Fuel Pressure Problem at Startup - Miata Turbo Forum -Boost cars, acquire cats.

Welcome to Miataturbo.net   Members

Engine Performance This section is for discussion on all engine building related questions. KMiata

LinkBack Thread Tools Search this Thread
Old 04-06-2011, 09:25 PM   #1
Junior Member
Thread Starter
Join Date: Nov 2009
Location: Dumfries, VA
Posts: 109
Total Cats: 2
Default Fuel Pressure Problem at Startup

So, when I first start the car sometimes, fuel pressure is way low. I know this because my AFRs go crazy high like 18 and 19 when they should be about 14, actually much less with WUE at startup. Anyways, I tap on the brakes and the problem magically disappears. So, I'm thinking that maybe the VAC line to the FPR has a slight blockage and a quick tap on the brakes lets loose the blockage so that the FPR can see VAC. I did stupidly bend the vac connector on the FPR a while back when installing the 99 head on my 96 so that I could install the FPR right-side up. Now, I've decided to turn it upside down. Maybe I always had this problem, but have only recently notice with the turbo build requiring an AFR guage. Any thoughts? Blockage, or should the FPR really not be upside down, or should I just replace my FPR? Could it be a vac leak? My vac looks pretty good at about 26 or 27kPa at idle.
sccaax is offline   Reply With Quote
Old 04-07-2011, 02:17 AM   #2
Elite Member
iTrader: (4)
MartinezA92's Avatar
Join Date: Aug 2009
Location: Sunnyvale, CA
Posts: 1,567
Total Cats: 9

Uhm...check fuel pressure. FYI, when the FPR sees vacuum, fuel pressure goes down. Well not really down, but it isn't at its max. When the FPR sees atmosphere it will let more pressure build. If you have a MS, which has a MAP sensor, a vacuum leak will do nothing but raise your idle.
MartinezA92 is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 52 08-28-2016 04:18 AM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 03:00 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 12:25 PM
Walbro 255lph Fuel Pump $50 lsc224 Miata parts for sale/trade 2 10-01-2015 09:17 AM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 12:45 AM

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 04:49 AM.