w202 1994 struggle going uphill

[rmt6668]

I have just repaired the engine wire harness, new ignition wire set, cleaned the spark plugs and one new coil pack. After all this my car still have the symptom of struggling going uphill. It will struggle 20-40km/hr & very slowly pick up speed. Can any you help me diagnose?

 

[Aussie Nick]

This is not what it is supposed to do once you have done the work you have described. Is it the 200 motor? Are you sure the other coil pack is ok.They develop tiny cracks and it is hard to see them sometimes. The 200 will struggle uphill unless you boot it hard in the guts.
Maybe you need to clean your air filter and check the Mass air filter located just south of the air intake filter box. I am a little suspicious of cleaning the spark plugs. Try putting in some new ones . I used to use NGK but I would prefer that you stick to the Bosch .

 

[rmt6668]

My W202 is the M111 engine 111.961, the other coil pack was 1 yr old, look like the same makefrom Slovenia (Bosch).

Is it true I can check if the MAF (air mass) sensor is the culprit by unplugging the plug onto the Bosch sensor & try driving uphill & if it dont struggle with it unplug then its the MAF at fault.

The Air filter is squeeky clean & I'll just try replace with the Bosch spark plugs.

Can a scan done by MB detect whether its the MAF, Knock sensor, spark plug or fuel filter etc? I read somewhere it will not be able to detect a faulty MAF?

Thanks

 

[Aussie Nick]

Before testing for MAF malfunction try the new plugs. It also sounds like clogged injectors. Would suggest you try a strong dose of good quality injector cleaner and take it for a long run at high speed . Is this c180 or c200? Does the car sit unused for long periods ? Do you only mainly do short trips? If you can get 98 octane put this in it .

 

[rmt6668]

Th engine chasis is 202.022, its a C220 or 2.2 litre. The 98 Octane, do I just add to the fuel tank & no need to phycally remove each of the Fuel injector from its rail & have them cleaned? I had been using normal unleaded Fuel instead of the recommended Premium Unleaded, do this have an impact?

I will get new spark-plugs & 98 Octane at autobarn, repco or supersheap auto tommorow. Should I replace the Fuel Filter as well, is Feul filter same as Oil Filter. Thats the one with the black cap?

The car had been idle for 1 month plus when I was slowly attending to the wiring harness & new coils, new spark plug wires. Yes only travel short distance. Once I attend to the list above & i'll run the car in on the highway.

Rgds

 

[Aussie Nick]

Ok rmt I think we are now getting somewhere. Sounds like you are in AUS.When you buy the fuel injector cleaner I suggest you buy enough for two tank loads .You wont have totake offt he injectors .this is a delicate job for the novice.You should tip both cans of injector cleaner for one tank.It will not harm the motor.Give it a long run so that the motor gets hot . The fuel filter will be near the rear diff under the car. Dont do this yet as this is a bit tricky for the novice .Suggest that you buy the proper Mercedes fuel filter or the Repco equivalent as some have beeen known to leak and incinerate the whole car.(The leak happened to me but i was able to find it in time)Lets deal with the plugs and the injectors first before we consider the fuel filter. How old is your battery and have you got a battery charger?

 

[rmt6668]

Thanks.I'll do them. Do you know of any dealership or mechanic who can help to scan the engine using special diagnostic tool?

Should I fill in with premium Unleaded Fuel to say 95% & then straight away pour 2 bottles of the 98 Octane (how many ml in a bottle?)

Hopefully its not Fuel Filter.

 

[rmt6668]

Also I may need to top up my refrigeration, I had inadvertantly let the gas out slightly. Where do you suggest the economical ppl who remove & replace the refrigerant?

Thanks

 

[Aussie Nick]

Are you in Australia and which state? Also put both cans of the injector cleaner first before the petrol. The injector cleaner usually comes in one bottle for 52 litres except the Nulon where they give you one bottle for two tanks

 

[rmt6668]

I am in Melbourne, Victoria. Which town/state are you in? So I add the 98 Octane Fuel Injector Cleaner.

I have a batter charger, the current battery is about 5/6 yrs old & I do have a spare battery in storage. Are you suggesting I re-charge or check the condition of my battery?

Thanks

 

[Aussie Nick]

Yeah hi mate. Im in Melbourne too. Suggest you change the battery as well. The 98 octane is the rating of the fuel .Suggest you try the Mobil 8000. It is expensive but you should notice the difference. Try a new battery. I think yours is specific like mine but one of the battery outlets should have it. Make sure you get the right one otherwise it will not bolt down in the boot and a loose battery is dangerous. I would think your Current battery could be causing you some of the grief.They are required to have a pretty large capacity battery because the current draw, especially for the coil packs is pretty huge. Expect to pay$70 to $140 for the refrigerant Where are you in Melbourne?

 

[rmt6668]

Good 'day
Just return from buying a NULON Octane Boost & Clean (Repco recommended) & aslo bought 4 Bosch Super Plus (YTTRIUM) FR8DC+ Spark Plugs. I will try do this all tonight & I'm in the eastern suburbs.

I will try out my other brand new spare battery as well. Why do you think its the battery as well.

Where do I top up refrigerant, like to be one where they have a diagnostic scanner. Does Ultratune, Midas, K-mart, Bob Jane? Is it a quick process ie just a 1 hr wait to do this?

 

[Aussie Nick]

Gday mate. I'm in the east too.Try George at the One Service Centre Park Orchards .He is the only servo there. He has the refrigerant, knows mercs and is reasonable in his prices. He can get a hold of a diagnostic machine for $100.00. I would recommend that you try the remedy I have prescribed first before you go and start blowing the bucks. I think your bus has been sitting for too long without long trips.I think the battery has failed or is on its last legs so accordingly with dirty injectors and clapped out plugs the obvious has occurred . I would suggest you tap out your air filter and run some compressed air through the opposite side to the air flow to clean it out. Report back with the outcome.

 

[rmt6668]

Thanks for the help. Lets see how I go tonight.

Any refridgerant person closer to the city?

Rgds

 

[Aussie Nick]

yeah no doubt there is but i suggest you try george because i know what he charges

 

[rmt6668]

OK just replace the battery but waiting for the car to cool down b4 changing the new spark plugs. My fuel tank is 90% full, can I pour in the Nulon Octane Boost & clean now & top up 10% fuel tommorow. But will need 2 to 3 days before I can run the car in at high speed & long duration. Is it oK for me to top up now?

Thanks

 

[bigasotonuk]

Hi,
Could,nt this lack of power be down to the prolonged use of unleaded fuel, instead of the recommended super plus unleaded? It could of caused possible damage to the valves, valve guides and seats. Even when cars were converted to run on unleaded they still needed a tank of leaded every fourth tank.
If what Nick has suggested is unsuccessful try doing a compression check this should give you some indication of any valve damage.

 

[rmt6668]

Thanks. Can you confirm If I can pour in the Nulon Injector Cleaner but top up with Preminum Unleaded Fuel say tommorow & run/warm up the car for drive in a couple of days?

 

[Aussie Nick]

Hi again mate.

The manufacturer of the Nulon suggests you put the cleaner in first before you fill up........ It is on the ****** directions of the canister you have bought mate.:idea:...... I think it is necessary to do this to ensure even distribution of the cleaner through the fuel mix.Take the car around some speed humps to mix it up a bit. I think as you are using a stronger mix than normal and that you have 10 % capacity left it will be ok if you apply the noxious gargle now. Make sure to wash the tonic down with the extra 10% of fuel at 98 octane.
I have to respectfiully disagree with senior member Bigasatonuk. His advice about the leaded may be more relevant to UK than here. Since the introduction of unleaded in 1985 the motors have been purpose built to run with unleaded.Yours being a 1994 would fall within this category.If you run leaded through it at any stage there is a strong chance that you will damage the engine .So dont do it.
Senior members Bigastonuk's advice about running leaded every so often with unleaded fuel is valid with pre 1985 cars which were Leaded specified. There are special leaded additives available for those cars .

As for the compression test this is good advice which I would agree with. However I do not recall you indicating that there was any loss of oil.... or was there and have you checked?
Lets try the course we have adopted so far and we will see about the compression test later if necessary.

 

[rmt6668]

Aussie Nick

Just to confirm again, what I have done.

(1) 4 new spark plugs with 4 new ignition wire set
(2) 1x300 ml Nulon Octane Boost & Clean & top up with Preminum uleaded. Total 60 litre fuel mix.
(3) Change with brand new battery
(4) Drove the car around at high speed & long duration & reaching engine temp approx 100 deg C.

Result:-
(1) A very noticable difference, more power (pick-up)/responsive.
(2) Going uphill still slight struggle but gradually reaching 60km/hr
(3) Initially the Fuel Gauge shows an empty fuel with warning amber light comes on, when initially start engine. But when shut down & restart it gave the correct gauge. BUT now it constantly display a FULL tank. Right to the top???

I am still running the car in around the freeway when I could, to hopefully run-out that mix of fuel. But now I'm worried I may run out of gas without knowing. Normally it runs out in a week. It been around 3 days now.

Can you help me to resolve this?

On the A/C refrigerant I have organise with a closer by mechanic. Is George an auto-electrician, does he have a scan tool or is it for sale $100?

Thanks again.