steeler Posted February 12, 2020 Share Posted February 12, 2020 2008 MP7 start it up, runs ok but after it warms up a few minutes will start slowly developing a miss, then eventually all throw codes for #1 and #2 injectors with an fmi 5'. Kinda strange to me that this 2 injectors shut off at the exact same time. New engine harness and tried a different ecu. Any other ideas besides replacing the 2 injectors? Quote Link to comment https://www.bigmacktrucks.com/topic/60960-mp7-engine-miss/ Share on other sites More sharing options...
Mack Technician Posted February 12, 2020 Share Posted February 12, 2020 I once had an OHC engine break a unit injector top spring. When I’d start the engine the broken piece would start dancing around striking and shorting out the harness connection. It had that symptom only didn’t take minutes to develop. I’ve also had an ECM losing injector drivers for sister cylinder injectors simultaneously, 1&6. Again, not your case. Quote Link to comment https://www.bigmacktrucks.com/topic/60960-mp7-engine-miss/#findComment-442616 Share on other sites More sharing options...
steeler Posted February 15, 2020 Author Share Posted February 15, 2020 I changed number 1 and 2 injectors and cups. That appears to have fixed it! Quote Link to comment https://www.bigmacktrucks.com/topic/60960-mp7-engine-miss/#findComment-442829 Share on other sites More sharing options...
fjh Posted February 15, 2020 Share Posted February 15, 2020 Thanx For posting your fix Bro! Quote Link to comment https://www.bigmacktrucks.com/topic/60960-mp7-engine-miss/#findComment-442843 Share on other sites More sharing options...
steeler Posted February 15, 2020 Author Share Posted February 15, 2020 32 minutes ago, fjh said: Thanx For posting your fix Bro! Always! Been working on Macks for 26 years and always come here for tips. If I can save someone else a headache that I went thru fixing something all the better. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/60960-mp7-engine-miss/#findComment-442846 Share on other sites More sharing options...
Mack Technician Posted February 16, 2020 Share Posted February 16, 2020 Posterity salutes you!!! 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/60960-mp7-engine-miss/#findComment-442897 Share on other sites More sharing options...
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