04flspecv

iTrader: (1)

I would like to have some help or insight on my problem..

i have an 04 nissan sentra spec v w/ a vq35 swap. back in feb '10, i started to misfire, so i switched the spark splugs for a new set of oem's from nissan. problem fixed

just about a month and a half ago, it started to misfire again. I changed the spark plugs out for a new set and still misfiring. I switched the coil packs on the front head with each other and still misfire. When i pulled each coil pack one by one, the 1st and 3rd cylinder have an idle change. the 2nd one doesn't.

so once i had more time, i took off the Upper IM and put the front 3 coil packs on the back head and the 3 coil packs from the back to the front head. Still misfiring.

I haven't done a compression test yet, i do have the tester and the spark plug socket but no extension or ratchet wrench to use.

I was wondering if anyone can provide more help or insight on what could be the problem?

thanks chris

po8pimp

Chris, have you checked the CSP sensors to ensure they are working right? Also when the engine was put in did you do anything to the cams? if they where put in incorrectly, that would cause your problem. Sounds like you have the spark portion taken care of. the fuel is obviously getting to the cylinders. Could also be an intake leak believe it or not or maybe it is the compression of the cylinders. I would check for leaks in the intake and get the tools to do the compression check. then check your cams to make sure they are in correctly. if the lobes aren't in the right spot at the right time, you will get what you are describing.

04flspecv

iTrader: (1)

hmmm i thought i posted a response.

whats the csp and where's it located?

how would i diagnose that as well?

i read through another thread that it could be an injector that could be have failed.

the motor was dropped in and was never opened. its been in the car for 1.5 years now and the issue started this past february when it first misfired. then again mid to late june.

once i can get my hands on an extension and a socket wrench, then i'll be able to do a compression test.

thanks

essential1

iTrader: (5)

Excuse my post if I read your explanation wrong, but you just solved your own problem. Of course it will still misfire if you just put the same bad coilpack in another cylinder. That 2nd coilpack that caused no idle change is the bad one. Replace that one with a bran new coilpack and problem solved.

04flspecv

iTrader: (1)

whenever i pull the middle coil pack from the front head, i still hear the sparking. it does the same when i swap it with any of the other coil packs. like putting the left clpk on the middle cylinder or the right clpk on the middle cylinder. that same middle cylinder is still misfiring, or no idle change when i pull it one by one. like when i had the middle clpk on the left or right cylinder, it made the idle change when it was unplugged.

i'm thinking that if that original middle coil pack wasn't working then, it wouldn't work on any other cylinders?

sorry im not that knowledgeable on fixing cars im still learning. this is the most i ever did myself.

thanks again

i'll look into a new set of clpks just in case.

do you know the size injectors we use, if its the same injectors on a vq30. my friend has a set of injectors that he said i can use to test out but we don't know if they are the same type or size?

04flspecv

iTrader: (1)

btw, do you know any one with a spare set of injectors, or clpks, i can buy?

should i try ebay?

essential1

iTrader: (5)

Just so I understand completely. Lets say the following is your cylinder configuration:

[Firewall]
1 3 5

2 4 6
[Radiator]

By what you told us, cylinder #4 is the only one missfiring correct?

You determined this by unplugging the electrical connector for this coilpack and noticed no change in engine tone at idle.

After swapping the coilpack from #4 with (lets say) the coilpack from #2. Cylinder #4 is still the only one missfiring?

essential1

iTrader: (5)

By the way. Any injector from an 00-present VQ will work.

04flspecv

iTrader: (1)

yessur that is correct. i tried swapping 2 and 4, or 4 and 6 and even 3 and 4, still no idle change from cyl 4 when i pull the clpk out.

i can use any injector? even from a 3.0 on a 3.5?

i wasn't able to pull 1 and 3 clpks to hear a change, only 2, 4, 5, and 6 since i could reach those w/ the IM being connected. and only 4 is the one i've noticed no idle change

essential1

iTrader: (5)

Thats weird. What are you using for engine management since its in a sentra? Using a maxima ECU? If so, what year and do you have any CEL? Or are you using some sort of stand alone ECU?

And about the injectors, 00-01 maximas actually come stock with the same injectors that non-HR 350Zs come with. This is the only VQ30 with injectors that can be interchanged (with no modification) with any VQ35. So if you did have a bad injector, you can use these also.

Pretty much stay away from 4th gens.

04flspecv

iTrader: (1)

cool thanks for the help.

oh **** wait, the vq30 injectors my friend has are from a 300zx. would that still work? they are brand new.

using the 03 maxi ecu. No, CELs.

essential1

iTrader: (5)

300zx injectors will not work for you. The 300zx engine is actually a VG, but it's common practice for 4th gen guys to use those injectors.

Are you in south florida by the way?

04flspecv

iTrader: (1)

ne fl. thanks

04flspecv

iTrader: (1)

you know anyone near you selling any parts for cheap?

04flspecv

iTrader: (1)

what year of vq's can i use the injectors from?

po8pimp

from reading the original post it sounded like you had more than one cylinder misfiring. If it is just #4 then it is not the CSP sensor <-- Cam Shaft Position. I think you might be right in saying it is an injector issue. if the fuel isn't getting there when it is supposed to, you will get the misfire and it could be inconsistent.

04flspecv

iTrader: (1)

if anyone is selling some good injectors, ill be interested depending on price.

once i get more time and find a set of injectors, im going to do that ASAP. Wish i had another car lol

where is the csp located?

i hope its just that cylinder, but how can i tell if i can't pull the #2 and # 4 coil pack?

thanks for all the help

chris

04flspecv

iTrader: (1)

bump.

I got a set of injectors which im going to replace the one injector on the misfiring cylinder.

is it hard to replace it? i tried to search for a how to but couldnt' find any how to threads for injectors

04flspecv

iTrader: (1)

so before i tried to swap the injectors, i did a compression test.

so my cylinder 3 is not keeping compression. actually it didn't even reach 2 psi. checked the next one and it was close to 180.

im guessing could be possible a head gasket? anyone think of any other issue?

thanks