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No check engine light on dash
Posted: Sat Aug 18, 2012 6:20 pm
by trev66
Hi all newbe here so 93 liberty intermittant loss of power now constant. so went to do diagnostics test & dash has no check engine light ? has anyone come across this. how do i get around this. thanks in advance trev.
Posted: Sat Aug 18, 2012 7:01 pm
by El_Freddo
Welcome to the forum.
I'd first check the status of the check engine globe - is it broken. If it is replace it then check for codes.
I've not heard of the check engine light not working when the green connectors are connected and the ignition in the ON position unless it's blown.
The check engine light should normally be lit before you start the engine when the ignition switch is in the ON position.
Other things to check are the spark leads, spark plugs and air filter condition. The ECU is pretty useful at self diagnosis but it won't tell you everything
Cheers
Bennie
Posted: Sat Aug 18, 2012 7:11 pm
by TOONGA
+1 check for a broken or missing globe.
Some crafty people remove the CEL, so the repeated code isn't there when the buyer takes the car for a test drive.
TOONGA
trev66have
Posted: Sun Aug 19, 2012 9:42 am
by trev66
Hey thanks & sorry should have been more specific have checked globes , in fact have pulled the dash head completley out & put a tourch up the back of each globe area. There is no apature that says engine check! just the usual park brake/ABS ETC. As far as what i have done, plugs, leads, coil pack, crank angle sensor, ignition module, fuel filter & new fuel pump , ran fine then started again, just of song intermittantly, but now is running constantly busted a--. Have also noted that no 3 injector is damp on the plug. I dont believe its the injector.very sure its electrical because when it kicked the other day & ran spot on for 1x 35km trip i checked all the plugs & they were all fine.Have had the injectors flow tested also!, have also done compression check all cyls within spec +/_ 3/4lb.
Just unable to get the lights to flash & give me the codes ?
Posted: Sun Aug 19, 2012 7:52 pm
by RSR 555
Please turn you ignition on, so the lights on you dash come on, then tell us what lights you see (even a picture can help).
How are you trying to get the codes out of the ECU?
Do you have a copy of a Gregory's (or similar) repair manual?
Posted: Mon Aug 20, 2012 9:11 am
by TOONGA
The other thing I forgot was the black tape over the light trick, where the clear plastic cover is taken off the speedo cluster. black electrical tape is then placed over the CEL, to hide the fact that the "mechanic" couldn't repair the fault.
TOONGA
Posted: Mon Aug 20, 2012 5:44 pm
by trev66
me again so got sick of looking & took her up to local sparky, he couldn't pull the codes also
drove home like a pig pulled the bonnet had a fiddle checking connections. the ballast resistor was dirty so cleaned her up & bingo runs sweet.so now the ? have played with these resistors in the past & don't recall them getting hot whilst the car runs fine now the ballast resistor is quit hot does any one know if they run hot on these or should i just replace it ? thanks again everyone
Posted: Mon Aug 20, 2012 6:03 pm
by littlewhiteute
If it is a ceramic ballast resistor, they do run hot.
I'll assume the resistor is for the injectors.
Posted: Mon Aug 20, 2012 6:24 pm
by Gannon
The only ballast resistor I know of in a Liberty is for the auto transmission. Has nothing to do with the engine or ECU
I recall that the EA82 ECU has a little LED on the circuit board that also flashes codes. It was visible through a hole that was in the side of the ECU case, if not, can you try to find the wire from the ECU that goes to the check engine light, maybe rig up a temporary light for testing purposes.
I'll see if I can find the pin number and wire colour for you
Posted: Mon Aug 20, 2012 9:53 pm
by trev66
Thanks Gary that helps as far as it getting hot ''that I was not sure of " As far as I know the ballist resistor regulates the strength of the spark through the coil.
I have taken it for a couple of good runs tonight & running perfect. Hope she starts like that in the morning.
Gannon, that info would be great as I would really like to be able to check it properly im still not confident because its lured me into this trap before! CHEERS.
Posted: Tue Aug 21, 2012 6:14 am
by Gannon
Is your car an auto? The coil is a computer driven wasted spark so there is no need for a resistor there, the injectors are high impedance and dont need a resistor.
I'll get the wiring diagram this afternoon
Posted: Tue Aug 21, 2012 8:06 am
by steptoe
is this an L Series mpfi from the last batch and somehow scored a Liberty badge ??