CL500 lacking power under load

[LostKiwi]

A blocked cat will make the exhaust sound like a demented dyson under full throttle- a very distinctive wssssshhhh sound.

 

[Craiglxviii]

Nope, at full chat it sounds just as beautiful as at low throttle. No whooshing.

 

[Paul Beer]

On the basis that the engine revs OK when not in gear, but doesn't when in gear then could it be something to do with the gearbox, rather than the engine?

 

[Craiglxviii]

It revs fine in gear, just doesn't want to lay down the power. Gear changes are as smooth as... well, as smooth as my bum if you'd credit such a thing.

 

[Craiglxviii]

Some more digging around this morning brings up the following codes (although I have cleared the warning lamp):

Hot film air mass sensor short to positive or open ground
Intake air temperature sensor ditto

Battery voltage indicated at 13.93V.

 

[alexanderfoti]

Some more digging around this morning brings up the following codes (although I have cleared the warning lamp):

Hot film air mass sensor short to positive or open ground
Intake air temperature sensor ditto

Battery voltage indicated at 13.93V.

Possible wiring fault?

My friends CLK55 that I am currently driving has the same fault. Unplugging the MAF sensor doesnt change the code on mine, making me think there is a wiring issue somewhere. I read that the maf is new?

 

[television]

I have said that pin 5 is the output from the MAF, 2volt at idle and the voltage should rise a lot with the RPM up to more than 4 volts.

 

[Craiglxviii]

All DTCs cleared now. Hmm.

 

[Craiglxviii]

Possible wiring fault?

My friends CLK55 that I am currently driving has the same fault. Unplugging the MAF sensor doesnt change the code on mine, making me think there is a wiring issue somewhere. I read that the maf is new?

It makes me wonder. A break in the sensor harness, I can see that being a pleasant job to fix. Yes it's brand new.

Is that CLK flat? Like, will get upto speed but just lacks the grunt it should have?

 

[Craiglxviii]

I have said that pin 5 is the output from the MAF, 2volt at idle and the voltage should rise a lot with the RPM up to more than 4 volts.

Which is pin 5 Malcolm and how would I test?

 

[alexanderfoti]

It makes me wonder. A break in the sensor harness, I can see that being a pleasant job to fix. Yes it's brand new.

Is that CLK flat? Like, will get upto speed but just lacks the grunt it should have?

Its faster than I would expect considering it has that maf fault. It hesitates on the bottom end, but is powerful at the top.

 

[Craiglxviii]

Sounds similar. Hesitation... 11s 0-60 but will carry onto 100 (I'd imagine) easily.

 

[alexanderfoti]

Yours sounds like its in limp. Do you get kickdown still?

Mine still drives normally enough.

 

[Craiglxviii]

Yes, kickdown, gear changes fine... Limp home usually restricts one to 30-40 no?

 

[alexanderfoti]

Yes, kickdown, gear changes fine... Limp home usually restricts one to 30-40 no?

Not normally. Had had cars in limp mode up to 80-90 without issue.

 

[Craiglxviii]

Ah, the only limpy car I had was a Firebird.

 

[Craiglxviii]

MAF values at idle. Varies between 4.69 & 5.30g/s.

 

[AMck]

Is it Bosch?

 

[AMck]

As your code reader shows live data - are the O2 sensors showing normal reaction and wave form?

 

[AMck]

MAF values at idle. Varies between 4.69 & 5.30g/s.

When I was chasing a fault that ended up being MAF on my M112 engine. Idle readings were fine, but WIS gave specs for testing and it was, I believe, full throttle in 2nd gear at a specified engine speed. Mine was reading too low in this test.