tdsmith8

Recently got myself a 91 4Runner that is a salvage/rebuild so I figured I would run into some problems with it, the previous owner said that it ran and drove fine. And for the most part it does. However every once in a while I have a starting issue. Basically it turns over and then dies within a second or two. This only happens maybe once for every 10 times I drive it. Bought a new battery (needed to be replaced regardless) and checked the alternator and those are fine. The starter seems to be working fine too and it doesn't click when I turn the ignition so I figure that isn't what is causing the problem. When it does do this I am generally able to get it started if I floor it and crank the ignition a few times. I looked around a bit on the forums but wasn't able to find a post addressing a similar problem. Any suggestions would be greatly appreciated. (its a V6 automatic if that makes a difference)

scope103

"turns over and then dies within a second or two." is the classic sign of a problem with the VAF-COR circuit. The ignition switch in the STA (start) position closes the Circuit Opening Relay to power the fuel pump. When the engine starts sucking air, a switch in the VAF http://personal.utulsa.edu/~nathan-b...92volumeai.pdf closes, powering the COR (and hence fuel pump) after the ignition switch comes off STA.

A problem in that system will cause the fuel pump to shut down, letting the engine die within a second or two.

Use your multimeter on the VAF and your finger on the Measuring Plate (vane) to see if the switch is bad or the vane is sticking.

tdsmith8

thanks, I'll test that out!