Spark plug upgrade

[JUSTJEFF]

Just bought a 87 190E and the handbook list,s the plugs as "Bosch HR7 D+" or "H7 DC". My local Halfords dont stock these and i was wondering if there is a more modern equivelant of them. NGK do some to fit the car but i am worried about the quality of them as they are £10 for 4 and Bosch plugs seem to be on average 20 odd quid ( is dearer better ? ) I want to get it right as the plug change is my starting point for a "lumpy" running engine.

 

[kth286]

Go to dealer with your VIN and you will automatically be given the right plugs for your engine.
Dealers are best because there is a programme of constant evolution and rationalisation, even for their discontinued models.

Merc parts prices are good value compared to all other car makers parts
prices.

My Bosch plugs from dealer were £1.83p+Vat each.

 

[kth286]

Go to dealer with your VIN and you will automatically be given the right plugs for your engine.
Dealers are best because there is a programme of constant evolution and rationalisation, even for their discontinued models.

Merc parts prices are good value compared to all other car makers parts
prices.

My Bosch plugs from dealer were £1.83p+Vat each.

 

[Ron Palfrey]

Morning Jeff,
I've never had a problem using NGK plugs in place of any specific make recommended in any handbook with any of the cars I've owned.

Having said that I have not used NGK plugs in my C280 yet because they are not due for change yet. However I have bought 8 new NGKs (the engine will take 6 of them but they came in packs of 4) ready for the next time that new plugs are due. I shall have no qualms about using them. The last plug change was done at 72,118 miles and the car has done nearly 98,000 so they won't be due for another 14,000 miles or so. When I do use the NGKs I'll put some feedback on but that won't be for another 18 months I guess.

If new plugs do not cure the misfire I'd look at something else as the cause. Not worry about whether using new NGKs might be a cause.

Good luck,
Ron

 

[type49]

Dealers are cheaper for plugs than a lot of factors so get them from MB and you know they're correct. Remove the air pipes near the rocker cover ( about 20mm diameter pipes ) and check for any splits, check 10amp red fuse on overvoltage protection relay fitted next to the battery behind crappy plastic partition, check condition of dizzy cap and if you have a multimeter, check resistances of HT leads ( cant remember want ohms they should be but check they are all roughly the same, King lead/coil lead is different again though. These are common 190 faults so and get your hands dirty!

 

[JUSTJEFF]

Thanks fellas.Not that technically minded and the Haynes manual is a bit of a joke for my old banger but can do them checks now i know what to look for. NGK,s that were in it seem newish so today its new leads,rotor and dizzy.
Also,... its hard to start first thing which i think is the auto choke not working properly. I read a thread somewhere about the cold start valve sticking.... If i knew what it was and where it was i would check/replace it if its a fairly simple DIY job.

 

[ecol]

NGKs

Don,t worry about using NGKs ,my wifes 190 ran on them for years and never missed a beat ,she has recently changed the car with 190,00 on the clock having owned it for 9 years



Ecol

 

[JUSTJEFF]

Dealers are cheaper for plugs than a lot of factors so get them from MB and you know they're correct. Remove the air pipes near the rocker cover ( about 20mm diameter pipes ) and check for any splits, check 10amp red fuse on overvoltage protection relay fitted next to the battery behind crappy plastic partition, check condition of dizzy cap and if you have a multimeter, check resistances of HT leads ( cant remember want ohms they should be but check they are all roughly the same, King lead/coil lead is different again though. These are common 190 faults so and get your hands dirty!

I cant seem to find the red 10 amp fuse on the overvoltage protection relay.Pulled the crappy plastic cover off from behind the battery and i saw i presume, was the ECU and to the left of that some other bits. Is the fuse i am looking for the standard bullet type ?

 

[television]

If you have one its item 146 in the box look for your car here


http://www.detali.ru/cat/oem_mb0.asp?TP=1


Malcolm

 

[JUSTJEFF]

Thanks all... found it .
I am beginning to get the hang of these here Merc,s. . . .waist of time looking in the obvious places but llook in the least likely,fiddley cramped space and BINGO there it will be ( as in oil filter tucked away below and behind air filter ) ;-)