I've had my 1972 Tii for 6 months, and it has always had a misfire at light throttle settings. It idles and accelerates fine. I've done the usual tune up items. Does anyone have suggestions?
JMorrison, I know this is an old thread, but if you are still enduring the miss...adjust the timing. It could be that simple. I just picked up a 320i with the M10 engine in it. I replaced the cap/rotor/plugs/wires, and it had a miss like that from 1900-2200 rpms. I retarded the timing a bit, and now the car PURRS! I think someone compensated for bad wires/plugs by advancing the timing... Good luck. I hope this helps. By the way, I had thought that the timing was dead on, but this made all the difference to performance... Tim
Thanks, Tim I got the car last December, and I think I've eliminated ignition. I installed new secondary leads, transistor ignition, adjusted the valves, etc. Tried advancing and retarding the ignition timing and checked the FI timing. It doesn't miss until the engine warms up. There's a small amount of slop in the throttle linkage which may be causing a problem in sync between the throttle and the Kugelfisher pump which I'm working on now.
You probably have exhausted the simpler things. Does the tii have an O2 sensor? I disconnected mine on both of my E21s, and they both idle, accelerate and cruise better than with them connected. One still has the cat, and one has it removed...didn't make a difference. Cold start still works like always. Just a thought...might help troubleshoot if nothing else. Good luck! Let me know what finally does it for you. Have you recently changed the fuel filter? Tim
This is a 1972 2002. Not likely to have an oxygen sensor. Electronic engine controls mandating an oxygen sensor didn't debut on BMW's until the 1977 E23 7-series. They rapidly trickled down to other cars over the next few years. The E21 debuted a rather crude engine control system with an oxygen sensor starting with the 1980 to 1983 models.
It has no oxy sensor, cat converter, air pump.etc. (and never did have). I checked the fuel pressure and volume, both within spec. Thanks for trying, JohnM
John, Don't know where you are located; but I would call Sean Casey in Petaluma, CA. He is a BMW CCA member (of course), has a Tii, factory 02 turbo, and has hosted "Tech Sessions" on Tii fuel injection @ the Bay Area Swap-n-show. Fabulous resource, and if he has the time, is usually very willing to talk to you. His # is 707.938.2002 Or, even better, email him sean@caseymotorsports.com - that way he can respond during off hours. ...and a fabulous resource is the www.bmw2002faq.com site. There could be answers there too. //Mark Wicker 72 2002 (sahara) 88 M5
I've found that adjusting the K-pump linkages really helps. Any slop or misadjustment causes problems with these cars. You can adjust it for slop a little, but if anything is worn slam out, you should replace it or have it repaired.
Thanks for the suggestions. I'm presently removing the KF pump in order to get at the ball on the end of the lever which links the throttle linkage to the pump. The ball was originally riveted to the lever, and is loose. Unfortunately the only way to get to it to weld or braze it is to remove the pump. Wish me luck! JohnM
It'll run way better when you fix that and adjust it to spec. You can tweak the settings a little if you have any non-standard equipment (fat cam, exhaust, intake, etc.) but the factory tune was pretty darn good on these cars. The slop is probably just making it run a little too lean at cruise.
Jack Fahuna in Van Nuys, CA has the plastic end pieces which are prone to breaking off, and carries the complete no-longer-available throttle linkage kit. http://www.probimmer.com/Kugelfischer.php
