• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

Air Intake Question 86 Bronco II, 2.9


ox1969

New Member
Joined
Jan 28, 2016
Messages
14
Reaction score
0
Points
0
Vehicle Year
1986
Make / Model
Ford
Engine Size
2.9
Transmission
Manual
I have a question, not critical ATM not driving the Bronco II, waiting to upgrade to a 3G alt. Anyway, when I first start the vehicle:

1. It does not stay running on the first try, about the 3rd time I start it, it will stay running at idle.

2. Once I get it running it sounds like it is sucking a lot of air into the intake, almost like hearing a vacuum cleaner draw air in. Has an aftermarket air intake. Just sounds odd, because I am not used to the air sucking sound on an engine, not to this extreme anyway.

3. If you get the vehicle under a load it wants to stall out, does not matter if it is hot or cold, once you get up to speed it seems ok, but if you stomp on the throttle it wants to stall and it does backfire at times.



86 Bronco II, 2.9l, 5 Speed manual.

I have checked and cleaned a few items, throttle body, MAP, TPS to name a few. I have not however, pulled codes or checked the timing. Plan to dig into this issue down the road, but just curious if anyone has had an issue with too much air into the system.
 


2trux

Member
Supporting Member
TRS 20th Anniversary
Joined
Oct 22, 2014
Messages
181
Reaction score
16
Points
18
Location
Albuquerque NM
Vehicle Year
1989
Make / Model
Ranger
Engine Size
2.9 L
Transmission
Manual
1. Sounds like the check valve in the fuel pump is bad.

2. The sound is probably just the design of the intake, it won't take in too much air.

3. Could be a bad fuel pump not supplying enough pressure. Also fuel filter that is getting full of dirt.
 

ox1969

New Member
Joined
Jan 28, 2016
Messages
14
Reaction score
0
Points
0
Vehicle Year
1986
Make / Model
Ford
Engine Size
2.9
Transmission
Manual
Thanks for the input

I have changed the fuel filters already, plugs, wires, cap/rotor. I do hear the fuel pump running so guessing that is not an issue. I do believe the motor is not the original motor, so may see if I can find the data tag and identify the year. Could be the computer and the engine do not match.

I bought this Bronco a few months ago and have only driven it a few times. Wiring is a nightmare and needs some serious clean up. Appears may have had some bad connections at some point do to evidence of electrical burn on a few of the wires.

Was just curious if anyone has ever run across any of these motors sounding like that. I truly appreciate your input, and hope I can get most of these things cleaned up soon. Really hoping I do not have to rewire the entire vehicle.
 

2trux

Member
Supporting Member
TRS 20th Anniversary
Joined
Oct 22, 2014
Messages
181
Reaction score
16
Points
18
Location
Albuquerque NM
Vehicle Year
1989
Make / Model
Ranger
Engine Size
2.9 L
Transmission
Manual
Fuel pump running does not rule it out for being a problem. My fuel pump was running up to the day I changed it. It did however fail to keep up the pressure after running awhile. Pressure would drop below 20psi and the engine would die. After sitting for 5min it would start back up.
I figured out that it was a pump problem by leaving my pressure gauge on and looking at the pressure when it was running bad.
The check valve does not affect the run ability, it causes hard starting. You can check it by leaving the pressure gauge on after you turn the engine off and see if the pressure drops. It should hold pressure for a long time (many days).
 

enjr44

Active Member
U.S. Military - Veteran
Joined
Mar 24, 2013
Messages
1,143
Reaction score
9
Points
38
Age
79
Location
Renton, WA
Vehicle Year
02 2X4; 08 FX4
Make / Model
Ford
Engine Size
4.0 SOHC
Transmission
Automatic
My first guess is the thing that tells the computer the engine is cold is not doing that. Fuel injected engines don't have chokes, so computer has to increase injector plus width on cold engines. Needs a functioning ETS to do the telling.
 

ox1969

New Member
Joined
Jan 28, 2016
Messages
14
Reaction score
0
Points
0
Vehicle Year
1986
Make / Model
Ford
Engine Size
2.9
Transmission
Manual
Non issue I guess

Finished the 3G upgrade over the weekend. Started with no issue and ran perfectly, no sputter no bog down. So my guess is computer not getting enough juice or it was a ground issue, I cleaned all the grounds as well. Either way the BII is back on the road. I appreciate everyone's comments and advice.

BTW the air intake still sounds odd to me, but runs normal so not an issue either I guess. Started on the first try this morning, idle was perfect and kicked down once warm.
 

CrowRanger

New Member
Joined
Mar 5, 2014
Messages
23
Reaction score
0
Points
0
Location
Vancouver BC
Vehicle Year
1990
Make / Model
Ford
Transmission
Manual
Intake sound is normal my 2.9 has lot of intake modifications (ported, bigger tb, etc) and its does that before and after all the work, just the design.
 

ox1969

New Member
Joined
Jan 28, 2016
Messages
14
Reaction score
0
Points
0
Vehicle Year
1986
Make / Model
Ford
Engine Size
2.9
Transmission
Manual
Thanks for the input, I figured as much.
 

Sponsored Ad


Sponsored Ad

Members online

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Kirby N.
March Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top