Will Posted April 24, 2023 Share Posted April 24, 2023 Have a Mack 470 etech engine 1998 model. Boost pressure gets to 200kpa on gauge then starts to de rate itself, does this every time it gets to the 200kpa boost pressure. Throwing a 3-4 code which is engine position sensor, replaced both and still doing it. Just wondering if anyone out there would have any ideas what would be the cause. Thankyou will Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 Did the code go away? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 200 kpa converts to 29 PSI.. that's pretty good.. I don't recall a boost sensor on that engine, or a waste gate turbo.. what else was done to the engine recently. Quote Link to comment Share on other sites More sharing options...
Will Posted April 24, 2023 Author Share Posted April 24, 2023 Yep the code went away, why would it be de rating itself? When it gets to 29psi the lightning bolt flickers on and off while de rating then go back to flat ground and everything goes back to normal? No boost sensor or ease gate on this engine. Nothing has been done to the engine recently or in fact for the last 12 months other then regular services. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 Low coolant, off the sensor when facing up hill? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 Is this in a CH/CX? Quote Link to comment Share on other sites More sharing options...
Will Posted April 24, 2023 Author Share Posted April 24, 2023 Coolant is the correct level. CHR Mack trident. I can’t work it out Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 Is this an Australian spec. Truck? Just curious.. do you have stored codes. Any codes for the throttle pedal? I'm at a loss right now, sorry... Quote Link to comment Share on other sites More sharing options...
fjh Posted April 24, 2023 Share Posted April 24, 2023 I believe if it was coolant related it would shut down! Joe maybe he has the front cover flex issue! Also check the engine ECU for coolant push! (green pins) 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 Coolant shutdown, is delayed, I figured because it flashes the mil light. For some reason, I can't really think of a cause for this yet.. front cover flexis a good thought. Quote Link to comment Share on other sites More sharing options...
Will Posted April 24, 2023 Author Share Posted April 24, 2023 Yep Australian spec, no stored codes at all. How to you fix the front cover flex? It could be that! Where abouts are the green pins? Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 Check the front engine mounts under the stantion. See if the rubber has disintegrated. Also look behind the balancer to see if the 18mm bolts are loose. I doubt they are, but... Quote Link to comment Share on other sites More sharing options...
Will Posted April 24, 2023 Author Share Posted April 24, 2023 Front engine mount is new mate, replaced 6 weeks ago. Ok will have a look at them Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted April 24, 2023 Share Posted April 24, 2023 I'm grabbing at straws.. This one is hard for me, without being there.. I'm sorry.. I would ask if there is an adverse condition on the road/terrain, that may be causing an issue, also, did you ever have speed sensor codes.. I know you said no stored codes, but didnt say when they were cleared last.. Keep us posted,, jojo Quote Link to comment Share on other sites More sharing options...
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