Missing and Stalling at idle.I've Spent 2,000$+trying to fix. Its Cursed HELP!

[redsx13]

Ok so here is the deal-After spending thousands of dollars trying to fix my SR i really need some advice on what my problem could be, I am completely out of Money, so i need to get this thing running myself.

Rundown, I'll keep it brief--Motor is stock redtop sr, car is 93 240sx-Motor has never run correctly after swap-Like the post says, Motor seems to miss-fire at idle (mechanic says its running very rich)-lopey idle, its all over the place!-In the higher RPM's, car runs smoothly, but also lacks power.-After a drive, it will stall at idle, but then start up and and idle again (still misfires)

What has been done- (if you think its something i checked, ill check it again)-No codes on ECU-replaced TPS (bad)-replaced MAF (bad)-replaced injectors -replaced ecu -replaced coolant temp sensor -replaced spark plugs (ngk iridium)-checked for boost leaks-checked for vaccum leaks-checked vaccum hoses (correct hookup locations)-checked timing-checked grounds-checked power and grounds on ecu plug -checked Greedy Bov (closed all the way)-checked turbo (for runout/ missing teeth)-checked compression (150psi x4)

I have been to two shops, both can't figure it out, One shop hooked up a power fc and got it running pretty well like that.

I will take any Ideas at all!


Modified by redsx13 at 1:16 AM 1/16/2009

[burntricer]

harness.

I had a similar problem, i ended up fixing it by changing the harness.

[redsx13]

harness.

I had a similar problem, i ended up fixing it by changing the harness.

thats the only other thing i could think of. what was your car doing exactly?

[burntricer]

could hardly boost, ran super rich, idled like crap, only pulled 10 inHg vacuum, couldnt set the timing cuz it was bouncing all over the place, thick, black, smoke coming from the tail pipe...search my name in this thread. you should see all the threads lolturns out it was a CAS plug issue, then the whole harness took a dive, i could at one point shut my car off by moving the ECU

[redsx13]

could hardly boost, ran super rich, idled like crap, only pulled 10 inHg vacuum, couldnt set the timing cuz it was bouncing all over the place, thick, black, smoke coming from the tail pipe...search my name in this thread. you should see all the threads lolturns out it was a CAS plug issue, then the whole harness took a dive, i could at one point shut my car off by moving the ECU

wait... i just went through your posts, and it said you still had problems after you put in your harness here: zerothread?id=383712

[Seishuku]

Sounds like one of the injector signals from the ECU is grounding out somewhere.I had a similar problem as well, one cylinder was flooding out, wouldn't run right under load and would puke out fuel from the exhaust. But I have 450CC injectors too, so it might just show as a misfire on idle with the stock 370CC injectors.

I would put a 12v LED test light (make SURE it's an LED one, anything else wont turn on/off fast enough) on the back of each injector plug, and see what's going on there. I'd bet that one injector is being held.

[burntricer]

yeah, that re-surfaced a year or so later, i fixed that. turned out to being the IACV gasket. but that wasnt what was causing my issue before

[redsx13]

Well, i just picked my car up from the shop today, this is what we checked...(1/10/09)

-re-checked ecu (good)-re-checked maf (good)-checked coil packs-checked coil pack harness-checked ignitor-checked to make sure all cylinders are fireing-checked to make sure all cylinders getting fuel***- installed and tuned Apex-i Power FC (still has same problem!!)***- injectors are not giving feed-back to power FC (wtf???)

yeah, that re-surfaced a year or so later, i fixed that. turned out to being the IACV gasket. but that wasnt what was causing my issue before

what you described is exactly what mine is doing! But i wonder if i just have a bad CAS?

I would put a 12v LED test light (make SURE it's an LED one, anything else wont turn on/off fast enough) on the back of each injector plug, and see what's going on there. I'd bet that one injector is being held.

im going to try this as well
Modified by redsx13 at 4:40 PM 1/10/2009

[burntricer]

here is what i want you to do my friend. lol

take off your CAS plug, check all the gold tabs inside of it. that ended up being the main problem in my car.... if that doesnt change anything, try another sensor.

[redsx13]

here is what i want you to do my friend. lol

take off your CAS plug, check all the gold tabs inside of it. that ended up being the main problem in my car.... if that doesnt change anything, try another sensor.

don't replace the harness?

[burntricer]

well this will be cheap to check. if it is the problem, then you know...and then replace the harness. if not then you can start looking else where...

[redsx13]

i just looked, didn't see any bad corrosion or anything.

[duffman1278]

This is wierd. Why not try removing the entire harness out of the car and remove ALL the wire loom to expose all the wires. Then check each and every wire to make sure nothing touching or somethings missing.

[redsx13]

This is wierd. Why not try removing the entire harness out of the car and remove ALL the wire loom to expose all the wires. Then check each and every wire to make sure nothing touching or somethings missing.

Sounds like thats my next step, I found brand new harness for 200$, i could just do that and save my self some time?

[SpeedRacer1]

Were there any ECU codes thrown?

[burntricer]

yeah i would just get a new one, its super easy to do for the swap. eliminates a LARGE possibilities...

[redsx13]

Well... I pulled apart my wiring harness today, no frayed wires, no damaged insulation, I spent hours on it, i checked every single wire on the ecu plug with a ohm meter to make sure there was continuity on one end of the wire to the other.

NOTHING!!!!! everything looks perfect!

Were there any ECU codes thrown?

no codes

[duffman1278]

Hmmm you might have gotten a bad engine mechanically. Sounds like somethings wrong on the engine. That or a wires mixed up somewhere. Probably hooked up where it shouldn't be.

[burntricer]

man, my wires were perfect too, but the connections at some connectors were gone, my CAS plug was perfect when it was laying flat for testing, but when it was plugged in, it wasn intermittent....i had the sammmmmeee frigging thing... and where the wiring was done...was it all staggered properly, or just bunched up?

[redsx13]

man, my wires were perfect too, but the connections at some connectors were gone, my CAS plug was perfect when it was laying flat for testing, but when it was plugged in, it wasn intermittent....i had the sammmmmeee frigging thing... and where the wiring was done...was it all staggered properly, or just bunched up?

it looked really nice; soldered, shrinktubed, legit

ok, now im thinking iacv, what are the symptoms if a dirty iacv?

[duffman1278]

Your idle would be crap if its bad.

[Shift_Tommy]

Check fuel pressure regulator

[redsx13]

Your idle would be crap if its bad.

my idle is crap, that is my main problem

Check fuel pressure regulator

the shop said that they checked it, should i recheck? have you had the same problem?

[redsx13]

*****update******

Ok, i got some free time so i decided to try some more things on my 240.

-replaced fuel pump (walbro)-replaced injectors (440's)-installed Power FC D-Jetro

still nothing! this car is a pain in my ***.

[drifterhype]

did you ever fix? if so what was the problem

[240life]

Are you sure you have no boost leaks? I had rebuilt my Sr and it was idling great at warm up but after a minute it would stall... while driving it would boost fine, but at idle it would be all up and down.....bouncing between 100 and 900 rpm and stall if I wouldn't keep my eye on the tach. All as it was, and I had checked was a coupler not sitting right creating a boost leak. So even though everything was tight and looked good to the eye..it was not. I reseated all of my clamps and now everything is 100%. I hope you figure this out soon, good luck.

[redsx13]

Are you sure you have no boost leaks? I had rebuilt my Sr and it was idling great at warm up but after a minute it would stall... while driving it would boost fine, but at idle it would be all up and down.....bouncing between 100 and 900 rpm and stall if I wouldn't keep my eye on the tach. All as it was, and I had checked was a coupler not sitting right creating a boost leak. So even though everything was tight and looked good to the eye..it was not. I reseated all of my clamps and now everything is 100%. I hope you figure this out soon, good luck.

thanks for the advice, in answer to your question, i checked for boost leaks, and so did the shop that tried to fix my car. i couldn't find any leaks in the intercooler piping, but alot of air was coming out of the PCV hose. (the one that comes from the "T" fitting on the valve cover). not really sure if that is normal.

this is what i have done so far...

-No codes on ECU-replaced TPS (bad)-replaced MAF (bad)-replaced injectors (370's)-replaced ecu -replaced coolant temp sensor -replaced spark plugs (ngk iridium)-replaced fuel pump (walbro)-replaced injectors (440's)-checked for boost leaks-checked for vaccum leaks-checked wiring harness (pulled apart, looked good, but did not replace)-checked vaccum hoses (correct hookup locations)-checked timing-checked grounds-checked alternator-checkes fuel pressure regulator-checked timing chain (just top two timing marks, not bottom)-checked power and grounds on ecu plug -checked Greedy Bov (closed all the way)-checked turbo (for runout/ missing teeth)-checked compression (150psi x4)-re-checked ecu (good)-re-checked maf (good)-checked coil packs-checked coil pack harness-checked ignitor-checked to make sure all cylinders are fireing-checked to make sure all cylinders getting fuel-installed and tuned Apex-i Power FC L-jetro -installed Power FC D-Jetro (no more maf)

**here are the symptoms i still have**

-lopey idle (very very rough, whole car shakes, it actually broke one of my new autometer gages)-missing at idle-low boost 5psi max-low vacuum-almost stalls after revving-lack of power

[240life]

If you are positive that there is no boost leaks, then another suggestion is check your fuel pressure....when I installed my engine my FPR was adjusted wrong....I had assumed since everything was good when I removed it, that it shouldn't have to be adjusted....I was wrong...I was running way to much fuel pressure, my idle was erratic (more so then before) my car wouldn't boost more then 3psi and would drive as if it were N/A. I didn't have any black exhaust smoke either which was weird...I installed a reliable fuel gauge, tweaked the CAS and dropped my fuel pressure and everything was almost 100% (more like 80% untill I found the leak)

[redsx13]

If you are positive that there is no boost leaks, then another suggestion is check your fuel pressure....when I installed my engine my FPR was adjusted wrong....I had assumed since everything was good when I removed it, that it shouldn't have to be adjusted....I was wrong...I was running way to much fuel pressure, my idle was erratic (more so then before) my car wouldn't boost more then 3psi and would drive as if it were N/A. I didn't have any black exhaust smoke either which was weird...I installed a reliable fuel gauge, tweaked the CAS and dropped my fuel pressure and everything was almost 100% (more like 80% untill I found the leak)

I actually just bought a brand new AEM A/F gauge and nismo FPR just for this reason. i should get them in later this week.

as far as a fuel pressure gauge, can i install it here?

[duffman1278]

Yup, thats where I have mine.