Strange MPS issue, Lew's car Options

[914itis]

I am helping Brian with Lew's car. As most of you may know, it is a 2056 with djet.
The car was running fine, he drive it to CT one day and when he came back he noticed that the MPS was hanging. The car starts to run on 3 cylinders with #4 not firing. We checked for spark and injectors they are all fine, but if you remove spark wire #4, it had no effect.

The strange thing is if you elevate the mps about 6 inches up, it's all fine, even that 4th cyl works. All the electrical wires on the unit are fine

(IMG:style_emoticons/default/confused24.gif) ?

Dies the 2056 uses 1.7 or 2.0 MPS?

He would like to make it to Hershey.

[TheCabinetmaker]

You've had several very knowledgeable people tell you to check your diz,
so why don't you? One thing to rule out.

[achman_73_2.0]

You've had several very knowledgeable people tell you to check your diz,
so why don't you? One thing to rule out.

There clearly seems to be a misunderstanding here.


The initial problem (engine running on 3 cylinders) had nothing to do with the dizzy. Read the thread.


The high idle may ABSOLUTELY have something to do with it.

I have not had any time to go to the garage (I live in NYC, remember, my garage is not connected to my house--it is 15 minutes away) and my work has kept me incredibly busy.

I'm not resistant to checking the dizzy! Sheesh!
(IMG:style_emoticons/default/WTF.gif)

[worn]

You've had several very knowledgeable people tell you to check your diz,
so why don't you? One thing to rule out.

There clearly seems to be a misunderstanding here.


The initial problem (engine running on 3 cylinders) had nothing to do with the dizzy. Read the thread.


The high idle may ABSOLUTELY have something to do with it.

I have not had any time to go to the garage (I live in NYC, remember, my garage is not connected to my house--it is 15 minutes away) and my work has kept me incredibly busy.

I'm not resistant to checking the dizzy! Sheesh!
(IMG:style_emoticons/default/WTF.gif)

Actually the MPS can have an impact on both even if it isn't a prime suspect.

The MPS can make the car go lean. Somewhere during the adjustment of my own 2056 MPS I went way lean and produced an explosion that tore open a previously healthy muffler. I suspect a backfire, cause I heard popping at the time.

Any vacuum leak will cause high idle. The engine will respond to more air by giving more fuel and that will be that. The MPS hose is one of several that go to the manifold downstream of the throttle butterfly. If my idle will not go down the first suspect on my list is a vacuum leak.

When I first got my car it ran horrible all the way from Baltimore to Madison. I ended up stripping down and cleaning the entire induction system. It certainly needed it - the car had sat for almost 20 years. In my case the fuel regulator was stuck shut so the injectors were seeing 90 psi pump pressure. A bit, uhmm rich. The car ran for several years quite well even though I ultimately discovered the diaphragm in the MPS was cracked. Thank heavens for Racer Chris. (IMG:style_emoticons/default/pray.gif)

[achman_73_2.0]

You've had several very knowledgeable people tell you to check your diz,
so why don't you? One thing to rule out.

There clearly seems to be a misunderstanding here.


The initial problem (engine running on 3 cylinders) had nothing to do with the dizzy. Read the thread.


The high idle may ABSOLUTELY have something to do with it.

I have not had any time to go to the garage (I live in NYC, remember, my garage is not connected to my house--it is 15 minutes away) and my work has kept me incredibly busy.

I'm not resistant to checking the dizzy! Sheesh!
(IMG:style_emoticons/default/WTF.gif)

Actually the MPS can have an impact on both even if it isn't a prime suspect.

The MPS can make the car go lean. Somewhere during the adjustment of my own 2056 MPS I went way lean and produced an explosion that tore open a previously healthy muffler. I suspect a backfire, cause I heard popping at the time.

Any vacuum leak will cause high idle. The engine will respond to more air by giving more fuel and that will be that. The MPS hose is one of several that go to the manifold downstream of the throttle butterfly. If my idle will not go down the first suspect on my list is a vacuum leak.

When I first got my car it ran horrible all the way from Baltimore to Madison. I ended up stripping down and cleaning the entire induction system. It certainly needed it - the car had sat for almost 20 years. In my case the fuel regulator was stuck shut so the injectors were seeing 90 psi pump pressure. A bit, uhmm rich. The car ran for several years quite well even though I ultimately discovered the diaphragm in the MPS was cracked. Thank heavens for Racer Chris. (IMG:style_emoticons/default/pray.gif)

Thanks for all the great tips and info.

This car has a pretty newly rebuilt 2056 from SchantzMD that runs very strongly. I am not sure how much of the wiring was replaced, or if the dizzy was rebuilt, I will try to look at the papers.

The MPS is an 037 that was rebuilt by FI corp. So who knows if the calibration is correct anyway...