Dear F-fellows, Here is a situation currently encountered. I had the car ('79 400i, 20.000 miles) serviced last year. New fuel pumps, accumulators, filters on both sides. The mechanics had trouble to fix the injection but thanks Dave's contribution the problem was solved. It was a reluctant relay issue. So, the car ran perfectly until last month, where a strange thing happened : Cold start the engine, perfect. Then at some point when the engine warms up (can be 15mns or so) , the power disappears drastically, like if only half the engine was running. When checking the smoke at the back of the car, there is much more pressure from one exhaust side than from the other one. The engine can be stopped and started again, no change. Only when the engine is cold again, then both sides are ok again. The strange thing is that one day the smoke was ok on the left side, quite no smoke pressure on the right side, an the next day, the opposite situation : ok on the right, nothing on the left. What's going on ? In case any of you had a clue, it would help. Thanks in advance. Olivier
Have you checked the ignition ? Sometimes it is only a faulty contact of the condensator which cuts off one side. Jacques
Thanks Jacques. A clever guess. This would explain why sometimes the left side is off and sometimes it is the right one. I'll dig into the book to find this condensator location and see if I can do something by myself. The mechanics is 60 miles away, I don't feel like taking a chance. I'll tell what's going on. Many thanks, Olivier
Hi, a local independant Bosch workshop said the injection needed some tuning and tried to fix it, I've just had the car back today. The mechanics said the mixture on one side was too poor. Well, the result is that it's better, but not perfect. Something is still wrong when accelerating, engine warm. At the back of the car, the smoke between the two sides are still different. I wonder whether he really spent the labour hours the bill tells. On the other hand the lack of power can be perceived only when driving the car, which he did not, the odometer showed no change. As long as the car does not move, the noise sounds good and increasing the revs seems ok, Anyway it's better, it allows to drive the car to my usual mechanics. Different style : his workshop is in the middle of nowhere. there is a little road not far away with rare traffic. When reaching a specific milestone, he says the speed should be 146 mph. (230 km/h). Tips : the mechanics showed me where to tune the enrichment : on each side, on top of the Bosch thing, there are like two vertical tunnels. Requires a screwdriver. He also showed me another place he advised me never to touch, the gas pedal tuning. Olivier
Is this still happening?? If it is, this has got to be the key to narrowing it down, I'm still trying to figure out how this can happen. A 3mm T-handle allen wrench is the tool to use to adjust the richness on the fuel distributors, & use a gas analyzer up the tailpipe to measure. This is something you would be able to do once evrything else has been sorted outl http://www.ferrarichat.com/forum/showthread.php?t=197699&highlight=t-handle---------1st post by Dave http://www.ferrarichat.com/forum/showthread.php?t=192480&highlight=t-handle---------6th post by Dave
Thanks for this answer. I'm still confused. When I left the Bosch station, the engine was warm and I was not satisfied with the tuning. Better but not back to the normal. http://83.243.10.70/f/save_nokia_12_04_09_582.jpg But to the mechanics discharge, I must say that some days later, I started the engine and it ran beautifully. I did not take the time to actually drive the car, but what I fear is that once the engine got warm, then it won't rev as well. Let's continue to investigate. Next service in a couple of weeks. Eventually, there will be a gas analyser step, I promise. Olivier
Aahh, good to hear Olivier. One note to take into account, an engine sitting & revving vs. an engine under load (i.e., driving it or on a dynamometer---resistance on the rear wheel spinning) are 2 different animals. Do you have any references with respect to Bosch CIS injection systems? Those WUR's (warm up regulators), auxiliary air valves, & vacuum valves also have a role to play. Plus w/CIS, it is very important that there are 'no 'air leaks between the Bosch control mixture unit & the throttle body (where the accelerator linkage is connected to the exhaust valve cover) as this will fool w/your mixtures/running conditions. A great start-up reference to use is "How to Understand, Service & Modify Bosch Fuel Injection & Engine Management" by Charles O Probst, SAE , & published by Bentley Publishers.... http://www.amazon.com/s/ref=nb_ss_gw_1_10?url=search-alias%3Dstripbooks&field-keywords=bosch+fuel+injection+and+engine+management&sprefix=Bosch+Fuel It covers K-Jetronic, KE, KE Motronic, etc.. It's good to get your feet wet just on K-Jet, but I would recommend at some point (after reading it a couple of times) reading the whole book to better understand the evolvement of the technology. Once understood, you'll not only be able to be your own mechanic in this dept. w/ease, but you'll wish all further education was this inexpensive. Bruce
