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1996 454xl TBI stalling under load

C

Captrobk

New member
I have twin 454xl TBI crusaders in my Carver 355 ACMY. I had some water in my fuel and have drained all bad fuel and changed both fuel water separators, cleaned pancake filter and replaced small canister filter in front of throttle body. Also injectors and gaskets all replaced. Motor will start timing has been set, motor idles well, When load is paced on motor , rpms drop, sometimes backfires, then engine dies. It will restart but wont stay running.
I have replaced TPS, IACV,map sensor, cap rotor, plugs,temp sensor. Mechanics cant read codes with scan tool off motor. The red LED light Is giving off codes 12,14 and 33. I lost a whole boating season because of this motor last year, any help will be appreciated......
Boat is in Middle River MD
 
Just a WAG as I do not have 454s....

Did you check the anti-syphon valve? One of my engines, (350cu in) had the same symptoms........as a last resort I went to the anti-syphon valve and found that is was dirty and when at low power settings it was OK but under load the engine did the same thing as yours.

PS..The "mechanic" I had, (not at home base),told me there was no anti-syphon valve on either of my tanks......I found them myself....after replacing a ton of filters and numerous electrical components he said I needed.:mad::mad:
 
If installed, they are typically on top of the tank, in the supply lines feeding the engines....metal fitting between the pickup tube and the hose barb...

Is your issue with BOTH engines or just one? Common fuel supply or separate for each engine?
 
makomark said:
If installed, they are typically on top of the tank, in the supply lines feeding the engines....metal fitting between the pickup tube and the hose barb...

Is your issue with BOTH engines or just one? Common fuel supply or separate for each engine?[/QUOTE


Ok I will look tonight , just port engine , separate fuel supply
Click to expand...
 
Last post didn't make it thru like I typed it....the "...they may also be incorporated in the hose barb fitting" didn't make it....do a www search on moeller aluminum anti-syphon and you should be able to see a pic of one of the integrated units.

Also, your 1996 will have either a MEFI-1 or -2 ECU....for both the 12 code is normal, the 14 indicates an ECT issue, and 33 means MAP issue. Because you have both 14 & 33, I would start with the wiring harness. FWIW, if the mechanic can't get his/her scan tool to 'talk' to your engine, I'd look for a new one. Finally, just changing parts is a very expensive approach to troubleshooting...
 
makomark said:
Last post didn't make it thru like I typed it....the "...they may also be incorporated in the hose barb fitting" didn't make it....do a www search on moeller aluminum anti-syphon and you should be able to see a pic of one of the integrated units.

Also, your 1996 will have either a MEFI-1 or -2 ECU....for both the 12 code is normal, the 14 indicates an ECT issue, and 33 means MAP issue. Because you have both 14 & 33, I would start with the wiring harness. FWIW, if the mechanic can't get his/her scan tool to 'talk' to your engine, I'd look for a new one. Finally, just changing parts is a very expensive approach to troubleshooting...
Click to expand...

What is the ECT? I know what the Map sensor is. I can trace those wires and see if there is an issue. Don't know what the ECT code 14 is.. Thanks for all the good advice im going to start tomorrow after work, kids held me up today.
 
Captrobk said:
What is the ECT? I know what the Map sensor is. I can trace those wires and see if there is an issue. Don't know what the ECT code 14 is.. Thanks for all the good advice im going to start tomorrow after work, kids held me up today.
Click to expand...

I will check the engine temp coolant sensor wires also. Will these 2 codes make the check engine light come on ?
 
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