71 Type 3 f.i. loping

[whc03grady]

I'm starting to feel bad for hogging so much time/advice here, yet still having issues.

When in gear the car "lopes", for lack of a better term. With even pedal pressure, the rpms die off dramatically, but come right back up, and again, and again, and again, very regular-like. It's not as severe without a load.

MPS has been switched out, to no avail. I've got the TVS apart now, and am worried that that was a mistake.

Any thoughts?

[Amskeptic]

I'm starting to feel bad for hogging so much time/advice here, yet still having issues.

When in gear the car "lopes", for lack of a better term. With even pedal pressure, the rpms die off dramatically, but come right back up, and again, and again, and again, very regular-like. It's not as severe without a load.

MPS has been switched out, to no avail. I've got the TVS apart now, and am worried that that was a mistake.

Any thoughts?

With D-Jet FI, loping is often rich running, which is what this system does with vacuum leaks. Vacuum leaks can crop up at any instant, injector o-rings if yours or not new, intake manifold gaskets, vacuum hoses splitting length-wise at the nipple, etc.
Sorry to hear you are having issues. I miss my little Squareback.
Colin

[whc03grady]

vacuum leaks

How are they detected if they're not obvious? Carb cleaner?
The injector rings are not yet two years old (June 2009).

Also, wouldn't a vacuum leak cause a bad idling condition as well? Everything's pretty smooth when the car's just sitting there. I probably misled when I said, "It's not as severe without a load"; I don't think it's there at all without a load. The idle is a little nomadic (wandering between 850-900 rpms) in neutral, but it doesn't act the same, if you catch my drift. It doesn't fall off a cliff, recover, fall off a cliff, recover, ad nauseum like it does when it's being driven.

I should do a video.

[Amskeptic]

wouldn't a vacuum leak cause a bad idling condition as well?

Not with D-Jet, especially when cold. Engines like more fuel when idling and cold, and a D-Jet leak will make the engine happy . . . until it is fully warm and the richness finally chokes it.

Your engine is leaving factory parameters for some reason under acceleration. The ECU is going into caniptions trying to follow the sensors and throttle switch and MAP sensor around. Do you have a vacuum gauge?
Colin

[whc03grady]

Do you have a vacuum gauge?

I do now:

http://www.youtube.com/watch?v=iAMUpq9KF3c

According to the manual that came with the gauge, this condition indicates that the carburetor (or, presumably, f.i.) needs adjustment.

[whc03grady]

So all the spark plugs've been replaced. My fuel pressure gauge only goes up to 15psi, but it pegged it pretty quick. Point gap gapped within spec, timed, though that was difficult because I adjusted the idle in order to do the timing properly, and now the idle won't sit still. I'm going backward here.

Thinking fond thoughts of our 1995 Subaru,
whc03grady.

[Amskeptic]

Do you have a vacuum gauge?

I do now:

http://www.youtube.com/watch?v=iAMUpq9KF3c

According to the manual that came with the gauge, this condition indicates that the carburetor (or, presumably, f.i.) needs adjustment.

You cannot swap the MAP sensor vacuum supply for your vacuum gauge take off. Your engine went to full-throttle rich the second that the MAP lost its vacuum. You can tee to that connection.
That is like unplugging the AFM in the bus.
Colin

[whc03grady]

You can tee to that connection.

Okay, round two, line teed:
http://www.youtube.com/watch?v=TKRbd8v__0U

[Amskeptic]

You can tee to that connection.

Okay, round two, line teed:
http://www.youtube.com/watch?v=TKRbd8v__0U

Please give us a written report as well. I couldn't read the gauge through this pixelated medium, the idle sounded pretty good through my headphones, but what is the current state of running with gauge numbers? Was I correct that the gauge did very little movement from the "0" area? Might you have some dreadful vacuum leak that you cannot track down, like at the auxiliary air regulator/hoses?
Colin

[Bleyseng]

At idle you had about 12-13 in of vac, right? A little low but usually loping at idle is a vac leak somewhere!

[whc03grady]

At idle you had about 12-13 in of vac, right? A little low but usually loping at idle is a vac leak somewhere!

Ah, but it doesn't lope at idle--it idles just fine. In fact, I can't seem to replicate the problem in the garage; what you see in the video is not indicative at all of what happens when the car is in gear, moving (that is, trying to move) down the road.

I'll post again with the details Colin was asking for.

[whc03grady]

Please give us a written report as well. I couldn't read the gauge through this pixelated medium, the idle sounded pretty good through my headphones, but what is the current state of running with gauge numbers? Was I correct that the gauge did very little movement from the "0" area? Might you have some dreadful vacuum leak that you cannot track down, like at the auxiliary air regulator/hoses?
Colin

The needle spends most of its time around 13-14 with journeys into the upper teens when I rev it up.
Like I said, the loping only really happens under load; I can't get it to do it in the garage.
This one is in focus:
http://www.youtube.com/watch?v=Uyc16r9I5bo

Here's the car going down the road (best I could do):
http://www.youtube.com/watch?v=QuwC6V6Ol5g

Is a stuck valve a possibility?

[Amskeptic]

Please give us a written report as well. I couldn't read the gauge through this pixelated medium, the idle sounded pretty good through my headphones, but what is the current state of running with gauge numbers? Was I correct that the gauge did very little movement from the "0" area? Might you have some dreadful vacuum leak that you cannot track down, like at the auxiliary air regulator/hoses?
Colin

The needle spends most of its time around 13-14 with journeys into the upper teens when I rev it up.
Like I said, the loping only really happens under load; I can't get it to do it in the garage.
This one is in focus:
http://www.youtube.com/watch?v=Uyc16r9I5bo

Here's the car going down the road (best I could do):
http://www.youtube.com/watch?v=QuwC6V6Ol5g

Is a stuck valve a possibility?

If it idles OK, then a stuck valve is not an issue.
The engine is leaving ECU fuel map. Do we have known compatability between the ECU # and the manifold sensor #? Does your ECU have a mixture adjusting screw on its case?
Colin

[Bleyseng]

Looks more like a electrical spark issue with missing as it won't fire under load. Leaning out as you rev up usually is a missing thats constant.

[whc03grady]

The MPS and ECU are both Es. In any case, they'd been a perfectly competent team for thousands of miles when this issue suddenly arose. I will look at the brain for a screw, but I don't remember seeing one last time I looked at it.

I should say that it doesn't feel like missing to me. What it feels like, exactly, is running out of gas. But the car doesn't die, it just dies off (and comes back), if you catch my meaning. The spark plugs have all been replaced.