Got my main fuel issue fixed (FD), car running pretty great now good idle, power and cold start. Do though, have an odd (quiet) popping thru exhaust only when... I'm in a lower gear and decelerating from up above 3000 or so RPM. Sounds like a lean miss on a motorcycle. Cap/rotor/wires/plugs have very few miles on them, wires are NGK cap rotor is german beru I think, plugs are "r" but have correct ones on the way. Not aware of any exhaust leaks but I guess it's possible, but didn't show up before this work was done. I'd think maybe my EHA (not leaking) needs a tweak but the thing is, it seems intermittent. Ignition parts? Thanks

Abstemious, what brand are the ignition wires? Beru or Bosch are high quality wires. Check the condition of the wire to the coil because routing that wire properly takes some effort. Once you get the new sparkplugs make sure they are gapped correctly … per Owner's Manual specification.

__________________
Fred Hoelzle

good old days we'd advance spark to make that noise

__________________
1999 w140, quit voting to old, and to old to fight, a god damned veteran

First off what kind of car and engine?

__________________
1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

In another nearby thread he said it's a '89 300 TE, but it certainly helps to state the year, model, and engine every time you start a thread.

From the description it sounds like the engine is afterfiring on overrun, which is usually caused by a mixture too lean to ignite in the cylinder, and then it ignites in the exhaust system causing one or more "pops". This should not occur since the KE system incorporates a fuel cutoff on deceleration, but there's about a 1-2 second delay before it occurs, and I can usually feel it.

Fuel cutoff is controlled by the microswitch on the linkage. The recommended adjustment results in a significant "dead spot" between microswitch activation and actual throttle valve movement.

On my 190E 2.6 five-speed it results in a low rate of rev drop upon upshifting that results in jerky shifts unless they are made slowly, especially 1-2 and 2-3 that have wide spacing. I adjusted the linkage to minimize the dead spot. This helped, but it's still an issue, and I expect that the idle speed control valve opens with throttle application and is slow to close upon lifting to shift, so revs still hang.

The OP needs to check that the microswitch is functioning, and then possibly adjust it. It's probably more difficult to "feel" the fuel cutoff on an automatic than a manual, but he should try to detect it. Probably the best way would be to lock the trans in second gear, then bring it to about 4000 and lift off. If fuel cutoff is functioning you should feel a very slight "jerk" followed by an increase in rate of deceleration after a second or two.

Upon subsequently applying throttle, the microswitch restarts fuel flow to the injectors prior to actual movement of the throttle valve for a smooth transition, but my adjustment to minimize the dead spot did not result in any issues when reapplying throttle.

Duke

http://www.peachparts.com/shopforum/tech-help/402355-w124-cant-figure-out-fuel-pressure-drop.html