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-   -   Super stumped with fuel problem! 88' GTU. (https://www.rx7club.com/new-member-rx-7-technical-256/super-stumped-fuel-problem-88-gtu-1010003/)

Sean80501 08-29-12 06:08 PM

Super stumped with fuel problem! 88' GTU.
 
First off, I have to jumper the fuel pump to get it to pump fuel. But then when cranking, that car just floods, doesnt even pop a shot. So Ive done some more testing today and heres what i got.

The injector pigtails have a steady pulse on the primaries and nothing on the secondaries, (checked with a niod light) as it should be. The injectors themselves when secured to the fuel rails via zip ties, leak nothing when pressurized. So, all together I should get consistent puffs of fuel from the two primaries when cranking... But in practice, I get NOTHING! Yet, my problem is that the engine FLOODS on start up? How does this work out? I've even checked the EVAP system to make sure it wasn't pulling fuel through the vack like from the canister. Its not. When I first pull the injectors
After cranking the caps were wet with fuel... I'm so lost.

satch 08-29-12 08:22 PM

Are you sure you are getting proper spark? Does the engine flood on both cold and hot starts?

Sean80501 08-30-12 10:35 AM

Sean80501tch;11204939]Are you sure you are getting proper spark? Does the engine flood on both cold and hot starts?[/QUOTE]

So I guess I should have mentioned, I bought this car in this condition. Its got hot spark, but I have come to the conclusion that it may not be timed correctly. I plan on yanking the CPS out and retiming it. This still leaves me wondering about the fuel not spraying when out of the engine, but then working when its together at all? I'll overlook this issue for the time being and put it all back together, retime the spark and see what happens then. I'll post my findings once I've had time to do the work.

Nuggets 08-30-12 10:38 AM

Verify spark while cranking. When you do this, don't jumper the fuel pump. When you turn the key on, the fuel pump should prime for a few seconds. I'm not exactly sure how the 88 GTU is set up but in general, after the fuel pump goes through it's prime cycle, the ECU should close the fuel pump relay once it sees crank signal/injector pulse.

My SWAG is you have a crankshaft position sensor problem (if equiped), or a bad Hall Effect pickup in your distributor. I am a mechanic but I am not an expert on the RX7s. I'm just throwing out some general information fuel and spark control systems to try to point you in the right direction.

Edit: Prior post added while I was working on this one.

Nuggets 08-30-12 10:41 AM

Also, check compression to eliminate that very important variable.


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