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3200 rpms max on 502 XLi engine... Please Help!

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BoatinSteve

New member
I read these posts all the time, but this is my first request for help. I have a 1997 41 ft Silverton convertible with 502 xli TBi motors. About 3 weeks ago, I took my first real trip of the year... which was about an hour away from my home port. On my way home, at cruise speed (3200 rpms/20 mph) I started getting what felt like fuel starvation or a miss on my port engine. At lower rpms, it was okay. During that week I changed the fuel filters on my engine... the small racor and the metallic silver one just before the throttle body. I also cleaned the screen on the pancake filter before the fuel pump. On a test ride, I still had the problem... 3000 to 3200 rpms max under a load... I checked the distributor cap and pulled a couple of plugs and figured no matter what, based on what I saw, it was time to change plugs, put a new cap on, and rotor. didn't make a difference... I then checked the fuel pressure and on my starboard engine with a fuel pressure gauge. I had 18 lbs. of pressure. On the port engine, I had 6 to 12 lbs... So I figured, I found my problem and changed the electric fuel pump. $300 later, on a test ride, I still had the problem...3000 rpms to 3200 rpms and no more... Starboard engine was running great. Next step was to get a 5 gal gas can and bypass the fuel tank. I was barely out of the slip, and the tank was empty!!! wow! so I bypassed the port gas tank and ran both engines off the starboard tank... same thing... 3000 to 3200 rpms. No buzzers, gauges all read good. I've spoken to several locals and am being told its time to start switching parts like the MAP and TPS sensor from the port engine to starboard and visa versa. What a horrible way to try to fix a problem... There are no Crusader dealers in my area either. I have also been told that maybe I should pull the boat out of the water and that maybe there's something restricting shaft or prop... Please any real help at this point is really appreciated.
 
Good cone pattern of fuel spraying from the injectors? Hook up a timing light and strobe the injectors to check the pattern.
 
Thanks for the reply... I really feel its a fuel isssue (of some sort) and was even thinking it might be a fuel injector issue... but everytime I mention it, I am told the performance would be hindered at all rpms. Is the test you suggest one I can do sitting at the dock, or does it have to be done underway and under a load? If an injector seems to be a little "dirty" is there some way to clean the injectors?
 
Try to find a scantoll and see if the computer has set any codes....that should be an early (MEFI-1) type of ecu.

If the electronic spark advance feature is NOT implemented on that engine, check the distributor to ensure you have full advance.
 
Mako, I would like to have my own scan tool as no one around has one... Not sure why there are several marinas in the area (Mid Hudson Valley NY - Hudson River) that do repairs, and none are Crusader equipped with a scan tool. Maybe cost... For a problem like this, none of them want to get involved... I have a scan tool for my car that cost under $100. I could really use one for my boat at this point, if they are affordable. I was told, and maybe this is more wrong information, that if something electronic were wrong, my dash would buzz or the red "service engine soon" light would come on...
 
I have an OBD II code reader for my vehicles but I believe the scantool for the boat is a lot more money. My 1992's don't use it so I have little use for one
 
most buy a rinda scan tool and they really aren't OEM specific. worst case is it won't display anything.

the check engine light turns on when the computer finds an issue, assuming you hve one on the dash. the buzzer will sound if a serious issue arises. so, if you have a dash light, and it's working, then you performance issue is due to a problem with something the computer doesn't monitor. fuel supply usually falls into this catagory.
 
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