Misfiring/stuttering

[99GSX_emily]

I did some searching in the forums search but I couldn't find the answer i was looking for really. I have misfiring when i hit about 20psi in 1st & 2nd gear, & you can see a puff of white smoke comes out the rear! In 3rd & 4th gear its almost impossible for me to hit anything past 5psi, it feels like I'm stuttering like it wants to hit boost but can't! I checked the coil (14.80ohms on 20K ohms setting), plugs (gapped to .028), wires & they were fine plus I've replaced all of them about 8,000miles ago I would say. Boost leak's I've taken care of but Imma test that again tomorrow when i can get my hand on some air! I DO NOT have a APR which i know would make me run pig rich, but would that cause my issue?

But, back to the white smoke, would a blown head gasket have anything to do with misfiring? I do have some overheating issues but only when I'm using the a/c with boost, but no real signs of a bad gasket. And lastly, CEL is useless, it's has been on since i've bought the car. (code comes up as a bad fuel sensor in the tank & o2 sensor of course)

I'm runnin 99 GSX, big16, FMIC, 255lp hp pump, & I&E. Is there something else I'm missing? Thanks for the input!

 

[2gjlc]

I had a very similiar issue and it ended up being my plug gap. I read a thread saying that some peoples plugs have a tendency of opening up over time. My gap had opened up to like 0.05 when I had originally had them at 0.028. I kept over thinking the issue. Hope that helps.

I didnt see a AFPR on that list for that pump. I doubt thats the issue but if you dont have one you should get one for that fuel pump.

just read the original post all the way. Guess you know you need the AFPR. Sorry.

 

[fullCircle]

i concur on checking the gap. 3/4 gearing may be putting too much load on the engine that the spark plug gap is unable to compete with this.

 

[99GSX_emily]

My gap had opened up to like 0.05 when I had originally had them at 0.028. I kept over thinking the issue. Hope that helps.

Bingo, that would definitely make sense! Over thinking things for the win!
I can't find my gapper (that is also why i haven't changed my plugs for 8,000miles ) so imma had up to O'Reilly tomorrow & get another one for $3 & hopefully that's my fix!

EDIT: Bad news! Went out & got new plugs & gapped them to .028 & still getting the stuttering/misfiring under boost

I just can't figure out what else could possibly cause this problem, any more input i would really appreciate it!

 

[haswesley]

I've had the same problem twice. It is your spark plug wires. Wires deteriorate over time with the demand we put on our cars. I change my plug wires every six months. I use Bosch from AutoZone. I just return my old ones and get a new set under warranty. The white smoke, however, is usually due to coolant burning. It is not related to your misfiring. It just may be that you can see the smoke better when the car misfires.

 

[EvoRage]

I would say check for boost leaks again and do a visual inspection of all your piping and couplers. I had a friends supra that was doing this and he claimed he did a boost leak test. I went under there and found a fist size cut in on of the couplers which was the issue. Also, what are you tuning with? It could be a tuning issue.

 

[TenSecondSTi]

I would say check for boost leaks again and do a visual inspection of all your piping and couplers. I had a friends supra that was doing this and he claimed he did a boost leak test. I went under there and found a fist size cut in on of the couplers which was the issue. Also, what are you tuning with? It could be a tuning issue.

Evorage I like your car a lot .....


On topic here change that o2 sensor. It will throw off your air fuels a lot at idle and cruise conditions so change it. Your not lean at WOT so it shouldn't hurt your car.

also check the CAS change the coolant temp sensor if it's old. or original. Make sure your timing is right. Base marks and base timing is set correctly. In some cases lowering the base timing may help ease the tune 3*-5* whats your timing at WOT?

 

[staztrx250]

I DO NOT have a APR which i know would make me run pig rich, but would that cause my issue?

I'm runnin 99 GSX, big16, FMIC, 255lp hp pump, & I&E. Is there something else I'm missing? Thanks for the input!

Your oem fuel pressure regulator should be more than enough to hold back your 255. However if you have a lot of miles I would say its worn out. The fpr works by creating back pressure on you're fuel rail. When they wear out they lose the ability to create that back pressure which= no fuel pressure. In this case it would cause low fuel pressure. This would cause you to lean out under high load ie boost in a high gear. Do you have an A/F gauge(a wideband o2 gauge)? Is it leaning out? this would cause white smoke in most causes. if you were too rich it would be black. If you don't have a wide band you can also check this by hooking up a fuel press gauge before the fuel rail. it should read(and don't quote me on the numbers) around 36 psi at idle and 43-44 with the vac line off. If its any less it you're fpr is shot and don't mess around with an oem one because it'll most likely me more than a good afpr.


So if you check that and every things good move on to spark plugs. If they are gapped to tight you could be "blowing them out" causing a miss fire. Take them out and gap them bigger if there under .028.

If that checks out the only other thing that explains the smoke is turbo seals.



Also in regards to the head gasket you would most likely be causing your fuilds to change. If your oil is creaming it's shot for sure. if the exhaust smells sweet it probably shot. But if you're not overheating or using coolant i wouldn't think that would be the cause.

you said your running 20psi... what's your injector/ management set up???

But, back to the white smoke, would a blown head gasket have anything to do with misfiring? I do have some overheating issues but only when I'm using the a/c with boost, but no real signs of a bad gasket.

I would change your thermostat( 10-15 bucks tops) and check you're fans just to be safe. The thermostats on these cars don't really have a fail safe mine wasn't opening all the way cause my car to over heat under load (like ac being on) and eventually it got worse to the point where it would get to 230 unless i had the heat blasting away. so just change it, its a cheap reliably mod. and as long as you're doing that drain your radiator and put some new coolant in. Also inspect the coolant that comes out. look for sings of oil and what not.

 

[99GSX_emily]

Your oem fuel pressure regulator should be more than enough to hold back your 255. However if you have a lot of miles I would say its worn out.

Do you have an A/F gauge(a wideband o2 gauge)?

So if you check that and every things good move on to spark plugs.

If the exhaust smells sweet it probably shot.

you said your running 20psi... what's your injector/ management set up???

Going back up to what haswesley posted, my wires are less then 8,000miles old! Would they have worn that fast? When i first tested for leaks i borrowed a tester from a buddy & he's gone to college (of course he took it with him) so imma have to make one over the weekend & try that as soon as possible.

staztrx250,
I did just replace my plugs today & gapped them to .028 & still causing misfiring. Something i did notice is that it's not really the amount of boost im under it's when i hit between 4,000rpms to 4,500rpm is when it starts to misfire. I was driving on my way home about 20mins ago in 3rd & dropped it down to 2nd & it spiked to 18psi roughly with my foot still clean on the gas but no misfiring! In this case i would think bad plugs (from previous experience with a A4 that had the same conditions i am having) but i did just replace them today!

As for the smell, it is a very very strong gas smell from behind the car i was told but that would probably be caused by my bad gaskets in the exhaust system, right?

Lastly, I'm running stock injectors & feel free to laugh but i have no engine management system! I was gonna set a system up at the same time i got some more gauges to help monitor (wideband, fuel pressure, & oil temp ) a MBC & AFPR, so i could monitor/tune semi properly!

EDIT: tested the coil pack again & both are sitting at around 14.80ohm on 20K ohm setting. I never did mention that.

 

[rizzzo29]

well with stock injectors on 20 psi is definatly a no no, your over 100 percent injector duty cycle.

for your exhaust white smoke it usually coolant or water vapor. if the smell is very sweet and obnoxious it it most likely coolant, then your looking at a head gasket, do a compression test.

and no more 20 psi! your starving your system!

 

[99GSX_emily]

well with stock injectors on 20 psi is definatly a no no, your over 100 percent injector duty cycle.

for your exhaust white smoke it usually coolant or water vapor. if the smell is very sweet and obnoxious it it most likely coolant, then your looking at a head gasket, do a compression test.

and no more 20 psi! your starving your system!

So the misfiring is caused by the stock injectors not getting enough fuel to the motor? I've tested the whole ignition system & everything tested fine & with in spec so i've ruled out that being the problem. Which would leave fuel. Well, i need to get a MBC anyways, lowering the boost would end the misfiring at 4,000rpms?

 

[rizzzo29]

are you in peak boost at 4k?

 

[dsm03]

Are they Stock Spark PLugs? DSMs Hate any of that high end stuff.. Sorta had the same problem way back when..

 

[99GSX_emily]

are you in peak boost at 4k?

If i'm at WOT i'm around 20psi @ 4K, otherwise even under 5psi at 4K (higher gears though 3rd 4th) it just misfires & sounds like a damn stutter box & no not stock, i have NGK BPR6ES gapped to .028

 

[rizzzo29]

Well if you think about it at 20 psi your starving your stock system.

I"m afraid that you may have messed up some internals like that. you could run a compression test, something may show up as lower compression in a cylinder. Also turn your boost down! 20 psi is not safe on 450cc's

Yes, if its not spark, it leaves air fuel or exhaust.

For air check all piping including cold side of turbo to throttle body, are you still on the stock side mount?

For fuel check injectors, fuel rail and pump

For exhaust, check out if your cat may be clogged or anything of that sort, could assist in your lack of power.

 

[99GSX_emily]

Well if you think about it at 20 psi your starving your stock system.

I"m afraid that you may have messed up some internals like that. you could run a compression test, something may show up as lower compression in a cylinder. Also turn your boost down! 20 psi is not safe on 450cc's

Yes, if its not spark, it leaves air fuel or exhaust.

For air check all piping including cold side of turbo to throttle body, are you still on the stock side mount?

For fuel check injectors, fuel rail and pump

For exhaust, check out if your cat may be clogged or anything of that sort, could assist in your lack of power.

I have evo iii 16g with a FMIC & 255hp pump. previously before i installed the FMIC i could boost 18psi no problem but once i installed the FMIC that's when misfiring started to happen. I have a turbo back exhaust so very limited back pressure. I was actualy unaware of the stock injectors 100% duty is 32lbs/min & i know a evo iii 16g can produce 37lbs/min so that definitly makes sense that i am overworking my injectors. I'll start with geting a MBC & lowering the boost & go from there. Thanks for the input & advice!!

 

[staztrx250]

I have evo iii 16g with a FMIC & 255hp pump. previously before i installed the FMIC i could boost 18psi no problem but once i installed the FMIC that's when misfiring started to happen. I have a turbo back exhaust so very limited back pressure. I was actualy unaware of the stock injectors 100% duty is 32lbs/min & i know a evo iii 16g can produce 37lbs/min so that definitly makes sense that i am overworking my injectors. I'll start with geting a MBC & lowering the boost & go from there. Thanks for the input & advice!!

Yeah there is no way you can run a evo 3 16g on stock 440cc injectors. The fact that you have a 255lp pump wont change a thing if your fpr is working properly. The evo 3 actually produces 42 lbs/min. But yeah there is no way you can run that 16g to 20 psi safely. what I would do is turn the boost down to stock (just take your boost con off!!!!!) see if you can run through the gears like that. if you can't it sounds like you stock fuel pressure regulator is an issue. there finicky things so it could be getting stuck closed causing high fuel press or stuck open cause low fuel press. Either way you're killing your motor if you haven't already. let me now how it does under stock boost press and i'll give you some recommendations.


maybe get me a video if you can idle and in car that kind of stuff one now and one at stock boost.


This is what you should do for sure tho

1 keep that boost at stock for 2 reasons your injector can't handle it and you have stock internals anything past 18psi and you're asking for trouble blowing a head gasket
2 check your fuel press that can tell us so much just from that

I'll start with geting a MBC & lowering the boost & go from there.

are you saying you don't have one????

why are you hitting boost that high is it hooked up right? you should hit like 11psi if its a stock waste gate

 

[99GSX_emily]

are you saying you don't have one????

why are you hitting boost that high is it hooked up right? you should hit like 11psi if its a stock waste gate

HAHA! Yeah i do not have one , i just ordered one & i'll get it later this week. Keep in mind i have a evo iii 16g, the stock wastegate should open at 19psi. And i dunno how i was boosting 24psi but i was!

Idle is a little bit choppy, driving out of boost is fine, but once i combine boost with mid rpms then it doesn't work so well I'll try to make a video, if i can hear anything on it, ill post it up!

 

[Misterbeechy]

if you really believe that.. also check your ignition coils i believe ## cars has 2 of them.. u may have problem with that.. i had the same issue and i changed to MSD... and fixed.. also it doesnt throw a CEL when the problem happens?

 

[turboglenn]

been there and dealt with this too many times now...the first twqo things to do are

1.) gap plugs to .020

2.) make sure you're not running richer than 11.2:1 (anywhere in the 10's can drown out the spark easily)

edit: from your above post abhout no management the thing is just plain too rich if the injectors are keeping where the eCU wants them to be for AFR (which is like 9.8:1)..you can gap em anyhow you please but that rich an FR is gonna blow the plugs out easy..

i went MSD trying to solve it when i was just too rich a long time ago

 

[staztrx250]

HAHA! Yeah i do not have one , i just ordered one & i'll get it later this week. Keep in mind i have a evo iii 16g, the stock wastegate should open at 19psi. And i dunno how i was boosting 24psi but i was!

Idle is a little bit choppy, driving out of boost is fine, but once i combine boost with mid rpms then it doesn't work so well I'll try to make a video, if i can hear anything on it, ill post it up!

um stock evo waste gates are 11 psi pretty much all mhi waste gates are 11 psi. they have stock boost control solenoids that change the boost. so you shouldn't hit that in less you have a non stock waste gate. either way you can't use a mbc to turn down you boost lower that what the waste gate hits. it just doesn't work that way. what every you get out of you're waste gate is as low as you can go for psi. something isn't hooked up right.


if you just check your fuel pressure we could give you a defiant answer weather or not you're too rich!!

 

[99GSX_emily]

I went & checked to make sure i did hook my turbo up correctly since staztrx250 you said i probably wasn't hooked up right if i was boostin so high! So the 5th picture down on the link is what i have my vac lines hooked up like! The boost is back down to 9psi with that setup but the problem I have now is that oil is being spit EVERYWHERE! it's comin out at my air filter/maf & spittin everywhere & smoke is going out the back & into the car it's brutal! I'm so confused

The 4th picture is what i originally had it setup as. I was boostin 24psi but with misfiring which we already knew. So then i unplugged all the vac lines to see what would happen & i could boost to 18psi without misfiring & NO oil spitting or anything.

If i wasn't confused in the first place now i'm really confused????


http://www.dsmtuners.com/forums/turbo-system-tech/291956-turbo-vacuum-lines.html

ps. sorry i couldn't upload my pictures so please consult the link!

 

[shockracer]

blowin turbo?

 

[99GSX_emily]

Naw the turbo ain't blown, it still makes boost fine & it was just rebuilt 6,000 miles ago & very limited shaft paly. The white smoke is from the oil burning in the bay, my crank is splattering oil up through my air filter/maf & it's splattering on everything near by. I don't understand why if i connect my vac lines up a different way oil is coming out at the maf??

 

[boostNmetal]

Are you sure this isnt Fuel Cut and not just a stutter/misfire? 20Psi on an E316G will almost certainly give you fuel cut.