Hard starting?

[Ashman]

Hi all, The other week, I put some 89 octane in my car, only about 5 gallons worth, on top of a couple of gallons of premium that was still in the tank.

Immediately I started having loss of power, and harder starting, and some black smoke on startup, hot or cold.

After the gas was done, I put premium back in, and the problem was gone, no hard starting, no loss of power, no black smoke.

Well after that tank of premium, I refilled with premium again, and the problem was still gone. Buit now even with premium, my car is hard to start. I can crank it, it will engane, but then the engine will die unless I gas it to stop it.

It returns to idle just fine, and I am on my way.

I am thinking I might have a fouled plug, faulty cap, rotor, or maybe a wire.

Or perhaps is it the elusive OVP?

Either that, or the gas station has low octane in their premim pump so they can rip us off.

Whatever the problem is, I'd like to get it resolved.

What do you guys think? I will happily replace plugs, cap, rotor, etc if needed, or even the ovp.

What do you guys think is the cause? Remember this has only happened in the last week to week and a half, and the car did the same symptons with lower grade gas, but now it has high grade and its doing it again.

Alon

[mbdoc]

I'd start with a fuel system test & new filter! Have the fuel in the filter dumped into a clear glass jar & see if the filter has any water mixed with the gas.

[Ashman]

Thanks, I'll look into it. Where is the fuel filter? I'll buy one and change it regardless.

But I'll also run some fuel system cleaner through

Alon

[Q]

Not fuel system cleaner, but the gas antifreeze stuff with alcohol in it. It is not rubbing alcohol, so don't try that. The alcohol content will allow the water in your system to mix with the gas as a homogenous mixture so it can be run out.

Brother of The Benz, Alon
Your chasing your tail Alon.
The octane rating wil NOT create the condition your engine is having.
With your tank near empty your fuel pump may have drawn the accumlated crude from the bottum of the tank. This could explain why the Premium fuel momentarily corrected the provlem.
Add the Fuel Tank Cleaner as suggested.
You said you see "BLACK" smoke. This indicates an over rich fuel mixture.
Changing electronic components wholesale will only give you new parts and not address the problem.
Not to make you feel bad, but my 1987 300E with 176,000 miles still has the original distributor cap and rotor.
If the problem was with the fuel filtering, the engine would not recover after running poorly. The fuel filter(s) are located under the chassis behind a protection panel usely on the right side.
Alon you may have have numerous problems, but replacing parts without justification is not the way to go.
Address the dirty fuel approach first.
Happy Trails Beep Beep from The Spiderman in Houston!!!

[Ashman]

I suspect low grade gas in the high test tanks.

I always run premium.

I just happened to put a few gallons of 89 octane in the car one day to see if the car would run ok on it, and it did not run as nice, so I put premium back in, and all was good. then I drove for a bit, used that tank, and I put in a new tank of premium, and the problem appeared again, which leads me to believe that gas is the culprit.

so I am thinking they either downmixed the 92 with 87, or they put 87 in the 92 tanks to rip us off. I've seen it on several news reports that stations are doing it here in los angeles.

I'm going to run some cleaner through it, techron probably, and change the fuel filter and see how it goes.

I'm going to check for a fouled plug too it could be something stupid.

The engine idles smooth, and the car's gas mileage has not decreased, so Thats why it seems strange. Like its not getting enough spark on startup only.

The rich mixture is because when I turn it over, it turns over more, then catches, then dies, then I turn it over again and it catches and holds. Its like its not getting enough fuel or the wrong grade. Because it showed a similar hard starting symptom with 89 octane, but not with premium, but it could be 87. I'll run some cleaner through. I have no idea how water could have gotten in there between fill ups, its been nice and sunny out.

Even after a spirited run of 80 + MPH on the freeway the car still shows the symptoms, and feels like its a little less powerful, which is why I think it might be bad gas?

Is that a possibility?

I don't mind changing some ignition/fuel components, but I'd rather try the cleaning approach first and see if thats the issue.

And I'd also like to try another station and see.

Or should I get the gas tested to see if its low grade, in which case, the gas station will need to be dealt with....

Alon

I have to agree with Donald.

Another thing is, try filling up at another gas station, with our gasoline cars, we use Amoco ultimate clear, BS stuff, lol.

Try the fuel filters first and if that doesnt work, do a tune up, when was the last time you replaced the spark plugs, distributor, wires, etc.?

Brother of The Benz, Johnson.
Johnson, there is no set frequency for replacing ignition components.
When one fails replace it.
The exception being, if you have to do major disassembling to get to a component and other ignition items are removed at that time, you might replace all of the items removed to gain access to the problem part, thus saving double labor at a different time. This keep everything fresh at the same time too.
As for my 103983 engine with 176,000 miles and still on the original ignition system, for this reliability, I have no answer. Just plain old luck.
My spark plugs are a different story.
Using "Copper Core" Champion RS9YC at $0.99 each;I keep rotating 2 sets.
I remove and replace with the alternate set every 7-8,000 miles.
These are the eyes of the engine. The plugs tell you what is happenning in the combustin chamber.
With the fresh set properly gapped at 0.032 inches, my engine never misses a beat and I am aware of what's happenning.
Your misfortune has to turn around soon, Johnson. Or your eventually going to have the best old Benz rolling.
I replace the fuel filter per the maintaince schedule.
I ALWAYS buy my fuel from a major refinner and a filling station that pumps a lot of gas, thus their tanks are clean.
My old tub has never drank anything less than posted 92+ octane fuel; To me it's too risky.
Happy Trails Beep Beep from The Spiderman in Houston!!!

Donald,

You said my misfortune will come around, well it did, today. It didnt come around, it came again, lol. Your not going to beleive what happened.

I took it to Jiffy lube to have the AC system recharged with R134a.

They broke the vaccumm element where the hose goes to the master cylinder. So my car does not shut off, you have to pop the hood and hit the stop button. GRRR, i am pretty pissed, i guess monday i will have to go to the MB dealer for parts, AGAIN!!!!!

They are going to pay for the part and do the repair, but i am going to have a lot of lost time driving back and forth and its embaressing as hell to pop your hood to turn off your car everywhere you go.

[Ashman]

Well Just to try something,

I bought some techron fuel system cleaner, added it, and topped off with premium fuel from my usual station, and guess what. The car starts a little better now.

fuel system cleaner is in, And I did not get a fuel filter from pep boys, No way is a purolator going in my car and not at $49.99. I'd rather get a factory filter even if it costs more.

But For now we shall see. The moment I topped off with the premium fromt he other station, all was better...

I do have one question though, Could the fuel filler cap be the cause if it doesn't seal properly?

I noticed mine was a bit out of whack, so I readjusted it and it seems better now. But it was sealing well before, so its beyond me.

I also decided just for the heck of it to spend the few dollars on some new spark plugs. Copper core champions for my car. I was looking through the plugs at pep boys and almost every plug is platinum for my car. So I explicitly told the guy I don't want the platinum. it took him a few more minutes, but he finally got the page that had the copper plugs.

I'm gonna stick em in later.

Thanks for the replies guys, The insight has been most helpful. I think the fuel cleaner, new plugs, and new premium fuel should hopefully clear up the problem.

I did contemplate some octane booster, but the last time I used that stuff in one of my cars (the MGB), it melted through the fuel lines.

In anycase, I'll keep you guys posted as to my findings.

Alon

[Edited by Ashman on 06-09-2001 at 06:34 PM]

[Ashman]

New Update.

After driving for a bit with the fuel system cleaner, I decided to go ahead and change the plugs. The existing lugs, looked fine, but no harm done with new plugs.

The car starts better now than before, so there must have been something clogging an injector or something partially.

I did notice while changing the plugs, that the Cap has some cracks near the allen bolts that hold it on. I am thinking I will change the cap.

Alon

Congradulations, it sounds like your on your way to having a better car. I would replace the cap too, its not that hard to do and not expensive. Goodluck.

Brothers of The Benz
It's good to read good things are happening to we who have problems.
One thing that amazes me is why most of us build our houses from the roof down!
For me, when I am performing a tune-up; I establish wheither my engine is worthy of operating properly after the tune-up.
I establish the condition of my engine before I start to replace parts.
First and the easiest is the basic dry compression test.
This tells me if all is well with the valves and if needed the piston rings.
The test for the rings is the wet compression test.
If in question, a fuel pump pressure test is performed. This is not normally performed for a minor tune-up.
I visually inspect the air filter and clean or replace it.
Now I do a visual inspection of the old spark plugs, for these are the eyes to your engine.
So much information can be learned from the condition of the spark plugs.
Never overlook the battery.
Check the charge voltage, for a low battery can cause problems we weren't aware of.
Top of the electrolyte level using distilled water.
Check the battery cable end at the battery post.
It never hurts to remove them and clean both connections.
If all turns out well; you've gathered and logged this data for comparison at the next tune-up.
After all of this Mickey Mouse testing, you know better what parts need to be replaced instead of a wholesale attack from The Blue Light Special Parts Department.
I know this may be the technique most of us use, but for those new to DIY, I hope I've helped them in a small way.
Happy Trails Beep Beep from The Spiderman in Houston!!!

[Ashman]

hehe I understand the approach donald, and its very thourough.

For me, I knew it had to be either fuel or spark related, seems to me that it was a bit of both.

Bad fuel might have messed with the plugs, which were NGK copper core plugs, but They appeared fine, not burned or oiled or overly fueld, just the tips were greyish red in color as I think they should be.

With the fuel system cleaner, new premium fuel, and the new plugs, the car fires up instantly, and feels better.

I will replace the cap too, but since the cracks in it don't seem to be affecting it, I will just leave it for now as the cracks appear to be from the previous owners mechanic overtightening them. They are stress cracks at the bolt holes.

I will buy a new cap in a week or so just to be safe.

My approach donald is to spend the few dollars on cleaners/spark, then if that fails well $10.00 out of my pocket aint a harmful thing, especially when the stuff I did could cause no harm in the first place. If that fails, I start to look elsewhere. Fuel system pressure, Spark problems (I.E. Cap, rotor, wires, coil), and then I start looking into electrical.

I am not one to blindly replace parts in the hopes it will fix it.

I took some advice about fuel system treatment/cleaner, topped up the tank (the fuel system cleaner I used was Techron Complete, which also removes water from the fuel). I then decided plugs would not hurt.

Alon

[rdetoy]

You're not done yet...Techron is *very* hard on engine oil, so plan on an oil change pronto. If you're going to use Techron always use it immediately before an oil change. In my experience, though, nothing has worked better than LubriMoly Ventil Sauber for cleaning fuel systems. Check it out!