Rapid Backfire/misfire - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

90 DGRZ · 09-15-2009, 01:56 PM

I'll try to keep it short.

blacktop SR, exhaust, FMIC, hks t28, 10-11 psi.

I had a cage welded in my car (battery disconnected) about close to a month ago. A month BEFORE that, i didn't really drive the car at all since it's last event. when i got my car back from being caged, i took it around the block the day before an event, and it rapid backfire/misfires around 4.5-5k and loses power and stumbles. (sounds like back to back rapid gunfire) as long as i hold it WOT, it will do that, and eventually slowly make it way up the tach. Sometimes, like in second gear, it really won't stumble or backfire, it will just climb up the rpm range powerfully, then around 5k the power will seem to "flatten" out and will eventually pull to redline. but most of the time, it's the back fire issue. This only happens under load, the car revs fine in neutral.

The reason why i mention the car being caged, is because i really don't know if it's coincidental that it happened after being welded and it may be an electrical issue, or if it's completely a separate issue and it just happened to occur while being caged.

i am just now posting, because i've run out of ideas.
here's a list of what i've done or replaced, in order.

New spark plugs, gapped to about .28.
Coilpacks and grounds
Re-timed to double check timing
Igniter chip
ECU
Fuel Pump-Walbro 255
FPR
Injectors/injector seals
coolant temp sensor

the next thing i'm gonna do it pull the engine harness and go through it. i'm running out of ideas and am really hoping someone can help me. i'm becoming desperate.

thanks!

DUFFM4N · 09-15-2009, 01:59 PM

damn chuck, you always got the shittiest luck with your car

i love you

s15specR · 09-15-2009, 02:01 PM

I just posted in response to the same sort of thing, I've read about 20 of these threads because I'm having the same problem, the one similarity is that they all just changed plugs....

90 DGRZ · 09-15-2009, 02:07 PM

i know eddie...fml. when my car runs bad, it runs really bad.
i love you too. and freakin miss you. ass.

s15specr, yea the last time i kinda had a similar issue, it was a spark plug fouling out...but this time it wasn't.

YoungGun · 09-15-2009, 02:32 PM

Shit is weird fah real my dawgs.

chibo · 09-15-2009, 02:36 PM

Check your MAF and for leaks after the MAF.

bardabe · 09-15-2009, 03:12 PM

chuck i hope whoever welded your cage knew wtf they where doing, because you are supposed to disconect the battery ground, and put the ecu in a bag to keep it from touching any metal while they are welding if not. Bye Bye ECU

Other Than that check your Fuel Pressure make sure you have constant pressure and it's not droping all the way to redline. who Tuned your car?

zenkicookies · 09-15-2009, 04:49 PM

i agree with chibo,check the MAF. id also check the couplers just in case.

90 DGRZ · 09-16-2009, 04:49 AM

Quote:

Originally Posted by bardabe

chuck i hope whoever welded your cage knew wtf they where doing, because you are supposed to disconect the battery ground, and put the ecu in a bag to keep it from touching any metal while they are welding if not. Bye Bye ECU

Other Than that check your Fuel Pressure make sure you have constant pressure and it's not droping all the way to redline. who Tuned your car?

the sr is basically stock, no tune here.
they knew what they were doing, he's welded many cages into FD cars and has alot of experience in fabrication, etc.
Even if it was the ECU, i already have another one in there that came out of a running car.

i'll try out a different maf tmw, but it doesnt seem likely that it's the maf...when i unplug the maf it does it's thing where it'll bounce around 3-4k and not budge. but i have nothing to lose, i'll try it.

93sr20240 · 09-16-2009, 07:27 AM

I would say a coil pack but since you tried that......... I say dunno

GSXRJJordan · 09-16-2009, 07:33 AM

Quote:

Originally Posted by bardabe

Other Than that check your Fuel Pressure make sure you have constant pressure and it's not droping all the way to redline. who Tuned your car?

I guessed fuel pressure first too, but he's replaced the fuel pump and the FPR with known-working ones. I told him to inspect the harness too for burns in the electrical tape/sleeve/etc...

Quote:

Originally Posted by 93sr20240

I would say a coil pack but since you tried that......... I say dunno

I said that second - Chuck did you try wrapping the coilpacks with electrical tape too?

Also, MAF ground? Coilpack ground? I made a little grounding strap to ground all the coilpacks to the intake mani on my SR years ago, helped with some hesitation I used to have...

Blackparade · 09-16-2009, 09:58 AM

did you check for any boost leaks?
making a boost leak tester is easy and effective. try it out.

nieko · 09-16-2009, 11:50 PM

cas?

and ground your coilpacks bro... it cant hurt

GSXRJJordan · 09-17-2009, 02:10 AM

Quote:

Originally Posted by nieko

cas?

and ground your coilpacks bro... it cant hurt

CAS isn't going to give a bad signal, unless it's improperly wired/grounded... it's a very simple device. That being said, if you have a chance to replace it with a known-working one, try it!

And yeah, grounding those coilpacks can't be bad. Doubt that's the problem though.

nieko · 09-17-2009, 03:09 AM

i think we need to stop thinking of the obvious right now....

just start changing EVERYTHING.

lololol

you havent changed CAS

so try it.

dont think youve tried changing mafs so try it.

just try EVERYTHING llolo

charlie321 · 09-17-2009, 03:33 AM

Check the ground behind the head. And I second the CAS.

bardabe · 09-17-2009, 10:09 AM

CAS does make sence, try it why didn't I think of that. haha

let5l1de · 09-17-2009, 11:15 AM

just bring it to me chuck...

~m

4x4le · 09-17-2009, 08:07 PM

you can try to clean your cas with some sensor safe cleaner. If that dont work and a known good one does work but you have to give that back to your friend or something but it fixed the problem I can sell you a brand new cas with new cap and gaskets for cheap.

Good luck, its the small problems that give us the most grief.

90 DGRZ · 09-17-2009, 09:05 PM

Quote:

Originally Posted by Blackparade

did you check for any boost leaks?
making a boost leak tester is easy and effective. try it out.

the boost gauge doesnt show that it's leaking...and even if it was leaking a couple pounds, im sure my car wouldnt be running like to this extent.

Quote:

Originally Posted by GSXRJJordan

I guessed fuel pressure first too, but he's replaced the fuel pump and the FPR with known-working ones. I told him to inspect the harness too for burns in the electrical tape/sleeve/etc...

I said that second - Chuck did you try wrapping the coilpacks with electrical tape too?

Also, MAF ground? Coilpack ground? I made a little grounding strap to ground all the coilpacks to the intake mani on my SR years ago, helped with some hesitation I used to have...

yea jeff thanks for all ur help, i wrapped those bitches good.
i'm gonna pull my harness as soon as i get a day off. and put new grounds to the coilpacks. i was gonna swap mafs with my roommate, but the plug on the maf side was wider on his than mine, so i couldn't test it today. i'm gonna get some sensor safe cleaner and clean mine...it actually looked dirty.

a couple peopl told me it could be my alternator??????

just a quick note: my idle voltage is roughly 13.5 ........ when i'm flooring it andd it starts backfiring/misfiring around 5k, the voltage drops to about 12.7.
normal, or should there not be a drop in voltage?

Quote:

Originally Posted by nieko

cas?

i'm gonna go grab one off of cody's old motor.<3

Quote:

Originally Posted by let5l1de

just bring it to me chuck...

~m

i will.

GSXRJJordan · 09-17-2009, 09:16 PM

Normal for there to be a voltage drop at full load, as long as it stays above 12.5V or so comes back up you're fine. I've run my car full out with a bad alternator and it didn't start bogging until 11.8V, and didn't actually turn off until 11.3V, FYI.

Clean the MAF, swap CAS, re-time, and hope for the best? Otherwise I'd be happy to inspect the harness for ya.

BrokenWhite240 · 09-17-2009, 09:35 PM

Sounds like a MAF to me had alsomt the vary same problem with a swap I did. Reved in neutral fine and sounded awsome. As soon as I took it out and got up to about 5k I believe it broke up, stumbled, lost power, backfired..etc. Put a MAF in it and it fixed it..hope this helps.

90 DGRZ · 09-21-2009, 09:46 PM

finally my day off today. borrowed some maf cleaner and cleaned the bitch andddd...put a CAS from a known-working car. TDC, lobes out, timed it at 15 degs on second hash mark, whole nine, and still basically the same thing.

PLEASE anybody...help..im super desperate. i've really tried everything.

Do you guys think this happened during welding in the cage, or do you guys think it's pure coincidence? any other ideas??

steve shadows · 09-21-2009, 10:05 PM

If you are able to drive your car down to my shop on Saturday AM I will give it a look, just bring 80 bucks with you for the diagnosis fee I charge.
I will give you about an hour of my time and will pull out all the stops and give you my honest opinion. 99% of the time I nail the diagnosis.
I will check ECU, your ignition system with IR gun and with consult and with Voltage meter etc. I will also check your injectors and other parts as well
If you are REALLY DESPERATE I suggest you let me give it a shot rather than spending more money on replacing parts, let me give you my honest opinion.
I have a dyno apt at 12 PM but I can squeeze you in at 1045-11 ish if you want to come to the shop, we are located Canyon Racer Motorsports Home Page

Either way

It sounds like

- Ignition System Failure
- Fuel System Failure
- Possible major vacuum issue.

If it is a vacuum issue I can assure you 100% we will find it. I have a special smoke machine type of vacuum tester which NEVER FAILS, in fact we find leaks that people never knew could even exist and get cars running in amazing shape just by checking the vacuum system

If it is your wiring harness then your whole harness is trash and you need to buy an entire new harness and also check all of your grounds and check for charring or any other wear.

I would let me give it a shot first though lmk if you are interested if not I understand.

-PM me for details

90 DGRZ · 09-21-2009, 10:19 PM

Thanks Steve for your input, and i'll be contacting you when i have time to take my car all the way down there, it's quite a drive for me since it's not registered and stuff. between work and moving out the end of this month, i wont have time for a couple weeks.

any other inputs??

steve shadows · 09-21-2009, 11:23 PM

well if you I will drive up to where you are and check it out personally

YoungGun · 09-21-2009, 11:24 PM

This shit sounds like

BAD DAT DAT DAT DAT DAAAT DAT.

steve shadows · 09-21-2009, 11:27 PM

Quote:

Originally Posted by YoungGun

This shit sounds like

BAD DAT DAT DAT DAT DAAAT DAT.

thanks for the technical explanation my friend...

PacificDrift_Nick · 09-22-2009, 12:18 AM

this guy is a bad person and the Nissan gods are punishing him

steve shadows · 09-22-2009, 12:32 AM

well let him know I can come up and look at this thing in person on Sunday afternoon if he is fed up and wants a solid opinion on this thing

09-15-2009, 01:56 PM	#1
90 DGRZ Zilvia Addict Join Date: Mar 2006 Location: Los Angeles, Cali Posts: 908 Trader Rating: (2) Feedback Score: 2 reviews	Rapid Backfire/misfire I'll try to keep it short. blacktop SR, exhaust, FMIC, hks t28, 10-11 psi. I had a cage welded in my car (battery disconnected) about close to a month ago. A month BEFORE that, i didn't really drive the car at all since it's last event. when i got my car back from being caged, i took it around the block the day before an event, and it rapid backfire/misfires around 4.5-5k and loses power and stumbles. (sounds like back to back rapid gunfire) as long as i hold it WOT, it will do that, and eventually slowly make it way up the tach. Sometimes, like in second gear, it really won't stumble or backfire, it will just climb up the rpm range powerfully, then around 5k the power will seem to "flatten" out and will eventually pull to redline. but most of the time, it's the back fire issue. This only happens under load, the car revs fine in neutral. The reason why i mention the car being caged, is because i really don't know if it's coincidental that it happened after being welded and it may be an electrical issue, or if it's completely a separate issue and it just happened to occur while being caged. i am just now posting, because i've run out of ideas. here's a list of what i've done or replaced, in order. New spark plugs, gapped to about .28. Coilpacks and grounds Re-timed to double check timing Igniter chip ECU Fuel Pump-Walbro 255 FPR Injectors/injector seals coolant temp sensor the next thing i'm gonna do it pull the engine harness and go through it. i'm running out of ideas and am really hoping someone can help me. i'm becoming desperate. thanks! __________________ -Chuck

09-15-2009, 01:59 PM	#2
DUFFM4N Post Whore! Join Date: Aug 2006 Location: Southern California...where i stretch out haters like a bad thong Age: 37 Posts: 7,371 Trader Rating: (40) Rides Gallery: DUFFM4N Feedback Score: 40 reviews	damn chuck, you always got the shittiest luck with your car i love you __________________ *things may come to those who wait, but only the things left by those who HUSTLE* CLICK HERE FOR MY BLOG

09-15-2009, 02:07 PM	#4
90 DGRZ Zilvia Addict Join Date: Mar 2006 Location: Los Angeles, Cali Posts: 908 Trader Rating: (2) Feedback Score: 2 reviews	i know eddie...fml. when my car runs bad, it runs really bad. i love you too. and freakin miss you. ass. s15specr, yea the last time i kinda had a similar issue, it was a spark plug fouling out...but this time it wasn't. __________________ -Chuck

09-15-2009, 02:36 PM	#6
chibo Zilvia FREAK! Join Date: Sep 2005 Location: Tempe and Scottsdale, Arizona Age: 33 Posts: 1,425 Trader Rating: (0) Feedback Score: 0 reviews	Check your MAF and for leaks after the MAF. __________________ 1989 S13 \| 1996 S14 \| 2001 E46 \| 2009 ZX6R

09-15-2009, 03:12 PM	#7
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 31 Posts: 4,716 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	chuck i hope whoever welded your cage knew wtf they where doing, because you are supposed to disconect the battery ground, and put the ecu in a bag to keep it from touching any metal while they are welding if not. Bye Bye ECU Other Than that check your Fuel Pressure make sure you have constant pressure and it's not droping all the way to redline. who Tuned your car? __________________ Review Thread

09-15-2009, 02:01 PM	#3
s15specR Zilvia FREAK! Join Date: Oct 2007 Location: USA Posts: 1,021 Trader Rating: (18) Feedback Score: 18 reviews	I just posted in response to the same sort of thing, I've read about 20 of these threads because I'm having the same problem, the one similarity is that they all just changed plugs....

09-15-2009, 02:32 PM	#5
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	Shit is weird fah real my dawgs.

09-15-2009, 04:49 PM	#8
zenkicookies Zilvia Member Join Date: Jun 2007 Location: so cal Age: 35 Posts: 263 Trader Rating: (2) Feedback Score: 2 reviews	i agree with chibo,check the MAF. id also check the couplers just in case. __________________ Last edited by zenkicookies; 09-15-2009 at 05:13 PM.. Reason: typo

09-16-2009, 07:27 AM	#10
93sr20240 Leaky Injector Join Date: Apr 2006 Location: Tennesse Posts: 79 Trader Rating: (1) Feedback Score: 1 reviews	I would say a coil pack but since you tried that......... I say dunno

09-16-2009, 09:58 AM	#12
Blackparade Zilvia FREAK! Join Date: Sep 2006 Location: LA Age: 35 Posts: 1,022 Trader Rating: (0) Feedback Score: 0 reviews	did you check for any boost leaks? making a boost leak tester is easy and effective. try it out.

09-16-2009, 11:50 PM	#13
nieko Post Whore! Join Date: Sep 2007 Location: Westminster Age: 30 Posts: 2,694 Trader Rating: (14) Feedback Score: 14 reviews	cas? and ground your coilpacks bro... it cant hurt __________________

09-17-2009, 03:09 AM	#15
nieko Post Whore! Join Date: Sep 2007 Location: Westminster Age: 30 Posts: 2,694 Trader Rating: (14) Feedback Score: 14 reviews	i think we need to stop thinking of the obvious right now.... just start changing EVERYTHING. lololol you havent changed CAS so try it. dont think youve tried changing mafs so try it. just try EVERYTHING llolo __________________

09-17-2009, 03:33 AM	#16
charlie321 Zilvia Addict Join Date: Dec 2006 Location: Long Beach, CA Age: 30 Posts: 989 Trader Rating: (4) Feedback Score: 4 reviews	Check the ground behind the head. And I second the CAS. __________________

09-17-2009, 10:09 AM	#17
bardabe Post Whore! Join Date: Aug 2005 Location: SoCal Age: 31 Posts: 4,716 Trader Rating: (10) Rides Gallery: bardabe Feedback Score: 10 reviews	CAS does make sence, try it why didn't I think of that. haha __________________ Review Thread

09-17-2009, 11:15 AM	#18
let5l1de Zilvia FREAK! Join Date: Dec 2007 Location: 626DRIFT, ca Posts: 1,420 Trader Rating: (30) Rides Gallery: let5l1de Feedback Score: 30 reviews	just bring it to me chuck... ~m __________________ GR Performance facebook Pics & More! Comments! http://www.facebook.com/pages/GR-Performance/120477531339202 Read My Sales Review 626 Friday Nights San Gabriel

09-17-2009, 08:07 PM	#19
4x4le Zilvia FREAK! Join Date: Nov 2008 Location: Manchester, Tn Posts: 1,253 Trader Rating: (1) Feedback Score: 1 reviews	you can try to clean your cas with some sensor safe cleaner. If that dont work and a known good one does work but you have to give that back to your friend or something but it fixed the problem I can sell you a brand new cas with new cap and gaskets for cheap. Good luck, its the small problems that give us the most grief.

09-17-2009, 09:16 PM	#21
GSXRJJordan Post Whore! Join Date: May 2006 Location: << 626 >> Posts: 9,135 Trader Rating: (19) Rides Gallery: GSXRJJordan Feedback Score: 19 reviews	Normal for there to be a voltage drop at full load, as long as it stays above 12.5V or so comes back up you're fine. I've run my car full out with a bad alternator and it didn't start bogging until 11.8V, and didn't actually turn off until 11.3V, FYI. Clean the MAF, swap CAS, re-time, and hope for the best? Otherwise I'd be happy to inspect the harness for ya. __________________ Jordan Innovations has a new web site! www.JordanInnovations.com -- All your favorite FD Pro Drifters love it, trust me -- www.JordanInnovations.com

09-17-2009, 09:35 PM	#22
BrokenWhite240 Zilvia Addict Join Date: Nov 2007 Location: Cherry Hill, NJ Age: 36 Posts: 618 Trader Rating: (19) Feedback Score: 19 reviews	Sounds like a MAF to me had alsomt the vary same problem with a swap I did. Reved in neutral fine and sounded awsome. As soon as I took it out and got up to about 5k I believe it broke up, stumbled, lost power, backfired..etc. Put a MAF in it and it fixed it..hope this helps. __________________ Team Prettyboys

09-21-2009, 09:46 PM	#23
90 DGRZ Zilvia Addict Join Date: Mar 2006 Location: Los Angeles, Cali Posts: 908 Trader Rating: (2) Feedback Score: 2 reviews	finally my day off today. borrowed some maf cleaner and cleaned the bitch andddd...put a CAS from a known-working car. TDC, lobes out, timed it at 15 degs on second hash mark, whole nine, and still basically the same thing. PLEASE anybody...help..im super desperate. i've really tried everything. Do you guys think this happened during welding in the cage, or do you guys think it's pure coincidence? any other ideas?? __________________ -Chuck

09-21-2009, 10:05 PM	#24
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	If you are able to drive your car down to my shop on Saturday AM I will give it a look, just bring 80 bucks with you for the diagnosis fee I charge. I will give you about an hour of my time and will pull out all the stops and give you my honest opinion. 99% of the time I nail the diagnosis. I will check ECU, your ignition system with IR gun and with consult and with Voltage meter etc. I will also check your injectors and other parts as well If you are REALLY DESPERATE I suggest you let me give it a shot rather than spending more money on replacing parts, let me give you my honest opinion. I have a dyno apt at 12 PM but I can squeeze you in at 1045-11 ish if you want to come to the shop, we are located Canyon Racer Motorsports Home Page Either way It sounds like - Ignition System Failure - Fuel System Failure - Possible major vacuum issue. If it is a vacuum issue I can assure you 100% we will find it. I have a special smoke machine type of vacuum tester which NEVER FAILS, in fact we find leaks that people never knew could even exist and get cars running in amazing shape just by checking the vacuum system If it is your wiring harness then your whole harness is trash and you need to buy an entire new harness and also check all of your grounds and check for charring or any other wear. I would let me give it a shot first though lmk if you are interested if not I understand. -PM me for details __________________ Like Me on FaceBook !

09-21-2009, 10:19 PM	#25
90 DGRZ Zilvia Addict Join Date: Mar 2006 Location: Los Angeles, Cali Posts: 908 Trader Rating: (2) Feedback Score: 2 reviews	Thanks Steve for your input, and i'll be contacting you when i have time to take my car all the way down there, it's quite a drive for me since it's not registered and stuff. between work and moving out the end of this month, i wont have time for a couple weeks. any other inputs?? __________________ -Chuck

09-21-2009, 11:23 PM	#26
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	well if you I will drive up to where you are and check it out personally __________________ Like Me on FaceBook !

09-21-2009, 11:24 PM	#27
YoungGun Post Whore! Join Date: Nov 2007 Location: 818-951 SoCal Posts: 3,961 Trader Rating: (23) Feedback Score: 23 reviews	This shit sounds like BAD DAT DAT DAT DAT DAAAT DAT.

09-22-2009, 12:18 AM	#29
PacificDrift_Nick Zilvia Junkie Join Date: Jul 2008 Location: Where the Lakes are Silver (socal) Posts: 427 Trader Rating: (4) Feedback Score: 4 reviews	this guy is a bad person and the Nissan gods are punishing him

09-22-2009, 12:32 AM	#30
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	well let him know I can come up and look at this thing in person on Sunday afternoon if he is fed up and wants a solid opinion on this thing __________________ Like Me on FaceBook !

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