifically designed to work without any modification to the fuel system for projects of up to 400hp.

Modified by Neil at 5:53 PM 9/12/2008
Modified by Neil at 5:56 PM 9/12/2008

[idahotuner]

thanks for your concern. i havea stock fuel rail. witha nismo adapter in place of the stock FPR. and then am running my after market one. i have had it running good before and i am sure the o rings are the source of the problem.

[Neil]

What brand FPR are you using? If you're using one of the $20 OBX or Megan Racing ones from e-bay, GET RID OF IT. For all you know, it's running 60psi of fuel pressure and that's what blew out your injector o-rings, if you truly believe them to be the current problem.

Even if it's a $200 one I'd still try to get the FPR out of the equation. As I said before, It's best to troubleshoot a 100% STOCK setup. You might be thinking "**** it, its just a fuel pressure regulator, its not like an air/fuel controller or something" but you really don't know if it's working properly, and I'd guess that it isn't, since the gauge is reading 0psi.

and, to beat it to death, for your setup, an aftermarket FPR isn't even necessary, let alone useful. Bling points FTL.

[idahotuner]

the reason it was reading zero was because i had the fuel pump disconnected. and so it wasnt presurizing the system. whne i have it connected it runs a solid 43psi. yes it is a megean racing. i cant reallt swtich back to a stock fpr because with my enthalpy tune. i am suppose to up fuel pressure to 50 psi. and then work my way back wards. I bought it from phase2 so its nota nock off one cost like 80 bucks. i do wish i had gotten the nismo one with a electronic fuel pressure gauge. but that will come later.