Author Topic: violent stammering at 3500 ~4000+ RPM in 5th Gear (Read 8442 times)

bmwman91 · « **Reply #15 on:** June 03, 2011, 09:56:38 PM »

Any chance you can take a pic of the AFM guts? Maybe we could recommend a work-around.

jdirty · « **Reply #16 on:** June 04, 2011, 05:04:59 AM »

i already got a replacement afm. the old one, aside from a chip on the ceramic board.. the only repair for sure was if there was such thing as a filler for the ceramic track. well the "new" one didn't really help with the sputtering, i just put in some engine cleaner earlier and ran 91 octane, reverted back to the stock m42 airbox and after watching the hangover 2 with my fiance� tonight, the car went back to it's hesitation mostly on 2nd gear 2-3k rpm. and sometimes when i throttle too fast, i'm going to be replacing my throttle cable and icv in a couple days and see if it makes a difference, and i'll check my spark plugs later when i wake up.

bmwman91 · « **Reply #17 on:** June 04, 2011, 11:32:42 AM »

My car sputtered intermittently when an ignition coil went bad around 2006. Have you looked into that at all?

jdirty · « **Reply #18 on:** June 04, 2011, 03:58:28 PM »

when i got the car there were two new coils on it. i had no idea why it was only two and the other half looked original. i checked for spark on all four of them when i was trying to diagnose my hot start problem before.. but havent checked recently, i'm thinking of getting the cop kit.

edit: i have a feeling it's my coils. gonna test them later. -_-

jdirty · « **Reply #19 on:** June 05, 2011, 11:25:02 PM »

found out that spark plugs sockets 2 and 4 have oil in them. bummer. gotta order a valve cover gasket set. it'll take awhile.. but has anybody tried the non-fouler adapter things? how do they exactly work..? it's just like a sleeve so the oil won't go in? those i can get right away, i think even autozone has them. it's just that i've never used them before...

edit:
used two non foulers on cylinder 2 and 4. and never again will i. for starters, the car did not want to run or stay idle, as if it was on it's death bed.
then, i decided to take out those fucking non fouler crap, and they did not come out with the plugs. wtf.. had to go around looking for an 18 mm thin wall socket, and all of vegas did not have one. i kid you not. none was selling. and after going over my head with things with the car why it was hesitating was for obvious reasons, the spark plugs went bad. 3 of them. then i remembered the last time i changed them was 5 months ago. i even went to lengths of changing out the ecu, cleaning out the coil packs, checking for arcing, doubting my spark plug coils. but yeah.. it was just the spark plugs. period. -_-

now my real task/ dilemma:
order the ff:
new valve cover gasket set
profile gasket set
icv
throttle cable

thanks for all the input guys.

/thread

CalmGuy · « **Reply #20 on:** June 13, 2011, 05:51:10 AM »

Quote from: jdirty;104331

yep. did the whole resistance testing and came up with inconsistent values, up and down. so i popped it open and checked the carbon track. and sure enough its was like thinned out on the spots where resistance was off... long story short, i kinda fucked my afm.

When you was doing resistance testing the resistance between 1&2 terminals was consistant or was changing according to the movement of flap? It would be useful to know.

monty23psk · « **Reply #21 on:** June 13, 2011, 10:50:57 AM »

^ When I did this on my the other day, the resistance raises/changes steadily but then gets to a point, like mid point on the flap opening, where it goes back to the start as it lowers/changes steadily back. Like a pendulum. Goes up and then down. Is this normal?

CalmGuy · « **Reply #22 on:** June 13, 2011, 01:41:28 PM »

Quote from: monty23psk;104535

^ When I did this on my the other day, the resistance raises/changes steadily but then gets to a point, like mid point on the flap opening, where it goes back to the start as it lowers/changes steadily back. Like a pendulum. Goes up and then down. Is this normal?

Could you tell what values you was getting while testing resistance? Mine AFM behaves quite strange because it shows constant resistance between terminals 1&2 and only voltage changes when ignition is on.

monty23psk · « **Reply #23 on:** June 13, 2011, 10:50:46 PM »

I thought I wrote them down but I didnt. I will have to do the test again. Hopefully someone can state the figures, if not, I will try to do it again.

bmwman91 · « **Reply #24 on:** June 13, 2011, 11:10:44 PM »

http://www.m42club.com/forums/showthread.php?t=5098
Per figure 60 on page 6-61, you should see the resistance change smoothly between pins 1 & 2 as the door opens. It should only decrease as the door opens further. If it drops suddenly, or rises again at some point, it is busted.

Measure the output VOLTAGE between pins 2 & 5. It should increase as the door opens / air flow increases.

monty23psk · « **Reply #25 on:** June 13, 2011, 11:17:27 PM »

Good, mine is working as it should.

jdirty · « **Reply #26 on:** June 18, 2011, 07:05:55 PM »

yeah i got a new afm which i tested and the other problem was fouled plugs. both of which causing hesitation with throttle response(bad afm) and stammering on higher rpm (fouled plugs.. felt extra noob after that.)

but alas i have a new issue.. :\

lately there’s been a coolant leak in the engine bay, more towards to front of the engine, a fine spray has been hitting the hood, the side of the airbox and the shroud. the expansion tank seems to be bloated when i reach halfway temp on the gauge. i’ve inspected the plastic hose by the side of the block and that seems to be pretty solid. i gotta get my engine steam cleaned to see where the leak shoots out of.

one of the theories were that the head gasket was blown and that exhaust fumes are pressurizing the cooling system forcing the coolant to go out somewhere. probable due to the bloated expansion tank and upper rad hose.

second one was, the water pump going bad and also the seals down there.

third would be a clogged radiator.

if it was the first, we’d definitely need to pull the head have it machined and shit, have it pressure tested. and hope it’s fine. if not i’m gonna have to hunt for a new m42 head which is difficult. if i were lucky enough to score a used head, pressure tested if i’m extremely lucky, then i can go ahead and also replace other seals, timing components, cam gears and what nots and keep the engine.

with all of that being said, the cost may end up totally to used e30, or an S5x or M5x swap. as much as i want to keep an m42 for it’s torquee ness and gas saving abilities.. the baby six swaps and the big six seem tempting given the budget range.

suggestions?

bmwman91 · « **Reply #27 on:** June 19, 2011, 11:29:11 AM »

Hmmm, if the head-gasket theory you have is true, that would be a lot of work. Does your expansion tank change size visibly as the car warms up? Mine always looked a little bloated, but it was that way at all temperatures.

I think that if you were had a head gasket leak like that, you would be burning a lot of coolant. 2 of the 4 strokes would be pulling coolant into the cylinder. I would place my money on a pinhole leak in one of the radiator hoses, particularly the upper/feed line since it is right there next to the air box. Can you get the car warmed up & rev the motor while looking around, or is the hole too small?

jdirty · « **Reply #28 on:** June 21, 2011, 09:00:55 PM »

i checked this morning and the expansion tank does already look bloated as it is even with the engine cold. i tried the revving method on operating temp hoping i'd see something but nothing shot out or squirted. i guess i really have to clean the block and see where the leak starts.
no garage + vegas weather = extra crispy dehydration -_-

jdirty · « **Reply #29 on:** June 26, 2011, 11:09:39 PM »

i did my valve cover and spark plug socket gaskets yesterday... and found out i have coolant in socket #2... ughh