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Discussion Starter #1
So I just got my beast home after a 1,800 mile road trip, and I've gotta tell you. She just doesn't seem that fast.

I've owned and driven some pretty fast cars but honestly was expecting quite a bit more in terms of acceleration. Don't get me wrong I love this car and couldn't be happier with my purchase, but I know theres gotta be more umph to it!

I did some reading on here and figured that the car now has 55k miles and original MAF's I should probably do the MAF test in the "secret" menu. I live near a long stretch of country road so I took a few runs at WOT in 3rd to redline. The first go I hit 88 l/hr. The 2nd run I took DSC off and put in sport mode and hit 95 and the third and final run I hit 96.

This has to obviously mean my MAF's are on their way out and possibly a few other things need looked at.

My question is...How bad are these numbers that came up and should I do anything else in terms of the tune-up? I was going to clean and re-run, but with 55k I figure the MAFs need replacing anyways.
 

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96 on the MAF is about 540 territory. At that mileage they should not need replacing so I hope you got a PPI done...

Air filters, O2 sensors, CPS, are all big things to check for that can rob a LOT of power.
 

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I would add a fuel filter to the maintenance list to. Low MAF test is low air or low fuel. Mileage is low but years are long.
 

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I have a 2002 with 66K miles and original MAFs. I am running 128-129 on the MAF test.

Did you have a PPI done?

Do you have a SES light?

Are there any hesitations or hicups under acceleration?
 

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96 on the MAF is about 540 territory. At that mileage they should not need replacing so I hope you got a PPI done...

Air filters, O2 sensors, CPS, are all big things to check for that can rob a LOT of power.
Clemster bought a 2003 w similar mileage, MAFs were shot.
 

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Honestly I did not get a ppi done, however this car is in near pristine condition. I bought it from an avid car collector who trust me was not short on cash, and really took excellent care of this car. There are no lights.

The car runs great in terms of smooth acceleration and idle. There are no hiccups or unusual noises coming from the engine.

I'll re-test tonite if its dry out and see what I come up with. I'm going to stay with fuel filter as sailor suggests, then go down the list from there..
 

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More often than not in "alarm" posts like this, a new member is attempting a MAFS test, gets to Test 4, but forgets to choose the right units for read out.
 

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More often than not in "alarm" posts like this, a new member is attempting a MAFS test, gets to Test 4, but forgets to choose the right units for read out.
I definitely chose the 2nd test in test 4, but to be sure, I'll redo it tonite and see what it reads out.
 

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What we are refer to as the dynamic MAF test (under load) is really a test of the entire fuel system.

A quick check on the MAF's is to spray some MAF cleaner on them. If there is a temporary improvement, MAF's are defintiely shot and are part of the problem. The opposite is not necessarily true.

As noted above, check fuel filter (although for the cost of the filter, I would just replace it at that mileage since it is the same labor). Also, if there is no proof the plugs have been changed (should be as part of Service II, usually occurring around 55k miles), they are due.

A Peake reader (a must!!!) will also help you pinpoint codes thrown from poorly performing parts, like CPS, even if no check engine light is on.

Regards,
Jerry
 

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Discussion Starter #11
Thanks Jerry, I just ordered my peake code reader. I'll clean the MAFs tonite and see what comes of it.
 

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I would add a fuel filter to the maintenance list to. Low MAF test is low air or low fuel. Mileage is low but years are long.
It is not only about air or fuel.....

The so-called "MAF-test" is a calculated combination of many other factors as well.Like Vanos(CPS,Solenoids,...),even cam timing plays a role....

Also lower octane fuel plays a role due to re tarded ignition timing...
 

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This was a one owner car owned by an attorney in his 60s. He never really "got on it"

all that he had replaced on it was obviously oil. He also replaced p/s hoses and belts. EVERYTHING else is original. Im sure there has to be something that needs replaced right?
 

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I replaced the MAFs on my car - 50K miles - in a (futile) attempt to address the jerky throttle and somewhat lower "MAF" readings - mine are 115 or so. The MAFs made no difference. I've also replaced plugs and fuel filter - might have eaked out low 120s on the test the last time I ran it. I really have no complaints about the pull, however, which seems consistent with my 400HP, 6 speed, '05 GTO with the primary differences being (IMO) associated with the very different gearing in these two cars.
 

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It is not only about air or fuel.....

The so-called "MAF-test" is a calculated combination of many other factors as well.Like Vanos(CPS,Solenoids,...),even cam timing plays a role....

Also lower octane fuel plays a role due to re tarded ignition timing...
I was wondering because... Thanks! of coarse intake valves control how much air too. CPS say how long to do A or B. I will also add exhaust valves and NOx emissions.
How much of an allowance could we give those things? Would 20% be too much?
 

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I was wondering because... Thanks! of coarse intake valves control how much air too. CPS say how long to do A or B. I will also add exhaust valves and NOx emissions.
How much of an allowance could we give those things? Would 20% be too much?
No idea how high the percentage of the Vanos is...

Also exhaust side has impact on the flow(overlap)....

Also cat performance has an impact....if they are old and clogged,too high back pressure,less cylinder filling,lower performance...

I could go on with loads of other things....
 

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I see your point but most of those things would be gradual. So is a fuel filter and an air filter.ouich Which is what cab just posted to this thread. He has done lots But only pulls 120s. I would suspect a very low reading to be one of the majors however. You have to start with the basics and rule things out. Right or wrong fuel or air both would have to be ruled out before you move forward with more complicated diagnosis. Hopefully as you go through the basics with the poster, he feeds you some info that might help. So I agree every part of the engine plays a role in the MAF test. You have to start somewhere though and if you make it to complicated no one wants to DIY.
 

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My point is just that MAFs can help,but the rest basic maintenance(means CPS,fuel filter,solenoid O-rings) should also be done...

But this is the reason I changed EVERY sensor and replaced/rebuilt EVERY actuator on my engine(even use 2 new solenoid boards in my mental illness...:grinyes:)
 

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My point is just that MAFs can help,but the rest basic maintenance(means CPS,fuel filter,solenoid O-rings) should also be done...

But this is the reason I changed EVERY sensor and replaced/rebuilt EVERY actuator on my engine(even use 2 new solenoid boards in my mental illness...:grinyes:)
Well then we can be insane together because I will have done exactly the same. I made my list and have already burned a hole through my right pocket soon the left will be on fire. Well except for the boards you definitely got me on that one.

I could not agree more the general maintenance is absolutely critical for these cars. Especially the health of the vanos.
 
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