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Discussion Starter · #1 ·
So I first started replacing oil pan gasket and oil filter housing gasket along with a few other thing and when I first started the car it ran great with no issues but after I started driving it down the street for a few seconds it started misfiring and going into limp mode. The car would struggle to go past 1500 rpm and was really rough not able to go above 10 mph and as I was limping it to my drive way I heard a pop happing every other minute that kinda sounded like a car backfiring, but from the engine bay. So I thought it was exhaust manifold gasket so I replaced the gaskets for the exhaust manifold, the manifold to the rest of the exhaust and the sap gasket. After I started it ran great for about 30 minutes and it started doing it again except this time the popping started happing more frequently and like last time no acceleration revs limited and top speed is less than 10mph. I’m at a loss now there’s no smoke from the car and the only thing I can go off is that I smell burning oil a little and that’s it. I’ve replaced the valve cover gasket a few months ago too. I’m at a loss now of what’s going on with the car so any help is appreciated
 

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Discussion Starter · #5 · (Edited)
Ok so I finally got the car home after 5 hours of waiting for a tow truck and used the scanner. So it reads that there’s misfiring in cylinders 1-5, Lambda control limit bank 1 and 2 and Lambda regulator deviation for bank 1 and 2 as well. I never really got to understand what those really mean. For the lambda control limit and regulator deviation (they came on at the same time) Ive had those for about a month or so and it came on ever sense I replaced both my camshaft position sensors for both the exhaust and intake side. The codes for the camshaft sensors went away but the lambda codes came on after and I still don’t really understand what it’s about. And thinking it had to do with the intake boot I replaced the torn intake boot after and the lambda codes where still there.

and the car is a 2001 325ci automatic the abs and traction lights are on because they aren’t working and I have a separate code for thermostat stuck open. I’m also not sure what 4 fuel trims at hot idol means.
And from using my other scanner I got lean codes for bank 1 and 2, multiple cylinder misfires, and fuel cut off for cylinders 4 and 5.
And just in case it’s related I do have a mishimoto cold air intake that utilizes the mass airflow sensor and a tuner Motorsport silicon intake boot to replaced my old cracked one just before it all started and also I mostly took apart my exhaust manifold the first time before it all started as well. Right now my suspects is the egr valve (gasket is new) and the original ccv system which has been on the car since new and the car now has 142855 miles on it.
 

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2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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Thank you for the new information.

It sounds like you have a vacuum leak as they are the most common causes of the 4 Lambda codes you have. This can be confirmed by looking at your fuel trims. Each bank will have a short term and a long term fuel trim, so there are 4 in total. The OBD2 scanner will give the values in %. The normal range for the long term fuel trims is +/- 4%. -4% means you are running rich (negative) and 4% means you are running lean (positive). Once your fuel trims get to >-/+8% then you have problems to find.

Read these threads:



You can also get lean fuel trims from an exhaust leak before or at the Pre-Cat O2 sensors. A smoke test will not find these leaks. As you have had your exhaust manifold apart, check for exhaust leaks if a smoke test does not find any problems.

True "Limp Mode" can come from the Automatic EGS module and the ABS module. Some people get performance issues which they think is limp mode, but is just really bad fuel trims. As you do have the ABS and Traction control lights up, you'll need to get a scanner with BMW software are read the trouble codes from the ABS module. It may give you some good clues. See this thread: How to Install BMW Standard Tools

Does the Mishimoto cold air intake have an oiled air filter? Sometimes people over oil the filters and the oil contaminates the MAF sensor. About the only time cleaning a BMW MAF does any good is when there is an over oiled air filter in a cold air intake. The oil on the MAF will make it under report. This causes lean conditions. As you have a cold air intake, a quick test is to un-plug the MAF as see if the engine runs OK. If it does, then clean your MAF. If that does not improve things, the search for vacuum leaks.

Your BMW does not have an EGR valve. I'm guessing that you are referring to the DISA valve on the side of the inlet manifold.
 

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Discussion Starter · #7 ·
Thank you for the new information.

It sounds like you have a vacuum leak as they are the most common causes of the 4 Lambda codes you have. This can be confirmed by looking at your fuel trims. Each bank will have a short term and a long term fuel trim, so there are 4 in total. The OBD2 scanner will give the values in %. The normal range for the long term fuel trims is +/- 4%. -4% means you are running rich (negative) and 4% means you are running lean (positive). Once your fuel trims get to >-/+8% then you have problems to find.

Read these threads:



You can also get lean fuel trims from an exhaust leak before or at the Pre-Cat O2 sensors. A smoke test will not find these leaks. As you have had your exhaust manifold apart, check for exhaust leaks if a smoke test does not find any problems.

True "Limp Mode" can come from the Automatic EGS module and the ABS module. Some people get performance issues which they think is limp mode, but is just really bad fuel trims. As you do have the ABS and Traction control lights up, you'll need to get a scanner with BMW software are read the trouble codes from the ABS module. It may give you some good clues. See this thread: How to Install BMW Standard Tools

Does the Mishimoto cold air intake have an oiled air filter? Sometimes people over oil the filters and the oil contaminates the MAF sensor. About the only time cleaning a BMW MAF does any good is when there is an over oiled air filter in a cold air intake. The oil on the MAF will make it under report. This causes lean conditions. As you have a cold air intake, a quick test is to un-plug the MAF as see if the engine runs OK. If it does, then clean your MAF. If that does not improve things, the search for vacuum leaks.

Your BMW does not have an EGR valve. I'm guessing that you are referring to the DISA valve on the side of the inlet manifold.
Ok thank you so much, I’m going to get a smoke tester soon to see, I’ve replaced a lot of hoses and gaskets but who knows what else is still leaky. And what I was thought was the egr valve is the silver cylinder part that connects to the secondary air pump and goes into the block on the exhaust side of the car. I don’t know exactly what it’s called.
the filter came preoiled and before I put the cold air intake I also had a pre oiled air filter by k&n that went into the box.
and something I’ve just realized for the past two times that this had happened it has only Happened when the car was warmed up if that changes anything. And I’m still really confused about the sound it intermittently makes when it has low power I hear the car either backfire or make a loud clank noise but only in the front of the car by the exhaust side of the engine.

when I say in limp mode what happened is when trying move the car at all it just goes no more than 5 or 10 mph and won’t go above 1500 rpm even when the gas is pressed all the way down.
Again thank you so much for your help
 

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if you have touched your o2 sensor connectors that hang off the vavle cover, you may have swapped them. it happened to me and the car was a disaster until I swapped them back.
 

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Discussion Starter · #10 ·
I’ll need to check to make sure I got the O2 sensors connected the right way, but usually I put the connecter back into the socket after unplugging the O2 sensor. Just to be safe I will, is there a way to really know that it’s the right connectors?
and with the intake boot I don’t think that’s it, I really made sure I had it on tight, I’ve made the mistake multiple times not having that stupid intake boot not tighten all the way.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Agreed about a large vacuum leak (likely you raised the engine for the job?) and the sound you describe sounds like an intake manifold backfire.
Also double check (after smoke test) the O2 sensors are correctly (not mixed up?) installed.
 

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Discussion Starter · #12 ·
Yeah I raised the engine for the oil pan gasket and for the exhaust manifold gasket. And the intake manifold backfiring? What in the world could causes that? I don’t think a vacuum leak could cause that, could it? I didn’t even know that that was possible.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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Mostly...... intake backfires are created by excess unburned fuel. If you have a major vacuum leak and there's lots of fuel unburned, it can make that funny backfire sound up inside the intake.
 

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Discussion Starter · #14 ·
huh, actually the reminds me, when I pulled my DISA valve to replace the gasket I noticed that it smelled strongly of gas and same the the intake manifold smelling it from where the disa goes into. I did some research and it seemed to be from a gas leak so when I opened the fuel rail pressure relieve valve the gasket, that goes onto the cap, was pretty much plastic and thought it was wedged into the pressure release thingy and was letting gas out, but maybe there’s a more serious gas leak with it? And when removing the gas rail at one point I remember trying to pull it out and pulled too hard and it was at a 45 degree angle with the last 2 injectors still in there. Could that have caused a gas leak?
 

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E30M3 Race F10 535 R1150Rt M Coupe
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I think you need to apply the KISS method:
Keep It Simple Stupid. Go after the simple stuff first.
Smoke test. Get a higher level scan tool and look at fuel trims etc.

The injectors can "leak" however that's outside the intake.
Can dirty injectors drip down when shutoff and or have horrible spray patterns out of the nozzle? Yes.
However simple codes and fuel trim results can help you get to the bottom of it.

BTW, any intake manifold smells like fuel.
 

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Discussion Starter · #16 ·
Ok yeah I’ll do that, I have a scanner that can read me all the values of most sensors in the car and fuel trims, that’s the amount of fuel going into each cylinder right? And if so what is a normal amount?
 

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Ok yeah I’ll do that, I have a scanner that can read me all the values of most sensors in the car and fuel trims, that’s the amount of fuel going into each cylinder right? And if so what is a normal amount?
Fuel trims are a modifier to the amount of fuel which is meant to be going in. There is a short-term one and a long-term one, and the total fuel trim are those added together.
So for example, a 5% short term fuel trim (stft) and a 10% long term fuel trim (ltft) would be a 15% total fuel trim. So it would inject 15% more fuel than the engine has calculated it needs from the airflow sensor. It constantly adjusts the short term fuel trim depending on the O2 sensor reading, jiggles it up or down until the engine is running exactly right, and all the fuel is being combusted. Ideal fuel trim is 0% but in reality you'll never get that, even just running the regular fuel with ethanol in it changes the fuel trim a little bit, between -20% and 20% total fuel trim shouldn't cause any huge running issues.

I have a feeling it's the O2 sensors connected the wrong way round. Not sure how you could check which connecter they attach to. Maybe just swap them around and see if that fixes it?
 
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