98 280 2.5 Will Shut of for split second????

[bigboatin]

Hey Everybody i have a problem with a motor 1998 2.5 280 at about 6500 rpm it will shut off for just like a mili second and then bog for a second and get right back into it..it`s like somebody flipped a switch off then right back on.if you run it at 5000 it will do it but you have to run it about a mile before it will do it.also at 7500 it does the same thing off then on for just a split second and will get right back into it as long as you don`t let off the gas but what would cause this ???i think it`s an electrical problem mybe the crank timming sensor or the throttle control sensor or mybe a bad ground??? it is an efi and i have two electric fuel pumps feeding it all brand new filters.so it doesen`t feel or act like a fuel problem..maybe abad ground??? any info would be great Thanks Craigo:confused:

[Jay Smith]

Had a customer with a race engine that would act like that. There is a multi pin harness that comes from key at dash and ties in at the motor, take an ecto knife and spread the male terminals so that it contacts the female with more tention before attaching clean with contact or brake cleaner. If that doesn't do it check all Fuel management and ignition systems connections. Next check the grounds. Also I have seen on one RARE occation the battery was faulty and had a loose plate that was internialy grounding out in the case causing a momentary short...

good luck,
Jay

[bigboatin]

Thanks for the advice Jay i will give that a try and see what happens!!!! also i do have a optima battery thats my crancking battery..again thanks for the info..Later Craigo

[K-Dawg]

I think a guy I know was having trouble with his 225X, come to find out it had something to do with the optima battery he was using. I think it was low on charge and he had a hard time keeping it charged good enough to run his motor. I am pretty sure he ended up going back to a wet cell and that fixed his problem.

[Pachanga_rick]

Hey Everybody i have a problem with a motor 1998 2.5 280 at about 6500 rpm it will shut off for just like a mili second and then bog for a second and get right back into it..it`s like somebody flipped a switch off then right back on.if you run it at 5000 it will do it but you have to run it about a mile before it will do it.also at 7500 it does the same thing off then on for just a split second and will get right back into it as long as you don`t let off the gas but what would cause this ???i think it`s an electrical problem mybe the crank timming sensor or the throttle control sensor or mybe a bad ground??? it is an efi and i have two electric fuel pumps feeding it all brand new filters.so it doesen`t feel or act like a fuel problem..maybe abad ground??? any info would be great Thanks Craigo:confused:

I Had a problem close to that at the St. Clair race last weekend. The Port engine just cut on / off for a split second. Once it shut off were I had to re-fire it, Than it did it while hitting the north turn and hooked us I called it a day after that

Turned out I had a loose wire on the Hi-Pres. fuel pump..

[bigboatin]

Thanks for all the input!!! i`m going to check all the above.. and maybe this weekend give it run i`ll let ya know what i came up with, Thanks..Craigo

[johnt]

does sound like a ground connection..are you running a relay to power your fuel pumps? and why are you running two fuel pumps? inquiring minds want to know..

[Pachanga_rick]

does sound like a ground connection..are you running a relay to power your fuel pumps? and why are you running two fuel pumps? inquiring minds want to know..


Not sure if this is/was directed at me or not but I'll answer it the best I can.
I have 4 Pumps, 2 Low pressure Holly's and 2 Hi pressure Bosh pumps. The low press. pumps pull fuel from the main fuel tanks and fill a small tank in back, than the Hi-Press. pumps pull off the small tank. I was told it a slosh tank to keep the pumps from pulling air from the larger tanks during a rough water race.

Not sure if thats correct, I think I may have even posted a picture of the set up before on S&F and never really got a answer. :confused:

[donmac]

Had the same thing happen on a tripple OB setup. landed so hard all three engines quit. restarted them and never happened again. also ran the slosh setup with two main pumps per engine and two delivery pumps per tank. you need good check valves in the pumps so you don't lose pressure only running one pump per engine. also a fuel gauge on the slosh so you no it's staying fuel. if it starts dropping switch delivery pumps. a very fail safe set up. you don't spend all this money to go racing and lose because a pump failed.

[bigboatin]

does sound like a ground connection..are you running a relay to power your fuel pumps? and why are you running two fuel pumps? inquiring minds want to know..
I run 2 pumps one is low pressure high volume this one pulls from the tanks,the second pump is high pressure low volume this one feeds the motor the lp pump basicly feeds the high pressure pump and the high prs feeds the motor and there not on a relay i have them direct powered to a battery source and they are tied in to a stop switch just in case i was to be ejected from the boat they would shut down or if the ignition is shut off so are the pumps i hope that helps..pachanga rick pretty much answered the question..

[bigboatin]

Thanks for all the input guys i cleaned all the grounds on the motor and followed the harness to th helm and checked all the grounds on the switch there were some optional equipment attached to the ground wires that abviously were interfering and now the problem is gone thanks for all the input!!!!

[bigboatin]

Hey Guys just wanted to let all of you know that it was the optima battery that was causing the problem!! i thought it was the wiring but it started doing it again so i did everything possible and checked everything possible and the motor would skip even after the optima battery was charged. then i put the boat on the trailer changed batteries(wet cell) and put the boat back in the water, and ran perfect and has since then!! thanks for all the input and suggestions. what i found was with all the pumps and electronics running the motor could not charge the optima fast enough to keep the correct voltage so that inturn made the ecm go wacky the optima battery charges at a slower rate than a wet cell battery and can`t keep a constant higher voltage as a wet cell so for me, learn somthing new everyday.Thanks again for all the input