wx8sky Posted May 29, 2009 Share Posted May 29, 2009 Just found the site searching for manuals on this engine (no luck)...so I figured I'd try a post here.I have a 1992 CH612 with an EM7-300 engine. It was out on the road one day running fine, and all of the sudden it quit running...no warnings whatsoever. Got it back into the shop to check it out and here is the scenario so far:Fires on ether, but not with dieselChecked the pickup tube from tank - A-OKCracked 2 of the injector lines loose and cranked it, no fuelChecked the fuel shut off solenoid, seems to be operating properly...even tried to eliminate the plunger/spring and run without it - still no fuel pumpingTried replacing engine position sensor, no luckCalled a few people, one place says it could be electronic (fuel pedal module or fuel transfer pump) - another shop says it could be the fuel injection pump itself.Is there any place that I can find an actual troubleshooting manual or service manual for this year truck with a troubleshooting guide and component location guide in it? I tried mack direct, but wound up with an overhaul manual that did absolutely no good.Any suggestions/input on this hair removal engine, would be greatly appreciated!DonCleveland, OH Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/ Share on other sites More sharing options...
David Posted May 29, 2009 Share Posted May 29, 2009 Build yourself a small tank with either air presure or an electric pump to deliver fuel. Hook it directly to the injection pump and get the engine running. Then you can start looking for why your not getting fuel through the system. Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-35843 Share on other sites More sharing options...
fjh Posted May 29, 2009 Share Posted May 29, 2009 Just found the site searching for manuals on this engine (no luck)...so I figured I'd try a post here.I have a 1992 CH612 with an EM7-300 engine. It was out on the road one day running fine, and all of the sudden it quit running...no warnings whatsoever. Got it back into the shop to check it out and here is the scenario so far:Fires on ether, but not with dieselChecked the pickup tube from tank - A-OKCracked 2 of the injector lines loose and cranked it, no fuelChecked the fuel shut off solenoid, seems to be operating properly...even tried to eliminate the plunger/spring and run without it - still no fuel pumpingTried replacing engine position sensor, no luckCalled a few people, one place says it could be electronic (fuel pedal module or fuel transfer pump) - another shop says it could be the fuel injection pump itself.Is there any place that I can find an actual troubleshooting manual or service manual for this year truck with a troubleshooting guide and component location guide in it? I tried mack direct, but wound up with an overhaul manual that did absolutely no good.Any suggestions/input on this hair removal engine, would be greatly appreciated!DonCleveland, OHDon is there a valve on the front of the fuel pump with a wire going to it?if so remove the guts of that valve and reasemble!? question two do any of the accesorys work heater fan ect when the key is turned on does the check engine light come on then go out! if not you have a bad acssory relay in the dash under the cup holder 4 screws and your on top of it.If you don't her a clunk in the dash when the key is turned on its likly the relay even if you do it can still be the relay check it has power coming out when the key is on ,the heater fan should run if its ok.Check this stuff and get back.Fred Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-35855 Share on other sites More sharing options...
wx8sky Posted May 29, 2009 Author Share Posted May 29, 2009 (edited) Don is there a valve on the front of the fuel pump with a wire going to it?if so remove the guts of that valve and reasemble!? question two do any of the accesorys work heater fan ect when the key is turned on does the check engine light come on then go out! if not you have a bad acssory relay in the dash under the cup holder 4 screws and your on top of it.If you don't her a clunk in the dash when the key is turned on its likly the relay even if you do it can still be the relay check it has power coming out when the key is on ,the heater fan should run if its ok.Check this stuff and get back.FredGood Morning Fred,Yes, the accy relay is working. I did remove the "guts" from the shut off solenoid at the front of the pump, still no success.Someone that I spoke with yesterday, made mention of the fuel transfer pump and said it was seperate from the fuel injection pump...and that may have failed, that's why I was hunting for a manual with a component locator in it Don Edited May 29, 2009 by wx8sky Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-35857 Share on other sites More sharing options...
fjh Posted May 29, 2009 Share Posted May 29, 2009 Good Morning Fred,Yes, the accy relay is working. I did remove the "guts" from the shut off solenoid at the front of the pump, still no success.Someone that I spoke with yesterday, made mention of the fuel transfer pump and said it was seperate from the fuel injection pump...and that may have failed, that's why I was hunting for a manual with a component locator in it DonIt sounds electrical to me if it just up and quit with out sputtering!If it sputtered to a stop you will likly be looking at a transfer pump.mounted on the side off the fuel pump . remove the round plug going to the fuel pump and look at the the plug itmay need new pins does any of the holes look to be brown from geting warm.Also there is a ground faultbreaker on the fire wall black rectangular box 2x three in size jump across that make sure it hasent failed. Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-35870 Share on other sites More sharing options...
fjh Posted June 1, 2009 Share Posted June 1, 2009 It sounds electrical to me if it just up and quit with out sputtering!If it sputtered to a stop you will likly be looking at a transfer pump.mounted on the side off the fuel pump . remove the round plug going to the fuel pump and look at the the plug itmay need new pins does any of the holes look to be brown from geting warm.Also there is a ground faultbreaker on the fire wall black rectangular box 2x three in size jump across that make sure it hasent failed.Don did you nail this down.Please post your fix so others can benifit. Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-35986 Share on other sites More sharing options...
wx8sky Posted June 2, 2009 Author Share Posted June 2, 2009 (edited) Don did you nail this down.Please post your fix so others can benifit.Sorry about that, got tied up with a wheel seal/brakes and tires yesterday.I checked the harness plug, all pins look brand new, no burning or yellowing at all. As far as the fuel transfer pump, is that at the side of the fuel injection pump (looking at pump/lower right side)? I also checked the ground interrupt on the firewall, that seems to be working with key on (has continuity through).Normally this high tech stuff (low tech co. garage), we usually send it out...but have some time on our hands to try and save us a little $$ in the long run I am going to snap some pictures today, maybe someone can help identify component locations, etc.---Photos--- Edited June 2, 2009 by wx8sky Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-36000 Share on other sites More sharing options...
wx8sky Posted June 5, 2009 Author Share Posted June 5, 2009 Sorry about that, got tied up with a wheel seal/brakes and tires yesterday.I checked the harness plug, all pins look brand new, no burning or yellowing at all. As far as the fuel transfer pump, is that at the side of the fuel injection pump (looking at pump/lower right side)? I also checked the ground interrupt on the firewall, that seems to be working with key on (has continuity through).Normally this high tech stuff (low tech co. garage), we usually send it out...but have some time on our hands to try and save us a little $$ in the long run I am going to snap some pictures today, maybe someone can help identify component locations, etc.---Photos---Hey Fred,Could you offer an idea of where the fuel transfer pump is?Don Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-36128 Share on other sites More sharing options...
fjh Posted June 6, 2009 Share Posted June 6, 2009 Hey Fred,Could you offer an idea of where the fuel transfer pump is?DonSecond to last pic!Remove the fuel line from the injection pump elab valve and crank it with the line off in a pail its likly not the pump but if its working it will show ya.your positive you gutted that elab valve ????? take the wire off and tape it up!When you turn the key on you should hear a faint click in the rear of the fuel pump if your like me and cant hear get someone with good ears to listen.Check the ecu fuse or breaker for power.Also Don right around or below the washer bottle the there is a rectangle plug that goes to the fire wall have seen that plug get wet inside look for the green stuff in there!Ya need a 1/4 or 3/16 inch socket to take the plug out!Also temporaraly jump over that ground fault on the fire wall just incase One mor thing i thought of is there is a diode in the fues panel far right that can cause greif some times. it looks diffrent than everything else in there. Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-36232 Share on other sites More sharing options...
ZackMan2022 Posted August 12, 2022 Share Posted August 12, 2022 Did y’all find out what the problem was having same problem with a 92 mack em7-300 motor turns over but wont stay running try’s to start up though but shuts right back off after initial hit I’ve had Mack dealer out three days looking at it they said if we want anything else done to it to have it hauled to the shop but my company don’t want to I don’t reckon plus it’s loaded we’ve checked fusses and relays ohmed everything on injection pump even rebuilt the rear of the injection pump (2800$ Just for the parts ) everything is ohming fine everything clicking and working properly getting fuel to everything checked fuel pick-up, ground wires battery’s all of that so far still no luck anyone have any ideas please let me know I got my bosses bosses down our throats about this truck and we don’t know what else to do Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-506058 Share on other sites More sharing options...
ZackMan2022 Posted August 12, 2022 Share Posted August 12, 2022 Tried computers also and will start and run with ether Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-506059 Share on other sites More sharing options...
fjh Posted August 12, 2022 Share Posted August 12, 2022 (edited) 1 hour ago, ZackMan2022 said: Tried computers also and will start and run with ether If it has an engine brake Pull the relays and try a start! One of our guys had this happen just the other day! Give it a shot! Edited August 12, 2022 by fjh 1 Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-506064 Share on other sites More sharing options...
Joey Mack Posted August 12, 2022 Share Posted August 12, 2022 so you have a duetch connector on the back of the injection pump, and not a pull stop to shut it down?? jojo Quote Link to comment https://www.bigmacktrucks.com/topic/9532-1992-ch612em7-300-no-start/#findComment-506076 Share on other sites More sharing options...
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