2056 MPS Rebuild Options

[OGmikey914]

I have a Raby 2056 with a dead MPS. We pulled it off and tested it and it doesn't hold a vacuum, but the car seems to run fine other than idling a little high. It doesn't have a 73 MPS, it has an 043 which I understand calibration can be a bit tricky with. If I just rebuild the unit, will it need to be re calibrated?

I am trying to get it done before WCR, so a little short on time, but any ideas/help?

[914Sixer]

Send it to Jeff Bowlsby.

[Mblizzard]

If you have an AFR you should be able to tune it pretty close. If you need instructions on adjusting pm me your email. Can be a time consuming process but doable.

If you really get stuck let me know I have a MPS set for a 2056 you can borrow.

[OGmikey914]

Unfortunately I work most days 7-7 or later so I won't have much time until this weekend to tinker with it so I may just have to run it as is. Put the current MPS that is not holding vacuum back for now, and I drove it on a couple 30 min quick trips this weekend and seemed to run fine once it warmed up. Was able to adjust the idle down to get it closer to normal as well

[Mblizzard]

Unfortunately I work most days 7-7 or later so I won't have much time until this weekend to tinker with it so I may just have to run it as is. Put the current MPS that is not holding vacuum back for now, and I drove it on a couple 30 min quick trips this weekend and seemed to run fine once it warmed up. Was able to adjust the idle down to get it closer to normal as well

As long as you are running rich I think it will be OK. But I don't think that you can expect the leaking one to remain constant. Meaning that it will likely get worse and leave you stranded at some point.

[ConeDodger]

Didn’t Chris Foley make a rebuild kit for these?

[BeatNavy]

Didn’t Chris Foley make a rebuild kit for these?

Yes he does. It's a good product and pretty straightforward process.

If your MPS is not holding a vacuum it's not really going to run "fine" when warmed up. It's still going to be rich to very rich, depending how badly it leaks.

As mentioned, you can send it to Jeff Bowlsby. I also have one you could borrow while it's out for service, but Mike (mblizzard) has also offered one.

[914_teener]

Didn’t Chris Foley make a rebuild kit for these?

Yes he does. It's a good product and pretty straightforward process.

If your MPS is not holding a vacuum it's not really going to run "fine" when warmed up. It's still going to be rich to very rich, depending how badly it leaks.

As mentioned, you can send it to Jeff Bowlsby. I also have one you could borrow while it's out for service, but Mike (mblizzard) has also offered one.

They fail just like this by cracking partly and seem to run fine until they fail completly and will leave you stranded in a busy intersection.

Get Foleys kit and have Jeff calibrate it close.

[OGmikey914]

Sounds good!

I took it out again last night and it was running a little rich now that you mention it.

Thank you for all the help, I will order a rebuild kit, but if someone has one I could swap and borrow for the rally that would be awesome!

Hoping I can get the kit in time (IMG:style_emoticons/default/type.gif)

[BeatNavy]

Sounds good!

I took it out again last night and it was running a little rich now that you mention it.

Thank you for all the help, I will order a rebuild kit, but if someone has one I could swap and borrow for the rally that would be awesome!

Hoping I can get the kit in time (IMG:style_emoticons/default/type.gif)

Send me a PM with your address, and I'll try to get one mailed out to you this week. I have an 043 that's been tuned slightly richer than stock 2.0. My 2056 has the stock cam, so it doesn't need a big boost, but this should keep your running fine.

[Mblizzard]

Sounds good!

I took it out again last night and it was running a little rich now that you mention it.

Thank you for all the help, I will order a rebuild kit, but if someone has one I could swap and borrow for the rally that would be awesome!

Hoping I can get the kit in time (IMG:style_emoticons/default/type.gif)

Send me a PM with your address, and I'll try to get one mailed out to you this week. I have an 043 that's been tuned slightly richer than stock 2.0. My 2056 has the stock cam, so it doesn't need a big boost, but this should keep your running fine.

It is really awesome to have an issue and find so much support here.

[OGmikey914]

Sounds good!

I took it out again last night and it was running a little rich now that you mention it.

Thank you for all the help, I will order a rebuild kit, but if someone has one I could swap and borrow for the rally that would be awesome!

Hoping I can get the kit in time (IMG:style_emoticons/default/type.gif)

Send me a PM with your address, and I'll try to get one mailed out to you this week. I have an 043 that's been tuned slightly richer than stock 2.0. My 2056 has the stock cam, so it doesn't need a big boost, but this should keep your running fine.

It is really awesome to have an issue and find so much support here.

Agreed! You guys are awesome and thanks a ton for the help!

[OGmikey914]

So I had a few minutes after work today to swap out the MPs. It seemed to normalize the idle but was running really rich. How do I adjust this bad boy?

[BeatNavy]

So I had a few minutes after work today to swap out the MPs. It seemed to normalize the idle but was running really rich. How do I adjust this bad boy?

Hmmm....it shouldn't be running excessively rich with an MPS that holds a vacuum and is generally tuned to 2.0/2056 specs. Why do you think it's rich, and is that at idle or through the whole range.

Here's the MPS adjustment theory / process: https://members.rennlist.com/pbanders/manif...sure_sensor.htm

But it could be other things, like fuel pressure or leaking injector(s).

[Mblizzard]

 FI_Troubleshooting_Guide.pdf ( 3.22mb ) Number of downloads: 155


Might start with the checks starting on Page 48 and 62 before adjusting the MPS.

You have to have a special tool to adjust the MPS. Do you have it?

[ChrisFoley]

You have to have a special tool to adjust the MPS. Do you have it?

And the MPS has to be modified to accept the special tool.

[Mblizzard]

You have to have a special tool to adjust the MPS. Do you have it?

And the MPS has to be modified to accept the special tool.

Chris's special tool! Don't lose it. (IMG:style_emoticons/default/headbang.gif)

And don't try to adjust without it. It just does not work!

[Mblizzard]

Almost forgot! Check your intake box for cracks. Mine was cracked and lowered the pressure which made it run rich.

[BeatNavy]

He's actually got a spare 043 that I sent him to get him running until he can repair his or source another. Mine was repaired with your kit, Chris. He doesn't have the tools (at least I didn't send him those). It was tuned to slightly richer than 2.0 for an 043 using my inductance meter, but who knows the accuracy of it as it's a pretty cheap Chinese knockoff? I did set it very closely to the readings for another 043 I have that was rebuilt professionally.

The MPS could be tuned slightly too rich, but I'd be surprised if that was the sole cause of it being significantly rich. Also, I don't think he has an 02 sensor, so need to know the actual symptoms that would suggest that.

[JeffBowlsby]

All this guessing for a 2056 MPS...on a Raby engine no less...too much risk. Even the several, same PN NOS MPS's I have or have documented are different from each other and the factory never made the 2056 obviously. The only way to responsibly know for sure what is correct for any engine, is to get it on a dyno or an exhaust gas analyzer to verify it is correct for that engines' needs.