It has happened again. The 400i has quit running on a warm day. Last time this happened was in Kansas City in slow traffic with an ambient temperature of 102 F or so. Today it was in the 80s F, I had been stuck in 35 MPH traffic, stopped at a show and left it after about a half hour. The car had no power though it would climb to 4,000 RPM in 1st and 2nd. It quit at the toll booth, restarted and limped on to a gas station about 3 miles on where it quit and stayed quit. The tank is full of no ethanol premium. After an hour or hour and a half the roll off truck arrived to haul us home. The driver asked if the car could drive onto the truck deck. I tried and lo, it had all the power in the world and climbed that steel ramp set at 35 about degrees. It also started and ran just fine when we unloaded it and I drove it onto my lift for future inspection. I will replace the fuel filters as soon as new ones arrive. Does anyone have any other suggestions? Could it be that the under hood temperatures are high enough to cause a vapor lock in an injected system? If so, what can be done? Greg
Good day Greg, I hope you will forgive me for asking, but why are you sure it is fuel related (although it could be)? Similar symptoms can be found with the ignition module too... Cheers, Sam
A good point. Until last month the air filters had never been changed in this car so I am assuming the fuel filters are OEM installed. The ignition has been changed to MSD. My experience with electronic ignition has been that it works all of the time or not at all. The next time I see the MSD guys at a show I'll ask for their thoughts. Thanks, Greg
It could be an issue with the fuel pumps getting enough amperage when hot. I remember reading something here about that a while back. Had something to do with the fuse or relay panel.
Good day Greg, MSD makes excellent products and it could be their module starting to fail, but the possibility is low... I would be more inclined to check the connections to the MSD and/or the trigger sensor. Given your observations, performing some fuel system maintenance/service is probably a good thing anyway. As AKJim has mentioned other electrical issues an as wreak havoc too. Perhaps a thorough once over is needed first to ensure that you do not have more than one issue that contributing to the problem. Cheers, Sam
Hello Greg As AK Jim pointed out could be worth checking the fuel safety cuttoff regulator if it is old they can jam or swith with changes in temperature which might explain why when left for a while the car started again. Its on the main board at the back of the passenger footwell. Regards Alastair
While this adventure was in progress I pulled the fuses thinking they might have blown. No such luck. I did not pull the relays but could lay my hand on the whole area with no discomfort. The panel shows no evidence of excessive heating. One other reason I suspect the fuel is that just prior to the toll booth incident there was a lot of buzzing coming from behind me. I thought the fuel pumps were failing. If the filters are restricted maybe what I heard was cavitation. I hope so. After the noise stopped so did the car. Greg
Thanks Alastair, I have read my electrical manual and can find no reference to that switch. The attached photo shows the panel and surrounding bits. I can see that there is a RH Fuel Pump, LH Fuel Pump and another Fuel Pumps relay all stacked up on the right. The Fuel Pumps relay has a gold stripe painted on it. Can you see and describe the location of the switch you mention? Greg P.S. While we are at it, does anyone know what that paper box looking thing in the upper right does? Image Unavailable, Please Login
Hi Greg I cant see it there on yours, on mine it is a large red plastic one, I will look tommorow and let you know. Mines a 400GT (carbueretted) 1977 so will be a bit different, maybe the FI system has a different fuel cuttoff system. regards Alastair
My 400i has been in re-wiring jail since six days after I bought it, so I have no hands-on experience yet. But I have found this "sticky" from a BMW forum to be very informative on the K-Jetronic system: http://forums.bimmerforums.com/forum/showpost.php?p=15904137&postcount=6 Much help specific to the 400i and 412 is also available at this site: http://www.ferrari400parts.com/kjetdownload.php I have also bought these two books. They are also very informative: http://www.amazon.com/Bosch-Fuel-Injection-Engine-Management/dp/0837603005 http://www.amazon.com/Modify-Bosch-Injection-Motorbooks-Workshop/dp/0879385707/ref=pd_sim_b_6 The second book I bought off eBay for about $25, not the three-figure prices quoted on Amazon.
No such paper box in my panel. Check the right hand 10 or 12 terminal plug on right side of panel. See if there are two terminals that are brown or black. They are the fuel pump leads. I have my fix for that problem previously posted. Ken
No kidding! I had no idea there are so many potential sources of vacuum leaks and how much of an effect they can have on how the car runs.
Ken heres pics of the 'fuel cuttoff regulator' mine intermittently failed cutting off the fuel supply to the engine. Usually while I was in the middle of a motorway in the Swiss Alps or in the very expensive carpark in StTropez! Again as mines the 400GT it may differ. Good luck Image Unavailable, Please Login Image Unavailable, Please Login
Good Evening Everyone, Thank you all for your suggestions. I really appreciate your thoughts. As of Friday April 6, 2012 at 7:00 PM CDT the consensus of all those I have asked is this. 1. Change the fuel filters. The manual says to change them every 10,000 Km which is a whole lot less time and distance than 40,000 miles. 2. Remove and re-install all fuel associated relays. Do this about 6 times and then throw out the relays involved. 3. Install fresh relays which have dielectric grease on their blades. 4. Follow the electrical harness and remove every crimped wire connector encountered. Solder the wires instead. 5. Tighten every vacuum hose clamp to be found. This is done and there were a couple that took a full turn. The big hose clamp on the intake rubber boot took several turns of the screw. 5. Run the car and report any further incidents. Does any one have any additional advice? Greg
My car is fixed and purrs like a kitten again. The cause was water but not in its vapor form. The right side filter can was half full of it. 30 miles after a filter change the problem reappeared. The fuel tanks were dumped as were the filters for the second time. About a shot glass of water came out of the right side filter this time. From what I have learned from CIS Flow Tech, nothing will shut down the Bosch system like water will. A very small a amount of water will plug orifices in the system stopping fuel flow. The surface tension of the water is the culprit. It will get past the various orifices over time accounting for the way it "heals itself" and runs well again after sitting for a while. I hope you never need to know this information but we are all subject to fuel quality issues. In my case the newly bought fuel smelled old and skunky in addition to being mixed with water. Henceforth I will buy fuel only at very high volume stations and change filters as recommended in the manual. Greg
Hmmm, water in the fuel was one possible cause of the problems in the other thread! Avoid the low volume stations as letting an underground fuel tank sit with low fuel volume increases condensation and thus causes water in the tank to increase, eventually above the fuel pickup level. All gas station tanks have water in them, the key is to keep the water level below the fuel pickup point. That and never buy gas where a tanker truck is dropping a load of fuel as that stirs up the water and all of the crap in the bottom of the tank.
Ah, ha! You know what I'm thinking...ethanol fuel/h2o seperation. Did the car sit all winter w/full tanks??
No, it had just come in off an 1100 mile run and was filled with no ethanol premium. Perviously there had been a little valve clatter whenever I filled at this station. The car runs better on 10% ethanol from the Shell station down the street. After three weeks of pondering this situation and chasing ever more complex solutions I have reverted to the simplest possible answer... bad gas. In any case it runs without the water and it didn't with it. Greg
Sorry for not re-reading the thread, I seem to remember you mentioning that before. Bad gas it is...good one John!
Attached is an out of focus photo of a kink in the right side fuel line between the accumulator and the filter. Perhaps this is the location of the vapor lock in hot weather? It seems to me the reduced volume of fuel at the kink would boil much faster than the fuel in the full diameter line. The background shows some of the extra heat shielding I've added in an effort to cut the radiant heat in the area. Does anyone have any comments? Greg Image Unavailable, Please Login
I'd say that a kink restriction would more likely limit fuel flow (and hamper high RPM operation) than cause a warm restart problem. Also, with the two independent banks on your model, you'd have to have a problem on both banks to prevent a warm restart (but this can occur because you don't really know you have a problem until both banks are having trouble). IMO, you first need to determine if the fuel pumps are running, I'd suggest that (when you have the problem) unplug the safety switch (located on one of the airflow metering devices) and turn the key "on" - you should hear the fuel pumps run. If they do, then try restarting. Otherwise, you need to measure the fuel pressure after engine shutoff to confirm/deny if each bank is holding pressure as it should. That's an added aftermarket ECU to add "with Lambda" functionality (for US importation). Although that high watt resistor looks like it's been post-kludged on for some reason. Do you still have the added frequency valve in the WUR plumbing, and do you have (working) O2 sensors in place? Example of 400i modified to "with Lambda": Image Unavailable, Please Login
It doesn't look like it to me from this photo of my engine. The engine does however, have the "DC" box and the O2 sensors in the exhaust pipes. I have no clue whether they are working but doubt it as the O2 sensor wires are oil soaked at the crimp connection. Greg Image Unavailable, Please Login
Yes, if your engine CIS plumbing ever had the FV added, it seems to be removed now. When you say: "The engine does however, have the "DC" box and..." do you mean that there is another DC Johnson box mounted in the engine bay or are you saying that the box mounted at the fuse-relay panel is a DC Johnson brand box?
