StayClassy94

Hi, i recently purchased a 1991 nissan 240sx coupe with a silvia front and sr20det swap. I got the car and it was pretty haggard, but it was at least running..for awhile at least.

Recently, out of no where, the car started to idle really rough and start missing a lot. I got home and the MAF was half way unplugged, i plugged it back in, unplugged the battery for about 10mins to try and reset everything, and then started it back up.

Again, it ran like crap.

I checked all the other sensors, made sure everything was plugged in. Everything looked fine.

So i pulled the plugs, they were all extremely black. The 4th cylinder was also saturated in fuel. I put new plugs in it, and started it up. Idled good for about 1min and then started to miss again.

So i pulled the injectors and changed the o-rings. Put everything back in today, started it up and now there's white smoke coming from the exhaust and it's still idling super rough!!

I checked the FPR and it was good, all the sensors are plugged in and i just dont know what else it could be. The car is a stock red top sr20det with a t28, megan racing bottom mount manifold, and a walboro 255.

someone please help! i need my car back and im not familiar with sr's at all! Thank you very much.

Javi'sSR20DET

do you have spark? check your coils n wiring harnes on the coils, u could have bad coil or harness it self

StayClassy94

Yeah all the coilpacks have spark and the harness looks good. The coils wouldnt cause it to run rich tho would it?

Javi'sSR20DET

yah only if your not getting spark, another thing that would make it run rich is your FPR stuck open or bad injector

StayClassy94

I also checked the FPR and it was good and so were the injectors haha. Im running out of options and that's why im asking for peoples suggestions on what else could cause it:/ thank you very much man!

Javi'sSR20DET

two more things make sure you have no boost leaks, and maf sensor pins are clean

ultimateirving

Running super rich and poor idle is normally a symptom of vacuum leak. Check your couplers make sure there are not any tears or leaks

StayClassy94

Cool will do guys! Thank you and i'll keep it updated.
Just one thing i dont understand now is the white smoke instant from start up after the reinstallation...I understand that white smoke usually means head gasket but the car never blew any white smoke when i took the fuel rail off and put the new o rings on. The white smoke never occured until the first start up after putting the fuel rail/injectors back on.

StayClassy94

Checked all my vacuum lines and cupplers and everything is tght.

StayClassy94

Ran codes today.
Got codes for ECT and MAF.
I tested the MAF the other night, checked all the wires on the harness, and even plugged into another MAF just to test...still ran like shit.
Keeping fingers crossed that it's the ECT.

StayClassy94

Well guys we rewired maf, i did new injectors and o rings, ran all codes, and it STILL ACTED UP!!! So finally we fixed that exhaust leak it had. The elbow coming off the turbo was not connected. So it was sucking fresh air past the upstream 02 sensor. We fixed that leak, got everything all bolted back up and BAM!!! Ran great for about 5 days(Better than it ever has) Then im sitting in drive through at McD's and the people ahead of me are taking HOURSSSS lol so i shut the car off, when i go to start it back up it doesnt start, clicks a few times like loose ground but i had ALL my power. I try to start again, no clicks this time, just fuel pump turning on, a small sort of growling noise(believe it's my power antenna trying to work..) then nothing. so i push the car over to a parking spot and park it for the night. I return the next day and make sure everything on the battery is all tightened up. I hook it up to my truck with jumper cables, let it charge for a sec and then it starts right up, but its running like shit AGAIN!! I am absolutely lost. Does anyone have anymore ideas?

StayClassy94

bump, help a fellow Zilvian out

cotbu

Next time you start your car, have multimeter handy and check the battery voltage(check for about 14v), then voltage at the mafs, ecu, etc. don't rev or drive beforehand.
The ecu has a low voltage value for the mafs, it would immediately trigger a code if the value is reached. That means the mafs and wiring, could be good and still throw a code.
just saying!

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LoverTechnologies "Half Broken Things!"

StayClassy94

Checked the alternator last night. Read 52 amps, should be around 80. Think thta solved the issue. Going to go more into depth with it today.

Megin

Update us. Got a similiar situation here.

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StayClassy94

It was the o2 sensor. took it out, blew it off, cleaned it off, then bam runs great for awhile haha. Originial o2 sensors blow.

cotbu

your problem was/is not the 02 sensor. even if you were obd2 would an 02 sensor give you those symptoms. Noobs are going to find this thread and believe doing the following "took it out, blew it off, cleaned it off" fixes a fouled, blown otherwise dirty 02sensor. also just in case you didn't know, you don't reset the ecu by disconnecting battery, what you did was probably clear long term and short term trims along with codes.

apparently all you have to do is

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LoverTechnologies "Half Broken Things!"

Megin

Nay. I even got a bloody brand new sensor waiting to be installed. That is, when and if I can find why I got no interior power and why it cranks over but doesn't want to start. Didn't want to hijack the thread, but might aswell do so, as I've checked all the fuses and they all seem to be fine, fuel pump works fine, battery ain't dead, alternator might be messed up (as the old battery died sitting 4 days straight). Throw me some bait if you can, as I couldn't get a lead through searching.

So, yeah, 8-10mpg is the least of my problems atm, as it doesn't even run...

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blkvrtswp

Make sure it is not flooded. Won't start easy with raw fuel sitting in the cyls.

Megin

Nope, not flooded.

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mantas

Had the same symptoms when my friend cut off the alternator wires by accident haha. It was kinda funny because i had the car towed home and when i did some digging around found the wires were cut. We were trying to hook up the speedo sensor and mixed up the wires lol.

xMOAR LOW S13x

my blacktop s13 sr had the same problems. im replacing th o2 today ill tell you how it goes.

xMOAR LOW S13x

Th o2 helped a great deal but i have timing chain noise so im gona pull the valve cover and make sure the timing chain didnt skip a tooth. But definatly replace o2 it helped alot with iddle and with running smoth in general