Surge / Idle Options

[lsintampa]

Well, plenum is out.

I'm too tired and sore to do any more tonight. It's time to start drinking!

Initial inspection of the plenum - it looks fine. What I thought were loose support rods must have been on something else. It was a long time ago - so I may have the parts confused.

In any event, the support tubes do not wiggle.

Interesting, I removed the left side manifold to get to what I needed so the plenum would come out. The middle nut - wasn't a nut on a stud at all. It was a bolt. I don't know how deep the stud hole goes - maybe the bolt was bottoming out and it wasn't sealing well? IDK.

Anyway, tomorrow I'll check the other manifold - see if it has something similar.

Manifold gaskets, injector gaskets - still like new.

BTW - how do I test the plenum (now that it is out) for leaks? Was thinking of putting some light inside and plugging all the holes - see if any light comes out in a dark room.

Is there a proper way????

Thanks,

Len

[r_towle]

Tape up the holes, sink in water.

[lsintampa]

Tape up the holes, sink in water.

Well that worked. What I learned - I'm not that good at taping up holes.

Lucky for me, I left the cold start injector and it's mounting plate on. That's where the leak was. The outer gasket (NLA) was hand made..... poorly I might add. Bubbled up like one of those fake treasure chests in a fish tank.

Anyway, I'm a bit peeved at a) myself for not finding it without going to such an extreme, and b) my motor builder that made the gasket. I never thought to second guess him.

As far as going to the extreme - well at least I can rest easily that my support tubes are in good order. Should I tape them now that I have the plenum out? Seems to me the tape on the bottom side would just melt?

One of the side intakes has a small ding on the lip - so it's a bit out of round. I'll crimp that out - and anyway, I'm putting clamps all around.

I have some honey-do things I need to get done around the house today. So not sure if I'll get some bench time or not.

I'm happy to have found a leak. (IMG:style_emoticons/default/smile.gif) Maybe I can get some good forward motion going on. (IMG:style_emoticons/default/piratenanner.gif)

Not done yet, but I'm on the right path. Thanks Rich!!!! (IMG:style_emoticons/default/cheer.gif)

[r_towle]

If you go look for a leather punch set, Harbor freight has them, it helps in making gaskets....

Rich

[lsintampa]

If you go look for a leather punch set, Harbor freight has them, it helps in making gaskets....

Rich

Was thinking red RTV high temp.

Thoughts about taping the support tube ends? They are solid and did not bubble, it just freaks me out - seems like a weak link in the plenum. IMHO

[r_towle]

I would make a gasket, they should sell gasket kit/ material at the local hardware store, parts store, or hobby shop.

If you are worried about the plenum tubes, clean the paint off the area and seal them up with JBweld, or caulking or whatever makes you happy, then paint it up.

You won't sleep right till you do that, so get it done. (IMG:style_emoticons/default/smile.gif)

[lsintampa]

I would make a gasket, they should sell gasket kit/ material at the local hardware store, parts store, or hobby shop.

If you are worried about the plenum tubes, clean the paint off the area and seal them up with JBweld, or caulking or whatever makes you happy, then paint it up.

You won't sleep right till you do that, so get it done. (IMG:style_emoticons/default/smile.gif)

Made a gasket, and used red high temp RTV on all contact sides for the cold start injector holder.

Plugged / covered the support tube ends with JB.

Waiting for the RTV to setup, then I'm putting the plenum back on. Sort of anxious to see what happens.

This is a picture of the gasket that was on the outside of the CS injector holder.

The water test showed the leak coming from the ends - DUH. The bolts go through and into the plenum. So air worked its way around the threads and out of the plenum (or into when mounted and the car at idle).

[lsintampa]

This is getting to the point of being a bad dream.

That middle "bolt" in the manifold that I found in place of a "stud"... well it came out just fine. But when putting it back on.. guess what? The thing was stripped (inside obviously). No way to get it tight. Builder used some thread glue to hold in it - so taking it out - I had no clue it was stripped. Putting it back however, well that was a different story.

I'll deal with that at some point. I think the manifold is on tight enough not to leak. I got as much on that middle bolt as I can for now. I wanted to see what the results of fixing the cold start injector port leak would be.

The surge is less but still persists.

For grins - with the car at idle, I tried to adjust the TB switch manually. I noticed that turning it full CW or full CCW - the surging got really bad. So what I did was turn it full CCW the slowly turned it CW until the surging either stopped or should I say "got way better". Perhaps not the best way to go about it, but there did seem to be a "sweet spot" - anywhere else the surging was wild.

I don't have a fog machine, but I'm gonna get me a 10 cent cigar to make some smoke and see if I can see where the leak is at.

Maybe it's been the manifold all along?

UGH (IMG:style_emoticons/default/headbang.gif)

[ThePaintedMan]

You can still test for leaks at the manifold first. Start it up without changing anything else. Then proceed with the carb cleaner/propane leak test around the manifold gasket.

If it's leaking, you might have to do a helicoil for that stud... or *might* be able to get a few threads tapped with a metric tap. But it's worth testing for leaks first.

[DRPHIL914]

surging always seems to be one of 2 things - lean running, or vac leaks. typically MSP and CHT failure are at the top of list , and a bad TPS but car should still run even without the tps hooked up , on mine i just found out that a back temp sensor- the one that screws into the top of the plenum right next to the TPS on the back side, can cause these symptons as well. Mine had gone bad and was causing some a lean situation aand resultant bad ilde, surging, and bad issues. i was sure i had an electrical problem the way it would cut out and go up and down. but after replacing the temp sensor, perfect idle. - once you have your manifolds and plenum taken care of, test that temp sensor.

[lsintampa]

At this point - it seems I may be near normal.

I reset the dwell and timing. I'm not sure why timing should be set with the car at or near 3,000 RPM? It's been my experience over the years to set timing at idle.

Thinking about that, it would be next to impossible to do, when at idle, the surging was nuts.

Anyway, with the help from my wife to jack the rpm's up to around 2500 - 3000, I set the timing. Ended up retarding the advance quite a bit from where it was.

That seemed to drop my idle way down to under 900 RPM - and the surging seems to be near gone.

I don't want to say it's resolved - it would be nice to know for sure if the timing may have been another part of the issue. (along with the leaking cold start valve).

I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Anyway, there have been times with I "thought" it was right - just to let it sit for a while and watch it go nuts on me.

Will test again later today. Keeping fingers crossed - that maybe it's settled down?

[lsintampa]

I'm at my wits end.

Every time I think it is back to normal - I'm wrong.

At this point I really don't think I have a air leak. Maybe there is still an issue, but I can't find it.

When cold, the car does just fine, then as the AAR valve begins to close and the idle goes lower - as it should - that's when all the surging starts.

In fact - and for what it's worth - when I first start it and PLUG the AAR valve, it still idles fine (no surging) - so it seems to me the surging is only AFTER the car is hot.

IDK, I'm really close to just living with it. Aside from idle - car runs great.

BTW - the adjustment knob on the ECU - I've yet to notice it making any difference, at total CW or total CCW - the car (idling) just behaves the same.

If anything earth moving happens - I'll follow up. At this point I'm just gonna (IMG:style_emoticons/default/hissyfit.gif)

[ThePaintedMan]

You're still just walking around in the dark until you can isolate entire component systems. You haven't told us whether you've tested for leaks yet or not...

The computer is working against you at this point because somethin ain't right and it's trying to make it right. Once we know for certain there are no leaks, then you can begin to narrow things down. The next step at that point is probably the CHT sender, as others have mentioned. Think about the symptoms - it runs fine till it warms up, right? You need to follow that logic through.

You're a smart dude Len, don't get frustrated. Isolate systems first, and then rule them out. Changing parts and turning dials is not a great way to troubleshoot IMHO.

[r_towle]

At this point - it seems I may be near normal.

I reset the dwell and timing. I'm not sure why timing should be set with the car at or near 3,000 RPM? It's been my experience over the years to set timing at idle.

Thinking about that, it would be next to impossible to do, when at idle, the surging was nuts.

Anyway, with the help from my wife to jack the rpm's up to around 2500 - 3000, I set the timing. Ended up retarding the advance quite a bit from where it was.

That seemed to drop my idle way down to under 900 RPM - and the surging seems to be near gone.

I don't want to say it's resolved - it would be nice to know for sure if the timing may have been another part of the issue. (along with the leaking cold start valve).

I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Anyway, there have been times with I "thought" it was right - just to let it sit for a while and watch it go nuts on me.

Will test again later today. Keeping fingers crossed - that maybe it's settled down?

Timing is set at 3500 rpms to guarantee you are setting the timing with full advance on which at that speed is purely based upon centrifugal force and not vacuum.

Its a unique way of timing, and if you use a zip tie you can easily pull the throttle to the right speed and set the timing accurately.

Now, when you change the timing by ear, or by hand, you WILL screw things up.
So, STOP doing it. its not right and it will certainly create an issue.

Go back, set the timing by the book.
I know you changed it again, so go back and reset it properly.
Then, and only then will things sort out.

1) set Dwell
2) set timing at 3200 rpms steady, not blipped (watch for variation in timing when the rpms are steady, that will define a new issue....if it wont hold steady)
3) turn the ECU knob to full rich
4) set the TPS to the only correct spot it can be set....(again, its not a tuning aid and its not adjustable...stop messing with it)

If you do all of these things, you are now setup properly.

See if that works.
If it is close and idle moves a little bit let me know.
If the timing mark moves while you are watching it with the light at 3200 rpms, let me know.

You need to stop messing with three things at once.
Set them all properly so this can be diagnosed and fixed.

Proper diagnosis involves changing one single parameter at a time, not two or three.

you stated
I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Number one, yup, so set it right
number 2, yup, so set it right.

Rich

[lsintampa]

At this point - it seems I may be near normal.

I reset the dwell and timing. I'm not sure why timing should be set with the car at or near 3,000 RPM? It's been my experience over the years to set timing at idle.

Thinking about that, it would be next to impossible to do, when at idle, the surging was nuts.

Anyway, with the help from my wife to jack the rpm's up to around 2500 - 3000, I set the timing. Ended up retarding the advance quite a bit from where it was.

That seemed to drop my idle way down to under 900 RPM - and the surging seems to be near gone.

I don't want to say it's resolved - it would be nice to know for sure if the timing may have been another part of the issue. (along with the leaking cold start valve).

I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Anyway, there have been times with I "thought" it was right - just to let it sit for a while and watch it go nuts on me.

Will test again later today. Keeping fingers crossed - that maybe it's settled down?

Timing is set at 3500 rpms to guarantee you are setting the timing with full advance on which at that speed is purely based upon centrifugal force and not vacuum.

Its a unique way of timing, and if you use a zip tie you can easily pull the throttle to the right speed and set the timing accurately.

Now, when you change the timing by ear, or by hand, you WILL screw things up.
So, STOP doing it. its not right and it will certainly create an issue.

Go back, set the timing by the book.
I know you changed it again, so go back and reset it properly.
Then, and only then will things sort out.

1) set Dwell
2) set timing at 3200 rpms steady, not blipped (watch for variation in timing when the rpms are steady, that will define a new issue....if it wont hold steady)
3) turn the ECU knob to full rich
4) set the TPS to the only correct spot it can be set....(again, its not a tuning aid and its not adjustable...stop messing with it)

If you do all of these things, you are now setup properly.

See if that works.
If it is close and idle moves a little bit let me know.
If the timing mark moves while you are watching it with the light at 3200 rpms, let me know.

You need to stop messing with three things at once.
Set them all properly so this can be diagnosed and fixed.

Proper diagnosis involves changing one single parameter at a time, not two or three.

you stated
I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Number one, yup, so set it right
number 2, yup, so set it right.

Rich

I just ordered a new TPS switch. But I can and will follow your guidelines to the letter and report back using the one I have. I believe it to be set correctly at this point.

Thanks,

Len

[rhodyguy]

nice write up rich. concise and to the point.

[lsintampa]

At this point - it seems I may be near normal.

I reset the dwell and timing. I'm not sure why timing should be set with the car at or near 3,000 RPM? It's been my experience over the years to set timing at idle.

Thinking about that, it would be next to impossible to do, when at idle, the surging was nuts.

Anyway, with the help from my wife to jack the rpm's up to around 2500 - 3000, I set the timing. Ended up retarding the advance quite a bit from where it was.

That seemed to drop my idle way down to under 900 RPM - and the surging seems to be near gone.

I don't want to say it's resolved - it would be nice to know for sure if the timing may have been another part of the issue. (along with the leaking cold start valve).

I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Anyway, there have been times with I "thought" it was right - just to let it sit for a while and watch it go nuts on me.

Will test again later today. Keeping fingers crossed - that maybe it's settled down?

Timing is set at 3500 rpms to guarantee you are setting the timing with full advance on which at that speed is purely based upon centrifugal force and not vacuum.

Its a unique way of timing, and if you use a zip tie you can easily pull the throttle to the right speed and set the timing accurately.

Now, when you change the timing by ear, or by hand, you WILL screw things up.
So, STOP doing it. its not right and it will certainly create an issue.

Go back, set the timing by the book.
I know you changed it again, so go back and reset it properly.
Then, and only then will things sort out.

1) set Dwell
2) set timing at 3200 rpms steady, not blipped (watch for variation in timing when the rpms are steady, that will define a new issue....if it wont hold steady)
3) turn the ECU knob to full rich
4) set the TPS to the only correct spot it can be set....(again, its not a tuning aid and its not adjustable...stop messing with it)

If you do all of these things, you are now setup properly.

See if that works.
If it is close and idle moves a little bit let me know.
If the timing mark moves while you are watching it with the light at 3200 rpms, let me know.

You need to stop messing with three things at once.
Set them all properly so this can be diagnosed and fixed.

Proper diagnosis involves changing one single parameter at a time, not two or three.

you stated
I can FORCE the surging by doing one of two things.

1) advancing the distributor a lot

2) at idle muck with the throttle plate switch - take it off it's idle setting

Number one, yup, so set it right
number 2, yup, so set it right.

Rich

So, I set the timing... had wife hold RPM (using the dash tach) at 3200. I did not notice the timing mark moving. Seemed to hold steady on mark.

Clamped down DIZZY, shut car off.

Turned ECU knob all the way clockwise (rich I think)?

Started the car.

No surging, but the idle is now LOW - like maybe 400 RPM. The generator light comes on. She does stall out sometimes. At times it will catch itself and stay running. If I get on the throttle and let go, that will usually result in stalling.

Turing (opening) JUST the air bypass does little for the idle. It makes a LOT of noise (sucking wind), but has no to very little effect. I turned it back to almost closed, which is where it was to start.

So that's where I'm at. No surge, low idle. ECU fully turned clockwise.

Thanks,

Len

[TheCabinetmaker]

Why full rich? Turn it back half way. Did you have the vacuum hoses disconnected and plugged when you timed it?







Edit: just saw that Rich had you do that ? Why full rich, Rich?

[lsintampa]

Why full rich? Turn it back half way. Did you have the vacuum hoses disconnected and plugged when you timed it?

Well, I'm just following Rich's routine to the letter, as I said I would. His bullet point number 3.

Yes I had the vacuum hoses disconnected and plugged... at the throttle body.

I saw no need to plug the vacuum on the dizzy.

I'm cool until Rich has had time to chime back in. I'm sure there's a method to what he's asked me to do.

At this point, I'm surely not in any rush. And it's becoming more obvious that I'm clueless! (IMG:style_emoticons/default/huh.gif)

[DRPHIL914]

Running rich will cause a slower idle. Slowly one click at a time turn back and you shod see the idle change while making it more lean.