Hello everyone, I have a pair of 572's with 4L Whipple in my 42 Fountain. I've been having problems with one of them. The motor seems to run out of power around 27-2800 rpm's. If I push the starboard motor up to 38 - 3900 rpm' the port motor with come up to around 3100 rpm's but that's all it will do. I'm not getting any alarms/codes on my scan tool. The motor seems to run good it's just way down on power, every now and then it will try to shut down when getting on plain. When it does that it's almost like the ingition is shutting off just for a second but it keeps running it my do that 2 or 3 time but then once it's on plain it's fine until it runs out of power at around 2700 rpm's. The heads were done about 15 hours ago with new valves and new shaft rockers. I've put new plugs and wires on it, I've put a new bypass actuator on the blower, I've switch the ecu's from motor to motor, I've checked for vacuum leaks, new IAC's, cleaned the throttle body and flame arester, I've checked the throttle cable and TPS volts are at 0.50 ( closed ). I've replaced the map sensor and the TPS sensor. I've tighten up the spark plug gap to make sure the blower wasn't blowing out the spark. I did a compression test to check for stuck valves. None of that helped. Next time I get time I'm going to change the coils, injectors and blowers from motor to motor to see if I can make the problem move. After that I'm out of ideas so anyone with a new idea I would love to hear about it.

Thanks

Can you monitor fuel pressure or can you easily add a gauge for it?

Also seems silly to ask but is never silly to re-check: ------ check wire routing for correct firing order?

Does your scan tool show manifold pressure and everything looks even there?

My brothers msd boxes did same thing. Changed it , fixed it. Don't know if you have for ignition just a thought

I can see fuel pressure and it stays at 40psi. I did bump it up to 50psi to see if anything changed. It didn't help so I put it back at 40. The firing order is cumpter controlled but I did make sure the wires were on the correct cylinder and coil. The motor idles good no missing to popping so I'm thing the firing order is good. Yes I can see manifold pressure one motor is 10.9 at idle the other is 11.0.

Thanks for your suggestions.

I can see that happening, that's why I'm going to put the coils on the other motor to test. I have 2 sets of coil packs ( 4 coils on each set ) on each motor. I'm thinking the ECU batch fires each set so maybe a few of them are weak. A few of the spark plugs looked black when I changed them witch is unusual but a accounted that to me bumping up the fuel pressure. Now I'm thinking it could be weak coils.

Thanks for you suggestion.

Great info. Can you watch manifold pressure when it's running out of power?

I could hook the scan tool to it and run it. I thank the scan tool is fast enough to read it underway. I haven't done that yet.