Misfire after Test Pipe install, help!

Ok, Firstly, I have minimal experience with Lambda control K -Jet systems, as most of my experience is with UK spec non cat cars.

BUT, I did fit a tubi and test pipe to a swiss spec 328 while in UK, and I didn't even tie the thermocouple to the pipe.. I just tied it up in the chassis out the way and all it read was ambient temp..

The car ran perfectly both before and after.

In fact, the owner loaned me the car to drive around Donnington race track, and it ran fine under track conditions too.

I even proposed to my girlfriend while driving on the track in this car.... I had the ring hidden in the car, but thats another story!

 

Vern -- None of the K/KE-Jet systems have the capability to "cut the fuel off".

Whether you call it an "injection ECU" or a "Lambda ECU", I think it's irrelevant, and my question is not about the system using the output of the warning light ECU to directly control the AF ratio, it's about whether a signal from the warning light ECU can cause the Lambda ECU to run only open-loop vs closed-loop -- and if it's really sophisticated, is it open-loop with some different default FV duty cycle or is it the same open-loop settings as when the idle or WOT switch is closed (these all connect to pin 6 on the Lambda ECU) -- i.e., is the signal from the warning light ECU pin 4 just a ground when cold, like a closed idle or WOT switch, or is it a negative voltage that might initiate some "other" open-loop mode).

Anyway, my head hurts just reading this thread -- if someone can ever get some facts about what's going on that pin 4, please post.

 

the K and KE systems differ in how they control fuel to the injectors. the K basic varies the slit opening on the plunger where as the KE varies pressure to control the fuel flow via the control regulator. the regulator is controled by the various sensors tied into the ECU. the thermo switch which controls open/closed loop the potentiometer reads the plate movement and smooths out the fuel delevery, it also signals a fuel cut-off for coasting. and ofcourse the O2 sensor directly controls the regultor to achieve stoichiometric.

the potentiometer can cause problems when it goes, becouse it no longer smooths out the plate signal.this will cause missing and stumbling on accelration. in regard to open/closed loop duty cycle. there is a lean stop and a rich stop, also a rich max of 95%. past lean stop and it goes into limp home mode. the open loop cold/warm are not controled by the Lamda but by the preprogrammed rate in the ECU. the O2 sensor is too cold to function. rich stop is 95% when no voltage is reading off the O2 sensor, the ECU sees a very lean condition and tries to adjust. this is why removing the O2 causes problems.
until the sensor is hot enough to adjust on the 'fly' the ECU sends a steady signal. once he thermoswitch heats up the signal is shunted from there to the O2 sensor and the duty cycle varies.

this is all quick and dirty, the bosch manual has a far leangthier explanation and trouble shooting technique. and yes the KE system can cut fuel to the injectors unlike the K-basic.

 

Hey guys just started reading this thread. Here's a thought, any chance that the temp sensors could effect the the timing. I know that on an 83 308 QV the thermos will not effect the CIS but I am wondering if the timing might be effected? Just a thought!

Bill

 

So my question; if on my 328 I go to the euro style exhaust (twin exhaust/one itermediate pipe for the front bank header & one intermediate pipe for the rear bank header, & if I maintain my O2 sensor (not even going to discuss the temp. probe!) on the intermediate pipe for the rear bank will this effect the readings on the O2 sensor since it is normally reading the exhaust volume from both banks?

 

it'll adjust both banks from the one bank your reading. worst case you run lean on the bank not being measured.