Re Optimax Missing At Idle

[MEATHEAD277]

Ihave posted my problem on the Hull Truth web site with my problem . I hvae tried everything to try to eliminate it the miss at idle but to no avail, so i figured if i copied and pasted my problem from the website to this one maybe i can get some fresh ideas?? Any and all input would be greatly appreceiatied thanks.

I have a set of 225's , My stbd motor has developed a slight miss at idle where as the port motor is fine. The wires have been replaced last year, just pulled the plugs from last year and they look great , only about 100 hrs on them, I cleaned ane checked the gap and re-installed them. I took a stepascope (sp)? to listen to them and they are clicking. I am thinking that that one of the injectors are partially blocked. My question is has any one taken an automotive injector cleaner canstier and hooked it up to the fuel rail? I assume i need to pull the fuel pump relay, is there anything i am missing? any comments or direction would be highly appreciatied.

Update, I partially filled the VST tank with sea foam and ran it through the system with no improvement. Checked all coils for spark with tool and all looked the same. Checked # 2and# 4 fuel injectors when i pulled of the leads independently the motor smoothed out, When i did the same to others it really made it worse, so basically those cylinders are not happy. Then swaped injectors still the same results. Next i swaped plugs, wires still nada. Next step was coil swaping still the same. Lastly i swaped out the ign modules and still nothing. I am thinking that there is a problem with the computer ??? Going to try and swap it outwith my other motor.. Any body have suggestions??????? thanks


Another update swaped ECM'S still the same. Dr 1532 the next thing i did was to pull the rail and pull the Air injectors #2,4 tried to clean them as best as i can and sent 12 volts to them and they were engaging . Soaked them in seafoam and powered them up and the seafoam came out the bottom. Reinstalled them and still nothing. Tommorrow i am going to to swap them out with 1,3 injectors and see if the other bank runs crappy

plugs were changed in those affected cylinders, When i pulled off the leads to the air injectors the motor smoothed out, Almost as if there was too much of a non atmorized mist being injected into the cylinder due to faulty injectors

Demeanor, I know it sounds crazy but that is what it did , (smoothed out) . I Pulled the air injectors 2&4 and 1&3 cleaned them agian with a de carbonizier , re installed them but swaped banks on the motor started it up and seemed better so i went out and ran it hard came back and i would say it is about 60% percent better. Tommorrow i am going to do a compression test

Update did a compression test on the motor with all plugs out and they were with in 4-5 psi of each other, Going to utilizie another tester to verfiy numbers today. Also checked L.P. fuel pump and it was in spec with the manual i believie 24 psi- 28 psi with motor running, H.P. fuel pump checked good at 93 psi i believie and the air pressure was at 82- 82.5 Psi the required 10 psi differential was there according to the manual. Basically i am done i have no other tests that i can perform Any Suggestions?????? I guess i will have to go to the dealer and have him hook it up to the lap top and see if he can tell where the miss is coming from?? One last question is it possible that i have to worn reeds on that feed # 2 and #4 cylinder???? thanks for any and all suggestions

[E-tec1]

can be anything from a chip to half the reed gone, u can hear it out the air handler if u take the airbox off

[merctech5591]

have you been checking air/ fuel together.. you may have a problem with the with the tracker valve possibly spiking fuel or air.. what year are these motor's.. older 98-2000 motor's were known for sputtering at idle..

[MEATHEAD277]

E-tec if i lost a reed or partial wouldn't i see a loss in compression or worse?

[MEATHEAD277]

Merc Tech the motors are 03's How do i check the air and fuel together? Itested them independently and i do have the required differental pressure.

[merctech5591]

Merc Tech the motors are 03's How do i check the air and fuel together? Itested them independently and i do have the required differental pressure.

you will need two gauges , when the motor sputter's make sure fuel is not spiking

[MEATHEAD277]

so one gauage on the fuel rail and the other on the air rail , what would you consider a spike if i am seeing 93 psi on the fuel rail?

[merctech5591]

spikes from say 93-97.. uneven fuel pressure when the motor act's up.

[Wayne Cammidge]

Have seen this problem with a faulty fuel or air pressure regulator diaphram or tracker valve. Is the Air in the Fuel rail dry. Tiny hole in in one of those could make the engine rich. Check the one that is closest to your problem 2 & 4 cyclinder. Only do the Air one last as the spring is super difficult to get back without the special tool

[MEATHEAD277]

Update did a leak down test it came out good, Brought it to the mechanic b/c it is still under warranty. Mech found partially broken reed pedal on #4 cylinder , the cylinder looked like it had no damage. #2 cylinder reed block looked fine but that cylinder was one that was giving a problem too. Merc is only covering the reed block for # 4 cylinder and not the whole assembly.So i guess i will wait and see if the one reed block was affecting the other cylinder. any thoughts???