Surge / Idle Options

[lsintampa]

sorry, had to get it off my phone.

See the middle brass contact finger?
See how it is touching nothing?
That is what it must look like at idle.

The one one the left sits on the first leg.

I found it alot easier to remove the throttle body along with the TPS and set it when its not in the car, so you can see everything clearly.

Rich

If you are talking about the one with the blue arrow pointing to it, that seems to be on something? I'll have to pull that puppy off and take a look.

[r_towle]

the reason the TPS can be adjusted is it was made for a large number of cars.
At the end of the day, it can only be positioned ONE way to work on a given throttle body.

The idle circuit is a special circuit in the ECU, so it needs to have the TPS in the correct position in order to make that special circuit activate.

[TheCabinetmaker]

Does the idle mixture screw on the ecu make any difference?
Have you verified dwell and timing?

[lsintampa]

Does the idle mixture screw on the ecu make any difference?
Have you verified dwell and timing?

Dwell and timing were checked a while back. No big changes to think they are off, but I can check it again.

ECU adjustments .... I've turned that thing all the way in one direction and the other. Seems to make no difference. I don't know how sensitive that ECU adjustment is, but it seems to me that it really doesn't do much.

I removed the Throttle Body and adjusted the switch using the Pelican method. At full CCW it reads 1 OHM, then I turn clockwise to Zero, then ONE more notch - OHM meter is still at ZERO at that point. Didn't seem to do much.

I opened the air valve on the TB so my idle goes up to like 1500 RPM. At that speed, the surge is minor, but still present. Seems to get really wild (surging) when I try to turn in the air valve on the TB - the lower the RPM the worse the surge.

IDK, It would be nice to figure out. I'm just not in the mood to yank the whole system out to check that plenum. I still think (and I'm most likely wrong) that if there were a air leak, the idle would just go high. Something I don't understand is going on. (as he states the obvious) (IMG:style_emoticons/default/confused24.gif)

[TheCabinetmaker]

The idle mixture knob will work only if the tps is correctly set. Your tps board is crap. Contact Dave sprinkle for a new board. They can ohm correctly but still not work.

[DRPHIL914]

The idle mixture knob will work only if the tps is correctly set. Your tps board is crap. Contact Dave sprinkle for a new board. They can ohm correctly but still not work.

(IMG:style_emoticons/default/agree.gif) I was still having a bucking at 2800-3000 rpm and issue with not having a steady idle. I had replaced the board a few years ago with one of Dave's but it did go bad too. I got a very lightly used original tps from Bruce stone and both of those issues are now gone completely and once the tps was put in right place- I used the picture that rich posted above, the ecu know will increase or decrease your mixture and effect your idle for sure. I think I counted 22 or 23 clicks so put in the middle and start from there.

[r_towle]

Does the idle mixture screw on the ecu make any difference?
Have you verified dwell and timing?

I removed the Throttle Body and adjusted the switch using the Pelican method. At full CCW it reads 1 OHM, then I turn clockwise to Zero, then ONE more notch - OHM meter is still at ZERO at that point. Didn't seem to do much.

Before you buy anything, please LOOK at the TPS as mounted, at idle, with the cover removed.

[r_towle]

Here is one

http://www.914world.com/bbs2/index.php?sho...lates++cleaning


Someone did a thread with pictures that may help more if you find it.


This
http://www.914world.com/bbs2/index.php?sho...lates++cleaning

[TheCabinetmaker]

I have gotten a few years extra life from a tps by sanding the traces on the board with 2000 grit wet or dry, then cleaning with lacquer thinner

[lsintampa]

Well, here are two shots of how the throttle switch is set.

I've not tried this setup yet, as I just took the TB off to set it.

I'm thinking it's right on - but I don't know for sure.

In any event, I'm going to give it a shot.

And so it goes.

[lsintampa]

sorry, had to get it off my phone.

See the middle brass contact finger?
See how it is touching nothing?
That is what it must look like at idle.

The one one the left sits on the first leg.

I found it alot easier to remove the throttle body along with the TPS and set it when its not in the car, so you can see everything clearly.

Rich

If the middle finger is "touching nothing" about the only way I could get it there was to take the TB off the car, then used a OHM meter to insure the finger was not touching the "brass tracers".

The pictures I just posted - the middle finger WAS still touching. So I made just a slight adjustment - used the OHM meter to insure it was not touching and installed that into the car.

To be honest, the surging is now worse than it was.

Question... would the Dizzy vac be suspect? Or the Dizzy advance plates?

The Dizzy is original - just new points / condenser....

The other suspect is still the Plenum.

Onward through the fog....

[DRPHIL914]

sorry, had to get it off my phone.

See the middle brass contact finger?
See how it is touching nothing?
That is what it must look like at idle.

The one one the left sits on the first leg.

I found it alot easier to remove the throttle body along with the TPS and set it when its not in the car, so you can see everything clearly.

Rich

If the middle finger is "touching nothing" about the only way I could get it there was to take the TB off the car, then used a OHM meter to insure the finger was not touching the "brass tracers".

The pictures I just posted - the middle finger WAS still touching. So I made just a slight adjustment - used the OHM meter to insure it was not touching and installed that into the car.

To be honest, the surging is now worse than it was.

Question... would the Dizzy vac be suspect? Or the Dizzy advance plates?

The Dizzy is original - just new points / condenser....

The other suspect is still the Plenum.

Onward through the fog....

when i went thru this first time, i did have leak at the plenum and at the throttle body, and put on new hoses for the intake runners-to-plenum, but those still leaked, so i put clamps on those and now no vac leaks at the TB, plenum or intake runners.
test by spraying a bit of water mist or some use carb cleaner- that will richen and change your idle if it is leaking.

[r_towle]

Question... would the Dizzy vac be suspect? Or the Dizzy advance plates?

The Dizzy is original - just new points / condenser....

The other suspect is still the Plenum.

Onward through the fog....

YES
YES

clean the distributor advance plates, I believe I posted a few threads above in this thread....go look at that.

IF you are diagnosing, take your time to see if you are doing something worthwhile.
So, when you take apart the advance plates, take your time, do they move and spin freely in your hand before you seperate them, or is there friction and binding???

Try to note the before and after condition so next time it happens, you know.

BTW, if the advance plates have never been cleaned, they will bind and in some cases be very hard to move, even cold.
When you grease them and clean them....you will be amazed how easy they move.


rich

[lsintampa]

Well carrying on with the experiment....

Since the last setting of the TB switch caused the surge to get worse, I went back to old school and adjusted it using the Pelican method, and now the surge is much improved, but still persists.

That in itself has to be a clue ?? or not, I guess.

I'm gonna try the carb cleaner trick - poke about the fuel runners, plenum, etc. See if there is some suction happening where it shouldn't.

I'm beginning to think that perhaps the dizzy may be the next component to inspect.

But as it pertains to the dizzy, I'd think if the advance / retard were not functioning correctly, I'd have issues while driving up and down the RPM range. Car runs fine at speed, so that's why I've not suspected that the dizzy was suspect. Can't hurt to check it out though.

[lsintampa]

Maybe I'm onto something here....

I don't have any carb cleaner, but I do have starter fluid and a fire extinguisher (IMG:style_emoticons/default/piratenanner.gif)

With the idle surge as good as I can get it, I started up at idle and started spraying about areas where no air should enter.

Left side fuel runners - nothing - no change. Right side however did change the idle. At first I thought it might be the fuel runner gaskets, but I don't think so.

The runner gaskets, manifold gaskets, TB gasket, all are new, as are the injector seals. So I don't think that's the issue.

HOWEVER, I do now suspect the plenum itself is an issue. I had asked this once before, but I wasn't really sure if my question was understood.

Simply put, there are two support tubes (columns) that support the plenum. They are on opposing sides, and the tubes are hollow - they go directly through the plenum. I recall that MY tubes are "loose" - by loose, I mean I can turn them, the ends are not connected to body of the plenum. They don't fall out, but they certainly are not "welded" to the plenum body.

I'm thinking the plenum needs to be taken out - OUCH - and repaired. ???? No / Yes?

Is there an easy way to get that puppy out without having to remove the manifolds? I guess I could cut the runner gaskets. Not sure how easy it would be however to put new ones on - once I yank that puppy.

[DRPHIL914]

Maybe I'm onto something here....

I don't have any carb cleaner, but I do have starter fluid and a fire extinguisher (IMG:style_emoticons/default/piratenanner.gif)

With the idle surge as good as I can get it, I started up at idle and started spraying about areas where no air should enter.

Left side fuel runners - nothing - no change. Right side however did change the idle. At first I thought it might be the fuel runner gaskets, but I don't think so.

The runner gaskets, manifold gaskets, TB gasket, all are new, as are the injector seals. So I don't think that's the issue.

HOWEVER, I do now suspect the plenum itself is an issue. I had asked this once before, but I wasn't really sure if my question was understood.

Simply put, there are two support tubes (columns) that support the plenum. They are on opposing sides, and the tubes are hollow - they go directly through the plenum. I recall that MY tubes are "loose" - by loose, I mean I can turn them, the ends are not connected to body of the plenum. They don't fall out, but they certainly are not "welded" to the plenum body.

I'm thinking the plenum needs to be taken out - OUCH - and repaired. ???? No / Yes?

Is there an easy way to get that puppy out without having to remove the manifolds? I guess I could cut the runner gaskets. Not sure how easy it would be however to put new ones on - once I yank that puppy.

sounds like you probably found your leak, those should not be loose. Get ahold of Bruce Stone, he will have a nice newly powdercoated one most likely or have one done for you - in the mean time can you tape over those to seal them off just to test it?
Phil

[r_towle]

put four large screw clamps on the rubber between the intake runners and the plenum, see if those are leaking.

As far as taking it off goes, well without the rubbers its about 1/2 inch or more away from the intake runner tubes, so if you can slide the rubbers back, you can do it...even if its just one side, then pull if off the other side.

Beware, you may need to buy new rubbers which I believe are NLA, so shop around for that first to make sure you get new ones the correct diameter before you shred them.

Rich

[lsintampa]

I just ordered new rubbers from Pelican - seems they still have some. Not sure what I'm going to do next though. I'll have them if I need them.

I'm gonna try the hose clamp thing - but not until the holidays are over - it's getting nuts around the house - and I'm not about to go shopping - that's a given.

Will revisit this in a few days...

Thanks for all the input.

Happy Holidays - !!!!!

(IMG:style_emoticons/default/beerchug.gif)

[r_towle]

buy a can of carb cleaner....its safer than starting fluid....

rich

[TheCabinetmaker]

2L intake runner sleeves are still available. 1.7 are not.