M30 air intake manifold

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wrote:


at
at
intake
Yeah, the plug boots just pull straight off. Just don't overtighten the new plugs. The injectors are best removed with the intake off the engine, just in case a pintle cap pops off an injector (it would fall onto the valve below and become an expedition to get it out!). Just a safe bet. The injectors just push into the intake and are held in by a rubber o-ring. The fuel rail runs across the top of the injectors and is held to them by an o-ring and a U-clip. I use a small screwdriver or long-nose pliers to get these off. Sometimes you can just use fingers if they're long enough. The fuel rail is bolted to the intake by 2 10mm bolts (on mine). Don't forget these or the rail will not move up enough to get the injectors out. The space is very tight under there, so be careful of dropping a clip. I have a full spare set from the junkyard, just in case. This all can be done without removing the intake, BUT... the whole job is easier if the intake is off the car. You will have to disconnect the fuel hose from the fuel rail (spillage) and the harness from the injectors (mark the injector number first!). I believe the harness will disconnect below the manifold and the injector harness will come out attached to the injectors. Be carful to label the other harness connectors on top when you disconnect them from sensors and senders. Otherwise, you'll get funny readings on the cluster when it all goes back together. This can be time consuming, but saves a lot of anguish. Plus you'll get the added benefit of making sure the thing is sealed right the first time. I'd replace all the intake-to-head gaskets (6 of them). If one is gone, good bet others are going. I did all this on an m20 325is. WHAT A BITCH doing it on the car! I replaced all 6 injectors on my '86 535i, intake on the car, in less than 45 minutes. Your big issue is the #6 intake gasket replacement.
Bill in Omaha '86 535i
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Hey Bill! This is exactly the question I had for ya today. I was up until midnight trying to figure out how to get to the intake manifold because there is a wiring harness and a fuel rail blocking the intake hex bolts. You're right, there is hardly any room to maneouvre in there. I couldn't locate the two 10 mm bolts - are these the ones closest to windshield? I separated the cylindrical object at the end of the fuel rail thinking it was the gas vapour ventilation return because it had a vacuum hose attached, but found out after slight fuel spillage that fuel was going through this! This can't be the fuel filter, can it? Anyway, I gave up because my baby was crying upstairs (room on top of the garage where I was working), rubbed on some Simple Green and off to bed. But I couldn't sleep and returned quietly to the car at 4 AM and spent two hours trying to find some type of connection that I could undo to remove the obstructions to the intake gaskets. So, from what I can gather I need to disconnect the fuel rail from the injectors first via the U-clip? And then how does the wiring harness go away? This is really the biggest obstacle...if I could get that damn harness off, I would be able to at least see all of the gaskets. Yes, you're right, #6 is completely hidden by the wiring inlet from the windshield side.
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No. It is the fuel pressure regulator.
Get a Bentley manual so you know what the hell you're doing in there. It may cost you $50, but it will save you that much in aggravation and time, if not money paid to *redo the job properly*, the first time you use it. -- C.R. Krieger (Been there; done that)
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Bill in Omaha '86 535i
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I got the wiring harness off, but there were several connections under the intake manifold, one of which was the round barrel type electrical connection you mentioned. Can I now just disconnect the manifold and replace the gaskets with the fuel rail right on there? I hope so (the less dismantled the better, although I would like to fix the oil leak now that I have the engine compartment laid out.) And do you recommend I clean out the air flow meter and the throttle (there is a bit of brown scum) by spraying some degreaser or will this damage anything on the insides?
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I got the wiring harness off, but there were several connections under the intake manifold, one of which was the round barrel type electrical connection you mentioned. Can I now just disconnect the manifold and replace the gaskets with the fuel rail right on there? I hope so (the less dismantled the better, although I would like to fix the oil leak now that I have the engine compartment laid out.) And do you recommend I clean out the air flow meter and the throttle (there is a bit of brown scum) by spraying some degreaser or will this damage anything on the insides? -----
12x 13mm nuts on manifold, 1x nut on the maniflold support and it should lift out. Use caution and watch for parts that may drop into the head as the intake side will be exposed. Also the 6 intake gaskets will be visible and may be stuck to the manifold or the head. Of course #6 (closest to the firewall) will be destroyed already. I recommend keeping one good one for a tracing pattern just in case (I do!). There will be some air hoses threaded in there. It's safe to clean the air flow meter (AFM), but DO NOT SPRAY THE TEMP SENSOR in there (it's a nub in the flow path. I just sprayed a little and wiped it out until it was clean and the door swung smoothly. Free motion is essential, NO BINDING. Flex all the connecting rubber to check for cracks. In a pinch, I wrapped black plastic electrical tape around them until I got another piece. It will seal, but only as a temp fix. The goal here is NO AIR LEAKS. Replace all those DAMNED crimp clamps with screw clamps... you'll appreciate it later when they get loose. Zip ties work in a pinch. Notice I have a lot of pinch fixes? LOL! So do these other guys. Also, a temp gasket can be made from the cardboard backing from a note pad. It's not too thick and is compressed like the gasket we should use. I once used one during a highway trip of 1000 miles and it was still good 3 years later when I sold the car.
Bill in Omaha '86 535i
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Bill, I know of a person who has a M50 engine in a 1994 525is. It has been sitting in his garage for a year because the engine will overheat if he turns it on. He took it to a dealer before he placed it in his garage and here is the report from the dealer:
'Started vehicle cold. Found running rough for first few minutes beforte warming up. Perfromed short test, No faults found in DME. Removed DME to check for corrosion or moisture . ok. Check ignition coils for cracks or defects. ok. Reoved spark plugs. Performed compression test. Compression test failed #6 cyl first time but passed second time. During compression test, noticed oil spraying out of cyl #3. Looked inside and noticed top of piston head covered in oil. Performed leakdown test ..results:
1 2 35 4 5 6
cyl #3 leakdown not acceptable. Heard air coming out of dipstick tube during #3 leakdown test. Vehile requires engine rebuild or replacement."
Now, I am very skeptical about the conclusion that the engine needs replacement. My question is: would a gasket change take care of the oil leak problem here in cylinder 3?
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Doubt it. Air coming from dipstick tube more than often means piston blow-by or a bore/piston/ring problem.
I would go for a strip down and a physical look at the bore (could be cracked or scored) Piston (cracked, holes, partial seize?) rings (broken, scuffed, seized and damaged.
$$$$$$$$$$$$$$$$$$$ seems the price unless you do it yourself. I don't think you can drop the sump on that model????
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wrote:

blow-by or

cracked or

seized
think
-----
Why won't the sump come out? You may have to lift the engine a few inches first. After parts replacement cost, DIY labor is just time. This would be best on a lift, but off the ground about 2 feet might do it.
Bill in Omaha '86 535i
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Just a thought Bill - as you say off the mounts and off the floor maybe with a bit of fiddling and twisting it probably will come off.
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-----
First guess is the rings on #3 have failed, thus the oil. You didn't mention smoke from the exhaust or anything about coolant, so I can't be more specific. Either way, I'd remove the head. If the rings need replacing, it can be done on #3 without removing more than the head and oil pan (I've done it), i.e. the engine can stay in the car. This will allow for direct inspection of all the cylinders, walls, and the bottom of the head and valves. You'll be able to replace nearly anything you need to at this point. New: head gasket, head bolts, rings #3 (they come as a complete set and I might just do them all to be safe since it's open), valve cover gasket. Check the timing chain guides or belt and tensioner, intake-to-head gaskets if removed. Maybe do the water pump and gasket. No need to replace the engine. They are built pretty well and this should be rebuildable easily. You will see the cause of the problem when the head comes off. Unless the rings gouged the cylinder wall or ruined the piston top (doubtful), this should be basic R and R. You may need the cam holding tool for the head removal. Time consuming but not hard, and uses basic tools. Get access to a Bentley manual first. Oh yeah, what about coolant system?
Bill in Omaha '86 535i
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SUCCESS !!! I am happy to report that I have this puppy purring like a tamed tiger. My intake manifold refurbishing seemed to do the trick. Note: I didn't use any RTV sealant on gaskets because I suspect (I could be wrong) that it degrades the gasket material. I also cleaned out the spark plugs, ICV and air meter and throttle, and replaced the PCV hose. Total cost about 40 bucks Canadian, and about 8 hours of labour. I did change the oil and filter and used some fuel injector cleaner in the gasoline tank. I guess the next steps will be to change the oil pressure switch and ATF. A very big thanks to all of you who helped me out with info. Now, how do I change out the oil pressure switch at the back of the head?
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noobiedoobie wrote:

Congrats.
Well, it (RTV, aka silicone sealant) makes great gaskets. But you do run the risk of fouling your O2 sensor(s), so best not to use it much.
--
-Fred W

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SUCCESS !!! I am happy to report that I have this puppy purring like a tamed tiger. My intake manifold refurbishing seemed to do the trick. Note: I didn't use any RTV sealant on gaskets because I suspect (I could be wrong) that it degrades the gasket material. I also cleaned out the spark plugs, ICV and air meter and throttle, and replaced the PCV hose. Total cost about 40 bucks Canadian, and about 8 hours of labour. I did change the oil and filter and used some fuel injector cleaner in the gasoline tank. I guess the next steps will be to change the oil pressure switch and ATF. A very big thanks to all of you who helped me out with info. Now, how do I change out the oil pressure switch at the back of the head? -----
It's located on the driver's side at the firewall end of the head.It just screws into the head. I think it's a 19mm or 21mm wrench. You just need enough grab to break it loose, then it will finger turn out. 5 minute job and about $12. Hopefully you can reach it with all the stuff back on! Congrats on the better running.
Bill in Omaha '86 535i
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... and I think that includes buying the wrench. It's at least a 21; maybe a 22 mm. I've never paid more than $8 for the sender. -- C.R. Krieger (Been there; done that)
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I may have to buy another one. The one I bought from the dealer today I clutzed down onto the transmission housing. Where could I find the cheapest one? And that hex nut was a big one. I didn't have the correct socket so I had to MacGyver it with an adjustable wrench. Ebay?
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Got a problem...I accidentally dropped the new oil pressure switch onto the transmission housing. I heard it roll all the way to the back somewhere towards the rear of the vehicle. There's 20 bucks down the drain, unless you can help me find a way to get it out. Can I access the top of the transmission from the interior of the vehicle perhaps through the dashboard somehow? I really don't want to take apart the intake manifold again...what a hassle. Help me...save 20 bucks...please...
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wrote in message

just
job
It's on top of the heat shield, between the underbody and the driveline. Jack up one side of the car and undo the screws along one side of the heat shield. Stick your hand in there to get the switch. I'd tap the heat shield to determine where the switch rolled to (kinda like finding a stud inside a wall).
Bill in Omaha '86 535i
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Now that the oil switch has been replaced, I have no more oil leaking and the car doesn't smell of oil after I have been driving it. The leaky oil switch is placed right over the #6 air intake vent, such that when it was leaking it spilled oil right onto the gasket and eventually over time, the oil got into the air intake and minute amounts of burnt oil made their way out of the exhaust resulting in the foul odour. Now it is completely gone! What a great remedy. Unbelievable. Just an FYI, I am just about ready to strap on the hydroxy generator. What is the official mileage claim for a 91 535i?
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On 18 Apr 2007 08:06:34 -0700, snipped-for-privacy@gmail.com wrote:

Why don't you go for the whole enchilada? Strap a titan missile to the trunk!
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