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Discussion Starter #1
Hi guys
I ran the maf test last week and got 120 in third, so I changed the mafs for new genuine Bosch units and ran it again and got 118?
What are the other parts that effect this test? The car has the original fuel pump and is on 154k would it be worth swapping out?
The car doesn't feel as good as when I first got it, i used to get wheelspin in second and no longer do. Any suggestions?
 

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You've answered your own question there, fuel pump or at least fuel filter for a start, you are not getting enough fuel flow.
 

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Discussion Starter #3
Pump and filter it is then. Am I right in thinking cps would throw a code? I have inpa but it's showing no faults.
 

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Where in England are you ?

There are a whole host of items that could contribute to lower than expected Fuel Flow numbers.

CPS are some of them. They will throw a code when they are very bad but may not do so if they are old and not doing their best.
 

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Try with fuel filter first unless you want to do both at the same time to avoid fuel pump failure on motorways, which I would do. Have you tested the vanos solenoids using Vanos DIS test?

My car still hits 110 LPH and spins in second gear. Vanos solenoids refresh bought power back and especially quieter running operation from vanos.
 

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Pump and filter it is then. Am I right in thinking cps would throw a code? I have inpa but it's showing no faults.
When my CPS failed it threw error codes, ran bad and sounded different/deeper, but the sensor was goosed, if you have one that's just reading badly then it may not throw an error.

However at the age & miles of your car, the original fuel pump is probably well past its best and if the filter has never been replaced, it will be restricting fuel flow. Mine has had both replaced at just over 100k, they're not known for lasting forever.

As a first step, I would at least replace the filter, it's quick, easy & inexpensive, then re-run the MAF test and see if things improve.
 

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Discussion Starter #8
Filter has been done in my ownership but probably 3 years ago now, I'll do them both.
I had the vanos rebuilt within the last 2000 miles at the same time as the bearings,chains and tensioners, so vanos should be ok unless it is cps causing timing issues.
 

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Filter has been done in my ownership but probably 3 years ago now, I'll do them both.
I had the vanos rebuilt within the last 2000 miles at the same time as the bearings,chains and tensioners, so vanos should be ok unless it is cps causing timing issues.
Filter is probably ok then unless you've done mega miles in 3 years.

Might be worth getting the timing checked...
 

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Before you do anything just drive the car for 500 miles. It has to adapt to the new MAFs. The other thing is yes 120 or 118 mean you are not getting enough fuel because this number is really a measure of the injector bandwidth. So in your case that means the computer via the O2 sensors is satisfied by not adding enough fuel.
If you had poor fuel delivery you would likely see a high number as the computer cycled the injectors to make up for the lower pressure. That said change your fuel filter just because, especially if you don't know how old it is.

How old are your O2 sensors? The MAF test is based on how well they read.
 

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Discussion Starter #11
The 02s are probably 4000 miles old I replaced all four not so long ago.
Reading through the service history the pump was done at 100k I'm on 150k now so I'm not sure it needs changing yet?
 

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Discussion Starter #13
I haven't looked for vacuum leaks, I haven't corrected them either, but both runs were done at 20c outside temperature.
Would deleting the adaptions on inpa speed the process up?
 

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I suspect you need CPS sensors. When were they changed last, if ever?
 

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Clearing the adaptions would help but then you still have to drive 500 miles to get the system to adapt.
Like others are telling you CPS could and likely are good candidates for doing this. If the CPS are lying and we know the old original ones do then the valves don't open and close when they should and less air gets in. So less gas goes in IE a low reading.

@20 no correction is required IIRC but feet above sea level might change things. I suspect you not very high so we can likely rule that out.
There are a few things on these cars that are no brainers if you don't know when they were changed. MAFs to a certain extent CPS if the skinny design, fuel filter, and I might suggest a fuel pump relay and pump. O2 sensors should have been first but yours are changed.
I would encourage you to look for leaks or at least do the test because it is free, if you find none then you have to throw money at it, which means the CPS.
 

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Question. I order new MAFs mine are original with 87k miles on them. Car seams a little sluggish in power lately. I also wonder if changing the plugs would help. Done about 10k miles ago and was about 2-3 years ago. Either I'm use to the cars power now and want more or it's lost something. What is the max speed in 2nd gear? Mine will only want to hit about 40 mph before it's at 7k rpm. Is that normal?
 

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Max speed in 2nd should be around 60mph. This is not dependant on power, the car has gear ratios. Not sure what you are getting at here, but unless your clutch is slipping (badly), you will not hit 7000rpm in 2nd doing 40.
 

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When my car was reading 120 LPH I also changed my MAFs for new Bosch ones. It now can pull 130LPH. A few months prior I changed the fuel filter and was forced into changing the fuel pump so they are new. The only parts I haven't changed that I think might get me a bit more would be fuel injectors and O2 sensors. My car has 82k miles on it.
 

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I just got a new clutch put in. I had to replace the inner seal on the tranny, so while it was opened up I replaced the clutch as it was original also...I put in a Clutch Masters FX250....doesn't seem to be slipping. But I did notice the power loss after the clutch work. I also have a metal noise when starting off. That I don't remember hearing before the clutch work. I was told it's the cv joint drying up and I will eventually need to replace the drive shaft. I guess it's the age of the car and the parts are just starting to go on some things. I just want my power back. I will see what happens after the mafs are changed. I believe the O2 sensors are original too, do they effect power?
 

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You may have a Dinan rear end which changes the ratio so you go slower speeds in each gear, but the theory is you get there faster.
O2 sensors will effect your power , certainly. They are like the adjustment screw on the carb. If yours are original you will be running much richer than you should.
 
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