Captain YARRR

If you've done injectors and pumps, there are two more things to check out:

Fuel lines could be bad and sucking air. Could also be fuel pickups. They are relatively cheap and good peace of mind. Also as mentioned, FPRs could be plugged up.

If all this checks out, yes you're needing to check out ignition.

nailit

I have coils coming. I dont think pumps were changed, injectors just redone by mallory.

Would FPR work fine then start having issues? And its both engines.... I will look at the pickups since they are right next to each other.

Captain YARRR

Yes. I lost one this year. Started up fine one day. Ran a while, went to start again that day after anchoring and eventually found out my FPR was bad.

nailit

ok, went out today, but between buddies going to "Cruisin the Coast" and fishing, I went out by myself.

Installed new coils and fuel filter/water separators before going out.

First couple passes, she was able to spin 5k and 65mph. Did notice that I have to trim to moon to get up there. Wind was blowing pretty strong today so it was consistently..... slow. Stopping to cool off doesn really do anything.

0-4500 rpms it pulls hard and sounds good. At 4k, you run it up to 4500 and its fine, past that and it feels it bogs out and falls on its face. If I ease it to it, I can trim to moon and get more rpms, but running 45-4800 it didnt pick up any speed and I can bring it down to 4500 and it will hold that speed... around 60-61. Other times I would just nail it from 4k it woudl fall on face at 4500 and 56ish mph!

Feels like maybe fuel or running out of timing? Both engines doing it. Which is even stranger...

Since motors had only 12 hours on long blocks and it came from VA, 1100 miles north, should I have the ECU reprogrammed and timing checked? I did lose a more than your normal power when I first brought it down here.

Grasping at straws... Running out of time to run boat and trying small fixes!!

SB

iTrader: (1)

Going North to South does not change elevation. Change in elevation causes a change in elevation. Warmer and more humid weather can zap some hp.

And power/drivability issues without a computer trouble code, one should check fuel psi, ignition timing, compression, and intake vacuum + check for vacuum leaks first...before swapping parts.

nailit

Thanks, I was referring to the hot a$$ weather down here.
I havent trying spraying wd40 around intake yet as I kept forgetting to get some more. I was thinking this seemed like timing, but not too familiar with efi. My old 350 carb was a lil easier.

How can I check timing on these 454 mag mpis?

nailit

UPDATE: I got in yesterday and started checking my vacuum lines (after I reviewed how they ran from a diagram online). Both motors has loos fittings coming out of the intake to the FPR line.

The P side was loose enough at the T connector where it was just sitting there, I pushed it to the side with my finger and it slid right off. The S side has a loose fitting going into the underside of the intake. It was a hard plastic line that was barely held on by the lil barb fitting and was more that likely leaking.

Replaced both hoses and put cable ties to make sure they stayed tight.

Next up is cleaning out the pickups. Not sure how I am going to do this yet, I pulled both elbows and the pickup tubes are connected to the inside of the tank somehow?? If I blow them out, whatever, if anything, will just be in the tank. There is a small fuel sender hole right next to them, but not sure my hand will fit in there..... will see!

nailit

ok, blew out both pickups.. while in tank since they dont come out.... that was fun! pressurize tank and watch fuel jump out of other bung. lowered bow and opened gas cap and was able to hold 150psi to both pickups!

Then blew out vent line by cap.

Hope this helps with my problem!

SB

iTrader: (1)

ummmm....150 psi to the tank ? Yikes !

Never tested an aluminum tank, but steel and plastic they say not to test with more than just a few psi + or - (vacuum).

nailit

Ok, I see how that can be missleading.... Sorry, I used 150psi 3 gal air tank blow into pickup tube with other pickup tube open and gas cap off so the aire was coming right back out. So, the air was blowing at 150psi, I did NOT pressurize a sealed tank to 150psi. That would have not been a pretty sight, I am sure my fuel sender would have shot out!!