1984 190e Cold start hesitation problems
 

I've been driving this 190e for many many years. I love this car, gets me to all the shows that I go with excellent gas mileage of around 32mpg. Its got a problem when you first start it. It starts right away, but then slows down to a stop. I have to restart it several times, and eventually it goes and stays running.

I cannot step on the gas while starting it, that kills the motor. After it idles for a bit, I can press on the gas just a little and wait and it stumbles and eventually will accelerate the motor up. If I drive off, acceleration is poor with alot of hesitation but once the car is up to operating speed it runs quite normallly besides a slight miss during hard acceleration.

I opened the air cleaner and cleaned off the throttle air plate, had some gunk on top of it and on the sides of the air intake. I noticed when I throttle up it doesn't open well, seems to hesitate and vibrate when the motor is finally idling but not all the way warm yet. Once the engine is warm I pull the throttle linkage and it opens well and accelerates quite well.

When its cold, if you just start it and go to accelerate the motor it dies or slows down. But I noticed if I put my finger on this plate and push it down the right amount while pulling the throttle linkage the motor takes off right away. So this tells me its not getting air and this plate is sticking somewhat until the motor warms up. I thought about a vacuum leak but I can't see anything obvious anywhere.

I tried to clean this plate again and again on the inside where it hinges by spraying carb cleaner in there. Doesn't seem like it helped alot.

That's my best diagnosis so far. Can someone please take me to the next step and tell me how to clean this thing so it works right and my engine can get some air to accelerate when cold? Seems like a hot motor loosens up the stickyness and that's what makes it work well after warmup?

Thanks in advance guys!

-=>Raja.

No replies?
 

This problem still exists. Nowadays in the cold weather I have to start the car 5 times in a row before it will stay running. I turn the key and it starts right away, but then the motor slows down gradually to a stumble and dies. Turn the key off and back on, start it and it starts again, slows down and dies. After about the 4th to 5th time it slows down and holds rpm stumbling, but then it just smoothens out and picks back up to a steady idle.

Now I have to wait a few minutes for it to warm up so I can drive away, as when you press the gas it just dies instead of accelerates. If you drive way early, you have to be light on the gas and acceleration is poor. Takes me about 1/2 mile to get to 35mph. Once I get there and am in 4th gear its better, and once warmed up its normal.

What's up with this? Any help will be greatly appreciated!

-=>Raja.

try the cold start relay at the back of the battery.it should have a fuse at the top under a plastic cap. it might be covered with a black cover also.fuse might be blown if jump started at any time.

Which one do you mean?
 

At the back of the battery? I can think of a relay unit with a red top and a fuse stuck into that thing, but that is in the back of the fuse box on the driver's side where the battery is on the passenger side.

On the battery end I don't think there is anything like that but it big black box with a huge connector cable like a big version of a printer cable.

If the relay you're talking about is the one in the fuse box, is there a way to test it with a voltmeter? I think I grabbed a spare one from the junk yard a while back, but don't know if that one is any good. I could try swapping them.

Let me know what you think and thanks,

-=>Raja.

Hesitation Answer?
 

RBORT -- Did you ever receive/find an answer to this issue? I have the same problem with my '86 190 (just bought it) and didn't see the cold start relay referred to by G.Woods.

The OVP/cold start relay is indeed behind the battery, but there is a plastic cover that needs to be taken off to access it. pull up the weather strip, then pull out the cover. If the fuse (usually 10A) is blown, you can replace it to test, but replace the whole relay if it is the problem. They are very common and only cost about $60. Don't get a used one, buy new.

Problem not fixed yet
 

I did buy a new OVP relay and put it in but that didn't solve the problem. If anyone could help that will be great. Its better in the summer than winter, doesn't need as many starts sometimes it just slows down to almost dying and picks back up, especially if its really hot outside. In the winter it would start right away slow down and die and I have to restart it like 4 times to get it to keep running.

Also I don't have to wait as long to be able to drive off. In the winter it needs a few minutes to warm up, in the summer its only about 1 minute.

Any help would be greatly appreciated guys,

-=>Raja.

It still sounds like a mixture control problem, particularly since it clears after warming up. These older CIS-E engine modules essentially only perform any control during warm up and then switch mostly passive. This is why they have so much trouble when the OVP fails, it controls voltage supply to the engine controls.

Anyhow, the next thing I would check is the injectors. You can check these from the outside pretty easily. Take a stethescope (or a long screwdriver if you don't have one) and place it on top of the injector where the fuel line enters it. It should make a high pitched screaming/whistling noise. If it makes a graveling or grinding noise, or a slow, loud ticking, it is bad and likely leaking fuel into the cylinder. (Some fast, faint ticking is normal.)

I've also seen a lot of cold start injector problems on these. Unfortunately, those can be hard to check without special tools.

Best of luck,
Alex