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#1
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Fire out of intake.. Quite a story..
Here is the story.. A month ago or so, I decided to clean up around my intake valves since the cylinder 6 on my X5 had slightly low compression (130 psi compared to others being around 180). I took the intake off, did some work on the valves (mostly filing their sides with fine finger nail stuff, hoping to get rid of any carbon deposits that may cause the compression loss. Once the work was done (Hoping for the best), I put the intake back on, (added some gasket sealant around each intake gasket) and tried to start the car. It cranked for a while, sounded like it almost started then it just completely stopped. There was a lot of fuel smell. Flooded? I tried to turn the crank by hand but it felt stuck, so I gave up for that day. Next day, I tried to turn it again by hand and interestingly it was turning loosely. So I tried to start again, but it kept cranking and no start, eventually, out of battery power and the crankshaft felt very tight again. I could not turn it by hand this time until I turned it back and forth and it eventually became loose. So, I took the intake out again, thinking I did something wrong. Looked like I used excessive gasket maker and it partially blocked cylinder 8, which may or may not have caused the flooding (and probably a hydrolock related to it). After the cleanup, I tried to start again. This time when I cranked it (starter motor power), there were weird noises, a lot of loud popping and eventually FIRE out of the intake. Of course, I was following the flooded engine advice on the internet, so trying to start with WOT (gas pedal down all the way to have minimum or no fuel in there). I was worried after the FIRE out of intake happened multiple times so I stopped trying. I thought, I might have messed up the timing as I was turning the crankshaft back on forth to loosen it so, I took off both camshaft covers and timing was perfect! (Checked with timing metal thingy inserted and the timing blocks on, on each of the camshafts). So that could not somehow leave the intake valves open at the wrong time to shoot fire out of there. Also, as I tried to start, before the fire out of the intake started, all the hoses from the air filter box connecting to throttle body popped out (shot up) during those big explosions. So, I started to worry about the fuel pressure regulator / filter being broken and sending fuel in there which may cause those explosions. So, I replaced the fpr which I hoped would be the solution. Once again, I repeated the same process of starting a flooded car (I checked several cylinders and there was 0 compression on them (meaning piston wash?), although I could get some compression back (around 30) by squirting oil in there and cranking the engine multiple times without the fuel pump fuse and spark plugs). I added around 10 ml of engine oil in each cylinder, cranked a bit and put the spark plugs on and everything connected including the fuel pump fuse. I really thought that everything would be ok this time, because couple of days earlier my wife cranked the car multiple times (as I watched with fire extinguisher in my hand, in case) with everything connected and there was no fire but the car would not start after 10 cranks (10 secs or so each time). She did not do WOT which I thought was the problem. I tried it again today by myself hoping for the best. Tried with WOT and there is a huge pop once again which seems to happen, so I kept cranking. This time I started hearing some metal noises (oh crap, something broken?) and eventually the FIRE out of intake once again. I decided this is a two men job and stopped. At this point I am really hoping nothing is broken yet, because the engine keeps cranking. What else would be the problem? I really like this car and I don't want to give up on it.. Cheers, Ozzie
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X5 4.4 01 |
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#2
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not sure if I have any answers, but why not use a valve lapping tool to clean up the valve and recess? filing will most certainly not be a perfect circle. That gasket probably didn't help, but not sure how that would cause a backfire. Does the vanos allow valve overlap at high rpm? Maybe there's something there
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#3
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I don't mean to be a jerk, but there's a whole lot of "you did WHAT?" in this writeup.
That said, there's definitely a morbid curiosity on my part to see how this turns out but I'm not sure I have time to list the MANY different ways one might have been advised to approach this issue.
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2005 X5 3.0i - 71k mi (9.2018) -> 81k (9.19) -> 100k 9.21 --------------------------------------------------------------------- SOLD : ( 2003 X5 3.0 - 177k mi (9.2018) -> 186k (9.19) -> 205k (9.21) SOLD : ( 1997 328is Coupe - Hellrot Red SOLD : ( 1988 528e w/ Bullseye s256 / MS2 Extra / GC Coilovers / Yukon Coils ~ 300+ HP |
#4
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Quote:
My attempt to clear the carbon out of particular valves with only taking the intake out was to simply avoid taking the head out and rebuild everything which is a lot more complicated and time consuming obviously. I will also agree that I used too much gasket maker for sure because I saw that part of the intake port was slightly worn and I was trying to make sure it was covered but it ended up covering the port when the intake got tightened. Other than that I followed advice from many bimmer boards, particularly how to start a flooded engine. You are definitely not a jerk for wondering why I did the things in such a way. I always try to be more creative but my lack of knowledge sometimes gets me in trouble. Let's hope I did not kill the engine yet.. Cheers, Ozzie
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X5 4.4 01 |
#5
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I am also reading, starting a flooded (and bore washed) BMW with WOT is wrong because newer BMWs (even 2000s) do not support that procedure. I may be simply flooding the engine again by flooring the gas pedal which may or may not explain the fire out of intake. When my wife was trying to start without WOT, it would not start but there was no fire or noise from the engine other than the usual turning sound.
Cheers, Ozzie
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X5 4.4 01 |
#6
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You just need to stop now. You are way over your head here. And I am saying stop before you hurt yourself or someone else. Your skill level/understanding of these engines is minimal. First off, you don't know where the low compression is coming from. Could be valves, piston rings, blown head gasket. So your nail file trick was useless. And thinking you changed the timing by rotating by hand. Can't happen. ALL OF THAT GASKET Material is not necessary, NONE! Lastly, this is a fuel injected motor that when operating properly will start right up and not need any excessive cranking. You totally missed something upon assembly and when it didn't start right away you should have stopped right there and diagnosed. Either do some research or take the car to a reputable shop.
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Dave S. Northeast 2003 4.6is 2005 E53 4.4 2003 E39 Msport(a REAL ONE!) 1959 Fiat 600 |
#7
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Quote:
Firstly, I have come to the conclusion of valve leak after multiple compression and leak down tests. The issue was with cylinder 6 on bank 2. Bank 1 and most of bank 2 cylinders had around 180 - 190 psi which I believe was good for a 200k+ engine. Cylinder 6 had around 140 psi. Although it was not so bad, mixed with the constant noise of ticking (after rebuilding then replacing all the lifters) I thought there might be something I could do about it. Then I did a leak down test and it confirmed that there was a leak on intake valves. I first used some german made foaming solution to clean the cylinder and the valves multiple times (Blue Chem carbon X) which did not change much. When I looked inside the chamber with a borescope, it was mostly clean inside but I thought I saw Carbon deposit spots on intake valves. I thought the reason would be the intake valve seal leak which would drop oil on top of valves and burn then to cause carbon spots. (I changed the valve seals to stop that from happening). So, I had to decide on how to clean the valves further. It would either have to be taking the head out and re-seating them or taking the intake out and trying to clean them with paper based very fine nail files first. So, I took the intake out and had access to valves from top and did the work and put the intake back in. I agree with you that there is no gasket maker needed on intake gasket area but as I mentioned, one of the ports was slightly worn out and that worried me so I applied 'some' there which obviously was too much and caused a blockage which I believe eventually caused a fuel wash of cylinders. I am also aware that it's 'almost' impossible to break timing by turning the crank by hand but a friend was actually successful on doing that when he was putting the transmission back on (which I rebuilt for him) and as he was putting the flywheel bolts back on, something was stuck and he was powerful enough to loosen his bank 1 exhaust camshaft which we found out when we took the valve cover off. I also re-timed his engine and it is nicely working now. I am aware of how much torque is put on the cams to tighten them, I re-timed my car multiple times when I worked on my lifters (rebuilt first, replaced second). Now, I am still dealing with fuel washed bores. I cleaned them up off fuel and put some minimal oil in there to get the compression back again and cranked the engine multiple times but I can't seem to get compression from some of them. Unfortunately, I got some bad advice on how to start the car in this situation (trying to start the car WOT, activating clear flood mode which apparently does not apply to many BMWs) which seemed to make things worse I think by flooding the cylinders again. Once again, I appreciate your concern and I'd like to hear from you about what else can be done. Andrewynn who posts here all the time, tells me to use starter fluid to get the engine going and establish compression that way.. Any other ideas? Cheers, Ozzie
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X5 4.4 01 Last edited by turquise1; 08-05-2021 at 09:35 AM. |
#8
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I have the 3.0i, so am not familiar with yours, and have only skimmed the above, but here are some thoughts, mostly about simple things to try:
If you're worried about too much fuel / flooding / hydrolocking, how about pulling the fuel pump fuse, let any fuel dry out, and see what happens just with starter fluid? Your comments about the engine binding and then being free the next day sounds like a cylinder filling with fuel. I've read of that happening with a leaking fuel injector. ??? Spark plugs out, starting with the cylinders you messed with, to see if that effects the binding. There's maybe also a chance that some of that gasket maker stuff is "in there." I know the back fire is a much more dramatic event, but this binding is important and figuring it out might get you to the solution to everything. Maybe pull all the spark plugs on bank 2, to effectively remove that half of the engine and see what happens with the part you did not touch??? But of course don't forget how dangerous gasoline can be while searching for the answer. Good luck.
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2001 X5 3.0i, 203k miles, AT, owned since 2014 |
#9
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Quote:
After doing some reading, I also suspected the fuel pressure regulator leaking fuel in there thru it's vacuum line which I replaced but it did not make a change. Right now, I am cranking with no spark plugs with some minimal oil inside each cylinder to establish compression again. What I noticed yesterday was on bank 2 side the intake valves are not completely closed when piston at TDC (looking inside with borescope). They would close right after piston starts to head down. That may definitely cause a compression issue, correct? It may also cause the fire out of intake problem if the intake valves are still open in compression stage? Would that be a retard position caused by Vanos because otherwise the timing looks ok with the pin on flywheel and timing blocks I placed properly holding each cam correctly. So today, I will take Valve Cover off one more time to see if I can see any problems with Vanos. Cheers, Ozzie
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X5 4.4 01 |
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