03-10-2021, 06:55 PM | #23 |
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The car obviously has multiple problems. One thing I'd check for that might be contributing to it running extremely rich is vacuum leaks. The ECM might be trying to compensate for what it perceives as a lean condition. If nothing obvious jumps out a capable garage can do a smoke test to either confirm or eliminate vacuum leaks as a problem. Good luck sorting it all out.
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03-11-2021, 07:54 AM | #24 | |
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03-11-2021, 02:02 PM | #25 |
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A vacuum leak is a good suggestion.....but this is an N55 Valvetronic engine, so engine 'throttle' isn't managed through a throttle butterfly and therefore there's no manifold vacuum. There might be manifold pressure since it's a turbo engine, but no manifold vacuum.
Somebody please correct me if I'm wrong. Your point still stands that there could be a gaping whole somewhere in the intake path that lets air bypass the MAF sensor. |
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04-25-2021, 09:23 PM | #26 |
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So I took a little break from this car, but I'm not done with it yet.
I checked for big gaping holes in the air intake path but couldn't fine any. I spoke to someone who used to work on bmws and he was wondering if the O2 sensor started going bad and causing the mixture to richen over time. I pulled the DME fuses to erase any fuel adaptations. I disconnected the O2 sensors, put a new set of plugs in (thank you FCP Euro), and started it up. With the O2 sensors unplugged, it idled fine. I let it idle for a few minutes.....everything was great. I did a fuel pressure leak down check: with the vehicle idling and good fuel pressure (about 10 MPa), I shut the engine off with the stop button. I turned the ignition back on (without starting the car) and saw the high pressure fuel rail pressure was down at 0.61 MPa (about 80-90 psi) I believe this is not good. I think the fuel rail pressure should remain high for some time after shutting the engine off. This may mean I have a leaky injector(s). ......anyway...... Took it for a ride, had ISTA connected and reading the voltage, high pressure fuel rail set point and actual pressure, and the charge pressure. I had my girlfriend video the ISTA readout. Drive down the street, and it did the same thing that it did on the previous 2 attempts: ran smooth, then start to drop a cylinder(s) and sputter, lose power, then stall. This all happens in about 1,000-2,000 feet. After it stalled, I could start it up again, but it would stall every time I put it in gear. It stayed in neutral after stalling, so I was able to pull it back home with another vehicle. Anyway, after getting home and reviewing the video, I see that the high pressure fuel rail pressure would drop to from 10 MPa to 0.61 MPa immediately when it stalled. Can anyone confirm that the fuel rail should retain pressure for some time after shutting off the car? I'm starting to think maybe I do have injectors going bad (leaky) as was mentioned earlier. |
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04-26-2021, 06:21 PM | #27 |
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Bad EKPS module?
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04-27-2021, 02:39 AM | #28 | |
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When I was testing the fuel system for leaks with ISTA on my X3, the procedure calls for fuel pressure buildup at the rail while the car is off. So I would say "yes" to your question. Pressure needs to be present in the rail even when the vehicle is not running but only for some time. This explains the noise the car makes when you first wake it up in the morning.
try the ISTA fuel system leak test. Quote:
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04-29-2021, 04:44 PM | #29 |
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Thanks for the replies.
Looks like injectors may be in my future. I'm going to search around ISTA as suggested, then likely replace injectors. It may be a couple days because I'm in the middle of repulsing an engine in a Mini Cooper S. I gotta get the mini block to the machine shop then I can get back on the X3. Thanks again! |
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04-30-2021, 05:23 PM | #30 |
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Can you tell me how to get to that test in ISTA? I looked around and couldn't find it.
Update: never mind....I realized I have an old version of ISTA that doesn't have that test....darn. |
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05-07-2021, 07:15 PM | #31 |
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Ugggghhhh!!!!!
I bought an injector removal tool. injectors 1-4 came out. They were tight, but came out. Injectors 5 & 6 are both stuck. These were the cylinders that had standing water on top of the valve cover. As I was trying to take injector 6 out, the freekin threaded nipple snapped off of the injector. Now I have nothing to grab on that injector except for about 1/4" of tube before it goes into the plastic case of the injector. I tried to get it with a slidehammed threaded into vice grips but I don't have a straight shot on it since it's #6 and is almost under the windshield. This stinks.....a super stuck injector and no great way to grab it. #5 is stuck but at least it's still intact....I didn't break the nipple off of it. I sprayed PB Blaster in the galley that the injectors slide into. I'm going to spray/wiggle/repeat for the next 24 hours and see if I can get some movement. I'm worried that if I can't get them out, the head will have to come off. I really don't want to do that. |
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05-07-2021, 08:09 PM | #32 |
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I'm thinking what I can do is weld something to the 1/4" of the injector that sticking out of the plastic. I can weld a bit of bolt to it then try to get it out with the skid hammer.
I'll obviously have to be very very careful.....but I think it's worth a shot if I can't get any movement with PB Blaster and vice grips. |
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