Wierd sound on startup

David74 · Post by **David74** » Wed Dec 20, 2006 5:10 pm

Ok guys here is the problem:
1999 Daewoo Lanos 1.6L DOHS
1.Things i've changed : New NGK spark plugs and cables ,Valve cover gasquet,Fuel filter ,Air Filter,all the belts Pulley,tensionar.

Every time i start the car in the morning the car makes wierd sound for about 15-20-sec,like a knocking sound,the engine vibrates a lot.If i don't step on the gas pedal i feel like the car will stop ,but it doesn't .After that its fine and it will run all day fine unless i don't drive the car for an hour or so.
But than the other thing is that lest week i didn't drive it for 3 days and it started fine.
Things i suspect :Possible fuel pump or injectors..????
Oil Pump ...,my mechanic thinks is the Valve lifters for the oil ,but if thats the case wouldn't it make that sound the whole time while driving.
I'm goint to replace the Ignition coil as well as the car has 120000 miles on it,but it doesn't sound like that is the problem ???
I don't know ???Any body with similar problem and idias to fix.
Thanks!!!

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

car starts with a vibration and hesitation if left off for an hour or so... if left a day or two it will start just fine, this sounds like leaky injectors man.

MMamdouh

David74 · Post by **David74** » Thu Dec 21, 2006 9:19 am

Thanks man you 've been great help for a lot of us here!!!Do i need to replace the whole injector or can i just get the O-Rings seals for each injector.Also are the Nubira or Leganza injectors the same as Lanos???
Thanks!!!

MMamdouh · Post by **MMamdouh** » Thu Dec 21, 2006 1:28 pm

no... this is not related to the O rings, the injector itself is leaking fuel so you depressurize your fuel system into the intake every time you shut the engine off... if the O rings are a problem then you will be leaking air into the intake and the car will idle at over 850RPM depending on how sever the leak is.

it is recommended to replace all 4 injectors as i don't think that cleaning injectors is a reliable long term solution for this issue.

the 1.5, 1.6, and 2.0 got different injectors... OK they all look the same but they are different when it comes to their flow rate, they are differenciated with colar color and most probably yours got purple colar since yo got a 1.6.

MMamdouh

boosted_to_zero · Post by **boosted_to_zero** » Fri Dec 22, 2006 8:13 am

i acutally i agree with wat ur mechanic said, valve lifters, wats happens is that when a car is cold the lifters need to build oil pressure, as hwen the car warms down the valve that normally keeps the pressure maybe blocked. its hard to explain. My suggestion to u is put engine flush in it run it for 100km then change oil, and another 50km change oil again, as this may clear the blockage causin the noise

David74 · Post by **David74** » Fri Dec 22, 2006 9:12 am

I think i'll try the injectors first as i found used ones for $30 all four.Lifters i think are hard to change as they are inside the head which rquires taking the Valve cover,Head,Timing belt..........etc off.Big job...$$$
Are those engine flush liquids safe to use,my mechanic said to stay away from it.Which ones have you used,any brand...???
Thanks!!!

boosted_to_zero · Post by **boosted_to_zero** » Fri Dec 22, 2006 9:27 am

Try Wynns engine flush, or just known brand of engine flush, i am a mechanic i wud recomend u try it for before u actually go n start replacing things i really dont think injectors are the problem. Ihave worked on daewoos with same problem and used engine an flush n couple of quick oil changes and they have worked. And if they didnt we replace the lifters