racing bronco
Thread Starter
|
New User
Joined: Nov 2006
Posts: 19
Likes: 0
racing bronco
first off id like to say hi to all you guys. youve got another newb in your midst.
my 1990 bronco xlt with a 5.0 and e4od will not idle down. intake manifold vacuum test did not indicate a leak. ive vacuum tested every vacuum line and found nothing leaking. codes pointed to tps and iac both of which i replaced. i also replaced the throttle body to intake manifold gasket. plugs wires cap and rotor. nothing has helped.
in park it idles at either 1500 or 2100 rpm. put it in drive it will idle 900-1000 rpm. in reverse it idles around 850-900 rpm. what in the world is going on ?
my 1990 bronco xlt with a 5.0 and e4od will not idle down. intake manifold vacuum test did not indicate a leak. ive vacuum tested every vacuum line and found nothing leaking. codes pointed to tps and iac both of which i replaced. i also replaced the throttle body to intake manifold gasket. plugs wires cap and rotor. nothing has helped.
in park it idles at either 1500 or 2100 rpm. put it in drive it will idle 900-1000 rpm. in reverse it idles around 850-900 rpm. what in the world is going on ?
Thread Starter
|
New User
Joined: Nov 2006
Posts: 19
Likes: 0
yes. im going to double check that tomorrow. i just rigged up a patch cord with tps plugs from another bronco to make it little easier to hook up the voltmeter. but when i closed the hood today it was reading .93
the thing that puzzles me is the different idle between park/drive/reverse. wouldnt the tps affect the idle regardless of gear ?
the thing that puzzles me is the different idle between park/drive/reverse. wouldnt the tps affect the idle regardless of gear ?
Thread Starter
|
New User
Joined: Nov 2006
Posts: 19
Likes: 0
well while messing with it today i put a small piece of cardboard over the throttle body openings with the engine running. the idle didnt change but maybe two hundred rpm. then as curiousity got me i pulled off a vacuum line from the tree tohook up a vacuum gauge and the revs went up alot. put the gauge on it slowed back down.
i am now inclined to think my intake manifold is leaking air. with the openings covered shouldnt the truck have bogged down ? it seems to get plenty of air without the aid of the throttle body.
so im going to dig into the intake tomorrow. if anybody sees a flaw in my logic by all means let me know.
i am now inclined to think my intake manifold is leaking air. with the openings covered shouldnt the truck have bogged down ? it seems to get plenty of air without the aid of the throttle body.
so im going to dig into the intake tomorrow. if anybody sees a flaw in my logic by all means let me know.
Fleet Mechanic
Joined: Mar 2005
Posts: 1,603
Likes: 1
From: St Louis
Remember to check the many feet of vacuum lines running to the engine. You should also check the canister purge valve just off the throttle body to make sure it isn't leaking past the valve with it unplugged from the harness.
Thread Starter
|
New User
Joined: Nov 2006
Posts: 19
Likes: 0
well guys just came home with the bronco. first time shes been here in two months. turns out the plenum gasket was shot. replaced that and now shes purring like a kitten. now onto the rear window motor.
thanks to you guys who responded.
thanks to you guys who responded.
Thread
Thread Starter
Forum
Replies
Last Post
PapaBearYuma
1973 - 1979 F-100 & Larger F-Series Trucks
16
Nov 13, 2016 08:18 PM
wlprice
1987 - 1996 F150 & Larger F-Series Trucks
5
Mar 23, 2016 09:20 PM
HEpTJJ
1987 - 1996 F150 & Larger F-Series Trucks
8
Sep 11, 2013 10:58 PM
