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Only because my '79 runs great, accelerates, decelerates relatively smoothly.

The '81 has a rebuilt throttle body, clean rebuilt everything. The idle switch is set perfectly, same as '79.

New negative battery cable. I have switched between three AFM's to notice no noticeable improvement. The throttle response is just plain harsh, swift, sensitive, jerky. Bouncing off the guibo if I don't cushion the pedal from my leg bouncing in the seat.

Rebuild an AFM ? Switch in the '79 AFM ? Maybe it's nothing to do with the air fuel meter, but it sure is throttle related. As the throttle body is so simple, mechanical, SOMETHING in the contraptions ain't right.

Whenever this happens to me, it's because the spark is too far advanced.

I had it timed as per the FAQ. Retarded it just a bumps worth, which needed a dab of adjustment on the throttle body (big) idle screw.

Seemed better on a (still warming up) run around the block. Less burble, hesitation, sensitivity. I'm sure all can't wait for the extended highway run report.

Didn't we address that last year here and here?

Yes. I have your wisdom on print outs in a folder.

That is as thick as I am for pulling the ones applicable.

As for grounds, I rebuilt the engine and had everything apart. All the brown wires were visible, to use a Dremel wire wheel to polish the connectors and look at the ends. New zinc plated washers and nuts. (As new). The braided strap from the rear of the block to the firewall was soaked in toilet bowl cleaner, rinsed, washed in 409, rinsed, blow dried to look new. Ends polished.

The car starts, runs, idles great. Except for the sensitive throttle. I am not stubborn, stupid opposed to cutting off connector ends of ground wires. The problem is replacement ends are not laying around at the corner hardware. It's a rather focused search process to find the L paddle shaped connectors or metric circles,...not a happy 50 pack of crimp ons.

Between the connector and wire coating, I'm not seeing any green, white crunchy nothin' anywhere to (so far) go on the cut and solder adventure.

But I am going to stick a vacuum hose up my testor to give you some revenge on a putse student.

T.Hanson wrote:Only because my '79 runs great, accelerates, decelerates relatively smoothly.

My 79 was 'hitching' most notably with 1st gear. Have you tried lubing 'ALL' points of the the throttle linkage....especially connections where it goes through the firewall ? Bushings fubar ?

Thanks for the continued patience, posts. It occurs to me I imagine, it's too bad members only experience driving one 528i. From having three and a Euro 635, the difference in feel of virtually the same cars after thirty years is quite interesting.

"Trailer hitching," in the 635 got me to this site ten years ago. No less than four shops drove it to report nothing wrong, while the idle switch on the throttle body was set to click off too early to guess any of them knew there was such a thing. Let off on the gas, blow the horn with your nose.

Or ride the clutch, " No problem." My last visit to a shop found the average tech was born after the car was built. They expressed awesomeness, as long as they didn't have to work on it. No computer diagnostics, etc.

Pretty apparent the wrenches who knew these cars are retired, or not in every BMW shop any more. Even the experts on Firstfives are fewer, to have to accept it's going to be about reading the L-jet, Haynes, tech references to figure things out, or stop complaining, posting.

Retarding the timing improved the hitching and hesitation with hard acceleration. Peter's method of timing to spec (2200 rpm) then twisting to fine tune seems to be art and experience entering the picture.

Anyway, it's driveable now, snappy by comparison to the '79, which may be grocery store mushy but I was used to it, to be copying the wrong way.