My Weekend

[T04GTR]

how a fuel injector ruined my life.

some of you may not know but i couldnt go to the trackday reasons being my motor crapped itsself finaly. well after 240000km of reliable service.

it started off as a missfire when it was cold in the mornings, just a light one. having a wideband afr meter made this easy to see that it was to lean on cold start up. easy fix, with the autronic i increased the cold start fuel multiplier. fixed

after 2 weeks it did it again :S so i re tuned the low rpm fuel sites for more fuel. that fixed it.

then.. the battery went flat, it some how lost its tune after sitting for a week. very strange.. so i retuned. fixed.

and after another two weeks it progressivly got worse and worse till it was missing under boost then just light throttle., so i did the logical thing and put a new set of plugs,and leads into it. that didnt help. ok..

so.. i thought it may may be the cdi unit playing up. i have a spare as one crapped its self earlier due to rain in it lol. it was a fixed one so in ti went. that made no differance. so i put some new coils in.

(the whole time chasing a spark issue.miss under laod while afr is ok)

the new coils made a slight differance. but still not fixed. i checked the wiring from it to the coils. turnes out the wiring was no good. so i made a new harness from the cdi to the coils. no change... f**k!!!

hrmm well i used my old bosses occiloscope to check the outputs on the ecu for the injectors and the cdi unit. they were ok. but being a lcd sreen scope the reponce was not quick enough to garentee a clean signal.

so for the hell of it i changed the crank angle sensor(i had to pull it apart and put a autronic chopper disc in it) that made no differance. gay!!

so out comes the compression testor. yay 5 was down. then 6, then 4, then 3. whoa my motor was dieing quick! ok so i used another comp tester. wtf it was all 140psi hrmmmm.. dodgy comp testor.

still missfirng, comp good. afr good, spark good. mayby its the ecu?? but not an autronic! mayby it was a broken valvespring. i recently put cams in.. so mayby the higher lift fatiged the old springs. oh well after a sold 10 hours changing the head over iin car. (not easy on a gtr) it still missed!!!! grrrrrrrr.

ok must be a broken ring land(s) cos they can give good compression and then not good as the ringland mioves around. oh well il just put my built motor in then.

soo on the weekend i swapped over my engines. pitty our work doesnt have a engine crane jjust a forklift and a big steel tabe. so it was out with the motor/box as one unit onm the crossmember.

anyway i got it done and wtf still missing. but now at idle. f**king hell. cos itr was at idle i could norrow it down to no.4 f**k waht is it.. i swapped my injectors around (there only a year old) and the problem moved. coool spo its a lasy injector.. i pulled the filter out of it and cleaned it. yay no more missfire!! woot and i have a new motor ready for 2 bar eheh

moral of this is never asume something is ok. ie..my new injectors and if its intimitant be prepard for what ive gone thru unless you put it on a dyno. it would of saved me a months stress for the sake a 1 hour on the rollers eek.

[WPN-O33]

Bad luck man, like life you live and learn shit happens at least your mechanically minded, as soon as my car seems a miss or not running correctly i get my mechanic or tuner to ckeck it out. Now you have a built motor ready for 2bar boost yeeeeh haaa..

[D_I_F]

That's so ghay Dave *hugs*

[d00dz]

That was a bit hard to read but I read it all.. Poor Dave!

Yes dont Assume.

As Anna said "Dont assume you'll make an ass out of u and me"

[Beer Baron]

that sucks mate. nothing worse than leading yourself up a garden path all for nothing. so what were the injectors? and I wonder why/how it failed

[skylinegtts]

yeah sucks dave.... good that u got the problem fixed though.

[T04GTR]

they are bosch 363's and it was a blocked filter basket lol

[Duncan]

lol great story so many twists and turns....on the bright side you worked in out before you lunched the new motor as well.....

I've put a whole heap of std gtr injectors through flow testing and cleaning - and they all flow horribly....rated at 440cc/min none of them, even r34 freshly cleaned ones pumped more than 400cc/min (except a freak set of 4 from a gtir that did 450, maybe they had been highflowed).

I had a similarly frustrating issue that turned out to be dodgy fuel pump wiring, almost cost me a brand new motor because every time we tried to run it in it ran like crap (missing) causing fuel wash one the bores....very frustrating I swapped bloody everything (wish we had a fuel pressure gauge)

[Cubes]

To4GTR,

lol quite an adventure. :S

Duncan,

400cc's was at 100% duty or Pulsed duty (80%)

I had a set of apparent low km R34 GTR injectors flowed and cleaned some time ago.

Before cleaning they were fine; after they were only slightly better.

Averaged 472cc @ 40psi (min 468 max 474)

After cleaning

Averaged 476cc @ 40psi (min 474 max 480

Pulsed duty (80%) they flowed 384cc to 390cc

[Duncan]

interesting question, I never checked, looked like they were open all the time but I am not 100%......

[Soulblighter]

Sorry to hear Dave but the good thing is that your misfortune might lead to me fixing my problem.

At the moment my car is missing under boost.

Dont know too much about cars but i was thinking maybe air flow meter or fuel pump or something in the fuel filter blocking it, sparks, coils... never though to check injectors...

Ill change them and keep ya informed. Thanks again.

Soul.

[Bunta]

I had a similarly frustrating issue that turned out to be dodgy fuel pump wiring, almost cost me a brand new motor because every time we tried to run it in it ran like crap (missing) causing fuel wash one the bores....very frustrating I swapped bloody everything (wish we had a fuel pressure gauge)

good story Dave! I wish I was able to sort problems like this my self!

And Duncan I hear you on the wiring issue its the reason I missed the track day

[Abo Bob]

Shit man that sux. Just out of curiosity, how would the dyno have helped?

[Brocaine]

I was wondering what it would take to get the new motor in.

[AdamsR33]

shit dave, i feel ya pain bud.

[T04GTR]

Shit man that sux. Just out of curiosity, how would the dyno have helped?

it would of showed up the issue in half an hour or less. cos it wasnt doing it at idle. very hard to isolate a cylinder whilst driving down the road.

[Abo Bob]

Ah right. Poor Dave.