Well all plugs make a difference and it misfires alot harder with each plug removed.

With heater off it still misfires.
Are there any places I should spray around where the heater vacuum's are to see if there is a vacuum leak there? Or will that not make a difference here?


Still searching for a shop in so-cal to get my smoke test done.

EDIT: Here ya go. Does this look right to you?

Heater off, car idling.


Heater ON, car idling.


Both my economy + oil change....

 

Looks normal to me. The AC compressor coming on dropped the RPM by about 75 or so which will decrease vacuum and oil pressure slightly. Does it idle more roughly with the AC on in the second pic?

 

Thats not AC. Its the heater or front defroster. Or am I wrong and it does use the AC?

But AC yes it does cause the idle to become more rough.

 

Just operating with the heater turned off does not isolate every vac circuit under the dash. You need to review the propane and circuit block off tricks and hunt for a leak. It's hard to find smoke testers 'cause most shops use above methods to test.

Leak hunting is almost free, just costs time. 100 guys have pointed out a common cause for rough idle is a vac leak. You've eliminated ignition with the plug bank test just performed. Now, eliminate vac with the simple block-off procedure listed a few posts back. I've done this leaving the car running and moving around yanking off hoses and capping the supply source with my finger.

If the idle smooths up you found it. Trace out all down-line hoses and diaphragm devices to isolate the leak. If you cannot create any change, vac may be eliminated.

 

If any button is pressed besides E, or no button at all (defaults to AUTO) the AC compressor is activated. Unless outside temp is extremely cold, which it isn't where you live. The exception is in AUTO, if system is calling for full heat it temporarily de-activates the compressor.

 

But will capping it with my finger (assuming I plug the leaky source) stop the misfire instantly or will I have to hold it there for a few minutes?
Are there any diagrams with all the possible vacuum's?
I have done the EZL and heater core. I'll get going on the other's asap.

Really? Good to know!!!

Thanks guys!

 

If the vacuum leak is the problem and you plug it then, yes, it should smooth out immediately.

 

Ok well cross that off the heater and EZL for vacuum leaks then.

I noticed something funny today though.....When the car is idling and I turn the wheel(a 90 degree turn), the economy gauge and rpms go up+down by a good 200rpm. Is that supposed to happen?

 

Normal at times. Your power steering pump is sitting idle and not requiring much pressure. Once you turn that wheel the pump kicks in and since it takes more power to turn wheels of a car sitting still it bogs it down a bit. My guess is that rolling at like 15 mph while off the gas if you turn the wheels for a turn you won't notice any drop off at all.

On a side note. Dude I am looking forward to when you finally get this one figured out. WE may have to have a meet just to celebrate it.

 

Oh trust me....I will celebrate LOL!

On a side note, for the past week the misfire has been really great. For a few days I could hardly even feel it...a few nights it was bad but then the following day was reasonable.

Its just such a strange inconsistent problem

 

Welcome to the age of electronically controlled everything. There is something to be said about having and old Chevy small block with a supercharger slapped on it. The only thing you ever worried about was breaking a motor mount or throwing a rod.

 

1)Well I found my coolant leak!!

There are growths at the very back of the engine and on the exhaust manifold in places where the coolant has leaked onto. Any ideas?

2)I just filled up....All city: 12.5mpg <--- WTF???? I was driving so smooth too. I never once put my foot to the floor. I've NEVER seen it that bad.

At least I have a double chicken chipotle burrito to cheer me up.

EDIT: I also am going to go and purchase the temperature sensors now as I have some flow back into my account
Should solve my Temperature sensor errors and MAYBE the problem!!

3) Can somebody tell me which sensors I need? I am seeing multiple sensors and as I understand it, the w124's have TWO temperature sensors; one for the ECU and one for the temperature gauge.
http://catalog.worldpac.com/mercedes...ppEngines=_any
^As you can see, there are a few different ones and I don't know which ones are the correct ones.

4) Last question....Where is the thermostat housing/what is it? Anybody have a picture of one so I can visualize? I tried doing some searching but I am getting confused as people keep mentioning the Radiator...and then they mention the temperature sensors (which are at the back of the engine by the firewall)...so I'm really confused.

Much appreciated
ps2cho

EDIT: Placed some numbers so you can see the 4 questions I have. Made it a little easier to read.

 

How bad is the coolant leak. How often do you have to add coolant. HAve you ruled out the head gasket?

 

I'd say every 2months my coolant light comes on from being topped up to full.

It looks like its probably the head gasket. Could this be related to my misfire at all?

 

Sure, espsecially if the coolant is leaking into the cylinders a little bit. Glycol and water don't really support combustion.

 

I would suspect that if your head gasket is faulty then your problems all revolve around it. Pinpoint that leak and if it is coming from between the head and block then your should really consider a top end job.

 

Great! I know we are getting closer every day!!

To resolve my MPG problems, it looks like replacing my coolant temp sensor should fix that....I'll identify which sensor I need tomorrow as there are two types listed.

Is a head gasket job DIY? I have done valve stem seals, so that should show about how much I can do...

Or should I just take it to a mechanic? and how much $$$ are we talking to have it replaced?

 

I was trying to find my engine serial # today(couldn't find it btw) and managed to get a good picture of the growth for you guys!


What do ya think?

 

If you have the book with step by steps and the tools it is not that bad.

there is the cheap way and the peace of mind way.

the cheap way is to crack of the head clean it up a bit and put it back on with the new gasket set. This is Ok if you know for certain that all the valves and guides are in good shape and there is no warping on the head.

The peace of mind way is to send the head to a good engine machine shop and have them dip it (acid bath) pressure test it and plane the surface. They will be able to tell you for certain that everything is in good shape with the head. With the issues you have been having and it were me, I wouldn't consider doing the job without having the head reconditioned.

Here is a cost for the Job (ball park)
This site has good priced and quality parts.
http://www.rockauto.com/catalog/raframecatalog.php

Head gasket set $110.00 -$140.00
Head Bolt set $39.99
Timing chain $35.79 (optional but good idea)
Timing chain tensioner $28.79 (optional but good idea)
Timing chain guide rails $12.00 (optional but good idea)
Head reconditioning $200-$320

Total DIY $500 - $700

The job can be done over a couple of days. make sure you get a very good instructional on doing this job with all the torque specs. I know some of the guys have the CD which has very good detail in them. Also there are some little tricks to doing this right that you only learn from being around the old greese monkeys (like my Dad) if you choose to do it yourself drop me a note and I will give you all I know on doing the job. If you like working on this car and you are good at detail this is a fun job to do especially on a W124. I have done almost a dozen rebuilds to engines and I never get tired of it. It is kinda cool to be able to say "yep I rebuilt it" plus you know what went into it.

If you pay someone to do it you won't be able to get it done for under $1000.00 and if some one says they can do it for less than $1000 chances are you don't want them doing it anyhow.

Hope this helps you.

 

Ok great that gives me a good idea of what to expect when I get some quotes today.

Would my timing chain really need to be replaced or could it wait with my current miles?

I can't find my engine serial # anywhere !
Where is it located on the engine??

 

My feeling on the Timing chain is that the labor should be less because you already have the engine broken down (though the dealership will charge you for both as full jobs). I just like doing it all while I'm in there. You could wait if you wanted that's why I noted optional. I have seen cars go for 300k and never had a timing BELT replaced so you will probably be fine but it goes to the "peace of mind" thing.

I will check my book and get back to you on the serial number of the engine for you.

 

The thing about the coolant entering the Cylinder possibly confuses me though. If this were the case, then when the spark plug is removed from the Cylinder with coolant leaking into it, shouldn't it be obvious which one it is? As I've said before, its random sputtering and I cannot locate the Cylinder if one is causing it. Logically, would this also go with the possibility of burnt out valves/cracked head as the problematic cylinder would be noticeable when the plugs are removed?

I picked up the Coolant Temp Sensor tonight. I'll have it installed in the morning when the cars cold. Fingers crossed! You never know if this is the problem all along. As I understand it...its a possibility although I believe I have something a little more complex that a Coolant Temperature Sensor. At the very least I hope my MPG and power increases.

I got a quote from the local place where I picked up my CTS for a head gasket to be roughly $1,500. Not looking too good and I really hope that I don't have coolant getting into the cylinders.
^
I hear there are ways to check this.

 

Sometimes it is cut and dry sometimes it is not. Sometimes the fluid isn't leaking badly and only is noticible under higher pressures of acceleration. What you should look for in the cylinder is a spark plug that is dramatically different than the others. Ironically some times it is cleaner than the others as is effectively steam cleaned as you drive (very loose analogy) you just gotta look for things that are out of the norm. I very well may not be the head gasket at all. But it may get to a point where you just have to do it in order to rule it out (kinda sucks to pay the money if you find out it wasn't needed). Let me know the result of the temp sensor.

 

EDIT: Nevermind managed to get at it. The original sensor and connector were "wet" with coolant. Not a good sign right away! Cleaned it up and I'll post back in a few hours on my lunch break! I couldn't tighten it as much as I would have liked as I don't have the right tool. I need to go get a long 22mm socket for this one as the newer connect was a little longer and so it couldn't reach all the way down.

Fingers crossed. Going to go fill her up too so I can get my new MPG in a few days. Maybe this will help bring my down my gas bill of $180 a month!!

 

How much $$$ did that sensor run?