Left bank cold- low power

[clarkb]

Just seeing what the Pro's think:
I have a late 90's model 225 promax that is giving me a few problems. Its low powered and running like its not hitting on all 6. At 4500rpm's the right bank is 1100 degrees and the left bank is 850-900. It stays colder than the right back through out the entire rpm range. And will only go to about 6200 rpm's. Normally not a problem to hit 7500.
So far I've changed/checked:
-The left bank coils (all three)
-Switch Boxes
-Checked Fuel PSI
-Checked Compression-135'ish on all 6

Im thinking next thing is the stator (I have a spare I can swap out with) 40amp system

Or could it be the right bank coils since the ecu reads those? Maybe over fueling the left bank? The plugs didnt look fuel soaked though. I does get the cough/snort like a cylinder is pre-detinating sometimes. Any advise
is appreciated.

[Tomanytoys]

I'm by no means an expert however I had virtually the same issue on a 260.
It ended up being a voltage issue. The battery was fresh and tested fine however a bad fuel pump was drawing to much power and pulled the voltage low enough to mess up the computer.
New fuel pump solved the problem.

[Go Time]

I definitely sounds like an ignition issue and the stator is a good bet...did you check the switch boxes using a DVA? Its most like one or the other.

[clarkb]

I didnt check them. I had two extras that I know where good when I pulled them off another motor(about 2 months ago), so I just swapped them out.

[Go Time]

Using a spark tester (or timing light) and spinning the engine over to confirm which cylinder(s) have lost spark should be one of the first things you do before replacing parts. Then you you know what you're dealing with and what needs to be done next.

[DOC W]

i had a trigger doing it to me once also

[myron]

I just had an issue, come to find out it was a bad spark plug. sometimes the most simple thinks are overlooked

[clarkb]

Going to put the spark checker on it this wknd. I "normally" dont just start throwing parts at stuff but I didnt have my spark tester and had the parts. So, I figured I'd see if I could get lucky. I changed the plugs as well.

[clarkb]

I was chasing somehting that wasnt there. I swapped the wires on the pyro and the problem moved with it. Idicating there is a problem with the probe, right.
I then swapped the stator, voltage rugulator(found a connection that got real hot) and swapped the ECU(becasue my buddy had one). Rain was coming in and I was just tryin to get one more test run done. Wind was nasty and I was trying to get to clean water when I felt the dreaded power loss happening (4300rpm). I immediatly looked at pyro's and water pressure (looked good and I hit the key switch). Luckily got a tow back to the ramp, pulled the plugs, and #5 had some metal on it.. FML This motor has only been run for one season. Got it home, pulled the heads and sure enough #5 is toast. Looks like a lean failure to me. Luckily, I shut it down before it completly seized. I pulled the injectors and sent them to Brucato, called John Marles and got another top pinned piston coming(just gonna hone the cylinder) and I have all the gaskets already. If there isnt anything wrong with the injectors, I have no idea what happened. Any ideas? Things to check?
I will post back when I hear from Tony about the injectors. Let me mknow if there is anything in the mean time I should look at.

[clarkb]

I did a compression check at the end of the year after I had been having the low power problem and it was all good there. Thats why I was thinking it was electrical.

[Go Time]

I doubt you find that the injector was leaning you out...they are usually rich when checked due to being dirty and slugish. check the #5 timing if you haven't already started tearing down the engine.

[clarkb]

Go Time, Your right. It wasnt an injector failure. They were all about 6% rich. Brucato adjusted them and got them back in specs. I put a new top pinned pison in it yesterday. Im going to index the fly wheel with every cylinder and see what that does. Also, taking the stock fuel system off and putting a high pressure pump with a regulator. Im "thinking" now that just about everything else has been changed that maybe I was loosing fuel pressure in the upper rpm range. At idle and static, I had 38psi but I didnt think to check it while running. Ill post when I index the fly wheel.

[clarkb]

UPDATE:
I have changed the fuel system and, rebuilt the motor, and had it out a few times. PYRO still reads 950 on the bleft bank. Still low on power too. However, I took a temp gun out with me the last time and the right side at idle (shooting at the spark plug) reads 95-99 degrees. The left side reads 83-84 degrees. I had a spark checker but the water was to rough to pull the cowling and run it with the checker hooked up. I can hold my hand (almost feels cold) on the left side too but can only hold the right side for about 4-5 sec. Someone told me earlier that it may be the trigger. Well, thats the only thing left to change in the entire system, so Im going to try that this evening. I OHM'd it and it checked good but there is no other pieces in the puzzle at this point. Fighting the battle still. If nothing else, maybe someone can read this and elimante a few problems for themselves. Ill post when I get it back out.