Just idles wont accelerate

[chrisdunk]

I have a 1977 mercedes 280se that will idle just fine but when you push the accelarator the car sputters then dies? Can anyone help identify this problem. Thanks

While i was looking today i seen that the person who owned the car before me the original fuel pump went out then they just purchased a off brand pump and added it after the original. Could this be the main problem? THANKS

[MunichTaxi]

you might not be firing all 6 cylinders. BTW, you have the M110 engine.

Have you removed the spark plugs to check condition and color?
Have you confirmed spark at all spark plug leads?
Have you changed spark plug wires?
Have you set timing?
Have you checked fuel & air filter?
Have you changed spark plug wires?
Have you adjusted the valves? (I believe they are mechanical lifters)

A 30 year old vehicle needs attention. How many miles?

[chrisdunk]

Originally Posted by MunichTaxi

you might not be firing all 6 cylinders. BTW, you have the M110 engine.

Have you removed the spark plugs to check condition and color?
Have you confirmed spark at all spark plug leads?
Have you changed spark plug wires?
Have you set timing?
Have you checked fuel & air filter?
Have you changed spark plug wires?
Have you adjusted the valves? (I believe they are mechanical lifters)

A 30 year old vehicle needs attention. How many miles?

79,000 miles

[have mercy]

Check exhaust. And munick taxi list. If car sit,tank has filter in it check it.

[JimFreeh]

If the way it behaves changes WRT the way you depress the accelerator, you likely have a fuel starvation problem.

That is, depress accelerator gradually, and depress rapidly.
If the symptoms change, I'd suspect gas flow. More specifically, a restriction somewhere, such as clogged screen, filter, or a low pressure from pump.

Jim

[nhdoc]

could also be timing...once I had a car that the distributor came loose on and would turn on its own wreaking havoc on the way it ran. It usually would idle, but never ran well above that speed. Bottom line is, check the basics and see what you can find...there is no silver bullet.

[MunichTaxi]

79,000 miles

That car has a 5 digit odometer, correct?

[ctaylor738]

Take the air cleaner off and make sure that the sensor plate moves freely. If it's stuck, clean it up with some carb or brake cleaner.

[chrisdunk]

Originally Posted by nhdoc

could also be timing...once I had a car that the distributor came loose on and would turn on its own wreaking havoc on the way it ran. It usually would idle, but never ran well above that speed. Bottom line is, check the basics and see what you can find...there is no silver bullet.

How do you set timing im not exactly sure on these cars. thanks

[rusty_parts2001]

A 30 year old car thats been sitting a while may idle fine but may starve for fuel upon acceleration. The likely culprits are the fuel filters (in tank filter and fine fuel filter under the hood), and rust and crud in the tank. The solutions include replacing the filters (cheap) and/or clean out the gas tank (slightly more expensive, but not prohibitively so). That should solve the problem if the ignition is otherwise in good condition. Let us know.

[pj67coll]

Originally Posted by MunichTaxi

79,000 miles

That car has a 5 digit odometer, correct?

The 116 has a six digit odometer.

- Peter.

[300SDog]

Originally Posted by MunichTaxi

Have you removed the spark plugs to check condition and color?

Yeah man, look to the plugs - even better yet snap picture of em and share it here.....

For example: dark brown 'wet-fouled' means running rich or blown out injector tips and/or could be not enough spark, crummy wires, weak coil etc. Plugs is always first tool for intuitive engine diagnosis you understand.

Another likely culprit is engine timing: specially centrifugal and vac advance could be stickin or dysfunctional. General rule says check timing with strobe light before chasing fuel/air mix ghosts. Also run feeler guage through valve tappets just to be sure couple of em aint slipped tight if ye want perfectionist performance.

Nevertheless yer suspicion of crummy aftermarket fuel pump aint bad - oughta produce somewhere around 22lbs pressure for that engine. Of course even radical vac leak like cracked hose line fitting at intake manifold can produce similar symptoms to what you describe.

C'mon back with exact descript of whats going on: Like is it sudden prob with daily driver, revival after hibernation and/or whats history of yer 280SE's performance? Agruably that m110 engine is the finest inline 6cyl longblock that MB's ever built you understand. And from what yer sayin it dont sound like major prob to me.

[chrisdunk]

Just purchased the car dont know a lot about it the guy who owned it before said eh was driving and it sputtered out. And when we got it, it would only idle but I have ti to where it will drive but only up to 20Rms and then it sputters out ill clean the filters tomorrow and replace plugs also i believe there fouled out. Also there is a vacuum line on the passenger side thats really long and i cannot figure out where it goes I think its low on the motor does anyone know about that either. Thanks

[cth350]

The CIS motors have a WUR; Warmup/Enrichment compensator. It can get gummed up from sitting a long time. It is about the size of a pack of cigarettes and has two fuel lines and a vacuum line on it. You'll find it on the driver's side under the intake manifold bolted up to the block (a pain to reach).

Ideally, you want a used one off of ebay, but that's just an idle shot in the dark.

-CTH

[300SDog]

Enrichment compensator for CIS FI.... now there's something i never woulda considered. Pretty much my advice is basic meat'n potatos stuff compared with that.

Meanwhile one practice I've always followed with every newly purchased Vintage MB - get the car tuned professionally first, this will make DIY maintenance helluva lot easier from that point forward. First time professional tune will set standard, and then if anything goes wrong it'll be obvious for easy diagnosis from that point on. Better than dealing with multiple unknowns from the git go, says me.

The long passenger side vac line probly runs to trans control valve that smooths out shifts. Look underneath for white plastic fitting on tranny housing. Could also be contributing factor to engine probs, though trans will shift if its disconnected. Good idea is cutting back 30 yr old rubber elbow vac fittings 1/4 - 3/8" to give em tighter fit, if not replacing all of em w/ new.

Otherwise yeah, if this is yer first fuel injected twincam m110 then professional tune (or post-purchase look over) is probly good idea that will help keep you from chasing ghosts, multiple adjustments the car might need. And then the next 100k miles will be walk in the park.