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

[spector171]

After your remove the upper an lower intake to clean carbon buildup. I see the ignition coils on both left an right on the valve cover an in the middle there is 6 pot cylinder like holes with carbon build up. Is that were the fuel injectors located plus could you also remove that to clean up all the deposits. Looks like some small valve butterflies in it build up with carbon deposit

[scotty nm35]

This is in reply to the original post in 2009.

I don't have a view on the GDI systems, but I disagree that the purpose of EGR and PCV systems are to re-burn unburnt fuel.

The purpose of an EGR system is to effectively reduce the displacement of the engine under certain operating conditions.

It does this by replacing some of the gas with gas that doesn't have oxygen in it (ie exhaust gas).

An analogy would be running your car at the top of Mount Everest - less oxygen, less fuel, less power, but better economy when cruising.

Thus EGR system is for economy, but not primarily by reburning unburnt fuel.

My understanding, of PCV valves, which might be wrong, is that the vacuum in the intake manifold helps draw out the small amounts of blow by that occur in an N/A engine. (Doesn't work with boost pressure). This would help prevent water and fuel vapour contaminating the oil.

By putting a catch can in place is a good fix if it is correctly hooked up. It also stops these vapours venting out to atmosphere.

Therefore, PCV (valve cover breather) systems are for engine longevity, and reducing blow by "emissions". I can't see how it is a method of increasing fuel economy.

Just my 2c on those points!

There are plenty of hydrocarbons left over from the combustion process, re-introducing these back into the cylinder can improve economy, more so if the recirculated gasses are cooled beforehand.

You are quite correct with the PCV operation, but catching the moisture will only mean you are emptying another can, for no real gain.

[Jazzadub]

There are plenty of hydrocarbons left over from the combustion process, re-introducing these back into the cylinder can improve economy, more so if the recirculated gasses are cooled beforehand.

You are quite correct with the PCV operation, but catching the moisture will only mean you are emptying another can, for no real gain.

Note I said "not primarily by reburning unburnt fuel". Some stuff will certainly burn, but the exhaust gas is mainly an inert gas that reduces the effective displacement. I'd say any economy gains would be 90% due to the effective reduction in displacement, and maybe 10% due to reburning fuel.

[scotty nm35]

Or ok. Am question my skyline is running rich an the only code am getting is the p0100 is this the reason my I have a engine running rich cuz I dis suspect fuel injectors

If you do a simple search on the code you will find it relates to the AFM. You can either buy a new AFM from Nissan for $330au or I sell aftermarket ones on my site for much less.

http://scottyscustoms.com.au/product/nissan-m35-stagea-aftermarket-afm/

After your remove the upper an lower intake to clean carbon buildup. I see the ignition coils on both left an right on the valve cover an in the middle there is 6 pot cylinder like holes with carbon build up. Is that were the fuel injectors located plus could you also remove that to clean up all the deposits. Looks like some small valve butterflies in it build up with carbon deposit

The swirl butterflies are usually caked with crap, you need to clean the entire plenum and runners, right down to the valves.

[spector171]

spector171, on 14 Jul 2014 - 9:02 PM, said:

After your remove the upper an lower intake to clean carbon buildup. I see the ignition coils on both left an right on the valve cover an in the middle there is 6 pot cylinder like holes with carbon build up. Is that were the fuel injectors located plus could you also remove that to clean up all the deposits. Looks like some small valve butterflies in it build up with carbon deposit

[scotty nm35]

The ignition coils are in the middle of the black plastic valve cover. The injectors are down in the V under the lower plenum. You can quite easily see they have hard fuel lines bolted to them.

Whatever you do, don't remove them. They are not your fault, the AFM is faulty.

[spector171]

So u suspecT maf sensor cuz the car running rich were the idle is rough it low rpm an engine also shakes badly with excessive exhaust fumes that u cud smell.

[spector171]

Were can I buy intake manifold upper an lower gasket for the 2003 Nissan skyline v35 250gt online. The g35 gasket shape different online so who have a website that sells these gasket

[scotty nm35]

Were can I buy intake manifold upper an lower gasket for the 2003 Nissan skyline v35 250gt online. The g35 gasket shape different online so who have a website that sells these gasket

They are re-usable metal gaskets.

[spector171]

I have a 2003 Nissan skyline v35 250gt and upon removing the top intake manifold I discovered alot of this black carbon build up also after removing the middle section I also discover oil in the intake coming from the pcv valve. Why is oil in the intake manifold plus what's the purpose of all that black soot looking carbon on the valve butterflies etc. Anybody need help

[scotty nm35]

All modern engines suck oil fumes in from the crankcase and burn them to lower emissions.

The black soot is because your engine has an 'EGR' valve (Exhaust gas recirculation) to improve emissions and get greater fuel economy when cruising and on light load. It needs to be cleaned out every 50,000k's or so.

[spector171]

Or ok I'll try this week end. Since the gaskets them are reuseable

[scotty nm35]

Or ok I'll try this week end. Since the gaskets them are reuseable

You should be fine, as long as you don't damage one.

Degreaser, kero, tooth brushes and scrapers. You will need plenty of rags too.

[Deep Dish V35]

Blanking off my egr dropped fuel consumption from 12.5l/100km to 10.6l/100km city driving. And no more soot.

[sonicii]

It was probably the clean that did that. No way EGR causes that sort of impact on fuel economy.

[Deep Dish V35]

Sorry yeah forgot to add that, was in a rush to get back to work. The blanking off definitely helps keep that plenum clean

[spector171]

Why is that my obd2 reader to picking up my card obd2. It always saying check the communication at the DLC port etc. I have a 2014 D900 obd2 scanner.

[scotty nm35]

The VQ25 is not OBD2 compliant, you need a Consult 3 unit.

[spector171]

So my 2003 Nissan skyline v35 250gt is not obd obd2 compliant. What I must used

[spector171]

Does anybody know if the Nissan skyline v35 250gt is obd2 compliant