i'm stumped

[The_rabbit1]

car had a slight backfire once in a blue moon, narrowed it down to the distributor cap screw was missing threads, got a new screw, ran fine for a day.

then on the way back from work a STS whooped me, and i lost power and now it's doing the same backfiring issue a lil more often, and still missing power. I'll be looking at it, figured someone may help narrow it down quicker.

[Jazz]

Ingition control module?

[The_rabbit1]

i think it'd be dead if that had gone out.

drove it a bit, only does when i stomp from no throttle to full, and only on occasion.

thinking lean condition? I'm still running stock fuel pump on decently modified fuel/cam setup..

[grn95t/a]

you may be onto something with the fuel pump. is it old? have you checked pressure and flow?

[The_rabbit1]

i think it's the orginial, doubt the owner changed or upgraded it.

fuel drops significantly at the manifold if i throttle it.

[grn95t/a]

pressure drops? from what to what? sounds like its time for a racetronix setup!


http://www.racetronix.com/RX-FL98-FPKG-2.html

[The_rabbit1]

thanks for the link, will buy this weekend!

[socalmach]

I'd say pump or filter.

[Jazz]

What are you calling significant? The pressure isn't constant in the fuel system. Its based on vacuum. Does it still flucuate if you remove the vacuum line from the regulator?

[novajoe]

With the vac line off and the engine at idle the pressure should be fairly steady

[Thundacat]

check your plugs and wires a cylinder miss fire will cause a back fire. but like chris was saying with the vaccum that will cause a major back fire. It always does with my car. do you still have cat? or no?

[The_rabbit1]

yes cat, the noise is more like a pop, not really a backfire cause it only does it from no to full throttle and only if the fuel pressure has dropped, significant as in going from 50- under 35 with a quick tap of the throttle. plugs and wires are right.

[Profit Of Doom]

check injector?

[The_rabbit1]

im guessing fuel pressure, pump isnt keeping up with injectors