fuel problem 1989 rx7 n/a
02-25-12, 07:47 AM
#1
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fuel problem 1989 rx7 n/a
when i start my car i have to give it just a little gas. and if it dosnt start with that then flooring it while trying to start it will work. but some tims it takes a few trys. shouldnt this flood my engien instead of helping it start? (it will not turn over with out giving it gas) i can smell the fuel in the air the first 2 or 3 times trying to crank it. also on random start ups i will get a small billow of white smoke. im not sure what any of this means so if someone could elabrate then id really apresheate it. thanks 
02-25-12, 11:12 PM
#2
The "gas" pedal doesn't give the engine more gas; it opens the throttle plates, which gives it more air. The ECU uses a set fuel curve (depends on engine temp) at start-up, so there will be no fuel adjustment to the additional air you give it with the throttle open. Opening the throttle on start-up will lean out the mixture. And on S5s, pressing the pedal to the floor will also trigger complete fuel cut.
You're running into problems with the engine flooding, which is why leaning out the mix or cutting fuel temporarily helps get it started. The stock start-up fuel map is especially rich under warm conditions, and many FCs have issues with hot-starts. S5 NAs typically don't because they have the highest compressor rotors, so you could be looking at a leaky injector problem. Some smoke after you start it after it floods will likely just be due to the rich mix.
You're running into problems with the engine flooding, which is why leaning out the mix or cutting fuel temporarily helps get it started. The stock start-up fuel map is especially rich under warm conditions, and many FCs have issues with hot-starts. S5 NAs typically don't because they have the highest compressor rotors, so you could be looking at a leaky injector problem. Some smoke after you start it after it floods will likely just be due to the rich mix.
03-01-12, 10:31 AM
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check the fuel pressure regulator also, theres been alot of talk about how those go out most of the time. if its leaking while sitting for a period of time then fuel pressure can take a sec to get to spec or at least enough to start.
03-02-12, 10:33 PM
#5
^ You may be thinking the FPD (fuel pulsation damper), which helps keep fuel pressure even as the injectors open and close. I don't think I've ever heard of a stock FPR that failed, but it's possible. The check for fuel pressure is to tee a gauge into the feed line, and check pressure with the vaccuum line on/off of the FPR. Fuel pressure should change by about 7-10 psi.
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