Any Direct Injected 300gt / 250gt V35's?

[Deep Dish V35]

plenum hoses need to be twisted gently on their fittings with wide pliers to break the seal

why disconnect battery?

[PN-Mad]

Fark me... those pics really had me ROFL. Don't know how it even ran. Whats the point of an air filter if the motor is going to do that to itself.

Make sure you do the EGR block off mod, and Clean it out good and proper.

[sonicii]

I can under stand the mess in the plenum with EGR and PCV messing things up.. but why is the throttle body covered in crap too?

[t5iv]

Would the good ol' $1 can of degreaser from supercheap be overkill?

[PN-Mad]

I can under stand the mess in the plenum with EGR and PCV messing things up.. but why is the throttle body covered in crap too?

Its the way the air circulates around the back of the plate when there is only a small opening/light throttle. Happens on VQ35s too. Just not to the same extent....lol!

Dish- is the stuff hard or soft? I would go the Brake/carb cleaner, soak it, then pressure wash off the non electric bits. Make sure you remove gaskets first. The throttle, thats a different story - cause you dont want to actually move the plate around too much if at all (conflicting reports of it stuffing up post cleaning if moved). In any case your going to have to nail the idle reset, cause that shits going to be way high.

Can you remove that lower collector and clean it too, so you just have the bare heads left? Or is there electricy stuff in there?

[PN-Mad]

...looked back at other pics and changed my mind...

[itsRICHARD]

I was reading on the g35 forums and apparently you're supposed to disconnect the battery and then you can disconnect the harness wire connecting to the throttle body, that way you don't get the high idle problem. I ended up cleaning it with the harness wire attached and now I'm having high idle issues atm, been trying to do the throttle relearn process, pretty hard to get it right, no luck so far, I'll try again later.

I used the Nulon Carby Cleaner you can get from autobarn, sprayed it on a cloth and wiped it down, works great.

[Deep Dish V35]

ive done all the learn procedures in the past, no worries there. besides that my throttle butterfly feels spring heavy - when manually moved it resets back closed. has been the only easy thing to clean

the whole egr valve is being removed and sealed off. the mounting holes wont line up when the plenum spacer is installed so i cant keep it on the car

all that black stuff... i can only describe it as dry looking crude oil. it smears like a wet substance but wont come off

will be soaking it all in unleaded for a few hours then using a high pressure gun to blow it off, including the runner manifold that is still fitted

[Deep Dish V35]

Fark me... those pics really had me ROFL. Don't know how it even ran. Whats the point of an air filter if the motor is going to do that to itself.

Make sure you do the EGR block off mod, and Clean it out good and proper.

i was thinking today, they make us run exhaust recycling because its less polluting..... but it has choked my inlet and increased my fuel consumption which makes it more polluting and resource wasting...

good work goverment laws...

[beercat]

As long as the plenums are off and if you can find it, use Zep Commercial Fast505 Industrial Cleaner/Degreaser.

Works like magic.

[itsRICHARD]

I'll have another crack at the plenum once the spacer comes in, I was going to take it to a shop to get it done for me but who knows how much their going to charge me to clean the lot..

[PN-Mad]

i was thinking today, they make us run exhaust recycling because its less polluting..... but it has choked my inlet and increased my fuel consumption which makes it more polluting and resource wasting...

good work goverment laws...

Yes, but it works well in the initial testing period, not when the car has upto 200k Kms on it. I wonder if the newer maximas and stuff with DDs have the same problem?

It's not the throttle spring that's the issue, it's the very sensitive electric measuring thingy in there that doesn't like being moved too much.

Good luck, and good on you for posting.

[sonicii]

Don't think nissan are using the DD engines anymore, they phased them out in the mid 2000's.. the maximas run a VQ25DE and a VQ35DE.. the V36 250GT is a VQ25HR.

[PN-Mad]

I thought the newer maximas were, but turns out I'm wrong. Ha, serves me right for listening to the brother in law who owns one. Well, they got rid of that quick smart. Guess it wouldn't have the issue if it didn't have egr.

[sonicii]

I wonder if the Commodore and Hyundai Di engines are going to have the same issues? If there was an easy solution I expect Nissan would have kept them..

[Deep Dish V35]

man, what a tedious job! and kinda scary to pull down a perfectly running motor past a point where i was worried i would cause a bigger issue...

i couldnt get a final result as good as others. left the bits soaking in unleaded petrol for hours, then scrubbed, then high pressure cleaned. all the intake parts seem to have been stained, but the worst is gone. even the secondary intake butterflies were caked badly in at least a couple millimetres of crap.

guessing it would only have looked perfect if i let them soak for 24 hours or more.... or had them acid dipped. didnt have enough time left to do that.

egr valve now blanked off, manifold coolant heating pipes bypassed, no ecu faults have come up.

plenum spacer installed

all learn procedures worked first time. had a big cough and misfire when it first started which scared the sh*t out of me, but the procedures sorted that out

car now accelerates with 3 people in it at the same rate as it did with just me. fuel consumption to be monitored. no change in sound as far as i can tell.

just need an oil catch can to stop crank case oil blow back to cylinder 1 and 2

thanks to all for tips and pics which were a big help

Edited September 6, 2012 by Deep Dish V35

[t5iv]

That is a remarkable improvement. Well done mate.

[Deep Dish V35]

for anyone considering doing this... take the opportunity to do the spark plugs at the same time like i did. much harder to do it with the plenum still fitted....

[beercat]

My 250 Gt is running terrible. 2002 model. De-catted.

Currently running rich as a pig, 1 full tank does about 280km.

Not sure what the problem is; started from light misfire, to heavy misfire, to lots of black smoke, and it goes into limp mode if it idles too long. I've had CKP/CMP, HO2, and EGR DTCS. EGR was blocked, the crank and cam sensors changed, o2 sensors changed. After which it was improving for 1 tank, up to 350km, and promptly went back to the crap consumption levels. Plugs were fresh OEM platinums, and I've tried iridiums and replacement coils. Now DTC just reads Bank 1/2 Rich and EGR problem.

I'm not sure if it's a cooling system issue or something else...occasionally my meters do go on the fritz. Tacho or the whole dash goes dead. Sometimes all AC button lights are on and temp/clock goes 88888888888.

Not a happy camper

Nissan Malaysia has refused to take a look at my car, and no one else has a CONSULT. I'm considering getting a Nissan Data Scan 2 to look at all the running parameters...Any ideas? I've been living with this for the past 8 months.

Oh, and at one point I had a back fire up the intake piping which fried the MAF. Running a new Nissan replacement.

Edited September 6, 2012 by beercat

[Deep Dish V35]

possibly an injector stuck open? or fuel pressure regulator issue?