• Don't miss out on all the fun! Register on our forums to post and have added features! Membership levels include a FREE membership tier.

mcx290 fat on wot

J

Jona$

Active member
Sep 29, 2012
241
33
28
40
Sweden
At 10500rpm the sled gives out 10.5afr

This is what i have tried to get it working

*pressuretested inlet and outlet, fine.
*checked all wires with multimeter, fine.
*sent the efi from mcx for test and was fine, got the brown bosch injector and corresponding map, sled acts better but still low afr.
*did a compression test and got 9.5 at all exept cyl3 giving 0.3 lower, so fine
*Tested the afr sensor and it works so i trust the numbers.
*The fuel pressure seem to get to about 4bar on full boost and around 2.5~2.9

The sled works flawless in all ways and i can really feel it but the afr dont lie
 
J

Jona$

Active member
Sep 29, 2012
241
33
28
40
Sweden
If its was that good, i tested the AEM sensor and it works as it should, and i the sled also throw a bang when letting of longer pulls, wich it only have done if the afr has been of.
 

up-high

Well-known member
Lifetime Membership
Nov 26, 2007
1,532
299
83
71
Alberta Canada
I'd check the spark plugs just to see what they look like. I don't think a 4 stroke would pop at WOT if it's lean. I think it just wouldn't make power without enough fuel. Does it run ok at idle and 1/4 to 1/2 throttle? Maybe a stuck injector? I think if it pops after you let off it's just burning left over fuel?
 
J

Jona$

Active member
Sep 29, 2012
241
33
28
40
Sweden
I said 10.5afr that's not lean, that's pig rich and not making a bang on wot, it's when rolling off, and yes it's burning fuel then,proving that my sensor is right.
I changed the plugs to rule them out and the old ones were the same and held good color, gapped the new ones at 0.18

And yes it works good at other throttle angels,I changed the injectors, they are brand spanking new.
 
J

Jona$

Active member
Sep 29, 2012
241
33
28
40
Sweden
checked the diagnostic

1 throttle angle 15-18 closed 95-100 open, mine was 16 and 97
2 atmosperhic pressure i got 100
3 intake pressure i got 100 so i guess they both are correct
5 intake temp 15 deg celsius
6 coolant temp was the same as above and its correct
7speed puls? checked out at 0 as it should
9 voltage 11.8
24 throttle switch should be off but my said on, is that because i disconected tors?
26 grip warmer 0
27 thumb warmer 0
29 shock rear on
30 coil 1 measured and correct
31 coil 2 the same
32 coil 3 the same
33 coil 4 the same
36 injector 1 sent for test and was tight and nice spray
37 injector 2 the same
38 injector 3 the same
39 injector 4 the same
50 fuel relay works
51 fan relay, works but i removed that cooler.
52light relay, works
58 dash meter, works
60 eeprom, works
61 engine code, none
62engine code repeat, none
70 meter of total engine run, works

i also messured the tps and got 0.72 closed and 4,08 open wich seems right as i found.

can you messure the fpr , at idle and without boost i got around 2.9bar, wheen full boost i see aroun 3.5-3.9bar

the sensor at the ecu must be the baro senor ? can you messure it
the other one that sat in the intake is assume go by intake pressure and both this ones give the same according to my reading of diagnostic.
 

Octanee

Well-known member
Lifetime Membership
Nov 15, 2010
1,188
217
63
44
Cranbrook Bc
I don't think a 4 stroke would pop at WOT if it's lean. I think it just wouldn't make power without enough fuel.

Mine popped at WOT, I thought it was the rev limiter until i got a a/f gauge which I discovered the pop was actually the fuel leaning out in boost. So it would lean out and pop and studder
 
Premium Features