Mercedes SLK World banner

41 - 55 of 55 Posts

·
Registered
Joined
·
49 Posts
Discussion Starter #41
@efair
I believe we have success with the hose! I got used to how the engine sounded with a tube in my ear... Looked around and found a hiss, told someone where i thought the hiss's general area was (but not the hose) and then asked them to tell me immediately when they hear the hiss.... SAME HOSE I THOUGHT! Its one of these.



What are those, and is there supposed to be a hissing noise there? Its next to the throttle body/intake manifold etc.
 

·
Registered
Joined
·
49 Posts
Discussion Starter #42
The hose rubber clamp was broken, I cut the end off with a knife, stuck it back on and plugged the white hose back on.... It no longer is going to a high fuel trim at all..... Still runs like dog-crap but I think maybe the engine is trying to figure out what to do?
 

·
Premium Member
Joined
·
4,452 Posts
AFAIK, the pump should come on briefly and pressurize as soon as the dash lights come on - you shouldn't have to turn the key all the way to the starting position before you see pressure. And you should hear the pump run briefly. If you're not sure, open the fuel cap and put your ear by the neck while a helper turns the key on and off repeatedly. If that's not happening, I suspect your K40.

I can't really tell what's in your photo, but if you think it might be leaking, replace it. Check all around the fitting, don't be shy to remove and inspect. The hard lines seldom crack, but the rubber boots and connectors frequently do.
 

·
Registered
Joined
·
49 Posts
Discussion Starter #44
AFAIK, the pump should come on briefly and pressurize as soon as the dash lights come on - you shouldn't have to turn the key all the way to the starting position before you see pressure. And you should hear the pump run briefly. If you're not sure, open the fuel cap and put your ear by the neck while a helper turns the key on and off repeatedly. If that's not happening, I suspect your K40.

I can't really tell what's in your photo, but if you think it might be leaking, replace it. Check all around the fitting, don't be shy to remove and inspect. The hard lines seldom crack, but the rubber boots and connectors frequently do.
It could be something wrong with how I did it. The fuel pump does work though, I can confirm that!

I just test drove it and it bogs down when full throttling.... HOWEVER, it drives really smooth now. I still get CEL's for misfiring and fuel trim too high, but I think thats because I re-used the broken vacuum boot. I will attempt to put new ones on. But yeah, it runs good for the most part now.
 

·
Premium Member
Joined
·
4,452 Posts
I'm just wild guessing - no idea what's happening at the higher rpms, but it's pretty safe to assume the compressor is kicking in plenty of boost by then. Maybe your issue only arises under boost? Maybe try disconnecting the supercharger bypass to prevent any boost from developing? Of course the car won't perform as well but if it will rev higher it's another hint.
 

·
Registered
Joined
·
49 Posts
Discussion Starter #47
crankshaft position sensor?
I only have a camshaft sensor available right now.. won’t be able to get crankshaft until tomorrow most likely.

I'm just wild guessing - no idea what's happening at the higher rpms, but it's pretty safe to assume the compressor is kicking in plenty of boost by then. Maybe your issue only arises under boost? Maybe try disconnecting the supercharger bypass to prevent any boost from developing? Of course the car won't perform as well but if it will rev higher it's another hint.
Im not sure how to do that, but I can try. The fuel is running rich so I thought maybe it’s another leak. Seems just like the last one, but it at least drives nice now.... revs up high in Park.... but feels like it downshifts and gets stuck at around 3kish RPM’s when I full throttle... oh also even though it downshifted and rpm’s went higher it’s still a loss of power OR sometimes it’s just the same speed I’m going (straight line not up a hill)
 

·
Premium Member
Joined
·
4,452 Posts
There are some ECU limits on rpms when in park or neutral. A plugged cat could also limit airflow at higher rpms - give your cat a rap with your fist and what do you hear?
 

·
Registered
Joined
·
49 Posts
Discussion Starter #49
There are some ECU limits on rpms when in park or neutral. A plugged cat could also limit airflow at higher rpms - give your cat a rap with your fist and what do you hear?
I havent been able to check the cat as I was busy this weekend... However, I did attempt to put it into drive (it was rough idling horribly) and when trying to push the brake pedal it barely would stop... It makes me seem like its a vacuum leak because theres no pressure to the brake booster?
 

·
Premium Member
Joined
·
4,452 Posts
That's a good clue. Is it consistent, or intermittent? I believe there is a check valve between the intake and the brake booster, perhaps it's failed?
 

·
Registered
Joined
·
49 Posts
Discussion Starter #51
@efair I’m unsure, I am probably going to take it to an Indy to diagnose now. I think it’s a vacuum leak but it’s possible it’s the check valve too. It’s bogging down just like how it always has and last time I knew for a fact it was a vacuum leak when I found the hose. Restoring the hose fixed it temporarily though.
@efair I do appreciate your constant support!
 

·
Registered
Joined
·
49 Posts
Discussion Starter #52
UPDATE:
I disconnected the tubing above the MAF and clogged it with a blanket (Intake hose to IAC?), turned it on and it ran the engine really nice ... rev'd up perfectly and everything... I tested it for a total of 10 seconds on a cold engine. I turned it off and came back in 3 minutes and tried turning it on and it will not start anymore. Turns on, and then stalls immediately. Almost similar to when the MAF is disconnected.

Is this indicative of anything?
 

·
Registered
Joined
·
49 Posts
Discussion Starter #53
UPDATE:
Put a third new MAF in (one guarenteed to work) and it revs up FAST and sounds like an ABSOLUTE CHAMP! Except for the fact that it stalls on idle but i can keep it going if I have gas while its attempting to start. Would this just be an idle reset...? I also bought an IAC and TPS from the junkyard today... Can swap those out. Also got a Camshaft position/crankshaft position sensor today too.
@efair

EDIT:
FOUND OUT THE REASON FOR DYING ON IDLE (Also did an idle relearn) -- The hose clamp slipped off, but after tightening it... sounds like a car i've never even heard (in a good way!) ... It's strange that my last MAF was the only one where it would slightly work... but after a few tries with other MAF's I found the one that worked!
 

·
Registered
Joined
·
49 Posts
Discussion Starter #54
UPDATE:
Drove it about 30-40 miles since the last update. Can safely say it's driving great now... acceleration is good, no bogging, no misfiring, and no more backfiring sounds on idle.

However, I will say that maybe whoever owned this car before me must have put an aftermarket muffler on because when I full throttle it super loud and raspy as if a quiet fartcan'd honda just drove by. I can only assume this is because of the CAT being used too much with misfires. But other then that, it sounds and feels perfect now. Strange how two MAF's were causing complete opposite reactions, but the third one was the charm.

For anyone that researches this thread in the future and tl;dr:
I had a vacuum leak originally, fixed that and it idled better.
I had a bad MAF sensor causing sluggish acceleration, misfiring, and eventually stalling.... disconnecting the MAF doesn't guarantee it'll keep your car on (mine stalled 95% of the time with it disconnected)
I had a bad k40 joints causing random trouble codes from evap system to supercharger clutch to other things.

I'd like to extremely thank @efair for all the support and help he's given throughout the week of diagnosing this car. I would also like to thank everybody who has attempted to help/chimed in their thoughts as well!
 

·
Registered
Joined
·
49 Posts
Discussion Starter #55
It ran and drove perfect for a whole day before it started to misfire badly again... causing a flashing CEL... Luckily I was only 4 miles away from the house. Could something be making the MAF fail? Every MAF I have used are USED (Junkyard cars) but OEM.

There are new things happening now:
-- It wont kill itself when I slam down the gas pedal.... It will rev up, extremely poorly (misfiring)
-- It misfires on ALL Cylinders which tells me it shouldn't be the plug.
-- Stethoscope DOES sound like there is more of an air leak UNDERNEATH the intake manifold... however, the car does not overheat so I am thinking the stethoscope I am using is just listening to the air flow in the manifold.

I knocked the cat and it didnt make no rattling noises... however I am going to lift the car up and unbolt the cat and see if maybe its an exhaust restriction.... considering I did run it with tons of misfires for my one week of ownership + the previous owners drove it down to Orange County (~50m) and back lmao... If anyone has a free MAF I can test let me know haha...:(
 
41 - 55 of 55 Posts
Top