Head Gasket Hell!

[Dirtymech]

Hello everybody,

This is regarding a 1995 Toyota 4Runner SR5 4WD vehicle which I recently did a head gasket job on. It's a V6, 3.0 overhead cam engine.

After putting everything back together, the engine would crank smoothly and quickly, but the car would not start! I checked the distributor and spark plugs for spark; no problem there. The ignition system is working just fine apparently.

But after smelling the exhaust when attempting to start, AND after removing a couple spark plugs and looking for vaporized gasoline, I found NO evidence that the fuel injection is working at all.

So there's good compression, good spark, starter is fine, but NO ignition, apparently due to no fuel. What might have caused this problem? I had to disconnect all the FI ports from the ECU wire sheath, as well as remove the IM (of course), but I put all that stuff back the way it was when I was done.

What I would like to know from all you mechs here at the Auto forums, is what kind of EFI troubleshooting techniques are out there? I KNOW that I can remove the EFI and intake manifold without having to touch the timing belt or distributor, so Theoretically I could turn the key to ACC, crank the engine over by hand, and look to see if the fuel injectors are injecting fuel.

But would it work?

I am committed to solving this problem 100%. I recently got a copy of the Haynes Fuel Injection techbook, and I'm ready to take the whole thing apart again if necessary to find out what the heck is going on. If anyone has ANY advice to give whatsoever, I am all ears.

[curtis73]

When you disconnected the fuel lines its possible that some junk in the quick-connect made its way into the lines. Its also possible that the injectors aren't firing at all. There is a tool with a little LED light that you hook up to the harness and crank the engine. If the light flashes, you're getting signal.

You might have a fried ECM or just forgot to hook up a ground wire or something.

[beef_bourito]

couldn't you pull an injector, crank the engine using the key, and see if it's squirting?

[curtis73]

Yes, at the risk of getting fuel all over the place. You can also use a test light on the connector, but sometimes its inconclusive. You may also overload a circuit depending on if they're high or low impedance injectors.

[TheSilentChamber]

Listen for the fuel pump to come on, if it does not, check your pump reset. Sometimes when you disassemble fuel stuff or electronics related to it the reset will trip cutting off power to the fuel pump.

[zagrot]

you may wish to check the wire harness in the area where you were working for any ring terminals that were not connected to ground and make sure that the engine is grounded to the chassis. these are not 4runner specific, but general guidelines as engine grounding is often overlooked during reasembly. the led that curtis refered to is commonly marketed as a "noid light," which are application specific depending on the manufacturer's wire harness connectors. i would not attempt to "pull an injector" since the injectors are usually held to the engine by the clamping force between the rail and its mounting and most injectors really don't have a positive lock into the injector rail.

[mazdatech177]

make sure you didnt hook the fuel lines up backwards... inlet into return, return into inlet. and by "good" compression what do you mean? are you willing to bet your life that the cam timing is right?