jswilliams Posted October 10, 2017 Share Posted October 10, 2017 I have a 97 ch613 with an e7-350 and it's very weak. Boost gauge only goes to 20 at the most and 90% of the time it only goes to 15. A little black smoke when I shift but nothing crazy. I have a blixxton box installed and it makes no difference what so ever. I pressure tested the charge air cooler and its fine I also bypassed the compressor intake hose by screwing it out and plugging the hole in the intake manifold. When I put air on the intake manifold I can barely get the pressure to 25 psi and it takes a while and as soon as I remove the air chuck it drops instantly. No air leaks can be found or heard and soapy water has been sprayed everywhere. Can it leak somewhere in the head and I not be able to tell? Also is there anything I can check to make it pull better? Also all of the filters are new. Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/ Share on other sites More sharing options...
fjh Posted October 10, 2017 Share Posted October 10, 2017 Check the torque limit switch on the trans unplug it! Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382073 Share on other sites More sharing options...
jswilliams Posted October 10, 2017 Author Share Posted October 10, 2017 I unplugged what I thought was the torque limit switch on the top of the transmission close to where the shifter goes into the top. Made no difference. It's a T2090 transmission if that tells you anything. Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382091 Share on other sites More sharing options...
jswilliams Posted October 10, 2017 Author Share Posted October 10, 2017 I don't understand why I can't pump air into the system and only get up to 20-22 psi. After that it just stops climbing yet I can't hear or see any leaks. And I'm using a compressor capable of 27 cfm. I hook on the pipe coming off the turbo and pressurize the air cooler, intake manifold, and so on. Even bypassed the hose that goes around to the compressor to eliminate it. Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382092 Share on other sites More sharing options...
scott67 Posted October 10, 2017 Share Posted October 10, 2017 I'm no expert but I don't think it would pressure up totally because some intake valves will be open. but that may be enough pressure to find a leak with soapy water , Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382098 Share on other sites More sharing options...
jswilliams Posted October 11, 2017 Author Share Posted October 11, 2017 Yeah that's what I was trying to figure out too. I've also read on here before that Mack recommended a 30 psi test and that the pressure could not drop more than 3 psi in 15 seconds to pass the test. My pressure drops to zero in less than 15 seconds. Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382104 Share on other sites More sharing options...
theakerstwo Posted October 11, 2017 Share Posted October 11, 2017 If you pressure up to the heads try rotating the engine slow watching the pressure gauge.At some point there will be intake or exhaust valves closed on all cyl enough to pressure it up but rotate slow.I dont pressure more than 25psi on the heads because i think you couldblow the intake seals off with more pressure. 1 Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382110 Share on other sites More sharing options...
jswilliams Posted October 11, 2017 Author Share Posted October 11, 2017 Just the info I needed. Thanks a lot. If I were to install larger injectors like the Rochester stage 2's for example, do I have to take the truck to Mack to have the computer reprogrammed for it to have more power or does it just spray more fuel with the larger injectors? Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382116 Share on other sites More sharing options...
theakerstwo Posted October 11, 2017 Share Posted October 11, 2017 No you do not. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382127 Share on other sites More sharing options...
fjh Posted October 11, 2017 Share Posted October 11, 2017 The torque limit switch would be mounted on the range cyl at the back the switch near the stick is the reverse switch!If you have a huge boost leak you would be trailing smoke all the time and if you have a pyrometer the temps would climb fast! Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382185 Share on other sites More sharing options...
jswilliams Posted October 11, 2017 Author Share Posted October 11, 2017 Oh ok so I probably don't have a boost leak bc Im not trailing any smoke. No Pyro installed yet. I looked at the fins on the turbo and they seem to have some buildup on them which may be causing the low boost issue. I'll try the torque limit switch and if that don't work I think I'm gonna install larger injectors and possibly a new turbo. Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-382196 Share on other sites More sharing options...
Duster Posted March 10, 2022 Share Posted March 10, 2022 On 10/11/2017 at 9:54 AM, fjh said: The torque limit switch would be mounted on the range cyl at the back the switch near the stick is the reverse switch!If you have a huge boost leak you would be trailing smoke all the time and if you have a pyrometer the temps would climb fast! Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-491497 Share on other sites More sharing options...
Duster Posted March 10, 2022 Share Posted March 10, 2022 Does the torque switch work for high or low range Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-491498 Share on other sites More sharing options...
JoeH Posted March 10, 2022 Share Posted March 10, 2022 They limit torque in low gears. Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-491501 Share on other sites More sharing options...
Joey Mack Posted March 10, 2022 Share Posted March 10, 2022 and in reverse as well.. jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-491502 Share on other sites More sharing options...
Duster Posted March 21, 2022 Share Posted March 21, 2022 I loose torque in high side Quote Link to comment https://www.bigmacktrucks.com/topic/51339-weak-e7-350/#findComment-492894 Share on other sites More sharing options...
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