Hey guys got another brain buster for you. When i drive my gen 1 3.0 for a while, say half an hour, so its warmed up, shut it down and try to start it five minutes or so later it doesn't want to fire. when you unplug the injectors then crank it, it will start and run as long as you plug the injectors back in really fast. Any ideas? as usual any help is greatly appreciated.

CAN you say ECM & RELAY ?

Hmmm.....just guessing here..but my 85 VW westfalia had the exact same problem. It didn't like to restart when it was warm. It would restart sometimes but not always. It had tons of cranking power, but no start. I replaced my fuel pump and fuel injection relays. I also replaced a crusty vacuum hose on the fuel pressure regulator that i suspected was leaking. I'm not exactly sure which spot was the weak link, but it starts up everytime now! My first thought was that it was a spark problem, but now I know it was a fuel delivery problem. Good luck!

It will start if you disco the injectors? That means there's fuel in the intake. Leaking injector is my guess. It will start cold because the mixture is marginally ok with a cold engine, but way too rich for a hot motor. Does it start immediately when cold, or do you have to crank a while?

The Westphalia noted above had a similar problem. The crusty hose was leaking, giving the pressure regulator a false high signal, thus causing an overinjection of fuel (the pressure diff between fuel and the intake mani vacuum is too high because of the faulty pressure regulation).

The ecu has to assume a constant fuel pressure diff over mani pressure, otherwise the amount of fuel injected is wrong, because all the ecu controls is the number of mseconds the injector is open.

hey, could a flooded or mess-up vapor canister cause this ?


How?

Or, why not?

i was thinking the injectors might be the problem, same with the ecm. but the engine runs fine off a cold start which is when most of the problems would happen. i'm probably gonna test/clean the injectors this weekend and see if that cures it.

If its ran within the last week it'll start right away (first crank).

Right because they are PWM by the ecm with the inputs from MAP, MAF, and o2 sensors

Still think it's a leaker.

hmmmm, anybody think of a good way to test injectors?

You can measure the resistance across the injector coil - should be about 13-16 ohms. To flow check, you'll need to remove them.

Frank