Rfoster Posted November 19, 2021 Share Posted November 19, 2021 My 2003 Mack ch is showing the codes 5079-05 m128, and 5080-05 m128 and idea what they are? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 2 engine codes with low/ open circuits,,, I dont know what 5079+5080 are... did you search the web for the answer? Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 I did it looks like I had something to do with engine brake the engine skips/ runs ruff at idle sometimes and sometimes has very low power just trying to figure out what’s going on it also shuts it self off when idling at times Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 if the lightning bolt is on, use the cruise control buttons to retrieve the code... ?-? will be the code... ie: 8-1,,, to do it..... cruise button off, then push down on the speed button and release, and the codes will start flashing.. have a pen and paper ready first... jojo Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 when you get the 2 digit codes, look em up, or ask us... Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 I got those codes they were 3-5,3-6 which are codes for engine brake would that cause low power though? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 no... has there been any top end work done recently? so do you have power leash or jacobs engine brakes? Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 I’m not sure I just bought the truck Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 gosh,,,, powerleash celenoids have an o-ring in the base, when it fails it can cause the engine to run rough, same if it is not installed correctly. How familiar are you with Mack engine brake heads? Quote Link to comment Share on other sites More sharing options...
R.E.D Posted November 19, 2021 Share Posted November 19, 2021 (edited) Mine has those same two codes because my original ecm pins corroded and I had to switch it with one out of a truck that had engine brake.it cant see the engine brake circuit therefore it throws the code. Edited November 19, 2021 by R.E.D Quote Link to comment Share on other sites More sharing options...
R.E.D Posted November 19, 2021 Share Posted November 19, 2021 So what I'm saying is that it might not be the original ecm to the truck,but since it didn't bother performance it never got taken to mack to be programmed to the trucks vin. Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 It’s got the button for a engine brake in the cab Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 does it run poorly, whether the engine brake switch is on or off? just curiuos,,, is there a 2" spacer under the valve cover and the jake wire plugs into it, or is it just a valve cover and the wire plugs into it? Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 It’s sporadic when it runs bad there isn’t a pattern to it I don’t see any wires going to the valve cover and 5 out of the 6 exhaust ports where the manifold bolts to the head it is wet right there Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 Where is the engine id tag supposed to be? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 the lower exhaust bollt are open into the pushrod bores,, when they are not sealed good or just old, they bleed oil. the engine brake wires are on the left side above the intake manifold. 2 wires total. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 the data plate is on the top of the front valve cover. is there a spacer under the valve cover? Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 No spacer under valve cover according to the data plate on the truck it’s supposed to be a e7 427 I’ll see if I can find the plate on the engine Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted November 19, 2021 Share Posted November 19, 2021 Are the wires connected through the cover? May have 2 different issues. Low fuel pressure causing erratic idle?? V 1 Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 The engine must not have a Jake brake because I can’t find any wires attaching to the valve cover Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 While driving the truck you can feel it have good power at times then like it has no power Quote Link to comment Share on other sites More sharing options...
R.E.D Posted November 19, 2021 Share Posted November 19, 2021 (edited) 4 hours ago, Rfoster said: No spacer under valve cover according to the data plate on the truck it’s supposed to be a e7 427 I’ll see if I can find the plate on the engine Spacer looks like the one the picture attached .has a grommeted hole for the brake control wire. Edited November 19, 2021 by R.E.D Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 19, 2021 Share Posted November 19, 2021 (edited) no spacer, you either dont have engine brakes or you have powerleash. the wire plug into the valvr cover on the left side's around cyl. #2 + #5.. "V" has a good point about fuel pressure.. put a gauge on the fuel outlet in the block and read it, 60-100 psi.... the wires for the engine brake run behind the water manifolds, and has a 90 degree plug end on it that plugs onto a small post that sticks out of the valve cover, or spacer depending on the engine you have.. jump up there and take a look... pics. would be helpful.. for engine brake I.D. the rough running part can be many things... More guys will comment on this, so do youre best to be specific about the symptoms,, keep in touch, jojo Edited November 19, 2021 by Joey Mack Poor spelling Quote Link to comment Share on other sites More sharing options...
Rfoster Posted November 19, 2021 Author Share Posted November 19, 2021 Thank y’all for the help so far I’ll try to get pictures of the valve covers but I don’t see any wires to it I tried using the Jake brake and it didn’t do anything and as far as the running rough it has been idling fine lately but it still shuts off if you let it idle for a few minutes it will start right back up but when it shuts off a red circle with a x through it pop up in the dash and when I drive it today I noticed some blue/grey smoke when driving it does have some engine oil in the air tanks I can’t tell if it coming from the turbo or air compressor Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted November 20, 2021 Share Posted November 20, 2021 have you checked???? ALL.... of your fluid levels?? Have you checked all of the ground connections on the truck.? hell.... is the idle shut down setting turned on? get it turned off..... or if youre in the seat, when the light comes on, tap the throttle or push the clutch once.... you may have a 5 minute shutdown setting... My guess is this is either youre first Mack, or youre first truck... No problem if it is.... Jojo Quote Link to comment Share on other sites More sharing options...
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