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'92 W201-Shaky and low idle. 2.3

5K views 8 replies 4 participants last post by  Jbrt1989 
#1 ·
I've got an accumulator, fuel pump check valve, and a filter on it's way that I'm hoping will cure my grumpy start issues. I'm shopping for a workable 2nd hand dash cluster to fix my rheostat/dash/console lights and hopefully the odometer all at once.

I'm now looking at running issues......The vehicle idles around 500rpm (based on the cluster tach) It's shaky and seems awfully low. If I throttle up the rpms a couple hundred, it smooths out nicely.

Also, while moving, it seems to lug down just a bit at lower idle.

Can the above mentioned, soon-to-be replaced parts affect idle speed? Is there a way to raise the idle speed?

I suppose most importantly, I should ask, what should the idle speed be on a 1992 190E (W201) 2.3?

Registers 188K on a non-functioning odometer.

Thanks.
 
#2 · (Edited)
I would like to know as well, my '92 2.3 is having the SAME issues!

Edit: On mine, I have replaced the plugs, air filter, ran a couple of tanks of good gas through, tried different OVP relays and no avail. I also have found a charging system issue and am replacing my alternator and serpentine belt tomorrow, I'll post if anything changes.
 
#3 ·
Let us know if you do find anything new Eurow.

I pulled the plugs and they looked old, but, fine. The gap is probably opened up a little I'd presume due to wear and age. I didn't have the correct plugs, so, they went back in and they're getting replaced this weekend.

I guess I need to learn more about this OVP business. What it does and what occurs when it has a problem. I see it pop up quite often as suspect. I haven't looked at mine. I see they're an inexpensive "just in case" replacement. I suppose that goes on my list this weekend as well.
 
#4 ·
Does it gradually get down to 500 rpm's? and the OVP is most likely not your issue if you had a bad OVP relay your ABS light would be on (just assuming it isn't because you didn't mention any thing about it), hard starts especially in the cold and a high idle of about a steady 1000.

My car does this to, i know it needs motor mounts because it feels rough anyway, and when i start it, it fires right up but it kind of goes, thump thump thump thump, then runs perfectly fine but sometimes it will gradually go down to 500 and stay there for sometime, and will eventually go back up to about 650-700. If you know what i mean.

It could have something to do with the idle speed control valve. look into that.

One more thing, i need a new accumulator because it kind of hesitates starting when hot outside (i was told it had something to do with that)

Keep us posted and good luck,
Jacob
 
#5 · (Edited)
JacobB,

Thanks for the response. It goes almost immediately to right at 500 rpm once it starts and sits there unless the gas pedal is depressed to raise the rpms a couple hundred. It smooths out very nicely at around 800-900. In fact, it's surprisingly smooth once you take the low idle shakes out of it.

It seems to have difficulty starting more when it's hot than cold. I've honestly never seen that before, so, I'm completely stumped. I thought it might be the accumulator or pump check valve, but, now, I'm not so certain. When stone cold, it actually fires up fairly well. But, once warmed up, I have to floor the accelerator and spin the starter several times. Then, it's a shaky idle until I get moving.

Thanks for the help. I'll take a look at the idle control valve.

I'm replacing the accumulator, filter and check valve anyway, even if those aren't the culprit, it can't hurt and it'll be peace of mind knowing those are done.
 
#6 ·
No problem!

To me it seems the car will start much easier when cold, rather than when its warm. I was told it had something to do with that fuel accumulator you mentioned. I guess its supposed to help keep pressure in the fuel system for easier starting. My car will get a bit shaky at around 500. But like i said it will seem to correct its self after a few minutes. It does smooth out very nicely like you said, if it goes above 500.

Good call with replacing that stuff too, mine has to have the fuel filter and accumulator replaced. Preventative maintenance as they call it!

Good luck,
Jacob
 
#7 ·
I've confirmed that it starts MUCH better when cold. And, by cold, meaning sitting overnight. It starts actually quite nicely in fact. First thing in the morning, it starts after only a 1-2 second spin of the starter and without touching the accelerator.

However, when warm, I have to floor the accelerator and turn the starter for several seconds. I'd say it averages around 5-6 seconds.

The rough/shaky idle seems to be just a shade worse once it warms up as well. I still haven't been able to determine if the idle speed is adjustable or not. Once it warms up after a cold start, it idles around 500rpm. I'm convinced that's too low and that's why it shakes so much. It feels as if the rpms are so low the engine might stall.

Once I shut it off, unless I give it at least 2-3 hours, it's a "warm" start, meaning I have to fiddle to get it running again.

I'm really hoping that the accumulator, pump check valve and a fresh filter will help.

But, I'm open to other thoughts from those who know far more than I.

If someone could tell me what would make one start better when cold than when warm, that would be helpful. Most my experiences with cars has always been the opposite.

Thanks
 
#8 ·
I've confirmed that it starts MUCH better when cold. And, by cold, meaning sitting overnight. It starts actually quite nicely in fact. First thing in the morning, it starts after only a 1-2 second spin of the starter and without touching the accelerator.
that's because of the cold start valve. when starting the car with coolant temp still below 40*C (not sure about the value tho), this valve assists you by putting in more fuel so the car starts easily.

however, after the coolant temp has risen to that cutoff value, the cold start valve no longer provides fuel assist, so if something is wrong with your fuel delivery then you get hard starts.

Warm start issues usually point to fuel pressure problem. most common fault among our 190E is the fuel accumulator and second is the fuel pressure regulator. of course, there are other ways for fuel pressure to bleed, such as the fuel pump check valves. since you have the parts coming, you can then install and isolate the problem one by one.

regards,
 
#9 ·
Great! Thank you raymondgallant, that helps a lot.

I've got the accumulator, a fuel filter, and the pump's check valve hitting the doorstep on Monday, those will go in probably on Tuesday. If that doesn't cure my ails, I'll look into that regulator.

Thanks again. I admit I'm in the beginning stages of learning this vehicle and many of the systems and designs are strange to me. But, so far, I'm enjoying the challenge immensely. :thumbsup:

Only 1 week later, and I've got it running as my daily driver already. I just need to address a few concerns and I'm confident it can become an extremely reliable vehicle.
 
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