Installing MP-8 on 2005 C-7

[Expedition39]

After much reading here and elsewhere, I decided to purchase an MP-8 for my Cat C-7 powered motorhome. As others have mentioned, the instructions leave something to be desired. I believe I have it installed correctly, but would appreciate any confirmation from others that have done the installation.

My MH is a 2006, built in April, 2005. I have the triangular connectors, FWIW.

I found what I believe to be the MAP sensor on the top of the intake manifold, close to the head, and near the front (as installed in the MH) of the intake manifold. I unplugged the harness from the sensor (white, green, and pink wires) and connected the MP-8 harness. I am pretty certain this is correct.

The ICP sensor is a bit more vague. I found a connector (with white, green, and brown wires) about 6 inches to the rear of the MAP sensor, next to the valve cover. This is NOT directly on the sensor, but I believe these wires go to the sensor. I disconnected this connector, and connected the MP-8 harness. Does that sound correct?

I just used the battery disconnect switch to disconnect the batteries, before starting. Not sure if that is good enough- I may have to actually disconnect the battery cables.

After installation, the engine started as normal. I did notice that it did not respond to the accelerator for about 5 seconds. I shut it off, restarted, and had the same effect. Anyone else experience that? I will not be able to drive the MH for a week or two, as I have other projects ongoing.

I would appreciate any comments. Thanks!

Tom
2006 Fleetwood Expedition 39Z
Freightliner XC, Cat C-7, 300 HP

[sandcar361]

Here is the spots I plugged my mp-8 into. Boost and the pulley side of the motor on the intake side.

[rver98]

When you say engine did not respond, was it cold? Have you taken it for a test drive?

[Expedition39]

Sandcar361:
Thanks for posting the pics. Things look a bit different, but, as best as I can tell, those are the connectors I hooked to.

Rver98:
When I pressed the throttle, the engine did not speed up. After running about 5 seconds, the engine would speed up as normal. The engine was just slightly warm- it had been run a few hours before. Now, I have only driven this MH about 65,000 miles, my memory is not great, I haven't driven the MH for a month, and I am undoubtedly being hypersensitive, but I don't remember this lag before. Probably not a problem.

I won't be driving the MH for a week or more- I have two windows removed for repair (fogged), and I am installing boost and EGR gauges. I will post the outcome, once I have a chance to drive it.

Thanks!

Tom

[rver98]

Tom,
You should not have much lag at all with the MP-8. Have you checked your intercooler tubes to make sure they are tight? I hope everything works out well. Keep us posted

[Craig P.]

Tom,

You may have to manually disconnect the battery cables to reset the ECM. The battery switch didn't work for me. I didn't notice any change in performance until I disconnected the engine batteries.

Craig

[Expedition39]

I finally got everything buttoned up and took a 20 mile test drive. I did disconnect the battery cables to reset the ECM. The test drive was on mostly flat roads, and I wasn't able to pull my toad, so I wasn't heavily loaded. I installed the MP-8 controller on the dash, right next to my new pyrometer and boost gauge. I started out with the control full counter-clockwise. I then turned the control up to the halfway point. Starting out from a stop, I felt a very noticeable increase in power. I can't wait to take a longer trip! I will be pulling a 10,000 lb trailer from IN to AZ in October, so that will be a good test.

My pyrometer (post turbo) reached a max of about 875 degrees- this was under full throttle acceleration up a small hill. Boost gauge showed a max of about 26 lbs, under the same conditions. The lack of throttle response I noted previously, seems to be gone, since disconnecting the batteries to reset the ECM.

I am glad that all seems to be working well. After taking a trip or two, I may install an Aero muffler. I wanted to get a feel for the MP-8 with the stock muffler first.

Thanks to all that offered advice!

Tom

[sandcar361]

Tom,

Good to hear. When I installed the Aero muffler I noticed that from a dead stop when you stepped on the gas the engine boost came up real fast. Let us know if you install one.

Daniel

[rver98]

Quote:

Originally Posted by Expedition39 I finally got everything buttoned up and took a 20 mile test drive. I did disconnect the battery cables to reset the ECM. The test drive was on mostly flat roads, and I wasn't able to pull my toad, so I wasn't heavily loaded. I installed the MP-8 controller on the dash, right next to my new pyrometer and boost gauge. I started out with the control full counter-clockwise. I then turned the control up to the halfway point. Starting out from a stop, I felt a very noticeable increase in power. I can't wait to take a longer trip! I will be pulling a 10,000 lb trailer from IN to AZ in October, so that will be a good test. My pyrometer (post turbo) reached a max of about 875 degrees- this was under full throttle acceleration up a small hill. Boost gauge showed a max of about 26 lbs, under the same conditions. The lack of throttle response I noted previously, seems to be gone, since disconnecting the batteries to reset the ECM. I am glad that all seems to be working well. After taking a trip or two, I may install an Aero muffler. I wanted to get a feel for the MP-8 with the stock muffler first. Thanks to all that offered advice! Tom

[lwasouth]

I purchased the MP8 and installed it in February 2011. In March we left on a trip around the country and Alaska, a total of just over 14000 miles. The coach is an 05 Itasca Horizon with a 350 Cat engine. The vehicle computer stated that the previous total accumulated miles of 16800 were at an overall MPG of 6.1. On this trip we averaged around 8.3 daily , which raised the overall average ( with now 30800 Miles) on the vehicle to 7.2. The vehicle computer is amazingly accurate, we hand calculated mileage several times on actual fuel usage and it exactly matched the computer. I wasn't totally sold when I purchased the MP8. Thought you might want to know that the claims on the MP8 are accurate. I ran it at the half way position on the entire trip.

[morrisrc]

The MP-8 folks have wiring errors in their harness!!
Call their tech support. I just went thru trying to get my MP-8 working and it kept putting the C-7 into derate with a check engine light.

After fixing wiring error, it now runs fine.

Rudy

[lwasouth]

I have had the MP8 installed and running half way for 14000 miles. Is this wiring problem in all units or only yours - PLEASE ADVISE

[morrisrc]

The wiring problem for the Total Performance MP8 power module started for me, in April. As the summer months rolled on, I went thru 2modules & 3 wiring harnesses before finally getting the situation corrected.

As far as I know it is a recent (last 6 months) kind of problem. If had the problem u would know it, as the module does not work & puts ur engine into derate! I'm guessing it was a new problem introduced when they tried to cost reduce the product by switching suppliers for the wiring harnesses. It is labor intensive & would be the kind of job you would outsource to Mexico or other cheap labor country. My guess is that the wiring problems were introduced when they made a change. Only TP knows all the details.

By now I would imagine they have fixed the problem cause it was severe in that their system would not work.

If yours is several years old and has worked then u don't have a wiring problem. Mine now works fine & I'm pleased with the product, just took too long to get a fix.