1989 2.6 190E Tune-up...part two - PeachParts Mercedes-Benz Forum

#1 05-30-2006, 10:45 PM

Alright, after retracing my steps with a clear mind, and plenty of advice...I switched to copper plugs, I checked my wireset and made sure it was properly routed...distributor to the plugs, button was fine, coil plug was doing great...before I replaced the air filter housing, I gave it a test crank...
THIS IS WHAT IT DID:

1. Key in ignition
2. Buzzers / Chimes / Vacuums engaged
3. When cranked, it makes a stuttered (da-da-da-da-da-da-da) noise...like it just does not have the strength or the amperage to turn the engine over. IT wants to but it just can not seem to do it...
4. Then, the throttle body, that big butterfly that looks like it belongs on a carburetor but sits nicely underneath the air filter housing, well it started backfiring and pissing flames...guess it had to burp, no biggie, I guess I flooded it so it had to let it go somewhere, the thing is is that, I did not put my foot in it...for once.

The reason for the tune-up was beacuse I noticed that my rpm's at 80mph are sitting at 3500, when I am at a stop light the poor car would lurch and heave like it had whooping cough. The oil pressure gauge will be at '1' when I know I dumped 5QT in there, and the 'Economy' gaugeis always in the red. So I am not just some meandering female wandering in looking for a quick fix for a car, my girls and I actually work on our cars, and I would appreciate any good long lasting tips to help out as this is my first Benz...My daily driver right now is my show car...T-Type Buick Regal and it's being painted so I am sneaking driving my hubbys car...Help

rickpark · #2 05-30-2006, 11:51 PM

Have you checked to make sure you haven't inadvertently left a sensor cable disconnected?

If you're 100% sure that the plug wiring is correct it sounds like either the fuel or ignition system is missing some key input for proper operation.

IIRC, there is a sensor that plugs into the air intake that I sometimes forget to plug back in when I change the filter .- you may have disconnected it when you took the cleaner housing off.

Other possibilities: the crankshaft position sensor, the TDC sensor.

mctwin2kman · #3 05-31-2006, 09:46 AM

First the RPM's on the highway are due to gearing not tune-up. Second if you have the vacuum gauge in the red then you have a serious ass vacuum leak somewhere. Third check the rubber boot between the Air Flow Meter and the throttle body, the AFM is that Carb looking flap thing. You are most likely getting that back fire due to no air going in and lots of fuel. Well it has to blow somewhere. The only othe thing it could possible be is the Cat is Clogged or Pre-Cats. Drop the exhaust at the joing between the manifolds and the down pipes. If the exhaust has an issue this will let you know as it will be disconnected. You do not need to drop it but instead loosen it enough to leak like crazy.

shandy · #4 05-31-2006, 10:07 AM

Is the vacuum pipe connected to the distributor ? also did you move the distributor body at any time and shift the ignition timing?. Sounds to me like the like the ignition timing is well out.

#5 05-31-2006, 01:24 PM

Hmm...ok after replacing the fuel relay, the ovpr, the manifolds do not leak, the butterfly (AFM) is still gasping for life, I have never seen as sensor cable on the air housing before (unless you are talking about that tube that runs from the engine and has a tiny side-pipe that runs to the electronic switches below), I never jacked with the distributor body in any way shape or form, the cat cons are fineand my engine is still suffocating.
Now, after all of that has been said and done...the three simplest things I have NOT done were A: Checked to make sure my rotor button was lined up correctly (yeah right...you can only put it in one way, but I at least could have put it in firing posistion 1, which I failed to do) B: Checked to make sure that I put the distributer cap on in it's correct position (I am almost certain I put it in the "1 o'clock" position) So I am going to check that battery first...and if it is the battery, then Ladies and Gentlemen my sincerest apologies for freaking out, but if it is A or B, you ALL need to talk about me...very very badly, because O had no business overlooking that simple stupid step.

MikeTangas · #6 05-31-2006, 04:46 PM

I would have to ask if you had much problem getting the spark plug wires off when you initially changed the plugs?

Often the plug ends adhere to the plug and some folks try to get a good grip on the lead to pop the plug end free of the porcelin plug. That is a sure fire way to ruin a set of plug wires. If you have a DVM (digital volt meter) check each of the wires for resistance, believe they should all fall about 1k ohms (or is it 5k??? someone refresh my memory). Any wire that read high or have no reading need be replaced.

Just another thing to check out.

skiier3_9 · #7 05-31-2006, 04:54 PM

BTW the 89 and earlier 2.6 did not have the sensor in the air cleaner assembly (see pic)

mctwin2kman · #8 05-31-2006, 05:51 PM

Make sure the cap is seated properly, I have put it on before and the cap was not seated all the way. Check plugs wires for resistance, cold they should be between 800Ohm and 1.3KOhm's. Perfect and great is 1KOhm as when they get hot they raise in resistance.