is it the coils ..?!

[OMRAN]

hi there .... its really nice to join u'r forums ,... this is my 1st thread .... and hope u can help me ...

i have 1998 r34 GT-T rb25det .... its stock ... only 3" exust ... and hks filter

when i start the engin in the morning .. i feel like there is some missfireing .... it idle rough ... and if i start driving ..( even after worming it up for f***ing 10 mints) .. if still miss fireing .. under 2500 rev ... approx. ... and over 4500 rev

also ..

but after driving .. for about 30 mint or somthin .. it gos perfect ... no miss firing .. no nothin

idle = 800 rev

spark gap is 0,8mm ( NGK laser iredum R1)

coil res = 4 OHM ( i dont know .. what is the right value for it ..is it 7 ohm ..??)

the cover is removed bcoz of the cold weather we have ..lol :wassup:

we have a hot weather in here ... about 28-30 in tha morning ... and f***ing 40-45 somthin noon ... :flamed:

so i hope u can help guys ... and thanxx alot ...

[OMRAN]

and sorry for my bad english ......

thanx again guys .....

[Revhead]

I dunno what the coil resistance "should" be, but if you compare them all, they should all be pretty similar. If one or two are way different, swap them with known good ones and see if the problem disappears. Also check all of your intake piping and the intake manifold gasket for leaks, and you could also swap the air flow meter for another one to see if it's faulty too. If it is, then obviously it'll need to be replaced.

It might be worth getting your injectors ultrasonically cleaned too, though in such a new car it's unlikely that they'll be clogged. Maybe check your fuel filter. Could also be vapourisation in the fuel lines with that kind of heat, though again, this is unlikely due to high pressure EFI setup and the fact that it goes on for such a long time before fixing itself.

PS Your English is better than a lot of forum-ers

[CWest]

I had pretty much the same thing happen to my 34 about a year ago. It would misfire for about 5 - 10 mins in the morning then would go away. This happened for about 1 month, then finally the ecu warning light came on.

It was a faulty coil pack. They are about 300 new or u could get second hand ones for about 150, just so u know the r34 coil packs are the same as a s2 r33 coil packs. If u know how to test them do it yourself.

Sorry just realised u are not in Aust so dont know prices where u are.

[CerealKiller]

yeah i sometimes have coil pack issues with my R32 (one would misfire and it'd sound like a Boxer engine).

Also make sure your injectors are cleaned.

[OMRAN]

thanx guys for replin .... its really nice to find some help over here ....

....

lets see ...

about the coil resistance ... they r all ( 4 ohm ).... only coil number 3 is (3.99 ohm) not a big diff.

all intake seems to be good ... no leaking ..

i did change my fule filter two weeks ago ...

high pressure EFI setup =-=-=- this is the only thing i do not know ... what dose EFI mean .. and how to check it ... ( sorry for that am not that good in shortcuts). if it can be fix .. can i do it t home .. i have all the tools that can help (i think)..

about the AFM .. i dont think its the problem .... coz i did face that AFM problem befor with my r32 ... and i think i know how dose it feel when u drive with f***ed up AFM ..

but this problem that i face only when i start the car after stoping it for some time ... i mean if i start the car in the morning to go to work ... it will misfire .. after i reach work the problem will be gone ..... after i finish working .. and go back home ... and weather = 45C or 50C .. (yesterday it was 50C ).. the problem will apper again ... i have to wait more than 10 mint and then drive ,, above 2500 rev .. and under 4500rev .... for a while .. then it will work perfect ..

thanx for u'r help (((( Revhead ))))

[OMRAN]

I had pretty much the same thing happen to my 34 about a year ago. It would misfire for about 5 - 10 mins in the morning then would go away. This happened for about 1 month, then finally the ecu warning light came on.

It was a faulty coil pack. They are about 300 new or u could get second hand ones for about 150, just so u know the r34 coil packs are the same as a s2 r33 coil packs. If u know how to test them do it yourself.

Sorry just realised u are not in Aust so dont know prices where u are.

this is really helpful ... but ... the price is too high

it is easy .... to test them ... take them out and check the 1st 2 pins from u'r left .... and thats it ....

can u please check u'r coil .... and tell me the resistance value ??? that will be really helpfull ....

thanx again man

[BigDatto]

Hi Omran,

You're a lucky one, living in Dubai - how I wish !

Testing coils is so easy - ridiculously easy. simply look at the coils in the dark at idle.

You'll see little blue sparks from all of them except the one that's causing problems. You might see a brighter spark - that's your problem coil, shorting out usually due to moisture which is to be expected with extreme temperature drops. Buy some Silicone spray (any auto parts shop) this will fix 9 out of 10 coil issues.

Good luck with it, Omran

[OMRAN]

hi BigDatto ..... how r ya ..?!

... u r the lucky one ... to live in sydney ....

hey man try to visit us here .. it'll be nice to see u here in dubai ...

...

thanx for the info man ... i'll try it .. hope it will work out ...

i start to belive that the problem have somthin to do with the air stuff ... mmmm

there was small pipe on the left top of the MAF .. which sucks some air ... this pipe was leaking .. i fixed it ... now its much better .. but still miss fire ... only in worm up ... ( its normal .. i hope )

thanx for the help ..... guys ..

[OMRAN]

but no one told me ....... what dose high pressure EFI setup mean ... and how do i check it ..???

sorry ... i ask alot .. :Oops:

[unwritten law]

idle = 800 rev

spark gap is 0,8mm ( NGK laser iredum R1)

coil res = 4 OHM  ( i dont know .. what is the right value for it ..is it 7 ohm ..??)

The problem sounds like coil. According to RB20DET.com, a healthy coil's resistence should measure 0.6 - 0.9ohm. I tested mine last nite and they were between 0.8 & 0.9ohm. My car was missing at about 4500 (full boost). Turned out it was my gap in plugs. I set them to 0.8, and its happy days.

Big datto, thats a good way to sus out a faulty coil. Might try that oneday, but u wont be able to see what is happening under full load tho.

[Revhead]

I fixed the miss in mine - it would seem that dielectric tune-up grease had a fair hand in it. I smeared a bit inside the plug and the cup on each coil, as well as both plugs on the ignitor box (series 1 R33). The problem "seems" to have gone away, but I haven't had a chance to properly test it yet, just one quick fang.

By "high pressure EFI setup", I meant that EFI by design runs much higher fuel pressures than a carburetted setup, ie carbs generally run 1-4psi, while EFI runs upwards of 40psi, sometimes as high as 65psi. There's not really much you can easily test, other than to change to a clear, easily-visible fuel filter (so you can see when it's full/bubbles/dirty etc), and to put a pressure guage on the fuel line somewhere. Remember that, if you're disconnecting any of the fuel line, you need to release the pressure first. The easiest way to do that is to pull out the fuel pump fuse, then start the car. Let it idle until it dies, then turn the key off and plug the fuse back in. There will still be a little bit of pressure in the lines (next to nothing though), but it shouldn't squirt all over the engine bay like it would with 40+psi.

Don't be shy about asking questions - that's one of the main reasons for online communities such as this! That, and whinging about police, grannies, 4WD's, etc

[OMRAN]

The problem sounds like coil.  According to RB20DET.com, a healthy coil's resistence should measure 0.6 - 0.9ohm.  I tested mine last nite and they were between 0.8 & 0.9ohm.  My car was missing at about 4500 (full boost).  Turned out it was my gap in plugs.  I set them to 0.8, and its happy days.

Big datto, thats a good way to sus out a faulty coil.  Might try that oneday, but u wont be able to see what is happening under full load tho.

thanx for the reply ... mmmm .. this is the resistence for the rb20det .. << this one has an ignition amplyfire ... which is fix at the end of the coils cover ...

but the rb25det ... has no amplyfire .... ( if am not wrong ) i havent seen any out there ..,,

so .. the Q now ... is .. : is it the same resistance for both rb20 &rb25 coils ..?

thanx again

[OMRAN]

I fixed the miss in mine - it would seem that dielectric tune-up grease had a fair hand in it. I smeared a bit inside the plug and the cup on each coil, as well as both plugs on the ignitor box (series 1 R33). The problem "seems" to have gone away, but I haven't had a chance to properly test it yet, just one quick fang.

mmm ... i think i have to try this one out ....

...

thax alot again revhead ....

one more thing .... mmmm i asked one of my friend ..about the problem ... he told me .. it may be the heat rang of the plugs ... i check that out ... its( 6 ) i mean the heat range ..

.. i know nothin else about that engin heat rang stuff ... so could that be the problem ...

i have NGK R ( heat range is 5 ) .. i'll try them out and see ... !!

and finally .... is there any good of buyin splitfire coils ... ,,, i found a new set ... for r34 .. rb25det ... ... price is $470 AUD is that price good ? .. dose it worth it ... i mean .. will i gain any power ...

hope u can reply me soon .. coz am getting sick out of my car ... :throwup:

and am planning to buy a gtr ... i found .. 2001 vspec II .... with ARC filter, nismo sus, dubleplate clutch , HKS SLD , boost control and nothing else .. done about 40,000 km

he is asking .. about $45,000 AUD ...

what do u think .. REVHEAD ,,??? in here ... this price is high .. i donno .. how much dose it worth there in AUS ..??

thanx again ...

[Revhead]

Heat range can cause some problems, but it's unlikely that the severe problems you've described will be caused by the wrong heat range plugs. Worth a try though, I haven't done much tinkering in Dubai-like heat

$AU470 for a set of Splitfire coils - that's a bloody excellent price! I haven't done much digging yet but the cheapest I've seen is around $800. The best way I can explain upgraded coils is like this: they won't give you any more power by themselves, but they can help you NOT LOSE power, ie if your stock coils aren't up to the task, they can be costing you horsepower that you would retain with 'better' coils. I am saving up for a set for mine - the price you've quoted is in Australian dollars, does this mean you sourced them in Australia? If so, can I ask where?

In answer to your rb20 v rb25 coils question, the earlier RB25s did come with the same kind of ignitor box as the rb20 one you describe. In series 2 R33's and in the R34's RB25DET Neo engine, this ignitor box is gone. IIRC the ECU takes over the functionality. I have no idea about coil differences or what impedance should be, all I can suggest is that they should all be about the same, which you say you've tested earlier.

Re the GTR - $AU45k is cheap compared to our prices - last time I looked, R34 GTR V-Spec II prices were still up around $AU70-80k, but I'm unsure how much of that is compliance, markup etc.

BTW just had a look at your pics, SWEET looking cars mate

[OMRAN]

Heat range can cause some problems, but it's unlikely that the severe problems you've described will be caused by the wrong heat range plugs. Worth a try though, I haven't done much tinkering in Dubai-like heat

mmmm i change into heat range (5) NGK R iredum yesterday ... same problem nothin new ... but i noticed somthin when i changed the plugs .... the plugs number 3,5,6 r not burning fuel ... i think .. i found the problem ... but i replace coil 2 with 3 ... (( to see what will happen with plug 2 ... )) ...

$AU470 for a set of Splitfire coils - that's a bloody excellent price! I haven't done much digging yet but the cheapest I've seen is around $800

I am saving up for a set for mine - the price you've quoted is in Australian dollars, does this mean you sourced them in Australia? If so, can I ask where?.

so .. i think ... am going for it .....

and ... about the AUD .... i'v convert it in ... XE.COM ..

its here in dubai .... if u want i can arrange it for u ....

Re the GTR - $AU45k is cheap compared to our prices - last time I looked, R34 GTR V-Spec II prices were still up around $AU70-80k, but I'm unsure how much of that is compliance, markup etc..

then i think ... i will buy it .... and resale it there ... in aus ...... .. for .. 50k-60k ...do u thinkany one will bye it .. there ...i'll send u some pic ...

but do u have any rulz in importing GTR ..?? .. and how much is the tax ..?!!

alot of Q .. lol .. sorry ...

BTW just had a look at your pics, SWEET looking cars mate

thanx alot man .......... u have sweet eyes ....