Tube removed from 4.9 EFI... trouble?

abelmoreno · #1 (**permalink**) 02-11-2005, 01:23 PM

Guys... My mechanic just removed this pipe that is attached to the engine on top of the injectors, propably for fumes, he removed it because one of the six pieces that attached it to the engine broke... and we could not find this piece anywhere in Ecuador where I live. Is this a problem? how would it affect to have the engine work without it? Any performance sacrificed? or would it only be for emissions?... please let me know...
Also... can you tell me where to get a set of vaccum hoses and a diagram to reconnect all of them..
Thanks!!

BigBlue88 · #2 (**permalink**) 02-12-2005, 08:43 AM

Sounds like the injector cooling system. Probably no harm done. Basically, it blows air onto the injectors to keep them cool for lower emissions.

optikal illushun · #3 (**permalink**) 02-13-2005, 02:41 AM

Quote:

Originally Posted by BigBlue88

Sounds like the injector cooling system. Probably no harm done. Basically, it blows air onto the injectors to keep them cool for lower emissions.

^what?

that tube he removed is the thermactor injection for emmisions. it takes air from the air injetion pump (smog pump) and helps burn the combustion gases fully or somethin to that effect (its late and i dont remember off hand). not sure how important emmisions are around there but its not nesseccary. just thread some bolts into the holes and make sure it wont leak.

BigBlue88 · #4 (**permalink**) 02-13-2005, 08:17 AM

Optikal- come to think of it, you're probably right. My truck has an injector cooling system as well; that's the first thing I thought of.

Twinscrew · #5 (**permalink**) 02-13-2005, 10:14 AM

The tube is not for cooling anything. It's purpose is to supply fresh air/oxygen to the exhaust. There is always a percentage of fuel/hydrocarbon that does not burn completely in the combustion chamber. The purpose of the catalytic converter is to complete the combustion of left over hydrocarbons. Fresh air is required for the cats, which are thermal reactors, to do this. With out the fresh air injection the cats cannot operate properly.

BigBlue88 · #6 (**permalink**) 02-13-2005, 10:25 AM

I understand the thermactor system. I'm talking about something different.

The EFI 4.9, and only the EFI 4.9, has a special air duct above injectors 1-5 that is connected to a dedicated fan, mounted behind the battery, that blows air onto the injectors too cool them, resulting in better injector performance, fuel atomization, etc., etc.. This is separate from the Thermactor system.

optikal illushun · #7 (**permalink**) 02-13-2005, 11:58 AM

happen to have any pics? i have never see or heard of this before.

924x2150 · #8 (**permalink**) 02-13-2005, 12:45 PM

Sounds like thermactor air to me. Ford used two systems to get fresh air into the cats, one basically used 6 pipes from the head intake area to send fresh air to the cat, and the other uses a single long pipe that runs along the top of engine from front to back and into the cat. The pipe is for emmisions, I don't have a truck with the six pipes, so I can't tell you how it will affect the air intake to the cylinder it is missing from.
I once saw a pic of the two systems side by side when I had to buy a 4.9L rebuilt engine. If you search for jasperengines you may be able to find a pic of the different systems. Jasper provided a pic of the two systems so that I could be sure I had the right head installed on my block.

ford4.9 · #9 (**permalink**) 02-13-2005, 01:24 PM

bigblue my 88 has what you are speaking of. Later models they rised the upper manfold to allow for more air "cooling". As far needing it ... i would keep it since it will allow your injectors not vapor lock.

300 4 ever · #10 (**permalink**) 02-13-2005, 01:37 PM

I think just the 87 and 88s had the tube and fan that blows the air on top of the injectors. It usually only runs on mine in the summer for about 10-15 minutes after the engine is turned off.

optikal illushun · #11 (**permalink**) 02-15-2005, 12:17 AM

ok that makes sense since the intake and exhaust are right there. i know fuel pressure is boosted to 45-60 psi on the efi 300 to prevent vapor lock. interesting...any pics guys?

abelmoreno · #12 (**permalink**) 02-15-2005, 01:36 PM

Guys thanks for all your comments, actually it is not the injector blower tube that I'm talking about... It is definately about the Thermactor system that bolts to the engine. So I should just leave it very well sealed and there should not be any performance sacrificed or any harm done... right?.

optikal illushun · #13 (**permalink**) 02-15-2005, 03:05 PM

right, unless u have visual inspection for emmisions.

codejunkie · #14 (**permalink**) 08-09-2005, 11:14 PM

Quote:

Originally Posted by 300 4 ever

I think just the 87 and 88s had the tube and fan that blows the air on top of the injectors. It usually only runs on mine in the summer for about 10-15 minutes after the engine is turned off.

Thanks, 300-4-ever, I've been trying to find WTH the little electric motor is on my '89 300 FI 4wd swb that sometimes stays on all night and runs down my battery! Even with the key out of the ignition, and only sometimes, the fan sometimes comes on, sometimes does not come on, and sometimes comes on and forgets to turn off. Like the other day at the firing range, 30 clicks from nowhere, I had toasted a couple of rounds, then went back to the truck for a drink. Bingo, there was that little motor running, not easy to hear and not usually audible from all sides of the truck. I quickly turned the key back to the start position, and the fan stopped. Took the key out, and the fan stayed stopped. Sure didn't want it to spend all afternoon draining the battery with a 30 click hike the result.
Now that you've mentioned the only thing it could be, all I have to do is figure out where the timer/controller for this little devil is! ;-)
Thanks again!

abelmoreno · #15 (**permalink**) 08-10-2005, 01:13 AM

I got rid of mine more than 8 months ago and have not had a problem related to that ever since . I posted a question on this issue at the time.
Everyone in this forum agreed in only one thing. (The fan doesn't do anything but annoying you). It was in fact removed afterwards in later models. If I was you, I'd unplug it and forget about it.