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        General >> Give/Need advice to/from others >> MAF  figures
        
(Message started by: pedropedro on May 19^th, 2010, 6:32pm)

Title: MAF figures
Post by pedropedro on May 19^th, 2010, 6:32pm

I have a gearbox flare problem 2-3 and it has been suggested that the MAF could be culprit. On another scorpio same model at 2000rpm maf reads 1.3 using obd2 sware . On mine it reads .7 at same rpm.

so i exchange the MAFs and the difference stays ..so in other words the maf from the scorp that read 1.3 now reads .7 at 2k rpm on my car...wouldnt that suggest ecu? so something in my car is causing the differential ,,its had a new wiring loom so thats not it. Maybe the difference isnt relevant i dont know enough about them but almost half the reading seems odd

why would there be that diferential? any thoughts appreciated

Title: Re: MAF figures
Post by Tompion on May 20^th, 2010, 12:04am

Did you turn off the aircon whilst taking the readings?
I don’t know off hand which way a high resistance connection would affect the reading, but have you tried unplugging the big connector on the wing to reseat the pins?
Have you tried driving with the MAF disconnected to see if that affects the changes?

Dave

Title: Re: MAF figures
Post by pedropedro on May 20^th, 2010, 7:12am

ah! maybe had air con on my one with low figures...will try with off tonight...doesnt have any codes in the system so assumed if maf was bad would show as a code

yes tried disconnecting maf and still get flare

yes had large connector off and cleaned all pins

tks for info john

Title: Re: MAF figures
Post by Mike H on May 20^th, 2010, 8:41pm

Have you seen this?

http://www.fordscorpio.co.uk/maftest.htm

According to that 0.7V at idle (hot) would be correct.

Title: Re: MAF figures
Post by pedropedro on May 20^th, 2010, 10:00pm

yes read that ...my concern was the reading at 2k rpm
one car read 1.4 mine reads .7

Title: Re: MAF figures
Post by scorpio_man on May 21^st, 2010, 5:14am

hi there

are you able to monitor the maf flow figure throughout the rev range?

is it climbing as the revs go up?

i've seen a faulty maf (flow figure was miles out (too high)), but there was no error code stored for it.

you stated that you had a new wiring loom. did that include wiring to the maf? if yes, then i'd check the output from the maf using a multimeter at the plug.

Title: Re: MAF figures
Post by Dave2302 on May 21^st, 2010, 8:52am

AFAIK, the MAF wiring is in the car loom, not the engine loom, and can go bad like the engine looms do. Normally at or near the MAF plug they go bad.

Title: Re: MAF figures
Post by pedropedro on May 21^st, 2010, 12:45pm

yes can monitor maf ..yes climbs as revs go up
new loom DIDNT inc MAF wiring it was the engine loom that was changed
the wiring looks perfect around maf area
will have to look at volts coming out of maf tks john

Title: Re: MAF figures
Post by Mike H on May 21^st, 2010, 1:44pm

on 05/21/10 at 05:14:09, scorpio_man wrote:

is it climbing as the revs go up?

Would that be the wrong way round then?

Only cos on the maftest page he says for the screen shot example this is not at idle, and it was reading 0.2 something, which implies it goes down as air flow increases, not up (?)

Title: Re: MAF figures
Post by pedropedro on May 21^st, 2010, 1:49pm

dont think so the maf output increases with increase of air flow

Title: Re: MAF figures
Post by Mike H on May 21^st, 2010, 2:05pm

Well that would allow for a bigger range! ;D

Title: Re: MAF figures
Post by Tompion on May 23^rd, 2010, 12:11am

As promised in the other thread here are the readings I got from my 2.3. I found the values for the MAF fluctuated a little & quite tricky to keep the revs steady.

MAF (pounds/min)

Tickover (884rpm)
0.3 (0.46 with aircon on)

2000rpm
0.9 (1.2 with aircon on)

With an air leak (the air hose to the fuel pressure regulator disconnected):

Tickover (890rpm)
0.161 (0.287 with aircon on)

2000rpm
0.64 (0.95 with aircon on)

I took some other sensor readings:
Ambient temperature 21.5C
ECT 194 – 208F
IAT 127F
Barometric pressure 30.3
Transmission fluid 173 – 191F
TPS 16.9%

Don’t forget the TPS can affect the changes, check it with ignition on engine off the readings should increase smoothly as you press the throttle. If the reading at rest isn’t around 16% disconnect the battery for a while to let it reset.

Title: Re: MAF figures
Post by pedropedro on May 23^rd, 2010, 10:36am

tks for that info...ive just run engine on ve sware and figures are same as yours..the tp is 16% at idle ..maf at idle a bit higher
with a/c on at idle .6 @ 2k rpm 1.2

I think a number of folk suggested maf could be main cause of flare 2-3, that's i was focused on that perhaps too much....it's had a replacement gearbox & flares etc ....perfect in winter mode, better with a/c on

changed ecu ......has to be the valve assy/chest in gearbox.
i had another box with same problem no one could fix..I am assuming the valves are difficult to test..will insist the gearbox people send it away for professional testing and sort this...tks for interest john

Title: Re: MAF figures
Post by Dave2302 on May 23^rd, 2010, 11:37am

I have a known good valve chest here if it's any use to you,

Regards Dave

Title: Re: MAF figures
Post by pedropedro on May 23^rd, 2010, 12:00pm

Dave

that would be really useful ...appreciate your help
yes if I can take you up on that please...how much carriage etc?

pm me ? rgds John