MVision

I have an 01 CX 427 that is sluggish down low as well. Have tried a few things with mixed results. Did 100 HP tune on ecm first. It did make a diff down low but was like throttle was way to sensitive to control at lower RPM. Then added Rochester stage 2 injectors and performance turbo. That made the biggest diff but caused problems under hard pull. Malfunction light would come on and would cut power intermittently until the pull was over. This turned out to be a erroneous timing signal due to excessive crank twisting. So I reflashed Ecm back to stock and solved that. Truck still pulls way better than stock and not as sluggish down low but still not a low end grunter like a cat. I'm thinking next step is cam advance and higher capacity radiator. If I had your model I would seriously consider deleting the egr and then going with the injectors and turbo like I have. My truck pulls very well for a 12 liter and has averaged 7.3 mpg for the last 2 quarters. I have a 13 SPD and have found that shifting up at 16 to 1650 gives me the best performance. That drops me back around 14 and it will pick right back up and go.

Thanks Refined Trucker. Good to hear real world experience.

Since your from Illinois also, who did you get to do the ECM flash? And can they delete the egr? Deleting a mack egr seems like a top secret mission that no one is allowed to talk about. There is info on how delete other engine manufacturers egr all over the internet. Hundreds of vendors offering the service. When I call some of those vendors and ask if they do Mack's I usually get shot down. What are some options?

Will a Rochester turbo even fit on my engine? What do I do with all the variable turbo stuff? Can I remove it without tripping a lightening bolt on the dash?

I've got a 2004 Vision with the 427. Has no power below 1400 rpm. It kicks in at 1400 and pulls great.Been reading on here and it seems to be typical for this engine.

Truck has a recent inframe. New injectors. Had Mack update software including the step 12 b upgrade that has been mentioned on here. Still is sluggish on the low end.

I talked to Rochester about their injectors. Says they will give me more power. From talking to them I'm just not sure if they would improve the low end. Don't really need more power on the top end. Also asked about their turbos. Said they can't do anything with the variable rate turbos. I would love to hang a big non variable turbo on this engine.

So I guess I'm asking if I have any options to fix the lack of low end?

Injectors?

Turbo?

Aftermarket ECM tuning/power boxes?

A mechanical issue that can be repaired?

Other?

Thanks in advance. The wealth of information on this site is amazing.

2004 Vision with the 427. Radiator sprung a leak. Trying to get it out for the repair. It appears that I have to remove the brackets on the frame that hold up the hood to get this thing out. Which means removing the hood. Am I missing something? Is there an easier way?

2004 Vision.

No matter what position the knob is in air only comes out the dash vents. The temp control and fan control work fine. I'm assuming a switch or blend door problem of some sort. What's the best way to diagnose this? If it is a blend door type issue, what is the least intrusive way in to the blend door?

Done a blend door on a pickup that required removing a lot of the dash....not fun. Probably didn't need those left over screws anyway. Lol.

Thanks in advance.

Wouldn't I hear some popping or something like that on the intake side of things if it was a cam?

Hi fellas!

I have a 2004 Vision with the 427 and 570,000 miles. The engine has developed a lope/miss. It seems to do it throughout the rpm range, but is most noticeable around 800-1200 rpms.

I suspect a bad injector. There are currently no blink codes. My low tech analysis of feeling the injector lines for a "heartbeat" suggests that injector #3 is misbehaving. I am going to put a infrared heat gun on the exhaust manifolds when I start it this morning to see if that shows me anything. The truck doesn't seem down on power. I haven't owned this truck very long and I have no history on it. Mack shop wasn't real helpful in that regard. So, I have no idea what kind of miles are on the current injectors.

I have searched the forums and it seems a lot of the posts pertaining to injectors are for older trucks. Wasn't sure how relevant those posts would be to my situation.

With that in mind...

A few questions:

1) is there anything else that could be causing the engine to lope/miss?

2) If I have to go in to change an injector should I just do them all while I'm there?

3) would this be the time to put in larger injectors? Can this be done without doing the turbo and an ECM upgrade?

4) does changing the injectors require any special tools? Any tips or tricks that I should know about?

Also, I'm in the St. Louis/metro east IL area. Does anybody know if there are any independent shops that work on Macks and do it well?

I know that is a lot of questions. So, thanks in advance for any help!

Thanks turckster and Mackpro68! While I had it apart I just went ahead and put the new sensor in since I already had it. Spaced it according to turckster's specs. Works great and no lightening bolt. Thanks again fellas!

2004 Vision with 427. 560,000 miles. Been getting an intermittent 3-4 blink code the last several days, but today it came on and stayed on. Picked up a new engine position sensor today at the Mack shop. What tips and tricks do I need to know to install this sensor? I know there are shims involved. Any info would sure be appreciated. Thanks.

Thanks for the welcome. Going to be pulling a hopper and a dump trailer. Also, may pull an RGN once in awhile.

I hope you got it cheap,'04 was a terrible year, especially for Visions. Good luck,hopefully you found one of the good ones.