having engine issues.. need a little help, Fuel or ignition. 350 mag mpi

[DirtNasty]

also .... my distributor doesnt look like that... it has a flat top (cap) with the post on the sides. and has no electronics goin to it like the one shown in your pictures... i have seen in like yours in the wiring diagrams but mine is not that way. it does have a spot (1) on the side that has four male pins coming off the side of the housing similar to the way yours has 2. but there is nothing plugged in it and never has been?????

[DirtNasty]

image_2.jpegimage (2).jpegimage_1.jpeg

this is what im workin with. sorry for quality but i wanted to get something posted to try and get this figured out. obviously i have an odd ball ignition or something ....maybe its not even the original motor.. bought the boat used so you never know?

[TeamAllen]

Sorry no one better than me is helping. What about these three things I marked with arrows?

[DirtNasty]

yes i was thinking the one on the left... but it is a 4 pin with ftwo wires? not like the 10 pin with the wire colors like you have and that it shows in wire diagrams. I appreciate the help... maybe someone else will chime in. I know somebody knows the answer to this and can help me get it timed. I know its a simple deal just need the right person to chime in

[TeamAllen]

The two on the right look very similar to the one I pictured. All those colors might be misleading? They go to other stuff in there. What does the end of the tool you are trying to connect to it look like? Can you take a picture of it? Is it a MEFI scan tool? Have you tried taking the ends of the those plugs off and matching it up with your scan tool/reader?

[Stingreye]

Any chance someone hacked together a diy check engine light confusing things? This link explains it. http://www.pirate4x4.com/tech/billavista/MEFI/

[DirtNasty]

I'm not trying to connect anything. Was just gonna jump the wires. The point is there is no dlc connection on this engine. I'm over the timing issue. Downloaded a service manual and it says nothing about setting time on a mpi engine only carbureted versions. So any way I'm on the water agiain today with all new fuel, filters. And still have the issue of it stalling out after running at high rpm. The higher the rpm the sooner it stalls. Runs fine until it stalls. It has got to be losing file somehow. Fuel pump??? Anti siphon valve?? I know the vent is not clogged already checked that. I know it's not bad fuel. It may even be in the ignition. I checked cap and rotor. Cleaned em up good. Seemed ok not perfect but not corroded bad or anything. Also cleaned spark arrester.

So where would you start?? I'm close to taking it to shop but I really don't want to

[TeamAllen]

It sounds like it goes into limp mode maybe when you get into the higher rpm? The ECM could be recognizing a problem at that rpm and shut it down to prevent damage. It could be anything from low fluid, temp, fuel injector, ignition or a bad sensor somewhere? Have you tried reaching those problem RPMs in gear vs. out of gear? I don't think it's a good idea to run those kind of RPMs out of the water.

I would start with finding out which MEFI you have. That link Stingreye provided was a great resource for that. The part number will be on the back of the ECM. At a minimum (IF you have MEFI 1-4) I would buy the simple Code Mate scan tool for $50 http://www.rinda.com/marine/marine.htm#merctool or splurge and get the software for $200 http://www.mefiburn.com/mefiscan.asp. The simple scan tool can also be used for your timing, so that might be the better of the two options and it's much cheaper.

I think the DLC is the one on the right or the middle of the picture. My guess is, if you buy the tool, it will fit one of them.

[Ruger761]

I dont know where the pin connector is, but sure sounds like its running out of fuel to me at the higher RPMs. Id be looking to see what kind of fuel pressure its holding at the higher RPMs. On a 2002 does it have a low pressure pump and a high pressure pump or just the high pressure pump? What I'm thinking is at idle and low RPM it has enough fuel to keep the filters full and pressured, the at the high RPMs the pump isnt keeping up, sucking the filters dry, and then loosing power. Then once it drops back down the pump has enough time to catch back up. Ive seen this happen on other motors. Swapped out pumps and never had the issue again. But a $30 fuel pressure gage is cheaper to try first vs buying a $300 pump.

[DirtNasty]

as far as the ecm... it does not match any of the gm/delphi ones like you have or the ones pictured... it is a motorola i believe which might explain why none of the wiring is the same.

[DirtNasty]

I dont know where the pin connector is, but sure sounds like its running out of fuel to me at the higher RPMs. Id be looking to see what kind of fuel pressure its holding at the higher RPMs. On a 2002 does it have a low pressure pump and a high pressure pump or just the high pressure pump? What I'm thinking is at idle and low RPM it has enough fuel to keep the filters full and pressured, the at the high RPMs the pump isnt keeping up, sucking the filters dry, and then loosing power. Then once it drops back down the pump has enough time to catch back up. Ive seen this happen on other motors. Swapped out pumps and never had the issue again. But a $30 fuel pressure gage is cheaper to try first vs buying a $300 pump.

I agree. anybody have a link to a fuel pressure gauge that will work? I'm pretty sure that it is the fuel. I ran this boat all last summer without one single issue. put it up and didnt winterize fuel and ran bad fuel through it and have had problems since i got it out. I just dont see ignition goin bad like that. not sayin its not possible but..

[Ewok]

I would guess its a fuel pump issue. If you can get your hands on a fuel pressure gauge, hook it up to the fuel rail and run the boat at the higher RPMs and see if fuel pressure drops off at that point. Some of the real mechanics may chime in here and be able to tell if it's the high or low pressure pump but that's what I would check next. If that's not the cause then I would turn to the computer and read the codes and see what could be tripping the ECU into limp home mode.

[IDBoating]

x10 on it being a fuel delivery issue. I bet if you run it on the trailer, it revs high just fine with no problems... which is the litmus test for fuel delivery problems, since it takes very little flow to rev an engine with no load (i.e. prop out of the water). Might be a worthwhile test just to confirm.

Harbor Freight carries an inexpensive fuel pressure gauge. I have one for exactly this sort of test.

[DirtNasty]

well after looking into fuel pressure gauge parts... I went ahead and ordered a fuel pump. It was 90 bucks on amazon... the pressure testing kits were 50 and up. So i opted to pay 40 more and go ahead and get it coming and save time in the long run. also have a anti siphon valve coming even though I think mines fine. I bought the (boost) pump which is the one mounted by the water sep filter. I believe there is another one on the cool fuel section. at least the parts diagram shows one that goes up into the fuel cooler manifold. hope its not that one that is bad. I will check when I get home and see if there is two

[boatwakes]

The DLC is the flat 4 pin connector at the front that says "Transducer"/"diagnostics" on the tag. YOU DO NOT NEED A COMPUTER TO TIME THIS ENGINE the ECM takes care of everything because of the crank position sensor. However, if the timing is off either retarded too far or advanced too far, it will run like poo poo above about 2400rpm (in neutral, no load) but be fine below that. If you adjust the timing and then can get the desired 3000-3500rpm to confirm the timing is correct, then you're done. If it doesn't change then adjust the other direction and check again. If there still is no change then we'll start talking about fuel and pumps.