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Old 03-07-2014, 10:04 PM   #1
Xeus
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P0101 related issues (How to diagnose the problem)

Hello fellas,

I have been on the forum for a while and I have learned a lot from you guys. Now, I am helping other BMW owners. Once again, I need your help and I am also here to share my thoughts on the issue.

First of all, I have done an extensive research before posting the question(s) so please bare with me.

The CAR: I have an auto 99 323i. In 2011, I made a semi-complete maintenance on the car that included replacing ccv and hoses, air lower intake boots, upgrading to KN air filter, replacing spark plugs, alternator, oil filter housing gasket, oil pan gasket, fuel filter, engine mounts, engine mount brackets and the list goes on like this. I just changed the Intake Camshaft Position Sensor (ICPS) today.

CODES: P0101, P1622 but NO CEL/SES on!

The SYMPTOMS: If the engine is completely cool i.e. if I am starting the car in the morning, it never hesitates and immediately starts. However, during the day, lets say the engine is at a mild temperature (little bit over the blue line) it won't start won't fire up. Sometimes it takes me 3 times to start it. Sometimes more than 5 sometimes 2. Sometimes pressing the gas pedal at start helps. Sometimes it does not at all.

For the first time ever, transmission and DSC lights came on and the car was on limp mode. After turning it off and waiting for 5 minutes, I started the engine back without any lights on, immediately drove back home without problems.

WHAT I HAVE DONE SO FAR:

Research, research, research and more research...

There are a lot of posts about P0101 error with additional CEL codes. Most common problems are TB, DISA, ICV and MAF and ICPS (I replaced it today). Some had success changing the MAF and/or ICPS, some had not. Replacing ICPS did not help in my case. I am going to clean all of them (TB, DISA, ICV and MAF) properly by taking them out tomorrow. I will do a vacuum leak test as well, I will check the CCV hoses one by one and will report back. I will also read the voltage on the MAF connector.

Occasionally, a few reported/suggested that it could be the fuel filter or fuel pump. (Let me clear one thing, this happens no matter how much gas I have in the tank). I replaced the fuel filter less than 10k miles ago (so I am eliminating the fuel filter) and I use seafoam before oil change to clear the gunk in the engine (I put some in the gas tank too, I know the procedure). I did an oil change 200 miles ago. Some said, O2 sensors might be the culprit but the OBD is not throwing any codes about them. So I am eliminating them for now.

DSC and transmission light coming on seems as a common error that some suggested changing the tranny fluid because it might be running low (which I will, not only because I think these may be related issues but also it is about time) and some suggested that the computer (ECU or whatever) "thinks" engine is not generating enough power that the tranny should receive.

The QUESTION(S):

Does pressing the gas pedal only effect the TB and/or does it also tell the fuel pump to send more fuel? I need to know this in order to diagnose my problem. I am more inclined to think that TB is getting stuck but I cannot understand and why not early in the morning (cold engine)? Could it be the secondary air pump kicking in and providing more air to the engine? If that's the case (the SAP is providing more air), then it cannot be TB, am I right?

Sorry for the long post but I wanted to be as descriptive as I could.

TIA

Last edited by Xeus; 03-07-2014 at 10:11 PM. Reason: typos
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Old 03-07-2014, 11:08 PM   #2
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Does your CEL work? If there are codes, it's supposed to be on.

If you have a buddy with the same model, swap MAF for trouble shooting.
The fuel pump doesn't send more gas when you press the pedal, the injectors stay open longer. I don't think you have a TB problem.
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Old 03-08-2014, 09:25 PM   #3
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Last night after I drove 15 miles, the engine stalled at the entrance of the apartment parking lot for the first time ever since I did a maintenance in 2012. It fired up after 4th try and I parked it.

Today, I could not do the smoke test but I took out parts to visually inspect the ccv hoses, TB, DISA and ICV. I found a little bit of oil leak at the CCV joint under the intake manifold (the pipe that goes to the top of the engine). Air intake boots are like new, no cracks or tears. Cleaned the TB, MAF and DISA, just in case, although they are pristine clean, no gunk, no spec of dirt in chambers. I did the DISA vacuum hold test. It is working properly. I changed the spark plugs but had not time to put the parts back on, I have not started the car so I do not know yet. I will measure the MAF voltage tomorrow. Although, I changed the ICPS, the ECU is still throwing the ICPS error code but it is a pending code (I do not know what it means), it is either the wiring or the DOA item, or the code is for the Exhaust CPS.

The only thing that comes to my mind is the faulty MAF at this point. I will try to run it with the MAF disconnected and inspect the changes. Then I will order new MAF and/or exhaust CPS accordingly. I will report back.
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Old 03-11-2014, 04:54 PM   #4
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More info and questions;

MAF seems to be working fine, no more codes after clearing them except p1622 which is a faulty thermostat. Intermittently P0340 shows a pending fault even after changing the ICPS. I cleaned the ICV because gunk built up inside which took me 45 minutes and half a can of break cleaner (TB cleaner did not do anything at all). Cleaned the leak around the CCV hose to the vanos, used a pipe clamp to secure it tight at the CCV joint. Cleaned the TB and the MAF. Last night for a second or two the cluster info lcd went black and came back on with pressing on the gas pedal. I went home after driving 30 minutes, the car was at idle in the parking lot and was hooked to a obd scanner over the bluetooth using Torque, revs significantly decreased (100 rpms) when I pressed the window buttons. I tested it several times, rpm decreased each time. Is it a bad battery? I will read the alternator and battery output today and report back. BTW no alternator (battery) light on yet (except when it stalls). This morning it almost stalled at the traffic lights when I tried to accelerate. 30 seconds later it stalled when I hit the gas pedal and fired up after 5th try.

Pulleys are bad and I will change them today but there is a rattle noise from the vanos although I changed the vanos seals 20k miles ago. Maybe the secondary timing chain tensioner or timing chain tensioner? I recently replaced oil to Mobil 1 0w-40 after 15k miles. Any relation? Is it normal to have crude oil in the intake manifold and the ICV? Is it a faulty CCV?

Last edited by Xeus; 03-11-2014 at 05:29 PM.
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Old 03-11-2014, 08:28 PM   #5
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Here is more info,

I checked the voltage on the battery. It read 12.45V before the ignition and read 14.08V after the ignition. I think alternator is working fine. Then I drove around a little bit stopped the engine, waited 10 mins read the voltage. It read 12.25V Before the ignition and read 14.01 V after the ignition.
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Old 03-11-2014, 08:43 PM   #6
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If you have codes, the CEL is supposed to be on. Does the light work?
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Old 03-11-2014, 09:52 PM   #7
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CEL worked the first time I replaced the spark plugs, cleaned the parts and put them back on and started the engine. After that I cleared the codes. CEL does not turn on now but when I scanned the ECU, Torque reads 2 errors, 1622 and 0340. 0340 is in yellow and says pending error. I think it is weird, maybe the problem have persisted longer than I thought but since CEL did not light up, I had not known.

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Old 03-11-2014, 10:52 PM   #8
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So the light works, but the codes are pending codes, so they don't trigger the CEL.
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Old 03-12-2014, 01:52 AM   #9
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Here is the video. Even after cleaning and tests. It may be a faulty starter but that alone does not explain the erratic idle and stalls.


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Old 03-12-2014, 02:56 AM   #10
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Here is the engine rattle, or maybe bad pulleys?
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Old 03-12-2014, 11:07 AM   #11
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bump
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Old 03-13-2014, 01:24 PM   #12
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Heeeeellllpppp!!!
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Old 03-13-2014, 03:33 PM   #13
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First...a bump for you.

Second...if the icps wasn't OE...that could be it. Also...I vaguely recall in the past that some weren't sure if the cps code was intake or exhaust...that I don't know about...never ran into this issue myself.

Third...you said that you'd 'upgraded' to a KnN filter...and if oiled, most regard that as a downgrade...and it can foul the MAF...have you tried running once started with MAF disconnected? That would point to either MAF or back to an airleak...though neither would explain intermittent start.

Get back to the basics for that starting issue. Among intermittent starting failures...Fuel pump seems to be the first and the starter is a distant second. Ditto, something the ignition switch, though that seems to usually also 'show' as other odd electrical issues...like with radio and other seemingly unrelated electric issues.

Check battery voltage too...though that doesn't seem to be your issue...easy enough to check. And make sure the cables are really firmly on the battery...pull up on them.

Also, you're assuming all the work you did was done properly with right parts. If there were other AM parts used...that again might explain your rough idle. Finally, don't assume that this is one issue (sorry), but you could have more than one common issue.

Anyway, work from simple to complex...and also know that AM electronics...like cps...often don't play nicely with our cars' delicate electronic soul.

hth a little.

Good luck!
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Old 03-14-2014, 05:24 PM   #14
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Here's some more info and research findings;

In the last 2 days, I tested the alternator assuming that it is not providing enough power. When I disconnected the neg battery cable while the car is running, the car kept running. That concludes alternator is working. However, I found something interesting, battery looked like it leaked from the top but not too much maybe less than 1/10 of an ounce and it still provides 12.2 V at start. I cleaned the top and will check back this weekend, would there be any other leaks.

Second test: I made my friend crank the engine while I watched the pulleys, it is intermittently turning them. That concludes starter is bad or electrical circuit to starter is bad. The starter relay is built on, so I will have to change the starter at any rate.

Today's symptoms and research:

The revs decreased and the engine stalled with pressing the gas pedal while idling at the same traffic light where it almost stalled 2 days ago.

While I was brainstorming why car would not start when it is hot, I thought of the relays in GM5. They have the same erratic behavior. They unlock the doors intermittently when the weather is hot. So, I thought it must be the fuel pump and/or DME relays. It may also explain the voltage drop when the window buttons are pressed. Then I came across this thread at http://forum.e46fanatics.com/showthread.php?t=865516. According to this thread, the thermostat and bunch of other stuff including the ICPS, DME relay, fuel pump relay, MAF, SAP are on this fuse. The p1622 code tells me thermostat is not working properly. I am wondering if it is shorting or drawing too much current over the fuse, maybe not enough to blow it but heating it. Although this is contradictory to laws of physics because when that fuse is heated due to more current, it must allow the electrons to vibrate quicker, thus allowing faster current flow rather than slowing the current. But therefore, maybe faster current flow is causing the relay to heat too? Does this sound plausible to you? Also, V = I x R, assuming a constant resistance on the circuit, when current decreases, voltage decreases as well. This may explain that the thermostat is drawing more current and decreasing the voltage on the circuit. Yet I could not find any relation between pressing the gas pedal and thermostat drawing more current because thermostat is heat operated not gas pedal operated.

Third test: I could not hear anything from the fuel pump. Took the rear seat out, the plastic gasket, closed the doors and all I could hear was the wind. Therefore, I am more inclined to think that the heated relay is the cause of this because the engine fires up intermittently and I can drive the car. If the fuel pump was completely shot, I would not be able to drive the car.

What I will do;

First, I will swap the horn relay with fuel pump relay and see if this helps. Second, I will check the #3 fuse, 20 amp in the engine bay. Maybe I can check it while the engine is running to see if it gets hot. Third, if I conclude the relays are the issue, I will buy DME and fuel pump relay. $14 a piece is not that bad.

Anyways, I will report back when I do the tests.

Last edited by Xeus; 03-14-2014 at 05:42 PM.
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Old 03-15-2014, 10:42 AM   #15
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Last night I replaced horn relay with fuel pump relay, it helped a little bit but I do not think my problem is the fuel pump.

I disconnected the MAF while the engine was idling, the revs decreased and the engine almost stalled for a sec but it kept running normally afterwards. I did this twice, same thing happened. Car kept running but transmission light came on at idle. So does this mean a faulty MAF?
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Old 03-18-2014, 02:19 PM   #16
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I did a little research in the mean time while I was about to give up. I found some threads that the MAF and air filter can cause the transmission go in limp mode. Then Doug had said, K&N is a downgrade because of oiling the filter. All these problems started to occur after I cleaned the air intake filter and oiled it. I must have used too much oil because the oil literally seeps from the crevices. I will change that oil filter to bmw performance air filter. The fuel pump, the fp relay, the dme relay, the starter, maf, exhaust cps, transmission fluid, timing chain tensioner, secondary tct, air intake manifold and the radiator are also on the maintenance list. I will miss the torque K&N provided, although not that significant.
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Old 08-14-2014, 02:51 PM   #17
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Solved the codes

First of all, this is going to be a long post.

I realized my problem(s) were related to bunch of different parts.

The intermittent transmission/rough idling/loss of torque problems:

These were only MAF related because of using too much oil for the K&N filter. After leaving the car under the sun for a 3-4 days, some amount of oil evaporated and transmission acted like normal, however I DO NOT recommend K&N oiled filters for automatic cars. The transmission leaps when the filter starts to get clogged.

No cranking/intermittent cranking:

The starter was failing, the solenoid was engaging intermittently. Replaced the starter (that was hell of a job) and no more intermittent cranking problems.

Due to extreme cranking and battery being old and not properly ventilated, it finally died, so I replaced that too.

P0101

Both CPSs were replaced since P0101 was related to these. There is an ambiguity that what code relates to which of the CPSs. So I replaced both. No more hidden SES lights.

P1622:

Since my radiator was leaking badly, every time after a long drive thermostat was stuck open in order to compensate the loss of coolant in the system throwing the SES code P1622. (This might be poor explanation so, correct me if I assumed wrong) New thermostat and radiator installed (NISSENS - it does not fit like a glove but not too bad, seems like a decent choice for the buck but time will tell), used BMW coolant and properly bled the system.

Rattling noise:

New belts and pulleys were also installed. Although the belts and pulleys seem irrelevant to the issues mentioned above, they helped increasing the performance of the water pump, A/C and the alternator, in general overall performance of the engine. Engine operates more quiet and smoother. No more whining, or rattling noise.

Fuel pump/relay/filter:

I realized I have only one problem left to solve after replacing those parts. I removed the intake manifold from the engine to reach the starter. As you might now, injectors/fuel rail is attached to the intake manifold. I removed the fuse #054 to disengage the fuel pump. Then I pushed down the schrader valve pin expecting fuel to spray out. Nothing happened as if there was no pressure in the fuel lines. This was the first hint that fuel system has a problem. I was not able to realize this since the starter solenoid was engaging intermittently.

The first fire-up took a little bit longer than what it was supposed to be, after replacing the starter. It cranked the engine finally in the first try but the engine had a rough idle for half a minute then, eventually became stable with proper idling. I assumed fuel pressure needed to build up in the rail so I was not that concerned. I drove the car for 15 minutes at lower rpm range, came back home safe. 2 hours later another firing-up took longer and there was a significant loss of power. Engine did not want to operate at higher rpms. This was the second hint. I replaced fuel filter 5000 miles ago and have had no problems before, so I doubt it is the filter. The other things I can think of are the fuel pump and the relay, especially a soft failing fuel pump. I already ordered them. I will report back.



P/S: Throttle body cable is tight, no slack. Injectors and the injector wholes on the intake manifold were properly cleaned and o-rings were replaced. No fuel leaks on top of the intake manifold. Valve cover gasket was replaced and I used proper amount of high temp. rtv silicone at necessary spots to seal it. All the vacuum lines were carefully inspected and I replaced the necessary ones, used zip ties around the joints where I can. There are no vacuum leaks.

Last edited by Xeus; 08-14-2014 at 03:01 PM. Reason: more info
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