318ti.org forum

Go Back   318ti.org forum > Technical, Maintenance and Modifications > Engine

Notices

Engine Tuneups, chips, wires, spark plugs.

.
» Recent Threads
Central wood panel
08-22-2021 08:49 PM
Last post by andre3
Yesterday 12:06 AM
2 Replies, 3,374 Views
95 318ti 5-Spd w/factory...
10-15-2021 08:22 PM
Last post by Mongwit
01-15-2022 08:05 PM
10 Replies, 9,220 Views
Rear Hatch cargo cover
03-08-2012 09:13 PM
Last post by vee030
01-14-2022 11:10 AM
34 Replies, 10,476 Views
Club Sport Red Millpoint...
01-04-2022 10:29 PM
Last post by J!m
01-14-2022 12:53 AM
3 Replies, 980 Views
Rhodes Racing Cage -...
07-25-2019 04:32 PM
Last post by saxman0321
01-13-2022 11:30 PM
4 Replies, 36,263 Views
Thoughts on 135 manual...
01-13-2022 03:41 PM
Last post by BMWChrisInVA
01-13-2022 03:44 PM
4 Replies, 285 Views
Age Demographics
10-30-2004 05:06 AM
Last post by Vilius 323ti
01-12-2022 09:52 AM
327 Replies, 122,515 Views
E36 compact M3 CSL style...
01-13-2015 10:54 AM
Last post by aluzjunior
01-11-2022 02:14 PM
9 Replies, 7,117 Views
Reply Share/Bookmark
 
Thread Tools Display Modes
Old 12-17-2009, 03:46 PM   #1
ecpreston
Member
 
Join Date: Dec 2009
Location: VA
Posts: 74
iTrader: (0)
Thumbs down So what's the deal with the vaccuum/air connection at the fuel injectors?

No other BMW I've had has had this, and searching here and google, I can't find an explanation. So what's the deal with the hoses connected to that 4-way splitter and then to the intake boot?


not a pic of mine, stolen from elsewhere in this forum:


Mine were split, cracked, and letting a bunch of false air into the intake, so it hesitated a bit until warm when it got in to closed loop operation. But what was that connection supposed to accomplish? I disconnected and blocked off the hole at the intake boot this morning out of curiosity, and sure enough, it ran *much* better when cold, no apparent change when warm.

Is it a cooling system for the injectors?
Safety system so if injectors start leaking, it goes into the intake instead of just everywhere?
Do these injectors adjust something individually based on pressure?
Emissions related thing when coasting?
Does any other car other than the E36 318 (i/is/ti) use this? My '91 M42 318 sure didn't. I'm pretty temped to leave it blocked off and remove that squid of hoses.

Last edited by ecpreston; 12-17-2009 at 03:52 PM.
ecpreston is offline   Reply With Quote
Old 12-17-2009, 05:18 PM   #2
b.u.ti-ful
Senior Member
 
b.u.ti-ful's Avatar
 
Join Date: Sep 2006
Location: Wisconsin
Posts: 1,895
iTrader: (1)
Default

http://www.motortraders.net/groups/g...roup=1&menu=88
__________________
...

ʎɐqǝ uo pɹɐoqʎǝʞ ɐ ʎnq ı ǝɯıʇ ʇsɐן ǝɥʇ sı sıɥʇ
b.u.ti-ful is offline   Reply With Quote
Old 12-17-2009, 05:41 PM   #3
ecpreston
Member
 
Join Date: Dec 2009
Location: VA
Posts: 74
iTrader: (0)
Default

Wow. That's like, the most perfect answer I've ever received. Thanks!

And yeah, I'm probably not going to spend money fixing that system. That looks like a pretty ghetto way to do something that could have been done by the ECU.
ecpreston is offline   Reply With Quote
Old 12-17-2009, 06:29 PM   #4
b.u.ti-ful
Senior Member
 
b.u.ti-ful's Avatar
 
Join Date: Sep 2006
Location: Wisconsin
Posts: 1,895
iTrader: (1)
Default

I guess if you blocked it off and it runs good it's probably fine.

I replaced the cracked hoses on mine - the parts were not expensive and it's an easy job.
__________________
...

ʎɐqǝ uo pɹɐoqʎǝʞ ɐ ʎnq ı ǝɯıʇ ʇsɐן ǝɥʇ sı sıɥʇ
b.u.ti-ful is offline   Reply With Quote
Old 12-17-2009, 07:17 PM   #5
ecpreston
Member
 
Join Date: Dec 2009
Location: VA
Posts: 74
iTrader: (0)
Default

it is fairly easy, and fairly cheap, but I'd rather not bother. I guess since the ECU expects the system to be there, it'll probably run a little on the rich side during low load, low RPM conditions, but this car isn't going to spend much time doing that. I'll likely dyno it in a few months and make sure the AFR is good to go.

Just so others might find this while searching, they're called "air shrouded fuel injectors". YEAH.
ecpreston is offline   Reply With Quote
Old 12-17-2009, 07:33 PM   #6
MPWR
Senior Member
 
MPWR's Avatar
 
Join Date: Jan 2009
Location: Columbia MD
Posts: 215
iTrader: (0)
Default

The air intake line for the injectors is taken downstream of the MAF. So if you securely block those air hoses, you shouldn't have any mixture issues- all the air passing through the MAF is still going into the engine.

The only issue I can think of with running without it is fuel atomization. If those injectors are designed to spray the fuel into the airstream from the hoses, if the airstream is removed the injectors might not spray optimally.

I'm getting ready to replace them on mine- I know they're leaking which means the engine is probably running a tad lean. I'm going in to do the plastic coolant pipes, but it seems silly not to do these also.

I'd be curious to hear if you get a dyno (or emissions) difference running without them.
__________________
*Except 318ti

'97 318ti M-Sport
'95 M3
BMWCCA
MPWR is offline   Reply With Quote
Old 12-18-2009, 02:27 AM   #7
pdxmotorhead
Senior Member
 
Join Date: Mar 2005
Location: Portland Or
Posts: 2,666
iTrader: (1)
Default

Hilborn, Kinsler, Lucas Mechanical injection have a similar air bleed to help fuel atomize at idle and smooth out performance, it also helps power a lot at high RPM. (Better Fuel Atomization?) Any way when they plug up on a sprint car teh performance tanks...

Dave
__________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black
pdxmotorhead is offline   Reply With Quote
Old 12-18-2009, 02:48 AM   #8
CirrusSR22
Senior Member
 
Join Date: Nov 2004
Location: Minneapolis
Posts: 1,587
iTrader: (3)
Default

Here's the work I did on those which I included in my cooling system write-up. It has seemed to fix all issues I had last winter with cold starts.

--------------

Last winter I started having trouble with very cold starts with my ti. I think I tracked it down to a vacuum leak somewhere, so I just did work to fix that. Since it involves taking the engine apart, like doing the cooling system, I highly recommend replacing the following parts while you're in there as they are rather cheap.

The goal for this project was to replace every vacuum hose and o-ring that could lead to a vacuum leak in cold weather.

Parts:
• Fuel Injector O-Rings: 13641743377 (4x)
• Fuel Line O-Ring (replace, as long as the fuel rail is off): 13531247953
• DISA O-Ring: 11611437690
• Vacuum hose between the intake boot and injector vacuum hose "Tree": 13411247782 (no ASC part#)
• 3' of Goodyear 5/16" (7.9mm) Fuel/Emission Hose, Auto Zone. Approx $1.19/ft.
http://www.goodyearep.com/productsdetail.aspx?id=10526

• 1' of Goodyear 5/16" (7.9mm) Fuel Injection Hose, AutoZone. Approx. $3.39/ft
http://www.goodyearep.com/ProductsDetail.aspx?id=5144
-----------------

I replaced the roughly 3" segment of fuel-rail hose with the Goodyear Fuel Injection hose. As you can see from the link above, it's a special high pressure, specially lined hose just for fuel injection supply. Do not use the standard fuel hose. That's for the vacuum work.

The top hose is the higher quality injection hose and the bottom is the emission hose.

--

Here's the new Goodyear injection hose on the left next to the little segment that connects to the fuel rail. This is an optional step, but it's worth it when you're in there. I think this hose can also be used when replacing your fuel filter. I know the hose at my fuel filter connections is in bad shape.

--

Next I replaced the fuel injector o-rings that seal the injector to the manifold. Surprisingly my injectors are MUCH cleaner at 185,000 than they were at 158,000 when I did the orginal project. I've been using the new BP gas with Invigorate a lot lately. Maybe that actually works?

--
Old, squished O-ring.

--

New, fresh o-ring, lubed with brake caliper grease. I hear that's a good choice for injectors since it's rubber safe.

Last edited by CirrusSR22; 12-18-2009 at 02:51 AM.
CirrusSR22 is offline   Reply With Quote
Old 12-18-2009, 02:49 AM   #9
CirrusSR22
Senior Member
 
Join Date: Nov 2004
Location: Minneapolis
Posts: 1,587
iTrader: (3)
Default

Next I tackled the injector vacuum "tree" which is getting notorious for hard, brittle hoses that crack. See elfhearse's picture above! Mine were not as bad, but were definitely starting to crack. They were also getting extremely hard.

Following elfhearse's advice, I found the Goodyear 5/16" (7.9mm) fuel/emission hose to be a perfect fit. I suggest slicing the old hoses off with a razor.

Cut replacement hoses from your 3' section of emision hose and reassemble the tree. You'll need no more than 2' of the Goodyear emission hose which will be under $2.50. You can also buy a new tree assembly from BMW for about $26. Replace the larger vacuum hose that runs from the tree to the intake boot as well.

Orginal tree.

--

Hoses removed

--


New hoses fitted. The tightly bent hose is a little finicky because the factory hose is molded to that curve, whereas the emission hose kinks a bit when you bend it that tight. It takes a little squeezing/working of the hose to remove that slight kink. That's the only downside I can think of by using the Goodyear emision hose vs. a new factory tree. Thankfully you can make the curves of your replacement hose larger than the factory hoses as there's no need to make an EXACT reproduction of the factory hose. All this is doing is carrying a little vacuum.

--

After that, I used the remaining portion of the emission hose to replace the section that runs from the throttle body to the "fuel tank breather valve". Not sure what this valve does, but it's electrically controlled and it sits between this vacuum hose and the carbon filter.

The hose in question:

--


Simply replace this hose with the remaining emission hose. The original hose is molded to keep it from touching the alternator. I found I needed to use a little electrical tape and attach it to the bottom of the intake boot to provide clearance from the alternator.

While everything was out, I also replaced the o-ring that seals the DISA valve to the lower intake manifold. Just remove the three bolts holding on the DISA valve, use a pick to remove the old o-ring, and install the new one using some synthetic caliper grease. Make sure you clean the bore the DISA valve goes into first with a clean rag.

Also, use a pick and replace the tiny o-ring that's in the hard fuel rail connection. Probably not necessary, but might as well as you have everything apart.
CirrusSR22 is offline   Reply With Quote
Old 12-18-2009, 03:24 AM   #10
pdxmotorhead
Senior Member
 
Join Date: Mar 2005
Location: Portland Or
Posts: 2,666
iTrader: (1)
Default

Nice pics and writeup there guys!

The tank valve is also called the purge valve it opens to evacuate the vapors out of the fuel tank. It allows the vapor to be sucked through the charcoal canister and burn through the engine. If this is not working its pretty common to have odor in the car...

Dave
__________________
Dave - PDX
1995 318ti - Active Black and Tan.
2005 330xi - Mtech 1 - 6spd - Orient Blue/Black
pdxmotorhead is offline   Reply With Quote
Old 12-18-2009, 05:17 PM   #11
ecpreston
Member
 
Join Date: Dec 2009
Location: VA
Posts: 74
iTrader: (0)
Default

thanks CirrusSR22, I had posted this in your thread but didn't get any replies. Good pics though thanks!
ecpreston is offline   Reply With Quote
Old 01-07-2010, 05:05 PM   #12
ecpreston
Member
 
Join Date: Dec 2009
Location: VA
Posts: 74
iTrader: (0)
Default

So, going on three weeks with the system removed and capped off at the injectors and intake boot and no ill effects, no apparent change in fuel economy, cold or hot driveability, or ECU codes thrown or anything. I ended up having to remove the top of the manifold to really get in there, but that wasn't hard and gave me a chance to inspect a few things, clean and adjust throttle and such.
ecpreston is offline   Reply With Quote
Old 01-07-2010, 06:32 PM   #13
ssimms
Junior Member
 
Join Date: Nov 2009
Location: Larkspur,CO
Posts: 19
iTrader: (0)
Default

This isn't that difficult to get to so I will just rebuild the tree with vacuum hose when necessary. I have found over the past 28 years of BMW ownership that BMW did a pretty good job of engineering things and the cars themselves are better off left to the expert engineers. I just do the labor and leave the fixes and parts to BMW.
ssimms is offline   Reply With Quote
Old 01-16-2010, 05:20 PM   #14
atlanta318ti
Senior Member
 
Join Date: Jul 2004
Location: atlanta
Posts: 145
iTrader: (0)
Default

nice writeup
atlanta318ti is offline   Reply With Quote
Old 01-22-2010, 07:30 PM   #15
6speed ti
Member
 
6speed ti's Avatar
 
Join Date: Jan 2010
Location: usa
Posts: 80
iTrader: (1)
Default

My hoses were cracked when I replaced the injectors at 200,000 miles. I went to a local auto parts store and purchased some hose and made up my own lines. BMW does sell the entire hose and fittings as one assembly if you want to go that route. The injectors on the M44 engine use air to better atomize the fuel coming out of the injector. So replace the hose(s) if they are worn or cracked. Do Not block them up. They are there for a reason.
6speed ti is offline   Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for fuel injectors... Mr.Squeelerz Engine 1 10-28-2008 04:33 AM
Fuel Injectors DeadpaN Maintenance 11 02-13-2008 08:48 PM
2 Fuel injectors for ti - free plus cost of shipping dano670 US and North America 0 02-10-2008 02:50 PM
200 gain horsepower in fuel injectors dguzzardo22 Engine 31 03-14-2006 04:25 PM
HOW TO: Replace Fuel Injectors cali-ti Knowledge Base 0 12-20-2005 06:03 AM


All times are GMT +1. The time now is 05:18 AM.


.
Powered by site supporters
vBulletin Version 3.8.8
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Copyright ©1999 - 2022, 318ti.org
© vBadvanced CMPS v3.2.2
[page compression: 123.73 k/147.23 k (15.96%)]

318ti.org does not warrant or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information or products discussed.