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old jeeper 07-19-2009 04:05 PM

Fuel to rail-new parts-STILL won't start
Please..SOMEbody...My '92 YJ had fuel problems. I replaced the elect. pump, sock, and rubber hose @ the sending unit (easiest fuel tank I ever had to remove). Replaced the fuel pressure regulator (a whoppin' $60+tax)..put on a new filter, checked all vac lines, pulled injectors and soaked them in seafoam. Here's the problem. SHE STILL WON'T START!!!! If I prime the throttle body with some fuel, she WILL start and run 'til that fuel expends. Runs rough, but will run..just won't start from the fuel in the tank. Clean fuel, fuel DOES get to the fuel rail. Please..ANY ideas out there?

yjwes 07-19-2009 04:15 PM

none of the injectors fire?

jpdocdave 07-19-2009 08:00 PM

no injector pulse most likely. use a test light on a injector connector to check for a flashing light when someone cranks it. obviously a noid lite is better. one side will be ground, the other will flash voltage, so try them both.

possible causes of no injector pulse are computer, usually, you will have no spark, and no pulse with a bad crank sensor. check your fuses.

old jeeper 07-20-2009 06:28 PM

Thanks guys..why would the engine run only while fuel is primed into the throttle body? Doesn't that mean that the injectors ARE firing? There is fuel pressure @ the fuel rail. Oh, yeah, the engine we're speaking of is a 2.5.

jpdocdave 07-20-2009 08:47 PM

when you poor fuel down the throttle body, the fuel is entering the combustion chamber through the air intake valves. the injectors fire it directly into the chamber seperate from the valves. so if you have fuel pressure at the rail, but no fuel in the chamber, the injectors are not pulsing. gotta think multi port injection, you're probably thinking of the old days when fuel and air are mixed, then sucked into the combustion chamber. multi port injection has the air and fuel seperate untill the injector "injects" the fuel in the combustion chamber.

morphious 07-22-2009 09:08 AM

so ur looking at either a ecu or maybe just the injectors as the prob

n4funjeeps 08-01-2009 08:09 PM

I found your post and I am currently experiencing excact problems keep us updated if you figure yours out, and I will do the same.

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