Bigzavs

iTrader: (4)

By misfiring bad, I mean that at 10psi I'm down almost 80whp, and I couldnt make more than 350whp at 18psi because I dropped 60-65whp each time it missed. While on the dyno we swapped the plugs for a set of BKR7E's gapped at .020", it really did not help whatsoever. I have also swapped out the 14yo wires and coil boots, and now the car will pull cleanly through 2nd gear up to 8K rpms, but will miss once in 3rd or 4th gear.

Heres the setup on the car, literally nothing has changed since this past March when I made 437whp @ 10psi, only difference is that it is now the summer. Just wondering if any of you guys have any idea what could be causing the miss?

Stock dizzy stripped out only giving cam position
VVTi coils and ignitor
AEM V1
new wires and boots
new ngk bkr7e gapped at .020"

Old dyno in march (smooth pull, not a single miss)

new dyno's (miss is more audible in the video from the rear of the car)

Just wondering if any of you guys have any idea what could be causing the miss?

sayayin

iTrader: (2)

At least yours pulls, mine dies when fully press on the throttle, I have 1jz single turbo had 400whp 19 psi, my car was fine like 3 weeks ago now is hot is really hot here in miami, I am thinking is tune, this weekend I will start checking spark plugs, fuel pump and do compression test, I have map ecu 2 and my car was tune like on march a 1year ago and temperature was like less than 70.

99SC42

iTrader: (44)

Ben ,

What's your afr at?

I was in the same boat, but i got it figured out , i got tired of killing $80-90 plugs every 2 days.

make sure the spring inside the boot is making good contact with the plug.

lexforlife

iTrader: (7)

i had the same problem but alittle worse yesterday on the dyno with trufantics build . fuel was spot on , engine purrs perfectly however whenever we did a full pull , right around 6500 and up she broke up badly and sputtered .. we tried changing coils from another motor , didnt help , tried another igniter , same thing , even disconnected exhuast from downpipe thinking maybe excessive backpressure from a clogged exhaust , same thing .. did a leakdown test afterwards cyl 1234 had less then 3 % leakage , couldnt do 5/6 , some reason couldnt turn crank to set valves tdc , piston was touching valve . removed timing belt , reset timing , now its back in time . could timing belt have jumped a tooth , but how ...

do a leakdown on your motor

Bigzavs

iTrader: (4)

Ya, when I did the 437whp dyno it was in the high 50s that day in march

My AFR's are in the 11's throughout the rpms at both boost levels, and I've reset the coil packs earlier today. What was causing your issue and how did you fix it if you dont mind me asking?

Unfortunately I do not have access nor do I think I know anyone locally with a leakdown tester, otherwise I would. We did re-do the timing and re-sync it with the AEM, not sure if it did anything.

_____________________________________________________________________________________________________

We got the car running on E85 today, drives strong, except when trying to boost.

While out of boost and just driving it is strong, doesnt skip a beat, but once trying to get into boost it is still missing badly, maybe a little more now. One thing my tuner did notice was that my voltage is fluctuating alot according to the AEM. Once we got back we checked my battery/cables setup and got a drop of .1 volts from the battery to the starter (I have a cable running from my starter to the fusebox, to power it) and in between the starter and my injectors/coils im losing nearly 1 full volt of power. He isnt sure but thinks that this might have something to do with it.

Anything else you guys can think of or something seem like it might be a problem in the previous paragraph?

Thanks again for your time guys.

99SC42

iTrader: (44)

Ben ,

Mine was doing the same , my plugs were done because car was running rich on E85 , then the spring inside the coils where old and it was barelly making contact with plugs. Then the wires that goes from the coil cylinder #1,#3 and #5 were some aftermarket crap so i was having a blow out, lol it was one after the other i know it frustrating ..
My car was tune on irridium plugs and i didn't even gap them, no missfire all the way to 7700rpm. Also make sure the plug are in there tight.
If i think of anything else i'll let you know!

chingpo05

iTrader: (2)

add more grounds to see if that helps with your voltage issue sometimes stupid stuff like that will disrupt your ignition system. what wires are you using? and have you talked to your tuner? and is it throwing off any other codes? it may have to do with the weather and time you got it tuned then and hot *** weather now

just saw your pix on the other thread. is your tps properly calibrated?

cartmill

iTrader: (3)

how exactly were you measuring the voltage drop?
and what voltage was it reading?
where is your battery? in the trunk?
does the car crank slowly?

there should not be a 1v difference in voltage between any two points on the car... 1v is a lot. if your ignition system is running at 11.5v that could definitely be the problem.
what about the alternator? did you measure the voltage across the two posts of the battery with the car running? it should be at least 13v at all times running (cruising, idling, boosting, etc.) probably more like 13.5-14.5

when reading your earlier posts above, my mind was immediately jumping to blame the vvti coil swap. i would do what Quick said and check those conductor springs inside the coil boots, as those are the only thing that actually conduct electricity between the coil and the spark plug... however, after reading the part about the voltage drop, i'm leaning toward that.

if you did a ghetto battery relocation like i've seen before, i would definitely redo it with some 1 or 2 ga welding cable and make sure you have a solid clean ground wherever the battery is. and i ended up having to add a ground strap to my intake manifold because my battery and battery ground were so far away from the starter and alternator.

99SC42

iTrader: (44)

Ben ,

I am going through the same BS right now it has been 4 days that my car runs like ***** and it's starting to **** me off , I wanna set it on fire and be done with it.

I bought new coils, plugs, ignitor, wires replaced all the stuff car still runs like crap. I have install more than $300 on plugs . My spark plug gap went from .044 to .018 and still runs like crap.

I am not spending anymore money on this piece .. till i figure out why it's running like crap

I Will let you know what i find.

sayayin

iTrader: (2)

Okay recently check for compression test and is okay the least cylinder was 170 psi, I redid some grounds for the battery, also, I bought and install the HKS DLI and improve the idling and acceleration but i am still breaking up and is annoying and can not press on the gas pedal more than 50%, I am suspecting is to much fuel, also I change gas station probably could be bad gas too.
Anyways I dont want to lean my car until I have properly air fuel ratio tool like on dynos, now I am in the hunt for 850cc injectors and call the tuner and see how it goes oh for sparks plugs I have BKR7E gaped to 0.22 I will probably will buy new ones and install them this weekend I have that works.

99SC42

iTrader: (44)

^^^ what ecu are you running? well if you the car is misfiring you afr will be all over the place .
How much boost are you running? did you check your coils? with the DLI you shouldn't have to run tighter gap unless you coils are done.

I will change my ecu tomorrow and and see if that helps.

maybe i have bad gas also but i always use the same station . I am probably going to drain the tank and pour some fresh E in the tank and see what happens.

It annoying when the car was running great 5mins ago and then all the sudden it sounds like like a WRX running on 2 cylinders.

I am out of options , all i can do it drain the tank and wait for my tuner to get back intown tuesday.

I just hope we figure this crap out..

sayayin

iTrader: (2)

I have Map ecu2, , I am on 19 psi boost, coils are used but they don't have cracks like old ones that a year ago, I am thinking is dumping to much fuel, I can smell it when I am stop lights, also will check for intercooler leaks and exhaust leaks I will do that tomorrow.

99SC42

iTrader: (44)

Did you try replacing the boot on the coils? check the spring inside the coil under the boot sometimes it doesn't make good contact with the plug.

Do you have a fP gauge? what is it set at?

I just thought about replacing my distributor base, because it's still there to pick up cam and crank signal, hopefully that's my issue.

Ali SC3

iTrader: (10)

remove the boot and see if the plastic on the side has a crack in it. if it does it can jump to the block.

Bigzavs

iTrader: (4)

Sorry guys, I have been out in SoCal on vacation for a while, havent touched the car yet. Ill be getting to it before the semester starts, taking in what you guys have suggested. Ill let you know what happens.