96bulldogpower

Replace fuse and try again. If it blows the new fuse then check wiring very closely to make sure the compressor clutch engagement wire is not shorting out somewhere intermittently with vibration. If wiring is good then perhaps the clutch is faulty. We had to run new wire from the a/c switch to the dashboard because we were never able to find the short. Ours was a 05’ CX, the new wiring fixed our issue.

Hey guys! I recently acquired a new-to-me truck to add to our growing fleet. The truck is a 2008 mack CHU.. truck is great and everything but as with all CH’s, the headlights really suck. We have 4 CH models in our small fleet among other model trucks. We’ve tried everything from 100watt bulbs to HID and LED ballast bulbs Nothing will make the halogen housings produce great light on these trucks even after replacing housings with new ones. Ive seen the new 2018-19 pinnacle set-forward-axle trucks that are coming from the factory with LED heads and turn signals, the shape and relative design is nearly the same as all the older trucks but with the added benefit of great visibility and lighting performance. So i got to thinking, what would the cost of purchasing these headlight and turn signals cost from Mack? I can re-use my factory bezels, and if there are mounting differences, they would be simple to remedy. Any input is appreciated!

By the way... I have the engine’s existing EECU at a ecu repair shop here local to me in Dallas, TX. They seem profesional.. I’ll let you guys know if it works! They claim the ecu will retain the factory data so that I wont have to take the truck to Mack to have it reflashed. They will save me a cool buck if it is successful.

I was able to finally pull the valve covers off yesterday and found all of the intake pushrods were bent. The truck has engine brake but the exhaust side pushrods with the spring on them were fine not bent at all. I bought six new pushrods from Mack and installed them this morning, i cranked the truck up still using my other truck’s eecu, and it runs much better now. However there is a very loud “thud” noise still present... the sound is reminiscent of one of my other trucks years ago when it wiped a couple cam lobes. I’m almost certain this truck has a bad cam or failed lifters. When I reinstalled the rocker shaft assemblies with the new pushrods i noticed that at least on two exhaust side rockers there was so much rocker play that the pushrods could nearly come off the socket on the rocker. I ran out of time to work on the truck today but I guess the next step is to remove the oil pan and begin taking apart the front of the engine to pull the cam. I’m not very excited about this job at all, the last time we did an in house cam job parts alone cost us over $2000.

Okay NEWS! I swapped VECU from my 04 and nothing happened, then I swap the EECU and it started!! Then I plugged the original VECU and it still worked. Even the transmission works just fine! This means the truck’s original EECU is burned out! Now I’m going to start looking for a used EECU and hope that my Mack dealer will program it to my VIN. On another note, I thought I’d be happy to hear the engine running... unfortunately now that it runs, it revealed another issue, there’s a sound coming from the engine exactly like when our other truck wiped a cam lobe It sounds like a loud thud coming from one cylinder Although the engine doesn’t really shake as badly as our other truck when it wiped a lobe, and idle isfaily smooth with exception of the thud noise. The engine also blows a medium amount of black smoke when you press the accelerator.. I ran out of time today to mess with it, so I’ll get back to working on it this weekend hopefully, I’ll first remove the valve cover to see what’s going on. Any ideas?

Perfect! Sounds like a long shot but I’m willing to try anything to get this thing working! Tomorrow I’ll go ahead and swap ecu’s around while my 04 is at the yard. Hopefully it does the trick! And yes, I did check every relevant connector I could find, they all looked clean and dry. ill report back with what I find out by swapping out ecu’s first thing tomorrow!

Unfortunately I do not have a tech tool to scan the truck, I’m doing my best with what i have. QUESTION.. I have a 2004 cxn613 with the same AC motor, but this one is manual as opposed to the truck with the problem which has Allison automatic.... if i pulled the eecu and vecu from the 2004 and put them on the problem truck, would that work to help me rule out ecm failure? Or would t not even start because it has a different transmission?

I’ll call my Mack dealer in the morning and see if they can diagnose computers on their bench, if that’s the case then I’ll pull them out and take them to the dealer to see what they have to say. I’ll report back as soon as I get an update!

Okay.. well I tested the resistance on the wires today. I had 60 ohms on the abs plug I disconnected. Then I reconnected it and tested both ways from the bulkhead connector at the firewall, I have 120 ohms both ways. I looked all over the harness coming down from the cab and even in between the frame rail and could not locate the three wire plug I did however find a two wire green and yellow connector (had black paint over the wires) but it had a cap at the end of the connector, I found this near the top of the transmission on the driver side frame rail. I believe what I found was a terminating resistor. Here’s a picture: I disconnected the batteries but the truck still has a blink code of 6-3, it turns over fine but refuses to start. could this really mean I have a bad ecm? If so, how would I go about finding out which one it is that’s bad?

Thank you SO much for these tips! I need to go out and buy a new multimeter tomorrow, I will report my findings as soon as I see what’s going on, thanks again!

Still not luck guys, I talked to my Mack dealership to see if they could help, their response was to purchase all new EECU, vecu, and vmack modules which totaled out to a crazy amount of money for something that may or may not fix the issue. I have blink code 6-3 and engine cranks over fine but won’t start, I’m stuck. Any help would be appreciated.

I still can’t get the truck to start, the oil and rpm gauges don’t even move when turning over. Any ideas guys?

I no longer have blink code 6-4. Now i have blink code 6-3. 6-3 is the only blink code in the system.

Not fixed yet, still trying to get the truck to start. So now that I have power to everything, I realize that the j1939 communications are still not working. The tachometer and the oil pressure gauge do not register anything while the truck runs on ether, the truck will not stay running on its own. This tells me that both the H and L wire (yellow and green wire) on the j1939 are not communicating. I cannot figure out why. I tested continuity inside and outside of the cab and verified the wires and connectors are in good condition. Does anyone have any tips on where to look next?

Update: found cause of no power to EECU, there were several damaged pins on the bulkhead connector at the firewall. Fuse #49 and abs now have power. Abs completes the test cycle “click” with key on run position. I tested power to the EJ2 connector at the EECU and there is now power to the EECU after repairing the damaged pins on the bulkhead connector. Everything is now live, abs, vecu, and EECU. Unfortunately I’m still not able to start the engine. I’m about to go get ether to try and carefully convince it to start, it has plenty of fuel in the tanks and filters are full of fuel.

Update, I checked power at the EECU, no power to any of the pins, there’s is also no power to fuse #49 under the hood fuse panel. In that fuse panel there is power to all other fuses except for #49 which powers ignition and abs, I believe that would explain why abs does not cycle its self test when you put the key in the run position. Inside the cab I have power to all power relays and vecu fuses.

Hey guys, we just acquired another truck in our fleet however we got this one as a last minute deal as a known non-runner. We had the truck towed to our shop where we began looking through it to see what was wrong. A little about the truck, this is a rare combination because it has a Mack AC engine and a Allison hd4560 behind it, it is a 2005 CHN613. When we got it we found that it would not crank, it was determined that the transmission power fuse was burned out, we replaced the 15 amp mini fuse and the keypad shifter lit up which also allowed the truck ignition to function again to crank the truck. Now that the truck cranks over, it cranks Over just fine. It has fuel but will still not start. There is a 6-4 blink code for “J1939 communication”. Fuse #49 on the epdm does NOT have current which I understand supplies the engine ecm and abs controller with power. The abs controller also does not do its start up test where it “clicks” when you first put the key in the run position to start the truck. I’m looking for help! I have run into a road block with this truck and I know the fix can’t be too hard, just difficult to find. The truck only has 250,000 miles, it can’t be that bad!

Hey guys! I have a question for those familiar with the Mack AC engines.. I have a 2004 Mack vision with the AC 427 and I’m having trouble with the engine going into de-rate as soon as it enters boost. This happens at any speed while the engine is at higher rpm and producing boost, engine already feels sluggish but when it de-rates it falls flat on its face. The lighting bolt comes on the dash when it de-rates however you can take your foot off the accelerator and let the boost come down and it makes the lighting bolt light turn off and de-rate cancels, until you get back on the pedal and builds back boost, then the cycle repeats itself. This truck has the co-pilot display and it shows me (MID 128, SID 269, FMI 7). When loaded the truck can barely sustain its own speed and on hills where it builds boost I can lose speed down to 35mph. I’m getting good boost up to about 37 psi. The turbo relief valve is good and the turbo vane actuator is cycling and doing its job. Egr valve seems to cycle and perform correctly as well. No smoke of any kind out of the exhaust pipe ever, even if you lug the engine.. you just never get smoke out of it. I just got off the phone with Mack but their shop is way too behind to even consider taking my truck off the road! Help guys! Thanks in advance!

I just got under the truck and had the driver flip through the shifter, it looks like it is functioning 100% correctly

With the shifter? But this is an older mechanical, cable operated transmission, the only thing electronic is the modulator. I'm not sure if that is what you meant, but the shifter has already been adjusted without a change in performance.

Hello guys! It's been a while since I've posted but I came back to my old friends for some help. A few years ago we completed an Allison HT740 swap into a 1991 Mack Ch613 that was equipped with a 9-speed originally. This is a dump truck, originally this was only supposed to be an experiment to see how we would like an automatic, but we have had such a great experience running this truck that it grew on us quickly. Now for the problem, two days ago the driver reported that the truck would no longer go above about 15 miles per hour. Upon a test drive I have concluded that the transmission will (manually selected on the shifter) go into first and second speed but will remain in second speed when shifter to third on the shifter. That transmission refuses to go into third and fourth now. While I drove the truck I played with the shifter until I got it to go into third at which point I began to slow down and I noticed that once in third speed the truck began to buck and jerk (I was coming to a stop) and it almost stalled the engine right before I tossed the shifter in neutral. I was not able to replicate third speed again and will only go in 1st and 2nd. It is worth noting that sometimes the truck will not want to shift into reverse unless you play with the shifter back and forth until it "grabs", also the back up alarm and back up lights do not come on until the transmission does finally fall into reverse. I have adjusted the shifter cable but it did not appear to be the issue to begin with. Please help guys I need to find a fix for this truck quick. i will trailer this truck from the job site to my shop this weekend and i already want to start brainstorming what to look for.

Brutus, what kind of 4 speed aux did he use? How much overdrive did it have? Anyone have any info on an atr box?? I've never heard of them

Well the whole intention is to have overdrive in order to gain more speed than the truck I already did the swap on. I have another 1996 CH613 that I plan to use for the swap. All of our trucks have 4.17 gear ratio and run tall 11r24.5 rubber. The one that currently has an ht740 only speeds up to 58 MPH. If it had atleast a .75 overdrive I'd be happy. What other transmission would be recommended for the swap? I understand all 6 speeds will be electronic. Oh by the way, the hd4560 I can get my hands on will come out of a 2002 Mack MR688 with E-7 etech. They seem to be durable.

Ok guys, I've had tons of help and support from y'all in the past and as some of y'all may already know... I do EVERY form of truck repair in-house for our small business. A few months ago we did an allison HT740 4 speed automatic swap in a 1991 e-7 CH613 that had a 9 speed Mack trans... The operation and all wiring was a success, the truck has been working ever since and we have noticed at our family owned dump truck business that this setup has given us great results not only in maintenance but in driver comfort as well! Now we're ready to tackle another swap! I'm looking at an HD4560 because it is 6 speed with double over drive and a low first gear. I know it is VERY electronic and requires a control module but we are comfortable taking on the challenge. What do y'all think about the swap? What are the biggest problems I would encounter? Anyone have any wiring diagrams to this trans?

Theakerstwo... Just the type of reply I wanted, I understand there are reasons why I should send my turbo off to the qualified professionals that reman turbos for a living. I also understand that I have never popped one of these open and it would be a learning experience. You're never too old to learn new stuff! Lol. I will consider your advice and tread lightly as I continue with the repair. If I spot anything out of the norm I will just call it all off and buy a reman unit from my supplier. I like coming back here for knowledge from you guys because y'all tell it like it is! Yeah yeah to be honest I have never messed with an e6!! Lol!