stevesxm

the mercruiser scan tool has a built in injector testing circuit. you plug the harness into the injectoer and set the program for the " pulse " you want and hit the fire button and off it goes... options are single 400 msec pulse , 5 , 10, 20 or 50 400 msec pulses.

the dirty plugs were two each side... not on same anything... but then again, im not claiming that iknow for a fact that the 4 injectors that pulse simultaneously are on the same bank or for that matter , what the absolute truth of the effect that having a shorted injector did to ANY of the other circuitry. all i can say is that i know what a motor that has dropped one cylinder sounds like vs one that is just "flat" and that was the case here... it sounded like it had done exactly what the plugs suggest ...lost at least one cyl on each bank or more...

it just never dawned on me that it could have been a single injector... it was exactly when i had done full tanks so thinking horses not zebras i started looking at bad fuel...

as for the cleaning

i simply took the high pressure line from the pump and hose clamped a 3/8 line to it to a brass shut off that with another piece of 3/8 off the other end. the injector is such that either end will fit nicely into that hose and you hose clamp it tight. then just feed the pump with a separate line from a container with death injector cleaner and a little gas... turn the key on and off a few times to pressurize your rig and fire the injector into another container with the scan tool... takes only a couple mins each once you get organized. i flushed backwards to clean the screens a couple of 50 cycle pulses and then 10 -50 cycle pulses at pressure... the close the valve, disharge one last time to clear pressure from the hookup and do another one... easy and effective and building a bench rig would take about 15 mins.... but i did mine right in the engine bay.

my injectors are the first picture NOT the " A1 " ones and i may be wrong but i think they are delphi. did notice that they shoot a concentrated stream rather than a fan which surprised me as the fan pattern always worked a lot better on the race motors. i paid about 86 bucks from bam for them and felt that wasn't out of line. gotta say that of everyone ive dealt with since ive bought this boat, those guys are the absolute best for pricing and service. beat everyone by 10 or 20 % answer their phone and are polite, and ship instantly...

also pursuant to the knock down drag out fight we had here about extrude honeing and smooth finishes... i had to laugh when i took the plenum off and see the orange peel finish on the inside... i maintain that that is on purpose. not a cheap casting and i wouldn't think of changing it...

Dave_N

I thought your engines were 1996. They must be 1999 or later since they are MEFI 3 (MEFI 1 would have the Keihin injectors and would not have the injector pulse test). My earlier comments about the VST (Vapor Seperator Tank) therefore do not apply. Sorry, my mistake.

Dave

stevesxm

well... can't argue or dispute year... guy that sold them to me says 1996 ...motor number OLxxxxxx say 1996 but ecus are mfe3's for sure.... paid 5 k each absolutely complete to every last washer and was happy to do it.

was wondering.... am a real fan of roller rockers.... anyone have a direct replacement part number for the roller rockers that would go in these motors without bouncing the valves off the pistons ?

ealesh33

iTrader: (1)

I know I am bringing back up an old thread, but I am having an issue that is very close to this. Except, all of my spark plugs are getting washed down, and I did in fact have bad fuel, that had water in it. A little back story, I have 502 mpi, cool fuel, full MSD ignition with 6M-2L box. Ugrades are a cam, lightening headers with 4 inch dry to the tip tails, and intake is modded with cut down runners and honed so looking around 540hp. Now motor just had bottom end done, and heads redone with new manley valves, springs, roller rockers, etc. First start up we noticed a miss, very slightly at idle, but apparent at about 2000-2500. We made a determination that it was ignition, boat had acdelco ignition, so replaced cap and rotor with no change. So I grabbed an MSD coil and did MSD 8.5mm plug wires. That seemed to knock out the miss, but just to cover basis we compression tested the motor at 160 on all 8, and went ahead and put a new billet MSD distributor in. Miss is gone, so we set timing (36 total timing) and took it for a test run. Boat planed out, and ran fine. cruised around to make sure it was as warm as it was going to get, also while taking it down to idle and bringing back up on plane. All seemed of so we did a pull up to about 4200 shut it down and checked plugs, plugs looked good, but noticed number 7 was a little lighter color, we just a put a brand new plug in that cylinder so thinking lets switch plugs on that cylinder and run again to see if it is running leaner. Did that buttoned it back up, cranked up and start idling. Then all of a sudden started to feel a rough idle, went to get up on plane it just felt lazy and started breaking up a little. Backed off thinking man did we leave a plug wire off, checked was all good. Cranked back up, idle still rough, and same symptoms. So we pull the boat out, and take off the fuel separator to dump in a jug to look at fuel. Fuel didn't look great, but not anything real alarming, so put a new fuel separator on, and it idled back to normal on the trailer. Dropped the boat back in the water and started heading out. Got about 100 yds and it seemed like it was idling rough again, try to get up on plane and same thing breaking up. Take it back in and park it. Take a look at that fuel again and it looks no good, pretty yellow, cloudy, and has a weak smell, so we decided ok fuel isn't good. I bought the boat in October I think, and the guy had filled the boat with 92 prior to parking it in July of last year, so we went ahead and pumped every oz of fuel/liquid out. We put some fuel pumped out early in a jug again, and sure enough there was some water in it as well. So pumped all 90ish gallons out, Then went and put little over 50 gallons of fresh 92 in it. Replaced the fuel separator again, and cranked it up. idled and revved great. Dropped it in the water started heading out, damn sure started idling rough again, tried to get up on plane and it went up on plane while feeling lazy, so i ran it for a minute to see if it just needed to get it out of the system, and it didn't, just seemed to get worse. While it was going it would spurt, like run lazy then lurch like it wanted to break out, but wouldn't. So put it back on the trailer, and put it away. Next morning pulled the 4 plugs on the port side of the motor and they were all dark and washed down with fuel. That afternoon when I got there I pulled the starboard side 4 and same thing, so all 8 plugs are dark and washed down with fuel. I can see one injector going bad and knocking out a batch of 4, but this would have to be an injector in each batch doing it to knock out all 8. These are also all brand new injectors, they are the new style 861260T injectors, now with a mefi 2 is there a chance the injectors aren't compatible considering the injectors were put out with the mefi3? We aren't thinking main harness, cause we aren't getting any electrical feedback in gauges, and its all been cleaned up cause we re rigged the boat. Now the ecu or injector harness I am not sure of.

keith2500hd

ealeash, if you pulled 7, you probably swapped with 5. make sure those wires don't touch and are not crossed. they fire close in sequence.