Engine Starvation / Fluttering

[Paul Workman]

Originally Posted by Ccmano

Make sure there are no bits floating around the botom of the tank.

Oh, you mean like a red shop rag, Dom????

My fueling problem may have contributed to a possible valve issue - waiting to see. I didn't seem to have a delivery problem at idle or even under WOT, until the rpm got past about 4500+ or so.

Testing the pumps individually (easily done using Marc H's trick and hot wiring them individually at the pump connector instead of the FSM method) didn't reveal anything under no or light load. But, adding an extension to my fuel pressure gauge and taping it to the windshield allowed me to see what was going on at WOT, exposing a weak secondary pump! (As my luck would have it, one of the new pumps had a bad check valve. So, after installing them once, I was back in there again doing a pressure test to isolate the leak. Can't win for loosin' sometimes!)



You can measure the resistance of the (hot!) injectors to see if the insulation of the coils is breaking down. You should have ~12.5 Ω Â± .5. Anything in the mid 11s or lower and you have the beginnings of trouble 'fer sher'.

AND...one more thing that fails under heavier loads is ye ol spark! You might (as Jeffvette will tell ya) start simple and replace the plugs. And, you can measure the resistance across each of the coils. If one is more than 3% lower than the rest, I'd put the evil eye on that sucker too!

Or, of course you could get lazy and put a scanner on 'er and run it to see what that turns up. (Best damn tool in the box was that scanner I bought about 5 years ago!)

Maybe you can find something useful here. Hope so.

P.

PS

AH! When I first got my Z I had some serious stumbling and bogging at WOT which turned out to be my accordion-snorkel tube collapsing. Marc H has some cute lil wire hoops that keep that from happening. Or, do like I did and make a sleeve out of aluminum sheet metal and line the tube with that. (Some say it smooths the air flow - working at least as well as punching the TB out. I about that, but it cured one of my stumbling problems instantly!)

[rhipsher]

If Jeff is close enough then take it to him. He will be able to diagnos and fix the problem quicker than you can.