Non stock 500EFI plug issue

[sweet addiction]

50lbs injectors, .030 over, been running this way a couple of years. Made a mistake last month, so the motor had to go to the machine shop for a refresh. Everything off and everything on the same way. The only thing that was changed were the pistons, the machine shop did not like the Manley pistons so we put Diamond Performance pistons in it. So, put it back in the boat, had the timing done, check plug wires, etc. Took it to the lake on Monday and ran it on the trailer to set the rings. Never above 2k RPM. Everything looked good! So we go to the lake today and it goes out of the hole great and we are off and running and about 2 miles into the run it boggs down and dies if left in the throttle, runs at idle. Never wants to get back on plane, when you give it throttle it bogs out. So back to the dock, new plugs. Runs again, same thing. Adjusted fuel pressue up, down, 55psi, 45 psi, it is getting fuel pressure we ran it and looked at the mechanical gauage I have on the fuel rail. What could be killing my plugs??? Dang, not the way I wanted to spend my Saturday. Just frustrated.

 

[MOBILEMERCMAN]

Why do you think its plugs? Maybe you have some debris in the fuel loop. . Check to see if the screens in the injectors are full of junk.

 

[sweet addiction]

Put new plugs in and it runs fine again. I guess I can pull the fuel rail off and see what it looks like, but the injectors were cleaned when we did the motor.

Why do you think its plugs? Maybe you have some debris in the fuel loop. . Check to see if the screens in the injectors are full of junk.

 

[MOBILEMERCMAN]

So back to the dock, new plugs. Runs again, same thing.

When it lays down check to see if the separator filter is still full of fuel. I would rule out all fuel delivery possible problems first.

Is it sooting up the transom?

 

[sweet addiction]

I checked the transom first to see if it had a lot of soot. No soot. First thoughts were it was running fat. My brother had an extra filter and then it got lost somewhere so I did not replace it?

When it lays down check to see if the separator filter is still full of fuel. I would rule out all fuel delivery possible problems first.

Is it sooting up the transom?

 

[sweet addiction]

Had to think about it a while. Maybe this could be an issue. First round it was towed down the road, back down the ramp, then we pulled it out back it down the ramp again so maybe it sloshed things around in the seperator enough to run a while and then back to its current running condition. But what confuses me is the pressure gauage shows 45 psi I had it at 55 psi and will probably turn it back up. We thought maybe we were loading it with fuel.

When it lays down check to see if the separator filter is still full of fuel. I would rule out all fuel delivery possible problems first.

Is it sooting up the transom?

 

[sweet addiction]

Also thinking maybe I have a tach issue like this guy? Maybe, guess I should just try.

http://www.seriousoffshore.com/forums/showthread.php?t=17365

 

[sweet addiction]

Worked all day today on it. Checked timing, looked at tachometer, took off the tach. looked at injectors, last thing we missed was clearing codes off the computer. There were some in there from way back when. So on Saturday I was trying a 190 degree thermostat because the engine builder thought there was too much condensation under the intake manifold. We think maybe the computer is in limp mode. We installed a 165 back in it. But I did not get to run it again after we cleared the codes. My buddy is going to consult in the morning with a computer guy, and if the code thing does not work then something is up with my computer, which sucks.

 

[sweet addiction]

Sent the computer out to have a look and see if something is going on. Computer guy said it would not do this just because it threw an engine code.

 

[TxHawk]

Do you have the computer on it while running? What does the TPS show when all this happens?

 

[sweet addiction]

No, maybe should have done that. Could it be a bad TPS?

 

[sweet addiction]

My guy said probably not the problem, it would show signs of issue at idle. Volts showed .05

Do you have the computer on it while running? What does the TPS show when all this happens?

 

[sweet addiction]

Found the guy who did the original Dyno and is willing to give us the password to unlock the computer. I hope we find something, if not where do I go? Get it back and try again? We will see.

 

[Griswald]

What ECM is it? I have all the mefi scan/burn software

 

[sweet addiction]

Mefi 4 not sure if it is A or B. Should know something tomorrow. If we do not get anywhere I will give you a shout.

 

[Griswald]

Any luck?

 

[sweet addiction]

he gave us one password and it did not work, so he had to look again for another one and that was late Friday, so not much else going on until Tuesday.

 

[Griswald]

don't need the password to run the scan and see what's going on

 

[sweet addiction]

We have a scal tool that tells us the codes, but touble codes are not the issue, we think?

don't need the password to run the scan and see what's going on

 

[Griswald]

I'm not talking about codes. We can take a scan of the major parameters as the motor is running and possibly see where it's falling off. Full dashboard of the ECM

i.e. map, rpm, timing, fuel, bpw, temp, etc.