Strange MPS issue, Lew's car Options

[r_towle]

You are not looking for water in the plenum, you are looking for oil
Oil may get into that line, caused by high pressure in the valve covers, high pressure in the case, filling the intake plenum with oil that would migrate and get sucked into the mps.

It may drain when you lift it up the six inches...

Or, you may be making the wiring harness happy in one position and not happy in another position.

Try strapping it up high, under the engine lid....drive on the highway and see if it happens.
Rich

[achman_73_2.0]

FIXED!

So I was finally able to go to the garage and look at the car yesterday.

I narrowed it down in my mind to the wiring. Either the wiring of the #4 injector to the MPS, or the #4 injector itself.

I pulled the plug to the injector, and closely examined it.

It seemed intact, until I noticed one of the two wires seemed to not be seated as far into the connector as the other one. I investigated further and found that the metal connector in the plastic connector was broken in half on that wire. The other one was fine.

Thinking this would explain the intermittent miss when we held the MPS up (it made the connection when held up and stressed) I clipped the wire, and soldered another one on the end‎ which already had a connector on it. My patch job is definitely mediocre and not permanent...but I fired it up and it ran perfectly! I let it warm up, then took it around the block...all seemed good, so I took it on a 45 minute drive, and it ran great!

Still idles way too high (around 1800rpm) but at least it runs correctly.

Now, just need to fix the idle, figure out why the fogs stopped working all of a sudden, and try sometime to get the MPS calibrated for the 2056 so it stops pinging under load/full throttle. The octane boost actually seemed to help a bit, but it still pings.

[914itis]

I read your email late last night. That's great need! We can certainly look at the high idle when you have the time .

[Big Len]

Glad to hear it !!

[r_towle]

FIXED!

So I was finally able to go to the garage and look at the car yesterday.

I narrowed it down in my mind to the wiring. Either the wiring of the #4 injector to the MPS, or the #4 injector itself.

I pulled the plug to the injector, and closely examined it.

It seemed intact, until I noticed one of the two wires seemed to not be seated as far into the connector as the other one. I investigated further and found that the metal connector in the plastic connector was broken in half on that wire. The other one was fine.

Thinking this would explain the intermittent miss when we held the MPS up (it made the connection when held up and stressed) I clipped the wire, and soldered another one on the end‎ which already had a connector on it. My patch job is definitely mediocre and not permanent...but I fired it up and it ran perfectly! I let it warm up, then took it around the block...all seemed good, so I took it on a 45 minute drive, and it ran great!

Still idles way too high (around 1800rpm) but at least it runs correctly.

Now, just need to fix the idle, figure out why the fogs stopped working all of a sudden, and try sometime to get the MPS calibrated for the 2056 so it stops pinging under load/full throttle. The octane boost actually seemed to help a bit, but it still pings.

too high of an idle speed and pinging are both signs of timing that may be too advanced.

Sometimes the advance plates stick on the old distributors, so they never let off at idle.

Sometimes the timing is set wrong by the tuner...which may be your situation.

Check your timing...

The MPS will have little to do with pinging...that is all about timing.

rich

[Mblizzard]

Also make sure you are connecting the vacuum correctly. I did it incorrectly and hooked it to the wrong side of the dizzy. I have an advance and a retard on my dizzy. Switch the and you get good idle with them plugged and very high when connected. I think the Cap'n corrected me on this.

Also check that the injectors are seated and that the do not have leaks. Yea I did that too!

Been playing with my MPS to adjust for my 2056. No air meter but I have it so it runs pretty well. I have two MPS's. One that I don't change and one the I adjust and see what changes. Be interested to seem what you come up with.

The oddest thing I have is what seems to be not pinging exactly but valve clatter when I start out slowly. Not there at higher rev or if I give it a good amount of throttle on the start. I think my TPS board is worn as I get a little bit of a slow start at times.

[r_towle]

I have always thought the two MPS bodies of the 1.7 and 2.0 liter are the same.....the only difference was in the calibration and adjustment of the diaphragm? (IMG:style_emoticons/default/WTF.gif)

That looks like a Fuel Injection Corp rebuilt MPS.

My bet is that the MPS came off the mounting bracket and cracked one of the harness wires.

I would check those first.

Harness was checked and is intact.

in the end, it was not intact.

Rich

[worn]

Pretty bummed, but looks like I may be taking the normal car to Hershey. Where can I get a 2056 calibrated MPS?

I went through the recalibration process last summer for my 2056. It is a trial and error process, and I would not attempt it without an air fuel gauge. But now it pulls real strong all the way. I could maybe calibrate one for my engine and send it. I have a webcam though. Not sure how much difference it makes.

There is no way for the MPS to affect the firing of only one cylinder. No way. However, the wiring for the mps, the hoses, the fuel injection, the spark plug wires all conspire to want to be right where the fuel injector wires plug in on the right side. I can easily imagine the MPS dragging one of the FI trigger wires out or out of whack by breaking one. It is a PITA, but the MPS has to be held down. It is like putting your iphone in the engine compartment tied to a string for heavens sake!

I did a lot of inductance graphing and I suspect a 1.7 body can work. Good luck! Let me know if I can help.

[914_teener]

"I did a lot of inductance graphing and I suspect a 1.7 body can work. Good luck! Let me know if I can help."


I'm going to start a thread on this subject. Depends whom you talk to.


Glad you got it going to the OP.......still think you might want to consider replacing the harness and checking the dizzy for correct functioning prior to any MPS recalibration.

Good luck

[achman_73_2.0]

I have always thought the two MPS bodies of the 1.7 and 2.0 liter are the same.....the only difference was in the calibration and adjustment of the diaphragm? (IMG:style_emoticons/default/WTF.gif)

That looks like a Fuel Injection Corp rebuilt MPS.

My bet is that the MPS came off the mounting bracket and cracked one of the harness wires.

I would check those first.

Harness was checked and is intact.

in the end, it was not intact.

Rich

We pulled the FI on the #4 cylinder, and unplugged the coil and tested it by cranking. The FI squirted fuel, so it appeared that the harness was intact.

It was partially intact, as I found out.

I am going to make a better repair on the wire, then try to set the timing, then maybe even attempt to adjust the valves, as I don't know when they were done last. Definitely might have to have some help on the last one.

After doing timing and valves, I will re-evaluate the pinging. If it is still there, I will look into calibrating the 037.

Thanks for everyone's help

(IMG:style_emoticons/default/driving.gif)

[914itis]

I have always thought the two MPS bodies of the 1.7 and 2.0 liter are the same.....the only difference was in the calibration and adjustment of the diaphragm? (IMG:style_emoticons/default/WTF.gif)

That looks like a Fuel Injection Corp rebuilt MPS.

My bet is that the MPS came off the mounting bracket and cracked one of the harness wires.

I would check those first.

Harness was checked and is intact.

in the end, it was not intact.

Rich

We pulled the FI on the #4 cylinder, and unplugged the coil and tested it by cranking. The FI squirted fuel, so it appeared that the harness was intact.

It was partially intact, as I found out.

I am going to make a better repair on the wire, then try to set the timing, then maybe even attempt to adjust the valves, as I don't know when they were done last. Definitely might have to have some help on the last one.

After doing timing and valves, I will re-evaluate the pinging. If it is still there, I will look into calibrating the 037.

Thanks for everyone's help

(IMG:style_emoticons/default/driving.gif)

I will text you later.

[76-914]

set your valves 1st, then time it. good job! (IMG:style_emoticons/default/thumb3d.gif)

[r_towle]

Mps has no impact on pinging or detonation.

[TheCabinetmaker]

"Either the wiring of the #4 injector to the MPS, or the #4 injector itself."

Please explain which wire goes from the injector to the mps? Do you mean the ecu?

[worn]

Also make sure you are connecting the vacuum correctly. I did it incorrectly and hooked it to the wrong side of the dizzy. I have an advance and a retard on my dizzy. Switch the and you get good idle with them plugged and very high when connected. I think the Cap'n corrected me on this.

Also check that the injectors are seated and that the do not have leaks. Yea I did that too!

Been playing with my MPS to adjust for my 2056. No air meter but I have it so it runs pretty well. I have two MPS's. One that I don't change and one the I adjust and see what changes. Be interested to seem what you come up with.

The oddest thing I have is what seems to be not pinging exactly but valve clatter when I start out slowly. Not there at higher rev or if I give it a good amount of throttle on the start. I think my TPS board is worn as I get a little bit of a slow start at times.

The valve clatter also changes as the cylinders heat up, so that may play a role here.

[achman_73_2.0]

"Either the wiring of the #4 injector to the MPS, or the #4 injector itself."

Please explain which wire goes from the injector to the mps? Do you mean the ecu?

Sorry, I mean one of the four wires which is plugged into the MPS through the connector. I really don't know where it leads...I'm not really electrically savvy.

[achman_73_2.0]

Also make sure you are connecting the vacuum correctly. I did it incorrectly and hooked it to the wrong side of the dizzy. I have an advance and a retard on my dizzy. Switch the and you get good idle with them plugged and very high when connected. I think the Cap'n corrected me on this.

Also check that the injectors are seated and that the do not have leaks. Yea I did that too!

Been playing with my MPS to adjust for my 2056. No air meter but I have it so it runs pretty well. I have two MPS's. One that I don't change and one the I adjust and see what changes. Be interested to seem what you come up with.

The oddest thing I have is what seems to be not pinging exactly but valve clatter when I start out slowly. Not there at higher rev or if I give it a good amount of throttle on the start. I think my TPS board is worn as I get a little bit of a slow start at times.

The valve clatter also changes as the cylinders heat up, so that may play a role here.

It's not valve clatter, pretty sure of that. I used to run a turbo Miata, very experienced with the sound of pinging...but on someone else's car, not mine. Mine is living happily in Florida right now, 12psi 245/whp.

I think it is the timing...but I will adjust valves and then set timing as suggested

[914_teener]

When I read the post and suggestions......there are two that suggest checking the distributer first....

Maybe that's not what you read? (IMG:style_emoticons/default/beer3.gif)

[worn]

"Either the wiring of the #4 injector to the MPS, or the #4 injector itself."

Please explain which wire goes from the injector to the mps? Do you mean the ecu?

Sorry, I mean one of the four wires which is plugged into the MPS through the connector. I really don't know where it leads...I'm not really electrically savvy.

The wires go to two coils, one inside the other. So there are 4 ends. All 4 wires go to the ECU aka brain to be used to set the length of injector pulse. It is one really cool analog system for measuring engine load. Incidentally, the plug to the MPS works in either orientation.

[Dave_Darling]

The MPS can affect detonation. An overly-lean mixture will detonate easier than a proper, or overly-rich, one.

As Worn just mentioned, there is no one-to-one correspondence between MPS wires and injector wires. There is just one "signal" produced by the MPS, and it is used as a basis for the injector pulse of all four injectors.

--DD