JerryB Posted August 28, 2008 Share Posted August 28, 2008 I see several replies to other power loss problems but none of them address my problem. I have a 2004 Vision/w 460/18sp @ 370,000 miles on it. With engine cold in morning it black smokes heavily from exhaust and has normal power, but after the engine reaches normal operating temp the smoke clears and engine loses power. Accelerating from dead stop the foot throttle has little effect but when I release the accelerator then mash again there is some power increase (not nearly normal power) and slight rpm gain. Traveling down highway the accelerator somewhat responds after several (3 to 5) seconds of dead pedal after being mashed but will not reach but around 1400 rpm with manifold pressure tops out @ 24-25psi. I have changed the fuel and air filters plus pressure checked the air to air. The only need so far has been replaced the EGR valve and EGR cooler with overhead run again 50,000 miles ago, The dash board shows no fault light and I have had a computer scan done at Mack which show no fault present. I know absolutely nothing about computer trucks so does this make sense? is it possible there is a fault code present but the Mack tech did not/cannot find it? Any help will be greatly appreciated so thanks guys--Jerry Quote Link to comment Share on other sites More sharing options...
bts-4120 Posted August 28, 2008 Share Posted August 28, 2008 you can see any active or stored code with out the scanner turn the key on hold the mode and reset button in at the same time for a few seconds and release any codes will show up on the display, but what you have to me sounds more like a loose or corroded ground, loose connection, or corrosion on a fuse I would start at the batter box, fuse box and ground breaker on the fire wall and connection to the ecu and ecm and also there are cab and motor grounds to frame Quote Link to comment Share on other sites More sharing options...
fjh Posted August 28, 2008 Share Posted August 28, 2008 you can see any active or stored code with out the scanner turn the key on hold the mode and reset button in at the same time for a few seconds and release any codes will show up on the display, but what you have to me sounds more like a loose or corroded ground, loose connection, or corrosion on a fuse I would start at the batter box, fuse box and ground breaker on the fire wall and connection to the ecu and ecm and also there are cab and motor grounds to frameGo to a dealer have em recalibrate the VGturboand clean out the egr cooler if its not been done latly! see if that will help! Quote Link to comment Share on other sites More sharing options...
JerryB Posted August 28, 2008 Author Share Posted August 28, 2008 Thanks guys. It still shows no fault code on dealer scan but today it seems to be running normal. I tried the self scan using mode and reset buttons but all that comes up is a single reading of < 1.2 > in the top right corner of display. I have cleaned all terminal and connections from batteries out. There is a sensor w/2 wire connection in the aluminum air tube going from turbo to charge air that upon removal looks dirty with slight heat damaged wiring. Do either of you know what this sensor controls? Thanks again--Jerry Quote Link to comment Share on other sites More sharing options...
bts-4120 Posted August 29, 2008 Share Posted August 29, 2008 the 1.2 does not make any sense to me if it has no codes it will show no faults on the display there are more to a code that 1.2 a letter couple of number a dash and a few more numbers, owners manual shows you how to read codes out on the dash display my truck is a 2001 and I do not have that sensor but heat damaged wires is not good Quote Link to comment Share on other sites More sharing options...
fjh Posted August 29, 2008 Share Posted August 29, 2008 Thanks guys. It still shows no fault code on dealer scan but today it seems to be running normal. I tried the self scan using mode and reset buttons but all that comes up is a single reading of < 1.2 > in the top right corner of display. I have cleaned all terminal and connections from batteries out. There is a sensor w/2 wire connection in the aluminum air tube going from turbo to charge air that upon removal looks dirty with slight heat damaged wiring. Do either of you know what this sensor controls? Thanks again--JerryI will say this one more time!!!THE TURBO CAN COME OUT OF TUNE and Will not throw a code Have it recalibrated and make sure its going full stroke!Have em watch the lever and push it full stroke if need be!The computer remebers the stroke in the recal sequence.Have em use the advance display in the vmac 4 program and make sure the egr flow and turbo are reaching their targets! The two wire plug you speak of throws a 270 code if faulty (compressor discharge temp code.) Quote Link to comment Share on other sites More sharing options...
JerryB Posted August 29, 2008 Author Share Posted August 29, 2008 I will say this one more time!!!THE TURBO CAN COME OUT OF TUNE and Will not throw a code Have it recalibrated and make sure its going full stroke!Have em watch the lever and push it full stroke if need be!The computer remebers the stroke in the recal sequence.Have em use the advance display in the vmac 4 program and make sure the egr flow and turbo are reaching their targets! The two wire plug you speak of throws a 270 code if faulty (compressor discharge temp code.)Thanks guys. When I said I had it scanned I meant that I have carried the truck into Mack again yesterday and had it scanned. I was listening to you the first time and did have the turbo and gates check performed. Thanks again--Jerry Quote Link to comment Share on other sites More sharing options...
Hook n ladder 1 Posted August 29, 2008 Share Posted August 29, 2008 Jerry, I had the same problem with my CH. Although mine is alittle older (98) the problem was the throttle. The roller and sensor on the back of the pedal weren't working that well any more(500,000 miles). The entire throttle assembly was replaced and the truck was like a race car. I don't know if there is a way to test it.Hope this helps.Rob W Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted August 29, 2008 Share Posted August 29, 2008 Jerry, I had the same problem with my CH. Although mine is alittle older (98) the problem was the throttle. The roller and sensor on the back of the pedal weren't working that well any more(500,000 miles). The entire throttle assembly was replaced and the truck was like a race car. I don't know if there is a way to test it.Hope this helps.Rob W There should have been some TPS codes showing that the throdle was down. Quote glenn akers Link to comment Share on other sites More sharing options...
fjh Posted August 31, 2008 Share Posted August 31, 2008 There should have been some TPS codes showing that the throdle was down.I have seen the tps cause power problems with out throwing codes but its very unlikly! Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted August 31, 2008 Share Posted August 31, 2008 I have seen the tps cause power problems with out throwing codes but its very unlikly! cummins will some times but the way it acts is it will be a dead spot but if you give it enough time it will set a code.Cummins like the cellect was slower than the new ecm. glenn Quote glenn akers Link to comment Share on other sites More sharing options...
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