Questions and Answers

Mazda 626 Will Not Start Q. I have a 1986 Mazda 626. I checked the spark from coil on all cylinders, good spark from coil and to all spark plugs. Checked fuel to injectors, Good fuel pressure. Its getting fuel and spark. It turns over like a champ, Not even a sputter/no fire. Checked the timing belt. Timing belt is intact and okay. What the heck could be my problem?? Thanks, Steve

A. Well Steve, you are obviously missing something. If you have good spark, try spraying some carburetor cleaner into the intake. if it starts and runs, you do indeed have a fuel problem. If you have good fuel pressure (35 to 41 psi) we can assume the fuel pump is working. Which leads us to the injectors. Since the chances of all four injectors going bad at the same time, we have to look at the injector power and ground circuits

As you can see in the diagram below, power for the injectors comes from the battery through the 30 amp main fuse. It follows the brown wire through the main relay and then the black/white wire up to the injectors.

So with the key ON, you should have power at the black/white, yellow and yellow/black wires on all the injectors. If not, then prime candidates for the problem are the fuse, main relay or a broken wire.

If there is power then the problem is most likely the computer, since I don't think both pairs of injectors would come up with bad wires at the same time.

Check all your connections to eliminate the possibility of a bad connection first, then do the checks I mentioned. You should have no problem tracking down the problem.