- Hey peoples, a friend of mine, who was an engineer with Volvo for a number of years and who also test-drove for Nissan commented one day that the engine in my car was basically bulletproof, except for the fuel injectors, whose location within the "V" caused them to eventually overheat under hard driving. He mentioned that the last generation 300ZX had a little fan to cool the injectors off. A quick check with the dealership ruled out having that fan retrofitted - the electronics are too tricky.
- So.... I'm planning on getting a CAI, then using the stock "Ram Air" thingee (the black funnel device right by the hood release up front) to channel air back to the injectors. It'll only require some tubing/piping from Home Depot. This way, the forward motion of the car will force the air in to cool off the injectors. Voila'! Bulletproof engine once again.
- Any thoughts on this matter would be appreciated.

 

where is the fuel injector? I know where the fuel filter is....I guess I can trace it from there to the engine block?
how does making it colder help? I am wondering....could you please elaborate more? Because I thought the fuel injector is inside somewhere unexposed....ok ok...I am just lost...
sorry...can anyone elaborate on this pleaseeee

 

fan? what fan??

<img src="http://www.cyberhosts.net/~gotrice/personal/60k/09.jpg">

<img src="http://www.cyberhosts.net/~gotrice/personal/60k/05.jpg">

When I pulled my upper intake plenum, there was no sign of a 'fan'. What's your friend smokin bro?

 

Each cylinder has it's own fuel injector. There are some good pictures in the Haynes manual on page 4-11.

 

The fan I was referring to was on the 300ZX, not a Maxima. My friend AND my dealership both knew about it. Perhaps it was a rare option or only on the turbo model.

 

[QUOTE]Originally posted by Zprime
[I]where is the fuel injector? I know where the fuel filter is....I guess I can trace it from there to the engine block?
how does making it colder help? I am wondering....could you please elaborate more? Because I thought the fuel injector is inside somewhere unexposed....ok ok...I am just lost...
sorry...can anyone elaborate on this pleaseeee

- Sorry this took so long to get back to you... The injectors (6 - one per cylinder) are located right around the intake manifold, which is just above the "V". Each injector connects to its respective intake manifold tube. You know, the manifold goes from one big gray chamber to six little tubes that feed into the head (think of an insect with a body and six legs). The injectors pump the fuel in through their hole in the tube to get the fuel to mix with the air, then pump on in to the combustion chamber, and then explode to creat internal combustion. Cool, huh?
- So if the injectors overheat, like my friend believes they will, the engine will burn lean and sustain considerable damage. the ram-air fuel injector cooler device that I'm going to try should counteract that and keep everything running as it should be. It's not exactly "cooling" the injectors to below ambient temperature, it's just pushing away the hot air that gets trapped within the "V." It's like a breeze on a hot day; not cold, but refreshing - at least for the injectors.

 

That is a pic of a Z notice the engine is not tranverse mounted... thus it is most likely a rear wheel drive...

 

I'm guessing those are pics of Phoung's NA Z. Guess the fan only comes on the TT....

 

I've seen a pulled TT engine before and I didn't notice fans either. Maybe it's on the Z31's or something....

 

You can find your injectors in the middle of the V. The front back are towards the back of the sparkplug banks. You can see them. The other set are under the intake manifold.

ZuM

 

Oh, BTW. That scoop has almost no air pressure. The lip of the hood makes sure of that. So your idea probably wouldn't work. Even if there was pressure. The turns in your tubbing will kill any velocity it had.

ZuM

 

Maximas from at least the 92-94se and the 95+ VQ have injectors that are immersed in the fuel and fuel rail. Since it's dunked, the fuel around the injector helps keep it cool. Got Rice's picture is from a na Z32 300z. There is no "fan" in any Nissan to keep the injectors cool. That would be a highly inefective solution. Tell your engineer to explain what he means becuase he's not making sense here.

 

Alright, I'll call him as soon as I can to find out what is up. I see what you mean about the injectors being "dunked," but that wouldn't make much sense as the fuel would heat up before combustion, losing some of its kick. I'll try to get back to this thread by tomorrow.

 

#1) Remember that fuel is constantly circulated from the tank, through the pump, through the filter, through the fuel rail, and back to the tank. It doesn't have a chance to pick up much heat.

#2) A gas expands (becomes less dense) when heated. That's why most cars have a plastic duct to "breathe" outside air rather than air from the engine compartment. However, liquids don't expand very much with a change in temperature. It's not important to keep the fuel cool, unless you are right on the verge of vapor lock.

 

Thanks. The injectors are not going to heat the fuel by any significant amount anyway. Plus, when modern cars went to fuel injection(read fuel under pressure), a lot of the vapor lock problems went away. I think anyway. Daniel, can you do me a favor and read this thread and give me your opinion. Thanks.

https://maxima.org/forums/showthread...threadid=11056

 

on a fuel injected vehicle, there's very little heat absorption in the fuel lines due to the amount of pressure at which the fuel is subjected to, along with the speed at which it travels.

I've been through TT engines.. they don't have any fans. (there's no room for fans on the fuel rail anyway..)

 

I had a 83 280 z and it had a fan on it.it was about midway on the motor and the pipe going up to the injectors and then going into two ways (breaking apart) to the injectors.don't know if it helped them or not but it was there.later shane

 

- Thank you for redeeming my story, Shane. I may have been mistaken with exactly which "Z" car my friend was speaking of. It could've been the 280 and not the 300. I still have not been able to call to verify, but I will within the next few days. Stay tuned.

 

The older Z's used a different fuel injector/rail setup that made them far more prone to heat soak-related failure. When the engine was turned off after running awhile, the fuel right at the injectors would heat up enough that it broke down and formed scaly (hard) byproducts, which over time, clogged the injectors. The solution from Nissan at the time was to run the fan for 5/10 minutes after shutdown to cool the injectors down to reduce byproduct formation...maybe they actually did have a separate injector fan, but the point is that the newer Nissan setup reduces the heat transfer to the injectors when the engine's shut down. The new setup uses side feed injectors and insulators that isolate the injector and fuel rails from the engine, the temperature of the fuel at the injectors stays far cooler, and deposit formation is greatly reduced.

Note that deposits generally don't form when you're running the engine because the flow rate of the fuel through/by the injectors cools them really well. At least on the newer fuel system setup.

I think your idea of the fan might help things, but personally think it'll end up looking pretty rigged and hokey. I prefer to simply use a bottle of Gumout Regane or Techron fuel system cleaner in the tank every couple thousand miles to prevent scale buildup in the injectors. Far simpler method, probably more effective than your fan idea.

[Edited by Keven97SE on 12-02-2000 at 01:44 PM]

 

- Thanks for the explanation on the injectors. This whole thing makes a lot more sense now.
- Do you favor one cleaner over the other?

 

I used to use Techron religiously, but recently I've switched to Gumout Regane and seen similarly good results. The Old One swears by Regane, and I pretty much do whatever he says blindly (kidding-well, only sort kidding) - the guy is exxxxxtremely knowledgable, and considering that Regane is about half the price of Techron...

A bottle every 3000 miles or so seems to be the general consensus. Try to keep from going awhile without using, because without it over time, the deposits will get worse and become more difficult, if not impossible, for the fuel cleaners to remove...pretty much gotta stick with the cleaners at that regular interval to ultimately see the benefits.

 

is this penzoil? available at your local walmart store, autozone, napa, pepboys?
Thank you....

 

The trade name is "Regane". It's made by the company "Gumout". Gumout make lots of car products like throttle body cleaners, etc. I've recently found Regane in Target here in Austin, actually. Previously, I mail ordered it. Got something like 12 bottles for ~$3.50 apiece. Haven't seen it in Autozone, etc, at least not yet. I think the stuff is fairly new to the market. The stuff is bright yellow-colored and comes in a clear bottle with a yellow label.

If you can't locate the stuff locally and don't want to mail order, I'm sure Techron will do a similarly good job. Just more expensive.