Can't get the 190e to run for long!!!
 

I am having trouble trying to get my 86' Mercedes 190e to run. I have just replaced the cylinderhead myself. Everything went smoothly, I replaced the headgasket and numerous other gaskets that leaked on the whole engine. The car started right up when I timed it. We adjusted the fuel mixture to the right mixture, but then I pulled off a stupid mistake. I had a brain fat :eek: , and wanted to see if the spark plug distributor was tightened down, and by twisting it, I threw off the timing :( . For some reason, I could not get the proper timing right. I have adjusted the mixture as best I could, but finally could only get the car to run for 5+ seconds and then shut off. It's at a mechanic right now, and he hotwired the fuel pump relay somehow and the car was able to run again. I replaced the fuel pump relay, but for some reason, I'm back to square one again. The car only runs for 5+ seconds when started.

What could be the problem? I have made sure there was no leaks in the intake manifold, r&red everything on the top end as supposed to, and have a new fuel pump relay. The car runs when 2 pins where the fuel pump relay goes(runs rich though, do to my desperate attempts adjusting the fuel mixture, and timing to get it to run again), and currently has a spanking new fuel pump relay. Someone please help me :o !

Peter v.

Check your alternator wiring -- the ECU shuts the pump off if the engine isn't running, and the alternator output may be a signal. You may have also disturbed the wiring at the dizzy so the ECU thinks the engine didn't start (separate computers for fuel and ignition on that car).

Most likely it's something at the dizzy.

It could also be that you have it so rich it just floods out and the ECU is shutting off the fuel pump. I don't remember which way to turn the screw to control the mixture, you will have to do a search or use a VOM with duty cycle function to re-set the mixture.

Inability to set the timing correctly indicates to me some sort of damage to the wiring and hence intermittant ignition. You should have only needed to get the dizzy close to correct to get it set.

Peter

Peter

Thanks for the reply, but, and sorry to sound so naive, but what's a dizzy?

Peter v.

Sorry to hear the anticlimatic startup after your rebuild.....

If it were my car I would smell the tail pipe for the smell of raw fuel.....

additionally, when I first got the old 190e it idled very poorly. I did so many things to try and get it to run right it was insane.

A friend suggested bleeding the injector lines at the fuel distributor which I thought was absurd. Well.... I finally tried it and i was amazed at the amount of crack that came out. My 190e is an 87.

I have also heard (forgive the unfounded part of this) but doesn't disconnecting the battery and waiting for over ten minutes reset the ECU? I thought of this after rereading your post about twisting the distributor.

Also, did you check the OVP relay fuse?

Keep us posted,

Haasman

Distributor!

Well, I was just spending some time looking at some old posts and I found one where someone was having the same problem on their 190e: http://www.peachparts.com/shopforum/tech-help/102737-help-190e-2-3-question.html?highlight=ignition+controller

Could it be possible that it would be the ignition control unit? Judging by the symptoms that graybenz190E had and how similar they are, could it be the likely problem? Is there a way to test the controller, because almost $300 is alot of money for a college kid like me :(

The fact that it runs for 5 seconds at start up is the clue that psfred is correct (as is usually the case) and also the thread you found says the same thing. I do not have a schematic for this car so cannot speak authoratatively, however assuming that the ignition control module does send a signal to the fuel pump relay, then if you can determine what "signal" it is supposed to send, you can put a meter or oscilliscope onto that wire and look for the signal. That would tell you where the trouble. I have a scope in my closet don't you?... Well on a college campus you should be able to find a scope, unless it's liberal arts. And try to get the scope operator (someone who knows how to use it) or you might not get any use out of it. Bigger problem might be figuring out what to look for: A square wave, high voltage, low voltage... Saving money isn't always easy but you can learn a lot.

Mike

thanks for your replies. I do have a digital multimeter, so I can record voltage. I do have access to an oscillascope in the lab, but it's attatched to the big "electronic workbench" in the lab :p now, I need to find out the electrical schematics. I wonder if my Haynes auto manual can help me on this one.

Peter v.

Check the crank sensor! Measure its resistance from the center pin to the shield of it. Should be between 660 or 680 to 1200 ohm's. This is what tells the Ignition Controller that the engine is running. If out of range it shuts the fuel pump off. Also if need be I will have a spare Ignition Controller, used, that I may part with if need be!

On further consideration, I do not think you will need a scope. Haynes should have the diagrams you need. It sounds like mctwin2kman is speaking from experience. So probably the crank sensor is bad or the controller is bad or some connection at one of those places (connectors are the root of all evil). With the diagram and your meter you should be able to find where the trouble is. Let us know.

Mike

One other thing
 

If I remember correctly, on the older models like mine as well, the crank sensor is located on the distributor, it's a green wire that goes from the "dizzy" :) to the ignition computer, it is possible that when you twisted the distributor it got disconnected or gets disconnected once the engine starts shaking. It's a rather delicated wire and without it you wont get a spark at all, make sure it is intact and plugged in correctly.

As for mixture, I've done a lot of adjusting with the screw on the air filter and I was never able to put it so far that the engine would flood. I had it so lean that the computer maxxed out, but the engine still ran fine. This is a very fine adjustment and if the car, it is probably something else, or fuel mixter with something else but not fuel mixture on its own.

Check the green wire, wiggle it, clean the connections.

xp

My 1986 has the crank sensor on the block above the crank pulley! There also is a wire going to the distributor as well though. I forget what it is called but it works with the CIS-E and Ignition Controller Unit on the fender!

I believe the sensor on the dizztributor is the pickup for the electronic ignition, basically what replaced the old points. Anybody remember points.... Crank sensor should be near the crank. Mctwin2kman sounds correct, again.

Thanks everyone for the great replies. XP, the wire that goes to the dizzy must still be intact, because the engine runs for 5 seconds or so before dying. I'll get the crank sensor and ignition controller checked out.

By the way, mctwin2kman, how much you it take to have you part with the spare ignition controller that you have?

Thanks again for your advice everybody,
Peter v.

Also, How should I test the Ignition controller? when the engine is running for the brief period that it can, or when the the key is just turned to ACC?

Tested it yesterday and it works so I will part with it for a small fee of $25 shipped. That should be about 20 bucks for the part and 5 for the shipping. PayPal me at jamison.marsala@verizon.net and I will send her out ASAP if you need it! Just let me know.