Daewoo Racer/Cielo '94 :: troubles with engine

Low Rider · Post by **Low Rider** » Tue Dec 19, 2006 8:41 am

Allright... please bear with me, cuz this is gonna be a longer post

Engine is 1.5i SOHC
Car runs fine on higher RPM, but below 2500 or 2000 it starts to jerk ... this is especially
evident on 1st or 2nd gear when throttle is sligthly depressed and on gearchange onless i shift at 5k

It acts as if the engine is being cut off fuel / elec or what and then back on like 2 times a sec
Once it gets above 3000 its all ok

You can see this frustrates during the rush hour when you need to drive slowly behinda someone like 10 mph in 2nd
and it starts to jerk like a rabbit on the heat LOL

Cables were changed few times by the previous owner,
Sparkplugs were changed 10k miles ago, along with fuel filter
Frow what i heard it could be MAP sensor, clogged injector or something with ignition or maybe O2 sens.
so help people what would be the most likely to go - starting with least expensive

Btw, so far i tried unpluging the MAP sensor, it doesn't change anything except CEL lights up
and STP injector cleaner...again doesn't help - i've run 3/4 tank with it

MMamdouh · Post by **MMamdouh** » Tue Dec 19, 2006 11:21 am

when the vacuum line of my MAP sensor was disconnected i got the same symptoms... i recon yours is acting up.

MMamdouh

Low Rider · Post by **Low Rider** » Tue Dec 19, 2006 11:51 am

How did you find that out? Did you just went replacing the tube someday or what

----edit------

I checked it. It's connected ok. Should I seal the flanges with gasket silicon or somethin? Altough
I dont think it'll help much

MMamdouh · Post by **MMamdouh** » Tue Dec 19, 2006 5:33 pm

it was one morning that i started the car and it was all jerky at idle and low RPMs and the CEL was on... when pushed hard it was going fine though.

i went to the dealership to check the car - wasn't that Woo educated at that time - and they said the vacuum line was disconnected thats all... the rubber end at the intake became lose and fell off due to engine vibration, i added a small tie rap on all them small vacuum rubber hoses to avoid this issue in the future.

if you can; borrow a MAP sensor from a friend and use it on your car to see if it is any different... sensors are expensive so i don't want you buying a bunch of sensors that you don't need.

MMamdouh

Low Rider · Post by **Low Rider** » Tue Dec 19, 2006 8:19 pm

Like I said, CEL is NOT on (unless i plug out the sensor wires)...
I dont know... I gues i'll try to test the hose somehow before i start looking out on scrapyards for sensors

But i think the problem isn't the vacuum line itself, it's either the sensor internal fault or somethin else

MMamdouh · Post by **MMamdouh** » Wed Dec 20, 2006 7:41 am

thats what i think too... anyways testing the vacuum line is easy, just take it off the engine and blow through it to make sure it is not blocked.

if that is OK then plug one end with your finger and suck the other end with your mouth to create vacuum in the line then plug it with your tounge... if it is leaking then you will find out that your tounge gets ditashed from the line due to vacuum leak from the line.

MMamdouh

Low Rider · Post by **Low Rider** » Wed Dec 20, 2006 9:27 am

LOL i was thinking more like checkin it with bycicle pump

anyways do you know maybe what the voltage output from the sensor should be

MMamdouh · Post by **MMamdouh** » Wed Dec 20, 2006 11:00 am

nope... but i recon one of the guys does.

MMamdouh