2nd Generation Specific 1986-1992 Discussion

frustrated

Old 11-08-2010, 08:36 AM
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im starting to get alittle ticked. everything is working but nothing is working. here is the story. 89 turbo. with a fresh rebuild. i droped everything into the car just a few days ago. keep in mind i didn't really replace anything other than rebuilding the engine and removing emissions everything else is the same way it was before the rebuild when the car ran good. ok so the fuel lines are run directley to the fuel rails. started the car up and it fired right up like a champ. ran for about 4 minutes and died. it hasn't started since. first i thought old fuel so i replaced it. no luck. then the plugs. no luck. then i checked for intake leaks (short of the LIM) no luck. keep in mind its getting spark. its getting fuel. and from what i can tell plenty of air. i double checked all the vacum lines that i caped off and from what i can tell everything is right. so im thinking its gotta be a electrical deal. i thought about putting the rats nest back on and reconecting all the sensors. i would like to avoid this couse its kinda working backwards. block off platesare used on everything except the omp. oh and i thought it was flooding so i installed a fuel pressure regulator(genenric one nothing fancy). and its allways reading 25lbs. witch to me seems low. but i can open the regulator all the way up and it will still only run 25lbs. so today im gonna run threw some more stuff before i reinstall the rats nest and all sensors. if anyone know what sensors HAVE to be hooked up let me know. im pretty sure i allready know witch ones but i need to double check. so today im gonna run threw some stuff

1. check TPS ( it worked fine before im not sure how it would get messed up sitting in the garage)

2. make sure the LIM isn't leaking air



if anyone has any ideas let me know. the car wants to start its right on the edge. it pops every few rotations like its gonna start and then nothing. i have gotten alot of rx7's running for other people it would figure that i can't get my own to run right.



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Old 11-15-2010, 04:26 PM
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25psi seems pretty low for fuel pressure. If I were you, I would take out the Fuel Pressure Regulator for now. Have you tried to pressurize the fuel system with the greenish-yellowish jumper pin?? (should be near the intake, underneath the AFM, 2-wire connector) Use a small jumper wire to connect these two leads ONLY FOR A FEW SECONDS, during which you'll hear the fuel pump kick on. There may be Air Bubble in those lines that make it run inconsistently, so it will just need to run for a little to get the lines completely primed. That may help.



And on first startup without emissions or anything, its not going to idle on its own at first. I had to mess with the fast idle screw and the TPS for a while to get it set right. If It seems like its flooded, turn the key off. Then try to start it again with the PEDAL ALL THE WAY TO THE FLOOR... I know its sounds like the wrong thing to do but it worked for me



Give it a shot.
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Old 11-16-2010, 09:55 PM
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allready did all that fun stuff. next step is to send the injectors out to be cleaned.(since i guess maybe they somehow got dirty in a zip lock bag on the tool bench but whateva).



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Old 11-18-2010, 01:54 AM
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Check make sure there is gas in the tank trust me after what i went through this weekend just check you never know. Then I would address the pressure problem should be around 40 psi. Maybe the fuel pump is on its lest leg? also test at the fuel pump if its getting 12v i would wire up a 12V constant to the pump for diagnostic purposes. another issue is if the air flow sensor is not hooked up it wont provide the ground to turn on the fuel pump.
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Old 11-18-2010, 01:58 AM
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forgot to mention add a little oil to the combustion chamber to help seal things up a fresh rebuild usually is problematic unless everything is installed new and even then can test patience to seal up. pull egi fuse and crank over a while with pedal to the metal and try again.
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Old 11-20-2010, 08:26 PM
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well a buddy and i messed around with it today. the walbro pump is pretty new but was making some nasty noises. so hes all like hey dude maybe you should throw your old pump in. so we did that (and yes there is fuel) the old pump is pushing 10 psi hahaha the walbro is pushing 25 psi. so i went to check the voltage. battery in the tester was dead so tommorrow ill test it. but if its only running 10 with a stoke pump and 25 with the walbro im thinking its a wiring problem



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Old 11-20-2010, 08:31 PM
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that or there is a blockage in the fuel feed line. I have learned low pressure in the line, blockage in the feed, high pressure, blockage in the return all else being normal that is. sounds like it is a voltage issue. The turbo fc's have a fuel pump voltage resistor that lowered fuel pump voltage under idle conditions but i think 12/25 psi is still to low. You might want to eliminate the resistor and give the pump 12V straight from the FP relay.



go to page 54

Factory service manual
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Old 11-20-2010, 10:08 PM
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Originally Posted by RX7 13B 4 UR AZZ View Post
The turbo fc's have a fuel pump voltage resistor that lowered fuel pump voltage under idle conditions but i think 12/25 psi is still to low. You might want to eliminate the resistor and give the pump 12V straight from the FP relay.


This is true. Its a variable resistor that keeps you from cycling an excessive amount of fuel though your system while you're at idle/slow rpms. Many people decide to take that resistor out completely and just run power right from the relay so that you get 12volts at all times.

I've been meaning to do mine actually.





Here's one write-up on it.

FuelPumpRewire
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Old 11-21-2010, 08:24 AM
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is the resistor in line with the fuel pump wiring? JUST to figure out if this is the proplem im gonna go straight to the battery first since its in the back of the car anyway.



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Old 11-21-2010, 08:29 AM
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wait only the turbos have the resistors right? well this car wasn't born a turbo so i don't have that anyway



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