07cl733 Posted April 16, 2017 Share Posted April 16, 2017 Hello all and Happy Easter. I have a 2000 ch with an E tech 460. I recently acquired the truck and it's history is unknown. I have never run a truck with this motor before and was wondering what I should expect for boost pressure. It builds 25 lbs at the most. It pulls ok, but I would say it is a weak for a 460hp motor. I replaced the fuel pressure check valve and get 70 lbs fuel pressure at idle. There are no error codes from the eecu. I've run the overhead, but aside from a couple intakes that were too tight everything looked good. The motor sounds good and does not smoke, other than a small black puff when I shift and press the throttle hard. The exhaust temp will climb to near 1000 on a long pull but boost pressure never changes. Is this normal, or should I expect more? Thanks for your consideration! Quote Link to comment Share on other sites More sharing options...
Lmackattack Posted April 16, 2017 Share Posted April 16, 2017 I cant comment on the 460 motor but the For a 95' with a 427 it shows 24-32 psi is the normal range.. I do recall a ECM flash that was very popular for the Etech but the EPA made Mack Kill it off years ago ... Quote Link to comment Share on other sites More sharing options...
fjh Posted April 16, 2017 Share Posted April 16, 2017 Like suggested you should have 30- 36 psi if every thing is tight *( no boost leake ) ect try running in cruise and see if this changes your values at all you may have a throttle pedal issue Quote Link to comment Share on other sites More sharing options...
Dirtymilkman Posted April 16, 2017 Share Posted April 16, 2017 Check your air to air for leaks. More than likely it is cracked. You should be able to pull 38 lbs. Mine have stage 2 injectors and it'll push 44 lbs of boost. Get the intake side pressure checked and you'll find your issue. Unless your turbo is getting weak. Quote Link to comment Share on other sites More sharing options...
07cl733 Posted April 19, 2017 Author Share Posted April 19, 2017 Thanks for the suggestions and info! I'll run the cruise, if I can get it to work. Sounds like I definitely have a problem since it's not building any where close to 30 pounds. I'll update as I learn more. Thanks again. Quote Link to comment Share on other sites More sharing options...
07cl733 Posted April 22, 2017 Author Share Posted April 22, 2017 I tested the cooler and charge hoses for leaks but they are all fine. I also ran the truck on cruise with the exact same results. Is there any way to tell if the eecu is programed as a 460? It doesn't say any where in the readout from the dealer. The software version is 1MS320 if that helps. Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted April 23, 2017 Share Posted April 23, 2017 Did you check the air cooler with air pressure? Quote glenn akers Link to comment Share on other sites More sharing options...
07cl733 Posted April 23, 2017 Author Share Posted April 23, 2017 Yes. I built a tool with a wheel valve stem and gauge out of pvc pipe. I tested from the turbo to the intake manifold. I believe that even if it were leaking boost a 5+ pound loss would cause very poor fuel mileage, lots of smoke and high exhaust gas temps. Quote Link to comment Share on other sites More sharing options...
fjh Posted April 26, 2017 Share Posted April 26, 2017 On 4/22/2017 at 6:05 PM, 07cl733 said: Yes. I built a tool with a wheel valve stem and gauge out of pvc pipe. I tested from the turbo to the intake manifold. I believe that even if it were leaking boost a 5+ pound loss would cause very poor fuel mileage, lots of smoke and high exhaust gas temps. On 4/22/2017 at 6:05 PM, 07cl733 said: Yes. I built a tool with a wheel valve stem and gauge out of pvc pipe. I tested from the turbo to the intake manifold. I believe that even if it were leaking boost a 5+ pound loss would cause very poor fuel mileage, lots of smoke and high exhaust gas temps. Correct? Quote Link to comment Share on other sites More sharing options...
fjh Posted April 26, 2017 Share Posted April 26, 2017 (edited) Is there any way you can build a test gauge to test fuel pressure needs at least 60 psi or better Under load to pull decent run a temp line into the cab with 1/4 plastic line! also have some one check the ambient air temp sensor if its running an odd number the computer may be being duped into thinking there isint enough air to burn the fuel properly!so its holding back! Edited April 26, 2017 by fjh Quote Link to comment Share on other sites More sharing options...
Dirtymilkman Posted April 28, 2017 Share Posted April 28, 2017 When you pressure test, pressurize it to 40 psi and shut air off. It shouldn't lose any pressure. Spray soapy water all over to find leaks. Quote Link to comment Share on other sites More sharing options...
07cl733 Posted April 29, 2017 Author Share Posted April 29, 2017 I may run a fuel pressure gauge into the cab. It certainly could be a worn lift pump. Since it builds enough pressure at idle I have looked elsewhere. I know the drive gears had a tendency to spin on the pump shaft. That doesn't seem likely either, since the problem is so consistent and still has decent power and response. The ambient temp sensor is new. It was causing an error code so I went looking for it and couldn't find it. I traced the wires from the eecu and came up empty. I installed a new sensor and fixed the error. No change in boost and no more codes. It may not hold boost for long, the charge air cooler is old. I've had substantial leaks in other trucks and never lost that much boost. Usually egts go sky high. Thanks for the ideas, I'll keep working on it. Quote Link to comment Share on other sites More sharing options...
99 ch mack Posted February 18, 2020 Share Posted February 18, 2020 Check tube from bottom rear of intake to compressor rubber hoses and tube that force feeds air compressor Quote Link to comment Share on other sites More sharing options...
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