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  #1  
Old 05-22-2012, 07:41 PM
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Join Date: May 2012
Location: Fort Collins, CO
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95 E320 wagon has gas at injectors, won't start.

I've been trying, with enormous amounts of help from this forum and my two German DIY manuals, to bring a 1995 E320 wagon back to life.

The initial condition indicated major overheating. I had the head machined, installed new cylinder head gasket, seals, fuel filter, etc. Everything went back together nicely (thanks again for all the warnings on this forum). Removed the injectors, cleaned them, installed new seals, they spray like mini fire departments.. There's spark at the plugs. There's gas (and pressure) in the rail.

Read up on error codes at the 16 pin connector. Built the code reader. Cleared the codes and they haven't come back, so now I have no fault condition throughout.

After pulling the plugs, all I detect is a whiff of gas vapor. With the cranking this motor has had, I'd expect flooding at this point.

So here I am, completely out of ideas on the next move. I hope forum members who recognize the symptoms can give me some direction. What should I TEST next and HOW, rather than run out and buy parts without a clear understanding of the remaining issues. (The above-mentioned German manuals are great on specs and procedures, short on trouble shooting!).

Many Thanks
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  #2  
Old 05-22-2012, 08:09 PM
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Quote:
Originally Posted by Big Yin View Post
I've been trying, with enormous amounts of help from this forum and my two German DIY manuals, to bring a 1995 E320 wagon back to life.

The initial condition indicated major overheating. I had the head machined, installed new cylinder head gasket, seals, fuel filter, etc. Everything went back together nicely (thanks again for all the warnings on this forum). Removed the injectors, cleaned them, installed new seals, they spray like mini fire departments.. There's spark at the plugs. There's gas (and pressure) in the rail.

Read up on error codes at the 16 pin connector. Built the code reader. Cleared the codes and they haven't come back, so now I have no fault condition throughout.

After pulling the plugs, all I detect is a whiff of gas vapor. With the cranking this motor has had, I'd expect flooding at this point.

So here I am, completely out of ideas on the next move. I hope forum members who recognize the symptoms can give me some direction. What should I TEST next and HOW, rather than run out and buy parts without a clear understanding of the remaining issues. (The above-mentioned German manuals are great on specs and procedures, short on trouble shooting!).

Many Thanks
Check this article as a guide to see if you missed something

Pelican Technical Article: Mercedes Benz - Fuel Injector Replacement
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  #3  
Old 05-22-2012, 09:45 PM
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Security Issue

Have you tried a light on one of your injectors to see if it is opening. iF iNJECTORS ARE NOT OPENING then I think it is the security system . maybe ignition module/key
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  #4  
Old 05-23-2012, 12:46 AM
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Thanks! Next step is in-car injector test

Thanks for your responses.

Lamp test raises a good point. My injector tests were on the "bench". I'll do the lamp test now they are back in the car and report the findings.
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  #5  
Old 05-24-2012, 01:34 AM
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For everyone who's having starting or idle issues with 93 -95 W124 3.2 or 2.8 liter. Here's how you get your car to idle or start correctly. These problems are mostly related to old parts on old cars.

You only have fuel and spark in this equation. You have to write down all the parts for fuel and all the parts for spark.

If you have not replace the upper wiring harness in your car, or don't know the condition of it, stop right there. Do this first. Just moving one these old wires can cause your car not to start.

If your harness is good, pull the codes from your computer and clear them. Drive around and see which codes come back. This is a good starting point of what to replace first.

Next make sure all the components on the fuel side are good. Fuel pump, relay, regulator etc. If this all checks out you can move on to the spark side.

On the spark side you some of the main parts are MAF sensor, Temp sensor, Crank position sensor, coils, trottle body, fuel injectors, spark plugs, control unit, etc.

Start replacing the cheapest parts first until your problem goes away. If you have a good mechanic who works on European cars , he has the tools to test most parts, and will save you time and money in the long run.
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  #6  
Old 05-24-2012, 01:37 AM
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Quote:
Originally Posted by olmectech View Post
For everyone who's having starting or idle issues with 93 -95 W124 3.2 or 2.8 liter. Here's how you get your car to idle or start correctly. These problems are mostly related to old parts on old cars.

You only have fuel and spark in this equation. You have to write down all the parts for fuel and all the parts for spark.

If you have not replace the upper wiring harness in your car, or don't know the condition of it, stop right there. Do this first. Just moving one these old wires can cause your car not to start.

If your harness is good, pull the codes from your computer and clear them. Drive around and see which codes come back. This is a good starting point of what to replace first.

Next make sure all the components on the fuel side are good. Fuel pump, relay, regulator etc. If this all checks out you can move on to the spark side.

On the spark side you some of the main parts are MAF sensor, Temp sensor, Crank position sensor, coils, trottle body, fuel injectors, spark plugs, control unit, etc.

Start replacing the cheapest parts first until your problem goes away. If you have a good mechanic who works on European cars , he has the tools to test most parts, and will save you time and money in the long run.
While your suggestion is good to trace the systems and look at the wiring harness, I disagree with the point of throwing parts at it and seeing what sticks to make things better. It's best to Test things out and replace whats needed then replace a ton of crap that dosnt need replacing.
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  #7  
Old 05-24-2012, 10:38 AM
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I said that at the bottom of my post.

But the fact remains, if you want a 20 year old car to idle and start like a new car, there's no silver bullet here.

Old parts = idle and starting problems.
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  #8  
Old 05-24-2012, 07:34 PM
Webbervillecarnut
 
Join Date: May 2012
Location: Austin, TX
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What kind of shape is your engine harness in? the overvoltage relay can cause this symptom, but I'm not sure of other symptoms not stated here.
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  #9  
Old 05-25-2012, 02:04 PM
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Thanks for the responses.

Wiring Harness
I should have covered the harness at the outset. It has obviously been replaced in the not too distant past. After doing serious background reading on this forum, I wouldn't have touched this car if it hadn't been. No guarantee that it's good, of course.

What this forum didn't prepare me for was Daimler's ingenuity in finding other applications for inferior plastics. But that's another story.

Why Bother?
I have this car because I hope it will be an interesting and educational experience. One of my day jobs is translating technical German to English. Mostly power tools and construction stuff. This car gave me an excuse to get German repair manuals and radically expand my automotive vocabulary. In that sense, I already got my money's worth.

My expectations for an E320 wagon this old are pretty limited. I don't expect a 17 year old E320 to pretend that it's brand new. Especially when it's only the 1995 update of an obviously very much older design, hampered by all manner of constraining gizmos that were never part of the original concept. I already have a 14 year old car with performance to burn. And isn't limited to some crummy 25 miles to the gallon, either. So this is simply an opportunity to explore a brand and engineering attitude that's new to me.

I would be amazed if the engine leaped into action just because I fixed a bad head and cleaned the injectors. And it didn't. So I'm now in search of a little direction along a path of systematic troubleshooting based on knowledge of these particular cars acquired by owners of much longer standing. Pointers such as "the ignition switch on these cars has a half-life of three weeks and is always the first thing to go".

With luck, we can also skip the "cars are complicated" intro. I've fixed enough of them to have learned that.

And while throwing parts at a car until it goes certainly qualifies as a strategy of sorts, it doesn't appeal to me. I'd be left wondering what particular permutation of parts actually solved the problem. And that's not why I'm spending time on this car.

When the rain stops, I'll get back to putting a light on the injector wiring.

Thanks again!
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  #10  
Old 05-25-2012, 02:08 PM
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You might be pleasantly surprised when all is said and done. These cars a brick houses and posses a lot of qualities newer cars can't provide. Good luck in the trouble shooting!
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  #11  
Old 05-25-2012, 04:37 PM
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i agree with post #9, and since you seem to have ruled out the wire harness, check the ovp.

a quick and inexpensive test can be found in the following thread:
(see post#33)

OVP's purpose in life is????

have an assistant crank the engine, while you perform the test.


good luck
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  #12  
Old 05-27-2012, 03:45 PM
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I finally got a chance to put a lamp on the #1 cylinder injector cable and disconnected the camshaft position sensor and crankshaft position sensor in turn.

Camshaft sensor connected..crankshaft sensor connected..flashing light
yes................................... yes.................................... yes
no.................................... yes..................................... yes
yes................................... no....................................... no

Is a cylinder head overheat likely to toast a camshaft sensor?
Am I correct in thinking that signals from BOTH camshaft and crankshaft sensors are required in order to fire injectors?
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  #13  
Old 05-27-2012, 04:29 PM
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crank and cam sensors directly relate to injector firing, they are read so the computer knows what cyl to inject and fire. faulty sensors will lead to no runs and crappy runs. and yes, if you overheat them it's a potential to make them faulty. Heat+electronics are generally bad
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