how can you tell if your MAF is on the way out?

[kth286]

MAFs are reliable on 124s.

An important sensor is the coolant sensor, as that controls the feedback to ECU for amount of fuel injected. They do go out of spec.

The lambda sesnor can get sluggish on that generation of car, and it is a recommendation to change them at 100,000 miles. Again very important for fuel injection.

I changed both my sensors and obtained approx 16% better economy.

 

[BlackC55]

It has a 111 engine and they are as troublesome as the rest!

 

[BillyW124]

Where do i locate the coolant sensor and also the breather hose?

i heard the breather hose can case issues????

 

[momomo]

Coolant sensor should be right at the front on the block, under the plastic cover. What breather hose?

 

[BillyW124]

humm breather hose?! good question, good answer too if you guys dont know then its a daft question LOL

 

[BlackC55]

How many miles does your car have on it?

Air mass sensors on your car rarely show a fault code either.

 

[BillyW124]

Mo/kth

it just occured to me from your reply that if this sensor is located here, i currently do not have that black cover with the merc symbol on the front of the engine block as it has been cracked.

ive taken it off. So im thinking that being covered or shal i say not covered, the sensor may be picking up different signals i.e. picking up cooler temps and/or breeze while in motion? this could play a factor??

just to make it clear we are lot talking about the coolant level sensor here are we?

 

[BillyW124]

olly, 96,000

 

[BlackC55]

The breeze won't make the coolant sensor read dodgy signals.

If the air mass is original then it is very likely to be your issue. It would take me 5 mins to diagnose the maf.

 

[BillyW124]

i'm pretty sure its original and doubt it has been touched, no paper work on this item from previous.

Olly, would you put it on the diagnostics to diagnose?

i'm very tempted to come and see you. As you are a good 70 odd miles away from me are you able to promise me on the way back home my return journey will give me 70 miles @ 21mpg!!????:bannana:

a thing to note is that one of my manifold bolts at the end has snapped off and there is some blowing happeneing (especially at start up you can hear a grunt sound) i have been told that there is a slight gap between gasket and where it should sit correctly. could this contribute to loosing power? and low MPG?

 

[BillyW124]

is there a cold start valve in my engine?

 

[kth286]

is there a cold start valve in my engine?

No

 

[kth286]

whilst the same engine is used in 124 and C class 202 cars where the MAF did cause problems, the 124 MAFs are reliable.

However, the wiring to the MAF can get degraded from insulation cracking on the 124 and the feedback signals can get lost/distorted.

 

[kth286]

A trip to Olly would be beneficial as he does know about these older cars.

However, you do not need STAR diagnosis as eveything can be done with simple 'light blips' tester on this generation car.

 

[BillyW124]

Thanks mate, i'm thinking lambda/02 change and MAF?

any opinions on the breather pipe? as MO was like what??

 

[BlackC55]

Ignore the breather pipe.

It needs proper diagnosis not just the fault codes read. I have just got your email and re-read the thread.

The laking manifold will not help at all as the lambda sensor will not get the correct reading if exhaust gasses are escaping and it COULD cause poor MPG. Get this fixed first.

 

[BillyW124]

thanks Olly,

this seems logical as this escaping of gasses could throw the reading off the lambda.

Olly, ive sent you a PM..