1982 Westy - Hesitation At High RPM, Now Pinging (fixed)

[Amskeptic]

Regarding tires, I guess I can take the them off and have them rebalanced. Maybe I threw a weight or it was done improperly.

Do not jump at opportunities to piss away your money. Apparently, the hesitation issue was taken care of with the new ECU so the tire balance/run-out deal is now irrelevant, am I correct?
Colin

[karl]

On another trip (my last), I had them install my EGR valve/canister/pipe (was missing both the valve and canister when they originally did the swap).

This raises another question.

What gasket did they use between the pipe and the top of the EGR valve?

California and Fed versions use different gaskets. The difference is in the size of the center hole.

California: 039 131 599 A and the center hole is 3.8mm
Federal: 071 131 599 A and the center hole is 5.5mm

If they used the 171 gasket, you will get too much EGR.

Before you do anything else, disconnect the rod between the EGR valve and the throttle housing and drive it again.

[Sheesh]

You are correct, Colin.

Karl, one of the issues I had for installation of the EGR valve was the inability to obtain stock gaskets. As a result, these were hand made.

On my attempts driving home Sat and when the ping presented it self after installation of the new ECU, I attempted on multiple occasions to adjust the EGR. Bentley states 1 1/16th turn AFTER a sudden drop in idle. I gotta say, that idle drop seems rather insignificant to me (but is present). In addition. doesn't the addition of exhaust gases retard ping? Meaning, too much is not going to make it ping? Unless, I suppose, that it makes the mixture lean, almost like a vacuum leak......(extrovert, think as I go...).

I will do as you suggest.

Chris

[karl]

I am addressing the hesitation problem.

The pinging just started, correct? Like maybe too much ethanol in the last gas you bought?

[Sheesh]

Yes. That could be as well, karl. I filled up with 91 octane (12 gallons) before leaving Mariposa. However, climbing out of town (w/ the old ECU) the vehicle didn't exhibit the pinging problem. Maybe it took awhile for the gasoline to mix.

Things I can try is:

* Octane booster for this tank.
* Cooler plugs
* Retime / reset the EGR (after checking on gasket)

Before I do any of the above, I think I will swap back to the old ECU and test.

Today, I'm heading to Merced to shop for our 11 year old (needs clothes) and will retrieve the old ECU. With that, I can swap back to the old ECU and see if the pinging is still present. That would indicate bad gasoline my last fill.

Still, given the state of the plugs I pulled (whitish deposits / minor glazing), the mixture appears lean.

Thanks again, karl.

[Sheesh]

Started playing with the CO/mixture screw today. Clockwise, turning it down to the bottom. Ready to count the number of turns for a baseline. Ready to then go up from the baseline. Ready to, then, use the advice given by Amskeptic for setting fuel/air mixture w/o an analyzer.

1/2 turn is all it was! 1/2 turn is all it was turned CCW from the bottom!

No wonder things were lean.....

Amazing I was so reticent.

Sorry for being a pansy, folks.

[Westy78]

If it was only a half turn from the bottom it was almost at full rich. Screwing that out (CCW) adds air making the mixture leaner. That screw also does very little to the overall mixture at cruising or under load. It's more of a fine tuning at idle.

[Amskeptic]

Started playing with the CO/mixture screw today. Clockwise, turning it down to the bottom. Ready to count the number of turns for a baseline. Ready to then go up from the baseline. Ready to, then, use the advice given by Amskeptic for setting fuel/air mixture w/o an analyzer.

1/2 turn is all it was! 1/2 turn is all it was turned CCW from the bottom!

No wonder things were lean.....

Amazing I was so reticent.

Sorry for being a pansy, folks.

As our alert Westy78 noted, 1/2 turn from bottom is near the "richer" end of that adjustment. It does not mean that the engine was necessarily rich, it means that somebody found it lean last time. Do your AFM adjustments, the "static" and/or "dynamic" ones only with that mixture screw at the mid-point of its bore (4.5 turns from the bottom) and you will then have lots of fool-around room for future tweaks.
Keep at it, you are not a pansy until you give up.
Colin

[Sheesh]

Got it!

Thanks for all the help, again. I am learning a great deal.

[Sheesh]

Alrighty!

I think I've solved the pinging problem, but still need to get this vehicle on a smog/LM1. I did the following, based on this topic: http://itinerant-air-cooled.com/viewtopic.php?t=3665

1. Started out with a cold engine and fiddled with the what Amskeptic calls the "trim adjustment" screw. Played with it until I could get 1/4" movement of the wiper in either direction without much change in RPM. Was about 2 1/2 turns CCW (or so). The engine was getting warm....

2. I knew my my mixture was lean (pinging). So, I then went to what Amskeptic calls the "static adjustment" wiper in the AFM and moved it over 1 tooth CCW to make it richer. I played with the "static adjustment" wiper again, moving it 1/4" either direction. RPMs down a bit CW, but not CCW (but, maybe I have a ham hand).

3. I then brought the RPM up 3,000 and held it there with a screw driver, and again moved the "static adjustment" wiper what I think was 1/16". Same as when I messed with it in #2.

4. The engine was getting hot now I checked the idle speed and timing. All was good. Knowing that I needed to get the engine GOOD AND HOT, I told my 11 year old to jump in and we went to the store (7 miles away; up and down hills) to get some pie crust and sugar for sweet potato pie.

On the drive home, it still had some pining under load and over 3,000 RPM, but not as severe as described in my post a week ago. A week ago, it would ping anytime under uphill load over 2,000 RPM.

5. When I got home, I clicked the "dynamic adjustment" cog CCW 2 teeth, rechecked the "static adjustment" wiper at 3,000 RPM w/ screw driver expertly placed, rechecked idle and timing, and set the timing to 6 degrees. Then, took it for another spin.

6. Now, the pinging is almost gone. I had one ping up the hill in 4th gear when stomped on the accelerator. 3rd gear, up hill, under load I did not hear pinging.

SO........

I think I'm on the right track thanks for the information found and given here, particularly the information provided by Amskeptic in another topic.

Question: why would swapping out the ECU affect the performance in this way? The engine didn't ping with the old ECU and only did AFTER the installation of the new.

Thanks again everyone, especially Colin. I've learned much and have become much more confident with the manipulation of the air/fuel mixture.

[Amskeptic]

Why would swapping out the ECU change your engine's behavior?

Like everything on this Earth, there are individual variations. Go to an appliance showroom and check the thermostat calibration of 20 brand-new ovens, and you will see variations all over the place.

The actual materials used in the assembly of an ECU will have slight variations, resistors will have different resistances, capacitors will kick slightly more or less than their bretheren, just removing the MPC at the ECU will clean up the contacts with fresh scratches on the pins, who knows?

BUT, I still have an issue with the pinging. The fact that it was even occurring leads me to wonder if you have excessive build-up of carbon in the cylinders. I had a similar issue, not pinging but dieseling, that I finally tracked down to loose valve guides that allowed way too much oil to burn in cylinder #2. I had so much carbon that the piston crown was pounded down on the upper compression ring due to carbon interference between the cylinder head and the piston. This was because my I Know More Than You machinist decided that the interference fit specification of the guides to the heads was "excessive".

If you ever get around to it, could you share your compression readings? If one or two are way high, like 115/110/145/120 you might have carbon enhanced compression induced pinging. Meanwhile, drive and use clean gasolines like Chevron with Techron.
Colin