Automotive Forums .com - the leading automotive community online! Automotive Forums .com - the leading automotive community online!
Automotive Forums .com - the leading automotive community online! 
-
Latest | 0 Rplys
Go Back   Automotive Forums .com Car Chat > Ford > Ranger | Courier
Reply Show Printable Version Show Printable Version | Email this Page Email this Page | Subscription Subscribe to this Thread
 
Thread Tools
Old 09-19-2020, 08:44 PM   #1
toddmbrewer3
AF Newbie
 
Join Date: Sep 2020
Location: Whittier, Alaska
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Brake Booster Failure??? IAC???

I have a brake booster issue with my 2007 Ford Ranger 2.3l. The brake booster passes all functional tests of the brake pedal and the truck brakes fine. However, every time I release the brake, the short term fuel trim spikes and then comes back down. There is no leak other than when brake pedal is moving backward. If I pump the brakes, then fuel trim will continually increase until the engine stalls.
My thought was originally a weak return spring inside the booster allowing one valve to open slightly before the other closed. This would allow an extra bit of air in but the booster would function normally once everything settled out. However, I started to question how the extra air from the booster is handled in normal operation and now I have questions.
In normal operation, the atmospheric side of the booster is evacuated by the intake vacuum every time the brake is released. This bit of air is added to the intake and is not monitored by the MAF. So, is this amount of air so small that it doesn't affect engine performance? If so, would this remain true if you pumped the brakes?. Or... Is this amount of air compensated for by the idle air control in some way such as through the brake pedal position sensor?
It seems to me that my booster is pulling extra air on each release of the pedal affecting the fuel trim. However, if the IAC is involved and not monitoring the booster, I could understand why my fuel trims rise every time the booster is evacuated.

So, do I have a bad booster or do I need to look further???
toddmbrewer3 is offline   Reply With Quote
 
Reply

POST REPLY TO THIS THREAD


Tags
booster , brake , ford , iac , ranger
Go Back   Automotive Forums .com Car Chat > Ford > Ranger | Courier

Thread Tools

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



All times are GMT -5. The time now is 08:09 PM.

Community Participation Guidelines | How to use your User Control Panel

Powered by: vBulletin | Copyright Jelsoft Enterprises Ltd.
 
 
no new posts