02-02-2011, 04:38 PM #1
1999 Mercury Optimax Fuel Injectors Not Firing -- HELP
Make a long story short, I have a 1999 Optipop that the fuel injectors on cylinders 5 and 6 are not firing on a static DDT test. The engine runs like dog crap obviously and will not idle. When the static test gets to cylinders 5 and 6, the fuel injectors are not clicking. On the cylinder misfire test with the engine running, they will not misfire either. We have tried a good ECM and still no fire. I switch the #3 fuel injector plug wire and #5 wires and #3 will not fire, but #5 will fire now which tells me tht the injector isn't bad. We changed the fuel injector plug wire and still no fire. The wire from the ecm to the injector tests good with the ohm meter. Any help is greatly appreciated.The Last One Across The Lake Has A Small Johnson
02-02-2011, 09:37 PM #2
Are you sure its the fuel and not the direct injector ? hf...
02-02-2011, 09:55 PM #3
I've rarely seen a fuel injector go bad, they just get leaky and drippy, which a trip to Brucato for a cleaning fixes 90% of the time. The direct injectors are high failure parts. The early (and late) ECMs have a trail of issues, and that is more than likely where you problem is. Simon Motorsports can check and fix the ecm. Like half says, make sure you have your injectors straight first.
02-08-2011, 09:40 AM #4
Just got a chance to look it over for myself. It is the direct injectors on #5 and #6 that are not functioning. I pulled them out and put the ohm meter on them and they appear to be fine on the ohm meter. I reconnected them after removing them and they are not functioning. The question of the day is, if they have continuity but are still not working, is that something that could be fixed by sending them off to be cleaned and flow tested? Thanks.The Last One Across The Lake Has A Small Johnson
02-08-2011, 10:38 AM #5
Contaminants ( compressor debris, and salt air/moisture) get into the air rails and rust the fuel injector tip and air injector internals. 5&6 are the worst because they're at the bottom of the rail where this stuff settles. If this is the case, the rest of the injectors should be cleaned and flow tested too.
Last edited by Tony Brucato; 02-08-2011 at 03:15 PM.Tony Brucato
02-08-2011, 04:17 PM #6
The ohm reading does'nt mean a thing, it's also what the diagnostic checks for when you run the test. What Tony mentioned is 100% correct. Another thing is to listen to the sound of each DI injector when you perform diagnostics, the difference of a healthy injector and one that is bad is easily noticeable. Then it's just a matter of getting out the check book for a ridiculously over priced component..
02-08-2011, 04:22 PM #7
ProMarine has the injectors at a much better price than Merc. I needed 3 after a compressor failure. Merc was over $300 each and I THINK PM was about $50 less per injector.