Hi,

I just bought a 1989 190 Evolution 1. Car has done 102,000mls and in outwardly good condition. Unfortunately the car has some sort of idle/running problem. I'm new to the 2.5 16V so would appreciate some pointers on where to start looking.

Symptons:

When I first picked it up, the car tended to stall on braking to make turns, or entering roundabouts, sort of the times you are backing off the accelerator and braking - not carrying a lot of speed just normal driving. The car was also very hard to start without pumping the accelerator and wouldn't hold a cold idle very well.

I mentioned this to a friend and we then found that someone had run a pipe from the top side of the idle control valve to a brass _plumbing_ stopcock and back to the other side of the vacumn multi connector where the original short pipe connected to. The stopcock is adjustable and they had it set to where the car would hold idle.

So I removed this and now the car is hard to start, won't hold a cold idle and has bags of hesitation on acceleration. Once you get the revs up she spins like a top. Plugs are a good colour. The idle seems to fall to 450 threaten to die, recover, run like a dog around 750 sounding like it's running on 2cyls then sometimes it climbs to around 1300rpm. The brakes also appear very hard like there is no or little servo assistence, in fact this changes, sometimes the brakes are soft and servoed then they are hard as a rock.

I guess I have a vacumn leak somewhere, but I gather the idle control valve is toast, and perhaps the positions on the throttle body air flow meter or whatever it is needs to be reset to fix the stalling problem.

I'm pretty handy with mechanics so am not afraid to tinker but some pointers on where to start would be great. Also where can I get all the setting info, sensor testing details etc I see in the archives. I can't get any info on the Evolution/2.5 anywhere ober here. Is that stuff all on the W201 CD?

Cheers,
Neil

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Neil,

Your specific car is pretty rare and you won't find too many people with experience on the EVO I or EVOII models here. The original 190E 2.3-16 made it to the States though, and there are a number of us who frequent the site.

Try a search on the 190E 2.3-16 idle problems, or stalling. It is a fairly commonly reported problem and not all solutions are horribly complex, but some are. In some cases there are some limit switches that get munged up and need to be renewed or cleaned, while others involve removing the idle control valve assembly and either soaking it in a solvent and blowing it out with compressed air, or replacing it. Still others have much more complex issues and get into recalibrating the fuel delivery/air flow sensing equipment. Some or all of it will apply to the 2.5-16 engine, but you will have to sort that out. Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Hi,

I hope people don't avoid the thread because it's an Evo, there isn't much difference at all between the 2.5 16V you got in the US and the Evo 1. The internals are slightly different, shorter stroke etc and the thing has a different FI map but the controls are basically the same. It has a lamda sensor which I don't think the early 2.3's had - at least over here in Europe. AFAIK the 2.3 and 2.5 are so closely related most of the issues should cross. Anyway, to my update!

I removed the idle regulator and vacumn connectors and cleaned everything out. Applied 12V to the idle regulator and she opens and closes. Now holds a decent idle (950) but stayed up high on decelleration - about 2000rpm and still stalled occasionally. I put the microswitch from my 190E onto the Evo and the car returns to idle ok. It also starts first go on the key now. But I still have a high idle condition.

It now likes to sit up around 1200 rpm, occasionally fall and still stall out. Now, the car just simply refuses to go above 75 deg. So does it sound like a rich mixture and a faulty ECT sensor? Or a busted thermostat? The fans seems to run all the time with the engine which is weird. I don't know these 16V's, is that normal? Permanently engine driven? The 190e is clutch driven yeah - ?

Anyway would appreciate any input. Tomorrow I am going to check the Lamda and try and check the EHA output. But I think the temp situation may be messing up the whole works.

Finally where the heck is the OVP? Is that the seperate fuse box all on it's own in front of the main clear plastic fuse box, or is it a relay in the clear fuse box?

The OVP should be easily seen in the space behind the battery, not on the fusebox side. There's a plastic shroud behind the battery that can be pulled away where you'll find the OVP and the fuel pump relay as well, I believe. Since UK cars are right hand drive, I have no idea which side is which!

Hi,

Thanks. The Evo is LHD fwiw, all Evo's were LHD.

I did some more testing. Can someone please tell me what these figures mean?

I hooked up my Dwell meter on it's % reading to pin 3 of the X11 and to chassis ground. Initially on cold start I saw a reading of between 49.3 and 49.7%. It didn't fluctuate much at all, maybe a tenth every minute or so up or down. I then disconnected what I guess to be the ECT sensor, it's a large black plastic covered connector with 4 pins. There are two other connectors in the same location a single pin and a dual pole exposed connector. When I removed the plug to the 4 pin connector the engine started to run badly and the reading dropped to around 28.7%. This is where it gets weird. When I reconnected the sensor the readings started to jump all over the place from 0.8% to up to 50% but mostly in the 20-40% region. The engine still seemed to run smoothly. I read that 50% is cold start or non function O2 sensor and 30% is bad ECT sensor but what about these .7 etc readings should it be whole numbers?

When the reading started to range after reconnecting the sensor was it just coincidence that it seems to have gone into closed loop from cold start or could this be something else?

Car still won't get any hotter than 65deg idling. I am getting a new thermostat tomorrow and will install that. When I test it tomorrow, if it's still ranging I guess I need to look for a vacumn loss somewhere?

Help!?!

I forgot to add that I installed the microswitch out of my 190E and the car now returns to idle properly. Actually it seems to go high initially to about 1200 when cold starting then drops to 1000/950.

I'm also going to check the ignition timing as this could be out causing a higher idle I guess.

Can someone tell me what the timing is supposed to be?

I think your car has a knock sensor, and the timing may not be adjustable.

Saw that car for sale I think - is that picture you posted the one from the advert?

Idle/running problems are common to the 16v, plenty of people hear have gone through what you are currently/are about to. Worth searching on '16v idle' if you havent already

__________________
190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg

Yes thats right. Haven't had a chance to fawn over it yet and take more pictures which is what I'd really like to be doing rather than tracing FI faults... lol

Some of the Euro 190's were fitted with an adjustible resistor switch to alter the timing, unlike the fixed (R16) resistor that were installed on the US cars. It is probably located on the driver's side of the engine bay, mounted on the fender well.