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

[Sheesh]

New to the site but have become a regular over at TS. Randy in Maine sent me here and I've already gained a great deal from this topic: viewtopic.php?t=3665

Seems everyone is very helpful here and hope to become not only a regular, but as helpful.

That said, I have an '82 Westy, 2.0L AC/CA emissions I have been working on for almost a year. New engine, distributor, fuel pump, regulator, fuel and vac lines - I've replaced all engine components EXCEPT the coil, AFM and ECU. I have a single remaining tuning issue that I can't seem to resolve.

I have a hesitation problem when under load and over 3,000 RPM. I've done all the Bentley checks for resistance/voltage from the pump to the TPS to the AFM to the ECU and all check out (AFM was only good after I repositioned the contact board to good carbon - ceramic was showing through).

Today I checked out the topic mentioned, above. Followed the very good instructions and finally clicked the nylon "dynamic adjuster" CCW and CW one click at a time. I would click once, drive, rinse and repeat. When I got to 5 CCW, the problem presented itself under 3,000 RPM. I only went 2 CW and the problem was still present.

That said, the vehicle appears to be running rich, indicated by both soot in the tail pipe and 12 mpg. While the CO reading was good from the start, I needed to get a new S-boot as the old was cracked and haven't yet had the CO retested. To add, I've also checked for vac leaks in all the usual places, including the brake booster, aux air, and the Y shaped piece connecting the booster, decel valve and plenum.

I'm at a loss of where to go next. I've thrown money at the van so far, which is OK because I want this to be a solid runner for my family/kids for the next decade and more. However, AFMs/ECUs are yet other expensive items and my wife is starting to look at me in that "will it ever end" kind of way that I'm certain many of you have already experienced.

Tomorrow, I am going to a nearby VW parts/repair place and I have talked them into allowing me to take a used AFM for a spin (took some doing). Interestingly, they have a few NIB Bosch AFM units they want $900 for Goodness.....

Anyway, thanks for allowing me to be part of this community and I hope to contribute in a meaningful way. And, thanks for any advice given to help me through this final problem.

Chris

[karl]

Since you have a alif version, 2 questions:

Why does it sound like your O2 sensor is not working?

What is the number on top of your AFM?

0 280 200 025 1980 Calif. subs to the next one

0 280 200 030 1980-1983 Calif.

0 280 200 028 1980 Federal subs to the next one

0 280 200 032 1980-1982 Federal

0 280 200 038 1983 Federal

If you are not using the 25 or 30, it will not run right......

[Amskeptic]

New to the site
I have a hesitation problem when under load and over 3,000 RPM.

Are you running the oxygen sensor? Unplug it when you're doing the dynamic adjustment. I have noticed that the oygen sensor loop cannot overcome normal leanout from wearing valve guides. Unplug the green wire and adjust the AFM as per procedure and see how it drives. . . after reading the below.

Now, this is going to seem crazy, but it is as true as it comes. . . if you have imbalanced or bent rear wheel/tires, you can have an incureable hesitation. The shaking of the engine/transaxle can cause a sympathetic oscillation of the wiper arm in the AFM.

Some tires, particularly the Continentals that came with the car, were noted as particularly irritating to the AFM. They must be balanced and if the tread already has scalloping of the tread blocks, you need to find other tires.

If you would like to check out this outlandish possibility, have someone else drive the car at 35-40 under acceleration while you look at the engine through the open access lid. You will see exactly what I am talking about if it is a contributor to your hesitation, the engine will shake under acceleration.
Colin
(keep us updated)

[Sheesh]

Thanks, folks.

Amskeptic:

Brand new engine with 500 miles on it. Shouldn't be wearing valve guides.

Brand new Hankook RA08s all around.

karl:

I'm not certain what your reference to an O2 sensor may be. Are you saying that my O2 sensor (which is new) may be malfunctioning?

AFM #: 0 280 200 030
Engine #: CV048293

Both:

I'm heading to the big town today to get a new coil at the FLAPS and to stop by the local VW parts/mechanic fella. I had to talk him into allowing me to use a loaner AFM to test. Took a lot to do that.....

Thanks for your help!

[Sheesh]

Well, swapped out an AFM at the used VW store: No change.

Swapped out the ECU: Problem solved.

So I thought....

We live in Mariposa, CA, in the Sierra foothills outside of Yosemite. On the way home from Merced and climbing the hills, the vehicle started pinging under load. Badly.

I must have stopped a half dozen times resetting timing and EGR valve, first retarding it from 5 to 8 then 12, then just bringing it back to where it was because the vehicle didn't have power. I'm lucky to have made it home. It ran HOT HOT HOT.

There is a new distributor in the vehicle and, I guess, I need to hook up my vacuum gauge to inspect whether or not the advance side is functioning properly. On my rebuilt unit, the advance hose sits on the bottom of the can next to the crankcase (touching). The old unit used to have the hose come out of near the top. I recently put on new vacuum hoses but they are not braided.

I know that pinging is pre ignition and will occur when timing is off, fuel mixture is poor (rich or lean?), bad fuel (I filled up w/ 91 octane before leaving Mariposa to go to Merced; no problem on the way there) and the EGR valve is not functioning properly (I had to get a used one months ago) to add exhaust to retard combustion.

Any advice on why swapping the ECU would cause a ping that wasn't present before? Might I have yet another defective ECU?

I was so happy, too. On the way home I almost had to have a beer at a tavern I stopped at on one of my timing/EGR resets. I'm so frustrated.

Colin, I see that you live in LA. Yosemite is very nice this time of year....

[karl]

What is the number on your original ECU and the replacement ECU?

Calif versions used 3 different ones that all sub into 1 number:
071-906-021 = Bosch 0280 000 192
071-906 021 B = Bosch 0280 000 194 or 195
071-906-021 E = Bosch 0280 000 194 or 195

The 071 906 021 and 071 906 021 E all supersede into ONE replacement ECU: the 071 906 021 B

[Sheesh]

Karl:

Thank you for the kind reply! After reading it, I spoke with my wife and we agreed that you not only have a wealth of knowledge but took some time to research these part numbers and were generous enough to provide an internet nobody like me with sage advice. =D> A rare thing such kindness!

Unfortunately, I inadvertently left the old ECU at the local shop in Merced. I wanted the unit, but got busy talking after the "repair" was completed and forgot it. Tomorrow I will pull the "new" and check for numbers. If it is 071 906 021 B, all is good and on to figuring out my pinging problem. If not, on Monday will head back into Merced to retrieve the old. At that time, I will compare your numbers and make an exchange with the parts shop owner. After that, I will report back.

Thank you again (from both my wife and I)!

[Amskeptic]

Amskeptic:
Brand new engine with 500 miles on it.

Okey dokey.
Just to keep our diagnostic skills crisp, let's pretend for the sake of the following observation that your hesitation was still with us. If it were, your reply that you have brand new Hankooks would not get you off the hook until you also were able to report that your wheels were all running true and balanced.

Anyways, "brand new engine" means you have a lot of internal friction during the ring break-in especially. This will exacerbate any hot-running tendencies. What I do when subjecting a fresh engine to road trips is to downshift into 3rd waaay early to keep that engine spinning over nicely at partial throttle. I strongly suggest that you bypass the oxygen sensor circuit, during break-in at the very least, and err on the side of slightly rich mixture. Ensure that your timing is 28-30* at 3,200 rpm with all vacuum hoses off. Then rev it briefly past 4,000 rpm to check that it does not keep advancing. Some people get the 28-30* at 3,200 rpm and never investigate that the timing goes into grenade-ville above that rpm. The centrifugal cannot be allowed to go past 30*, period.

Check any cooling system anomalies like flaps that are not properly open all the way when warm. You can here them clank at the end of their travel. I have had to double-vise-grip-twist the cross bar to synchronize the flaps to their open positions. It is a subtle check.

Do you have any questions about fuel pressure under demand? You can have decent fuel pressure at idle that drops under demand and this causes a lean condition that does not show itself under any of the usual checks. A fuel pressure gauge securely attached and visible from the interior allows you to confirm 36 psi under full throttle.

This is getting interesting.
Colin

[Sheesh]

Karl: The new ECU is from a 1980 model and has the number 071 906 021 B = 0280 000 194. Looks like the correct replacement unit.

Amskeptic:

Interesting because you want a trip to Yosemite?

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

Regarding the cooling, I've checked and double checked the cooling tin ware and flaps. In fact, I had this engine installed by a shop in Fresno, a shop that has been in business with a German national for the last 30+ years. In retrospect, I should have driven the old rod knocking engine home and done the work myself. Their work was terrible, as many rubber parts (including fuel lines!) were leaking. I've since replaced. That said and to the issue at hand, they also removed all but the left cooling flap that is over the oil cooler, and I have since replaced that whole unit, too (cooling flaps, bar, spring, etc.). Sigfrieds is the name of the place. Don't go there

Regarding fuel pressures, I thought that a problem before attempting this recent AFM/ECU swap. Since, I have replaced the pressure regulator (in fact, three days ago). New fuel pump, lines (see above) and filters, too.

So, since the ECU seems to be correct (might be faulty, though) and I have pinging at high demands, I now need to solve that problem. The next step is to, again, re-time. Additionally, I will do as you suggest by disconnecting the O2 sensor when running. Regarding timing, yesterday when on my fateful return trip, I did do a mechanical timing and noted that over 4,000 RPM it does not go over 30 degrees.

As a side note, I understand that it is kind of hard to make these engines ping. I'm kind of at a loss besides timing as to what to do to make this go away. Since the issue was not present with the old ECU, I'm right now inclined to believe I have a defective unit once again.

Thanks again for all your assistance, fellas.

[karl]

I have a spare 071 B, if you want to borrow it. I should have it back in the mail in the next couple of days.

What is the name of the shop in Fresno? I just moved to Coos Bay Oregon after living there 37 years.

[Sheesh]

Sigfrieds.

Very nice folks....but the quality of the work they did for me was very suspect. The elder fella did my engine swap and allowed the issues described, above, to occur.

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) and while they had the vehicle in the air asked them to replace my CVs/axles. Not only did they severely bend the "headwall" tin terribly, but when I got home I noticed that the CV boot on the driver's side was rubbing against both the EGR pipe AND the heating ductwork.

To me, the issue with them wasn't that they weren't timely nor friendly. Rather, the issue was quality of work. I've got $10K into this rig at current and made it quite clear I wanted everything right. The issue with the leaking fuel lines was, really, inexcusable and could have cost me the van itself.

In retrospect and looking at this positively, what they allowed me to do is become VERY familiar with my vehicle, as I had many tasks that should have been done to perform.

Before accepting your generous offer, would a swapping of the ECU affect fuel mixture? Meaning, would I be wise (after timing again) to play with the AFM settings?

Thanks again, Karl.

[Sheesh]

Just for fun (and with thought of Sigfrieds), I pulled the plugs, installed when the engine was installed. Bosch W8CC. All show whitish deposits and some glazing on the edges of the side electrode; carbon deposits on the ring; slightly brown deposits on the insulator. Unfortunately, two were gapped incorrectly - at or slightly above .30 rather than the recommended .23-.28.

Just some additional info I needed to satisfy my curiosity.

[Westy78]

Pinging can be a sign of running too lean. Have you verified the mixture?

[Randy in Maine]

Pinging can be a sign of running to lean. Have you verified the mixture?

Bingo!

Take that thing to a shop and pay to have them stick it on the exhaust gas analyzer. Don't spend hundreds of dollar on new parts that you do not need, just to help the local economy. Or rent an LM1 and do it yourself.

You are just guessing here on what you are doing. You need real numbers, not "just OKs".

[Sheesh]

Randy:

I made an appointment with the local smog man (who, incidentally, has a brother who has an '80 Westy Auto that he wants off his land; his brother said I could have that rig for $1,000) last week and must wait until 10/28 to do the job. There are only two in our town and I wanted to use him because, well, he advertises as "Mike Butler Automotive and Hang Gliding".



The vehicle was on a smog machine when the engine was installed. The reading was 2.0 (I saw it). That said, that was before I found various vac leaks of which I repaired (which should now make the mixture richer, no?).

My problem really began AFTER the new ECU was installed. I did NOT have this problem prior with the old ECU. I guess my real question is can a new ECU affect the fuel / air mixture that much? Put another way, perhaps the old ECU was compensating for a problem/malfunctioning whereas the new one is not?

I'm just kinda bummed now because my son from a previous marriage has come to live with us. He's 11 and has had issues with his step father and school. I wanted to take him on a trip up to Redwoods NP, down through Medocino and back home, a "turning the page to a new chapter" kind of trip before he starts his new school.

I guess I could fiddle with the CO adjustment screw and the wiper arm screw in the AFM (not to mention the nylon gear) now that I have a basic understand of the concepts involved.

Thanks again, folks. With your help and my persistence to learn, I know it'll be right before I throw a valve or bum a hole in a piston.