Hey guys,

I'm confused. I've searched and searched, and it seems that I have a mix of problems, and some undiagnosed ones. This all happens about a month after I did a complete maintenance job; 12 NGK Iridium IX's, gapped at .039 according to specs, used dielectic grease and anti-sieze according to splinter's guide. Torqued down to specs. Replaced oil and oil filter, along with new K&N's. Now the problem.

My m112 stalls. ALL the time. The first time this happened I was driving home from work, and my speed was around 40mph. It then suddenly dies on me, flashing a battery/alternator message, and I pull over to the side. I restart it, and try to gas it, but it's hesitating like mad, even with my foot on the pedal. It didn't make it past 2mph before it stalled again. This happens every time I restart it. So I get it towed back to my house.

Then the fun starts here. Now, whenever I start the car, it idles like it is dying. It would start up, hang in around 1100rpms, then drop close to 100-200; sometimes it would recover, most of the time it just stalls. But it always stalls within 30 seconds. Even worse when I step on the gas, as it immediately dies out. At first I thought it was the coil packs, as I was having problems with it before. About 2 years ago, I was told that 2 of the packs were no good, but I never got to replacing it. I borrow Temjinx's 6 coilpacks from his C32, and I replaced all of them. Same problem, stalls after startup. Misfires are not apparent however.

I then decide to try unplugging the MAF to see what the default fuel map does. Car stays idling, way past the prior 30 seconds! However, it stalls as soon as I push the throttle. I also believe I hear a vacuum leak, however it was too dark and late for me to continue my diagnosis.

So what I'm wondering is, is my MAF faulty? I want to clean it, yet it might not be it as it still stalls as soon as I step on the accelerator... Can anyone give me some insight on what I can do? I'm tired of this car already, so that's why I'm also parting out. Thanks in advance for reading this long post, but I wanted to get the details hammered out as much as possible, so there can be a better diagnosis.

 

Easy enough to check the battery cables and the ground posts under the hood. The usual clean shiney tight connections. I don't think your maintenence brought this on. You picked an excellent plug, and used correct techniques to install them. The car should limp home with the MAF sensor disconnected, and cleaning it with special MAF cleaner is easy.

The vacuum leak is troubling. These cars do not play well with leaky hoses. You need to hook up a code reader and see if any problems have been detected. I think knowing a code will point you in the direction of solving the problem without throwing time and money at parts that are OK.

K&N's are also a red flag. Even if they came "pre-oiled" there is still a chance that they put a coat on the MAF sensor. I've also seen the seal around the perimeter not mesh well with the Mann air filter housing. This allows dirty air to enter the engine filling the oil with dirt. It shows up as excess Silicon on a Blackstone test. On balance, unless you track the car I don't see how the minor amount of increased air flow is valuable. Run your finger down the intake with the air cleaner removed. Feel any oil or dirt on the walls? It should not be there.

 

Moviela,

Thanks for the reply. I forgot the mention that during this entire time, there were no CEL's, except for when I unplugged the MAF. I'll try to pull up some store codes, but the thing is I can't even drive the damn thing :/ I'll probably clean out the MAF tomorrow, but to me it seems that the MAF only contributes little to the problem.. my question is why the car is stalling when I step on the gas?

As for the K&N's, they have a rubber gasket that sticks to the air filter housing, but I'll double check the the intake for oil leakage. I still want to find out if I do have a leak, or if I'm just imagining things, but thanks for the advice again

 

how old is your fuel filter, please check and replace if not done so.........

just my 2cents

javvy

 

Is there fuel pressure?

Didn't you just have EIS troubles a few months ago? Now this.

 

i have read, i think yesterday, that similar symptoms are linked to the fuel delivery system i.e. fuel filter, pump, clogged injectors...but mostly the pump...so take one step at a time...filter first...pump second...i think injectors is in the extreme of such symptom

 

I know this is a long shot - but have you tried to put the old spark plugs back on?

 

The plugs shouldnt be a problem, but installing old plugs and try wouldnt hurt either. The fuel system is the first culprit I will check. And better get that vacuum leak solved too, goodluck.

 

yeah I was thinking it might be the engine starving of fuel. Check your fuel pump as javvy said to see if its working properly. sounds like some symptoms from lack of fuel.

 

Okay - Ive been through this and I have seen these exact symptoms - ONLY stalling when you step on the gas is a big reminder of my situation... When I first got the car, I thought K&Ns would be a nice little addition. Little did I know, they came overly oiled and killed a MAF. My Indy and Dealer told me to take them out, but I decided against their judgement to clean + reoil (lightly) the K&Ns and get a new MAF ($$). I was good for a while, then the same stuff happened again. I got another MAF ($$) and have since rolled w/ stock filters without any issues.

When I had the MAF issues, my car's idle and general RPMs would fluctuate dramatically and cause unusual behavior w/ the car, but the car would never stall, but when I had the fuel pump issue my car would flat out stall. This leads me to believe that you dont have fueling issues...

Last item: It might be your Crank Shaft Position sensor - its known to wear/fail over time. Its a PAIN to get to, but if you can get to it, I left information about how you can test it in my thread or something of the sort.

Good luck. Keep us updated on how it goes.

 

Odd... I had my K&N on for awhile and never had issues with my car's idle. I have a different setup now though. Did your car throw a CEL when your MAF got killed Tru? I had it throw a CEL saying I was running to rich but after I got it reset it never threw it again.

 

THanks for the response guys. I'm thinking it might be fuel delivery sytem too, but I would hate it to replace the pumps.. even with the MAF disconnected it still stalls, so is that a sure sign of fuel problems?

I've replaced the CPS at 80xxx miles, and I don't think it's that at all.

 

This has been said but check your fuel pump/filter. You say it shuts off when you give it gas or accelerate. Sounds like a fuel issue.

Good Luck

 

Wait, you're stalling. I must have read incorrectly earlier...

Sounds like a fueling issues IF you're actually stalling out. When did you last replace the filter? I believe it went from a 100K item to a 60k item...

 

I haven't done it yet, and I don't have prior service records. I hope that's the issue. Jon, would you happen to know the part number for it?

 

heres what rmeuropean has a part# 002-477-30-01 its like 45

 

Hopefully, this is the issue and you can have an easy fix Replacing the filter can be a DIY project. Keep us posted!

 

yeah theres a DIY on the fuel filter in the DIY section, looks pretty straight forward. I'm at 90k now and plan on replacing mine soon.

 

I will be doing mine too pretty soon, I am at 73K, at the next service I will replace the air & fuel filters...

javvy

 

CPS.

the only way the car will shut off while driving/slowing down is with the CPS. not the fuel pump because obviously you can start the car. if you can start the car then obviously it is getting fuel, so it is not the fuel filter either since if the filter is clogged it's not gonna magically unclog itself and let you start the car and then stalls out when you give it gas.

the only way this can happen is the CPS is at fault and the car shuts the car off to prevent valve hitting the piston because it thinks the crank timing is off.

so yea...CPS...change it.

 

Mu you know the whole deal. MAF, lack of fuel pressure (filter or pressure regulator in filter), fuel pump, CPS, TPS, stumble due to O2 sensors cycling too slowly, vacuum leaks, plugs, coils, wires etc. You have eliminated some already.

Check the fuel pressure at the injector rail in front at the test valve. s/b 3.8 bar. Sometimes you can have sufficient fuel supply to start but as soon as you demand more it can give up on you.

I thought you did a CPS a while back. Maybe screwed again.

Hope it's not the MAF

 

Like what Glyn said, even if the pump or fuel is troubled, there may be just enough fuel to start the car. But as the fuel supply falls below the demand, the car starts to sputter and stall out..

 

Sounds good! I'm gonna get a OBD-II reader and try to see what codes I got stored up in there.

Frank,

Really? Damnit, I replaced it less than 30k miles ago. And I don't have that cranking problem that I had before.. so I dunno..That's my next agenda, the fuel delivery system. I probably have to clean the MAF though; with that unplugged, it wasn't stalling while idling.. but when it's back on, it'll die within the minute.

Sounds good, I hope it's gonna be easy.

 

CPS fault is not just cranking problem. intermittent symptom can be engine shutting off while driving at lower speed, fail to start, start and shut off, etc.

the usual cause for CPS to go bad is due to oil leak from its seal or slow leak down from the valve cover to the back of the engine.

if you want to see if it's your fuel system...what you can do "old school" style is to pull the injectors out and see if it is working while cranking the car. still i highly doubt this is your fuel system.

if it's just the MAF, it is gonna give you crappy idle and misfires, but it's not gonna cause the car to stall out and shut off. if you have fuel pump problems (if the pump is dying) you are going to have a hard time starting the car. as much as i think what Glyn said could be a symptom it would be very odd that it only dies when you give it gas.

either way, start with the CPS.

 

CPS can cause all sorts of crap when the electronics don't know when the engine is at TDC.

Definitely a likely cause.