Jump to content
HybridZ

what is this part in the engine bay?


ktmp

Recommended Posts

On the passenger side of the engine bay on my ZX, there is an electric blower motor that looks like it blows air on top of the engine. What is this for and is it really needed? I would like to remove it. THANKS

Link to comment
Share on other sites

It's an injector/fuel rail cooling device that is only supposed to come on AFTER the engine is turned off. It has a timer, located under the right side of the dash (I believe, don't remember exactly), that keeps it running for 16 minutes, but it'll only come on if the engine reaches a certain temperature. It does NOT function while the engine is running and most people remove it entirely, however, it's real purpose is to avoid vapor lock in the injectors and fuel rail after you turn the engine off and it heat-soaks. Sometimes, in warm climates, the fuel can boil in the rail and injectors after it's been run, causing a hard-start situation when trying to restart the motor before it's had time to cool.

 

Refer to EFEC-77 of the 82 FSM for more information.

Link to comment
Share on other sites

It's an injector/fuel rail cooling device that is only supposed to come on AFTER the engine is turned off. It has a timer, located under the right side of the dash (I believe, don't remember exactly), that keeps it running for 16 minutes, but it'll only come on if the engine reaches a certain temperature. It does NOT function while the engine is running and most people remove it entirely, however, it's real purpose is to avoid vapor lock in the injectors and fuel rail after you turn the engine off and it heat-soaks. Sometimes, in warm climates, the fuel can boil in the rail and injectors after it's been run, causing a hard-start situation when trying to restart the motor before it's had time to cool.

 

Interesting.

Link to comment
Share on other sites

I recently had a situation where it would have come in handy to have been left on the motor. It was about 96 degrees outside and I had been running the car kinda hard, staying in boost alot during some spirited running around town. I parked the car to visit a friend of mine for a few minutes, came back out to the car and it was VERY hard to start...Felt the fuel rail and it was warm enough that you didn't want to hold on to it. I put a small fan blowing air over the motor, pointed at the fuel rail. As soon as the fuel rail cooled enough to hold on to without being in pain, the motor fired right up and ran perfectly. So, in actuallity, it might be ill-advised to remove it entirely, However, most people think it's some sort of hair dryer or something and pull it off. It really does serve a purpose if left alone.

 

Needless to say, I'm contemplating re-installing it and forgetting about the "looks"...

 

As always, your mileage may vary.

Link to comment
Share on other sites

The threads on this fan never cease to amaze me....

or what people call it...:-D

 

 

http://forums.hybridz.org/showthread.php?t=133007

 

 

 

LARRY

 

As soon as I saw the title of this thread, I knew my thread would be mentioned :)

 

I've removed my blower and had no issues to date.

 

BTW, in my (feeble) defense, I had referenced this as a "Coil blower" because I somehow thought there was a connection to this and the BMW coil/plug system (modern BMWs have the coil and spark plugs/plug wires into one unified unit per cylinder I believe.

 

Either way...lesson learned - glad you guys got some yucks out of it :)

Link to comment
Share on other sites

I parked the car to visit a friend of mine for a few minutes, came back out to the car and it was VERY hard to start...Felt the fuel rail and it was warm enough that you didn't want to hold on to it.

 

Exactly the conditions it was made to combat! There is a period from around 5 minutes after you do a hot-shutdown (in warm weather, above say 85 and running on the highway) to about 12 minutes where no matter what they tried, Nissan could not prevent the formation of vapor in the rail due to pressure rise, and FPR venting it back to the tank. Initially it starts with the fuel expanding and venting, then pressure drops and it flashes... The S30's with EFI does this, and it's the reason the S130's have a priming pulse, as well as the cooler on them. In JDM, they had a vehicles with plastic valve covers to combat heat transmission in un-vented hood engine compartments like the Cedric, Leopard, Gloria, Laurel, etc...

 

Timer criteria is coolant temp above something like 215F, and as mentioned no longer than about 15 minutes of runtime after shutdown.

 

It may turn on some time after shutdown as well, should the temperature rise to the point it gets triggered, but in any case it will not start after being 'ignition off' for 15 minutes no matter what happens.

 

One thing you can do to forestall the hard-starting is simply change the 'priming pulse' for your Fuel Pump---make it run for 10-15 seconds to take that heat out of the rail and get fluid petrol up there, it may be stumbly after the start, but it is FAR better than trying to crnak and bleed that vapor out of the rail using the normal pulse and cranking/cranking/cranking.

 

I've noticed it's exacerbated of course in hotter weather, but also as your tank level goes down. Ever do a fuel temperature reading when you go highway driving with less than a 1/4 tank of gas? Scary how hot it will get!

 

Yeah, I know, I got WAAAY too much time on my hands to be checking crap like that out of simple idle curiosity. What can I say? I'm diseased!:P

Link to comment
Share on other sites

i love my blower motor on my zx. the way it cuts on everytime i cut her off it sort of like my zx saying "thanks for driving come back soon". god i love my ZX...YEAh.

however if i were to throw some upgrades on the current motor i would design some cool looking blower shroud to coinside with the upgrades, to bad i dont need it for a v8 but then again.......... naw forget it

Link to comment
Share on other sites

The fan is the injector cooler, designed for the 280z, 280ZX application of the Bosch L-Jetronic fuel injection system. The designers, it seems, were worried of the injectors vapor locking due to the intake being on top of the exhaust manifold. It comes on after the car is shut off to keep the injectors cool while the main fan is off, and the iron exhaust dumps heat into the aluminum intake.

 

Ford engines had much the same setup, except theirs connected the blower motor to a copper pipe, with a nozzle spraying air directly on each injector. On my own 280zx, I've built this setup, as it seems to operate a little better than just pushing air in the general direction of the injectors.

Link to comment
Share on other sites

  • 1 month later...

Here in FL, I'm glad the fan is there for some of the hot soak conditions that the car sees. I believe most of the issue is that the fuel sits on top of the injector rather than circulating like most modern top feed systems. I'm sure if you converted it to a real top feed(if there is such a rail and injector/oring combo) that the fan would never be needed.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...