holy christ man theres a lot of variation in those compression numbers!

 

Saijin, I really wouldn't keep this engine. Like BSMUWK (yeah, that's quite a handful to type, FYI) :P lots of variation.

Buy another block and dump it in. See if you can find a 320 block. Don't change the whole engine, just the block.

It may or may not solve the slowness issues, but at least you'll have a decent engine. Rebuilding it is waaaay more expensive than replacing it. You can start from there. And TAKE A COMPRESSION TEST BEFORE PAYING FOR IT.

I know this is a basic and stupid question, but I'm not gonna go through 29 pages to get an answer. Did you change your air filter? Spark plugs? Does the engine still feel slow under no load (N and rev it)?

 

320 version of the m104 uses HFM, I'd have to swap all the electronics. Not desirable IMO, too much guesswork. I'm stuck with a m104.980 unless I want to change harness/electronics.

Yes, did K&N filter last summer (2010 summer). Did plugs/wires this past winter (nov/dec 2010). Engine is very slow to rev even in N/P.

I'm looking to replace the ignition coil, don't believe that has ever been replaced. Had the shop do smoke test for vacuum issues and flow/pressure test the fuel pumps. No word that either revealed anything too terrible.

The compression numbers do have variance yes, but I was lead to believe that the variance from spec PSI was not too terribly out of what it should be.

Headgasket and valve gasket kits total 150 from MB, I have valve guide seal kit already. What else would need to be done to rebuild it? Valve guides and rings, correct?

 

Brett

If compression is as you posted, you have more then one cylinder that is beyond the 1 bar cylinder to cylinder tolerance.
A healthy engine should be around 185 +/- per cylinder.

Is it worth rebuilding?
My opinion is no, as you can replace your car with one that has a strong engine for not much more then the cost of a rebuild.

Ed

 

Ok, so I just spent the last 5 hours reading through the whole thread. I hate you. :P

Like Ed is saying, you have 2 deceased cylinders. All they're doing is dragging the rest down.
When I said change the block, you don't have to change anything else. Keep your CIS system, just throw out your bottom end for another M104, be it the 3.0, 3.2, or 3.6. Don't downsize. :P

Hell, if it's that expensive, I'll send you one by sea. An entire M104 3.0 here costs 900$, which is what you and I have. I actually found a couple of 3.6's with all their peripherals for ~1200$.

More importantly, I think you should buy a parts car and use it. I had 2 spare VW Beetles lying around when I had my 1303S. You have no idea how useful they were.

Buy a relatively "clean-ish" W124 with your same engine and toss it next to your house, and keep it covered. Take the block from it, and over the months and years that follow use whatever parts you need from it. I'm under the impression an entire moving W124 there goes for under 1000$. Get it salvaged or whatever.

 

Your compression is nowhere near OK. As mentioned 2 cylinders are almost dead!!!
Stop spending money on the car and fix the problem YOU KNOW EXISTS!!!! Your bottom end is done with!!! At least the piston rings. All gaskets, valve stem seals etc will not solve the worn out piston rings!!!
At the very least, you need piston rings. This will give you decent to good compression, but if you are already there, the block will need honing, rod bearings etc etc.
If it was me, I would rebuild the motor because of the learning experience and I have 2 other cars. My car is a project car and I have the basic knowledge to do it. I have built a Ford 302 stroker for my 65 Cobra in my garage from a bare block.
In your case I would say find a decent 104 engine with the head attached and drop it in, or as Shoomakan a donor W124 with an M104.
For goodness sake, stop throwing money at it until you do the above.
The consensus is that your lower end is done with. Period!!!

 

Yeah, I'm aware the engine is fairly toast. I can deal with fact that until I have the 5-6k I'll need to have that replaced or rebuilt. Good, complete longblocks are looking to be north of 3.5k on ebay for a C36 motor, but they're typically well north of 100k on the engine and there is no guarantee they're actually in good working condition, only that they run (not a big upgrade if they're as ****ed as my engine is currently).

What I want to fix right now is the car stalling out on me when I make turns or the engine faltering or stumbling when I try and accelerate. These are severe driveability issues that I want sorted. The car being a 14s POS is a pre-existing condition, that while maddening, doesn't actually prevent me from driving the car around.

I've not seen any indication that the compression would cause those issues. It typically seems to be the fault of the EHA, weak fuel pumps, possibly Ignition Coil, or even severe vacuum leaks. However, I'm not sold on vacuum leaks as the car idles almost perfectly at 700-800rpm in P with little hunting and I just had it smoke tested.

Would low compression cause the engine to die out ONLY while making a turn at low speeds? From a stop for instance. Likewise with faltering under acceleration. Once the car is moving, the engine is perfectly smooth.

I've not been ignoring you guys, I just can't tackle the engine rebuild/replacement at this time. I'm trying to fix the less expensive ancillary problems that exist beside the engine being shot. Low hanging fruit as it were.

As for getting a parts car, it isn't reasonable. I don't have my own place, I rent and there isn't room to put a parts car. Furthermore, I don't have any tools beyond sockets and simple things, not even a lift or jack stands. All the shop tools are at home with my dad, and my mom would have a coronary if I put a broken down car in the yard. I almost got a complete 92 300ce for 100$ but my mother freaked a **** when I told her I intended to buy it to fix up my car.

Simply not possible. The engine must be replaced or rebuilt at a shop, unfortunately.

 

Gotcha.
The issues you are having are probably not realted to the compression issues.
Sensors, EHA, OVP etc. etc.
I don't remember from your previous posts, but have you made a code reader?
That will at least drive you toward the most likely direction.
Good luck with this, sounds like a real headache and not sure if it's really worth solving unfortunately, but emotional attachment has no value.

 

Brett, you make really valid points. But still, I would go to a junkyard or whatever and get a donor M104 block and drop it in. It's the cheapest route.

If you want to hold on to it till you have enough money for a 36 swap, that's something else entirely.

 

Current State of Repairs (As of March 2011)
O2 Sensor (Replaced Mar 2011)
Throttle Position Sensor (Replaced Mar 2011)
Exhaust Gaskets (Replaced Mar 2011)
Crank Position Sensor (Replaced Dec 2010)
Cam Position Sensor (Replaced Dec 2010)
Cam Adjust Solenoid (Replaced Dec 2010)
Engine Temp Sensor (Replaced Dec 2010)
Spark Plugs (Replaced Nov 2010)
Spark Plug Wire Set (Replaced Nov 2010)
Air Filter (Replaced July 2010)
MAS Unit (Replaced 2009)
OVP Relay (Replaced 2009)
Full Exhaust (replaced 2008)
-----------------------------------------------------------------------------------------

Yeah, sorry. I don't mean to come off as not listening or resisting, I'm just painfully aware of how long its going to take me to save up with less than 200$ of free money a month :P

I've a code reader which I've been using and so far, it has given me quite a laundry list of codes (which I've made repair/replacement upon already). So far, I've replaced the Cam Adjuster magnet, cam position sensor, crank position sensor, Engine Temp sensor, O2 sensor, and Throttle Position Sensor. These were all items that were throwing codes previously.

I'm going to reset the codes today and try and make a few "trips", which I believe are defined in 20 minute blocks of running-time, to see what codes turn up now.

OVP and MAS relay have also been replaced in recent history, along with plugs/wires which had cracks in the insulation, giving me severe issues with starting when it was humid or after a rain/snow event (which is mostly daily here in Northern NY).

Fuel filter also got replaced this year, and judging by my mechanic's reaction, it was long overdue. I've not cleaned the in-tank strainer yet, but I suspect that may have at least a little debris accumulation which may or may not restrict fuel flow when it settles in.
Edit: Mechanic just verified that fuel pumps put out 92PSI cold, and no vac-leaks were identified.

 

Ok, let us know what codes you get after the reset and the drive.
Some help might be available from folks here on these issues.
Man, not sure how many sensors are left to replace!!! EHA and EZL maybe but $$$$....

 

Brett

Stalling when turning and braking is typical of a vacuum leak either in the brake booster or any vacuum hose associated with it.

It would tend to lean out your mixture and be more symptomatic at low speeds.

Temporarily disconnect and plug the vacuum line going to the booster and see if it still stalls during a low speed braking and turning.

Do it in an empty parking lot,,,

Ed

 

Yeah, the EHA is on my list as well as the EZL. I'm looking for definitive tests for all the parts however, and that appears to be hidden knowledge.

So far, the best "test' I've gotten for the EHA is "look for fuel residue on/around the fuel distributor" and "if your car is running like crap, you should probably replace it anyway." Is there an actual, definitive test for it? A flow test, resistance, voltage? Something of that ilk?

The EZL is similarly tricky to diagnose. I've tested the Resistance Trimming Cap (the thing with the single Letter/Number in yellow on it), and my Trimming Cap is perfectly in-spec for resistance. Now, to test the functionality of the unit itself, I've no idea.

I believe the round 38-pin diagnostic port can give me better/different data, but I'm not sure exactly how to use that port.

 

YES! Thank you. This is the kind of definitive tests I'm looking for. I don't know how to diagnose (as 29 pages of me flitting about should have demonstrated), but I can do procedural tests.

I'm assuming the need for an empty lot comes from losing much of my brake force with the vac line disconnected, correct? May I use the Parking Brake if needed or?

 

I suggested a parking lot as you wouldn't have to worry about parked cars or traffic!

You'll require a bit more pedal pressure without the booster but you'll stop..

The slower you turn while applying brakes, the leaner your mixture will become to the point of stalling.

Even before you do that...start your car, leave in park, apply your brakes, turn steering wheel both ways full lock and note what happens to the idle or if it stalls..

Let's hope it's the booster..

 

I do know that the further I turn the wheel, the more "strain" I hear from the engine and I guess the power-steering pump. I can't recall if angle of wheel turn has any direct correlation to whether or not it will falter at low speeds, but I'll try and verify that now.

 

Ed's suggestion is an excellent one.
I broke the little check valve on that line by accident and the car stalled and would not even start. Assuming there is a problem there, you could be experiencing a leak.
Hope that is your problem as they are not too expensive (you will need the entire tube if it has a leak-you can not remove the check valve and replace. I tried it, can't be done).
If it is your booster, fairly easy to replace and not terribly expensive.
Keep us informed.

 

Hm, are these the parts in question?

 

83, this is a whole unit and cannot be replaced in pieces, and possibly 5. The booster.
89 is a grommet to the front firewall and NOT part of the
possible problem.

 

Haven't disconnected the booster line yet as I've nothing to plug it with, but I did test by braking and turning the wheel full lock.

At central position, the idle is smoothly sat at 700ish rpms. Once I begin to turn the wheel either direction, the RPMs dip very quickly to below 500 and then rise back up. The Oil Pressure also takes a bit of a dive, and the Economy gauge raises at the same time.

 

my parents m103 felt no power at all last week, and it wasnt going uphills easily (had to apply a lot of pressure on gas pedal).
i sawpped the eha with another used one i had and it runs a lot better now. power is back.
Didnt do any compression tests, actually i wish but since im away my brother changed the eha just out of luck and it worked.

I dont beleive there is a way to test the eha perfectly, so buying a used one is a test of luck, new one is 150$ from parts.com and thats the cheaper ive ever found

 

Brett

Try the same lock to lock but this time without applying the brakes.
See if the revs and other indications are the same as with brake applied.

 

Are you having this stall out say coming to a stop or getting off the gas? Idle air control valve was just doing that on my 88 300e. Swapped with one on my 300ce and stalling problem was fixed. Checked valve and it was sticking closed.

 

Yes, fully warmed up, the car behaves the same as with the brake applied.

 

Well, not really while stopping or letting off the gas, but more when I get back on the gas to turn and accelerate out of a stop or a really slow corner.