GT40

Solved.

Yea cranks but hard//no starting unless wot sorry that was pretty important

Nope just idles like nothing was wrong I pulled the injectors and they don't seem to leak at all. Primed the rail and not a drop of fuel out pf them until the inkector blew off the rail the second or third prime.

Went ahead and tested the tps the voltages were correct based on the chart in the RM. I also noticed when I was checking the injectors the plenum gasket looked wet on the back 4 runners. Went ahead and put a new gasket on after cleaning everything up. Cleaned up the FCC also changed the inline fuel filter that was installed by the previous owner. Someone in the shop at work had mentioned it sounded either like a tps or MAP sensor. So I went ahead and put a new map sensor on just for the heck of it. The cost was $35 from autozone with Toyotas commercial account there. Anywho threw it all back together took the boat out fired up the first try ran it around the lake and she screamed the Perfect Pass showed 5020 RPM and 45MPH where as before i though the boat had plenty of power but I was only seeing 4200 rpm at WOT. I guess we will see this weekend if my issue is fully resolved.

Sounds like a possible heat soak problem. Can you hear the pumps run for the prime cycle when ignition is switched to on position. This is a great starting point for any non start problems on the GT40.

I would also get a pressure gauge to test that it has correct fuel pressure when it will not start.

This Old GT40 Thread has lots of information that may help.

Will it still start if you go WOT? That is the weird part about your non start problem.

I just wanna throw a real curve here. If I were to pull the boat put it in the garage and put it back in the water tomorrow the first startup would not be an issue.

The IAC will not stop the engine from starting. May not idle that well but should still start. "Adjusting" (smacking) the IAC should have no effect except if you have a bad electrical connection somewhere.

Just to confirm, when it will not start you have approx. 40psi fuel pressure and the pumps are performing there prime cycle. The manual states the fuel rail should maintain within 3 psi of the approx 40psi for 3 minutes. I would jumper the STO and run the pumps for 30 secs to get your initial 40 psi for this leakdown test.

I hit other places today and the boats did start kne of then was the tfi module I'm at a loss here

Yea sorry about that I was talking to another guy on the boat. I was tapping the coil and the tfi module not very hard but enough to vibrate them.

Bri yes everytime wot fires

Tps voltage is different but as far as commanded fuel and spark values I am not sure i have not ran into it in the service manual yet.

Why the Coolant Temp Sensor you ask?

When this sensor isn't working, the ECU has to assume the engine is cold and makes a richer fuel mixture, kind of like a choke.

When the engine is actually cold, this assumption is correct and it starts fine.

When the engine is warm, this assumption is NOT correct, and the engine won't start.

However, when you give it WOT it overrides the enrichning mode and goes into the flood clearing/less fuel mode which allows it to start.

That's my story and I'm sticking to it.

Ect sensor checked ok after going a few more pages found out those resistances should be in Kilo ohms and not ohm.

Andrew, I would remove the TPS from throttle body but still electrically connected and see if it is actually having the throttle butterfly open that is helping the restart (correcting an over rich condition). Not the different resistance from the TPS at WOT that is allowing engine to start.

It may be a ECM heatsoak problem but I hope not.

And ecm heatsoak doesn't make sense to me. If I were to pull the boat every night it would start every morning without an issue. When I leave it in the water overnight wot is a must in the morning.