Cars revs keep dropping and battery light flashes.

C

connzy

New Member
Immediately after starting the car the revs drop down to the second lowest line, the car stutters, recovers and starts idling normaly.
when the car is running and you push the clutch in the revs drop back down to around that same second lowest line, the battery light then flashes and the car stalls.

Car was running fine before i started to install a air/fuel guage so i no it was something i have done.
this is exactly what i did.
I removed my headunit and fiddled around with the dinn slots trying to get a dinn guage holder to fit in with my headunit. It didnt fit so i plugged my headunit back in and decided to put the guage on the pillar.
Then i went down under my glove box and pulled out the ECU harness that has the 02 sensor in it. after fiddling around trying to get the 02 sensor pin out of the harness and i got a phone call and had to go, So i plugged the ECU harness back in. and started my car. (^the first 2 sentences at the top are what happened)

so i pulled over, turned my car off and checked to see if the ecu harness was loose. Pulled it out again, blew in it and put it back. Car was still having problems so i thought maybe something could be grounding out after i fiddled with my headunit so i pulled it back out again checked all the wires and put it back.

Anyone have any ideas before i take it to a mechanic?
im thinking maybe i damaged the 02 sensor pin when i tried to get it out.
Was i ment to disconnect the battery before pulling the ECU harness out?

thanks in advance.
 
If you unplug the ECU harness it will do this for a few trips afterwards while it resets itself... just keep driving and if it doesn't go back to normal after a week then start to panic.
 
you just have to reset your ECU this happened to mine after I installed my amp and sub, just unplug the negative terminal of the battery and leave it off for approx 10 mins, then reconnect the battery and leave the car to idle in your driveway for about 15-30 mins, whilst having EVERYTHING turned off, as in lights head unit... EVERYTHING. after this take the car out and give it a little bit of a flogging, and after that your car should be back to normal :) hope it all works out
 
Firstly reset the ecu.
Pull the battery and wait 10min.
Reconnect and start the car and let idle for 10min.

Once you rset the ecu. Check. If as soon as you start the car the for first time again and you get that same issue then something else is wrong.

Shouldnt have tried to install a pointless narrowband air fuel ratio gauge in the first place. Completely pointless junk gauge.
If you really must wire it up then you dont need to pull the wire out the plug. If you do the AMP connector has double locking mechanic. you first pop the white locking tab before you unclip the indivdiual wire with a very small tip flat head screwdriver.
But really you only need to splice into the wire to get a signal otherwise your ecu will no longer be receiving an o2 sensor input which will result in very poor fuel economy when cruising and at light loads.

If you never touched the thottle body, idle screw, idle speed control motor connector those wont be the issue unless it is a fluke coincedence.
 
thanks everyone, i reset the ecu and the car doesnt stall anymore. Its idling at 800rpm though, I cant remember what it used to idle at so is 800 normal? Ive been searching through the gregorys manual/internet but i cant seem to find the idle specs

Hens said:
Shouldnt have tried to install a pointless narrowband air fuel ratio gauge in the first place. Completely pointless junk gauge.
Click to expand...
True.
i new that before i decided to put it in, its just there to fill up an empty guage hole...

and another quick question i want to get my oil pressure and tmep guages to lit up (i have them installed for a long time but havent wired in the illumination.), there is an orange and a white wire for illumation. Can I just tap into the lightbulb wires in the cigg lighter/ashtray and will i need to put in a slightly bigger fuse?
 
Trondabron said:
Yer 800 is about normal, mine sits just below the 1K mark.
Click to expand...
Thank you! now i can stop searching haha.

Hens said:
But really you only need to splice into the wire to get a signal otherwise your ecu will no longer be receiving an o2 sensor input which will result in very poor fuel economy when cruising and at light loads.
Click to expand...
i was going to pull out the pin, put the wire from the guage into the pin with the sensor wire and then put the pin back into the harness.
so i should be sweet to use one of these? to tap into the 02 sensor wire under the dash?
http://www.google.com.au/imgres?q=wire+ ... 29,r:0,s:0
 
My mirage is also idling a little low after i rest the ecu. i installed a tacho cluster and it all went in no problem ( hooked in from the blue fitting/ white wire in the engine bay) and when i started driving again when i came to a stop it would dip to like 600rpm and the climb back to like 800rpm. so i reset the ecu again when it now dips to 700rpm and then back to 900rpm. so id say all is working as it should except the dip in revs as I'm pulling up which hopefully the ecu will iron it out because it didn't do it before.
 
So long as its idling below the 1000 mark I wouldn't worry about it...

My CJ starts and then idles in the 1200-1500 mark for a lil bit but then drops back down to ~700-800 IIRC...
 
Since I had my catback and larger throttlebody installed (all done in one go) mine idles at a constant 600 so i wouldnt worry about it, its seems to be doing fine for me, plus it may save a tiny tiny bit of fuel whilst sitting at the lights
 
It will say under the bonnet what the idle should be tuned to. iirc it says 700rpm plus/minus 100rpm.
And mine also idles at 1500 rpm for a few minutes while the engine warms up
 
You must log in or register to reply here.
Back
Top