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Wobba
19-04-2008, 11:52
Map sensor is there to report to the ECU the pressure in the inlet manifold right? In turn the ECU sends data to the ISCV on how to operate, right?

In theory, lets say u have a faulty MAP sensor that is telling the ECU there is too big a vacuum, it would have the ISCVopen full blast right?

If you take the hose of the inlet manifold > MAP sensor, block the inlet hole and leave the pipe open to atmosphere...if it was a working MAP sensor wouldn't it tell the ECU there was too much air and try to lower revs accordingly?

stan
19-04-2008, 16:07
ISCV doesnt come into it....that only controls the idle via a target rpm.

the map sensor gives an indication of load...ie. low vacuum=high load, high vacuum=low load.
load being the % of max power being produced, the ecu then relates this signal to a site on the correction map, and so a fuelling value is obtained (as determined when the engine is/was calibrated).

if you ad a faulty map sensor, or ose, it would give te ecu an incorrect signal for te engines actual operating condition, and so the engine wouldnt run right.

Wobba
20-04-2008, 00:09
ok thanks. I dont think its that then.

105epwr
20-04-2008, 15:15
it controls the ignition aswell..dont it?

teabag
20-04-2008, 15:17
it controls the ignition aswell..dont it?

isnt that crank position sensor?

105epwr
20-04-2008, 15:29
yes thats just the trigger point,but im sure for different loads etc it uses the map sensor,recent had a RR and we was getting different ign timing by unplugging the map sensor and i elongated the crank sensor bracket holes and moved it back to gain more ign advanced.BUT half of my loom is unplgged (injectors,tps,iscv and 5th inj)as i run carbs.

teabag
20-04-2008, 15:33
ahh i see

wouldnt is be easier to run a mappable ign. driver?

or an aftermarket ecu like megasquirt for example?

stan
20-04-2008, 17:11
yes, it does control ign, i was just using fuelling as an example.

what sort of max advance was yours running with the bike carbs mate?

I can supply/fit/map an ign only ecu...

105epwr
20-04-2008, 18:31
yes, it does control ign, i was just using fuelling as an example.

what sort of max advance was yours running with the bike carbs mate?

I can supply/fit/map an ign only ecu...
well it got confusing.b4 my RR prima said do away with the map sens.couple of long stories short we got more adv with the map sens plugged in.I dont no the actual ign timing but we found the peak advanced so then we had to bring the timing back abit so i told prima this and he said he ment to say disconnect the vacum pipe only-dont see this making a difference?
how much for the ign kit stan?cheers ricky

stan
20-04-2008, 18:43
the ecu is about 250-300...i'll check tommorow.

its an all round better solution than a half plugged in OE unit!

richy
20-04-2008, 18:51
if you elongate the TDC sensor bracket holes and allow it to move 2.65mm each way you can advance/retard ign by 1 degree

also unplugging the knock sensor gives 3 degree of retardation

105epwr
20-04-2008, 18:53
the ecu is about 250-300...i'll check tommorow.

its an all round better solution than a half plugged in OE unit!
ok mate cheers let me no.
just been thinking do you reckon its worth trying another rollong road?
i see in a mag once they took 1 car to many different rollers and every rolling was different even up to 50bhp!!!!

richy
20-04-2008, 18:57
if you elongate the TDC sensor bracket holes and allow it to move 2.65mm each way you can advance/retard ign by 1 degree

also unplugging the knock sensor gives 3 degree of retardation

i should say thats out of the clio cup manual! i havent personally tryed that!

stan
20-04-2008, 19:29
the ecu is about 250-300...i'll check tommorow.

its an all round better solution than a half plugged in OE unit!
ok mate cheers let me no.
just been thinking do you reckon its worth trying another rollong road?
i see in a mag once they took 1 car to many different rollers and every rolling was different even up to 50bhp!!!!

yes thats worth trying...

i wouldnt count on that making a whole lot of difference....

105epwr
20-04-2008, 20:16
[quote="richy"]if you elongate the TDC sensor bracket holes and allow it to move 2.65mm each way you can advance/retard ign by 1 degree

also unplugging the knock sensor gives 3 degree of retardation[/quote
Thats handy to no!cheers

Scougar
22-04-2008, 16:39
Stan should help clear this up.

I thought MAF was airflow based, whilst MAP was RPM based? MAF (i.e. an AFM) only measures air going into the engine and then adds the correct amount of fuel based on air intake, MAP simply determines the correct amount of air and fuel needed for a given RPM?

MAF is found on most OEM cars for safety, where as MAP is commony used for aftermarket applications where precise mapping is done to make it safe.

Stan, please correct where necessary :)

Matthew

stan
22-04-2008, 17:00
MAF is used on some cars, MAP is used on some cars. Both allow for refined load measuring.
A MAF sensor os different to an airlfow meter, like you find on old Bosch J-jet systems...they use a "flap" and resistor set-up to physicaly relate to flow. A MAF sensor uses a heated element, and mesures the cooling effect on the element to relate to airflow.

Typically you DONT use a MAP sensor on an aftermarket ecu on an NA engine.