To all who tried to help me with my problem that has been ongoing from the past 9 months, I have found the problem. My 04 Accent want to stall at idle and ran rough but got better at speed all after a buddy changed the timing belt. Bending 2 valves in the process and retiming it again, only for me to have to retime it properly after. Took my car for the emissions test and failed. Had no choice, but at admit defeat and take the car to the dealership. Hooked it up the real time computer (cost $150.00) and came back with all my sensor were bad. Took them every sensor was replaced and couldn't be. I reinstalled the old sensors if it didnt help. Only sensor not replaced was my coolant, as I couldnt find a tool to get it off. They said all the sensor readings were off. My coolant sensor was reading -23 deg up to 195 deg, back and forth, the O2 sensor was all over the place trying to compensate. The throttle position sensor was always at 100%. So they said it could be the main relay, or coolant sensor or ECM. I said try the main relay first (only $27.00), if that dont work the coolant sensor (had the part just had to be put in), total cost $160.00 combined. Didnt fix it, so that left the ECM (cost $1,100.00). Told them I would pay my bill and leave, that I would try out a junkyard, id get rid of the car for $1,100.00. He told me 2 wait he would see what he could do. Long story short, came back and said they would replace it for FREE. I said what......he said the ECM was under warranty, up to 130,000 km. Asked me how many kilometers....I replied 129,992 kms.....8 f**king kms. They replaced it and the car runs like it did before.



One little catch those, ok well two. They installed the computer differently then the original and shitty at that. Makeshift bracket and 1 nut.



ECM

ECM zip tied



I secured it with zip ties for now, going 2 take it back but dont really want them touching my car again. There were other minor problems. But anyway, now I get less kilometers per tank by like 30. And that worse from when it was running like sh*t. Car idles better, doesnt smell rich, only from cold start first thing in the morning. Smells normal when hot. SO IN MY TIME OF HAPPINESS WHAT COULD CAUSE THIS PROBLEM NOW? Doesnt make sense it runs better and uses more. Now I get under 340 kms per tank in city, where as was I first got the car I was getting 400 kms and after the timing fiasco, 350 kms in city. Nothings changed. Travel the same way to work, same distance, same weekend driving. Suggestions?????

 

You might have a dodgy wiring harness dude, if you can hook it up to a real time scan tool again (dealers aren't the only place that have these) and shake the harness, it might reveal some errors. Check all of your earths, and clean all of the contacts and connector pins too. Also, if you have any crazy stereo systems, remove them while you are getting the car to work properly.



How many km have you done since owning the car?

 

I'm glad you got it "fixed" anyway. For $1100 you could pay me to fly up and change the computer for you that's just stupid.



km/tank is no way to measure fuel economy. Try l/km if you want some more precision, and miles/gallon if you want murrkins to know what you are talking about. That said, how many tanks did you get 400, how many at 350, how many at 340?

 

I normally get 350 to 400 miles per tank. So you are well below where I would expect you to be unless you're living your life a quarter mile at a time.

 

Well if I figure it out litres per kilometer for what I am getting right now of 340 kms (which is right when the idiot light comes on for low gas), I used 10.9 litres per 100 kilometers. Now that is based on only 37 litres in the tank, not the 45 litres the tank holds. Cause I never trust how many litres are in the tank when the idiot light comes on. But know I only put in 37 to fill the tank from when the idiot light illuminates. Bear in mind I've only filled up the tank twice now since getting the computer replaced.

Convert that to kilometers per litres you get 9.2 kilometers per litre.

Convert that to miles per gallon you get 21.7 miles per gallon.



When my car was running like sh*t, I got 350 kilometers per tank, or 9.4 kilometers per litre.

Covert that to miles per gallon you get 22.4 miles per gallon. I filled up the tank from March till November, once a week on average, and got these numbers.



Before all this happen when I first got the car i was getting 400 to 450 kilometers per tank (was so long ago don`t remember exactly), or 10.8 kilometers to 12.2 kilometers per litre.

Covert that to miles per gallon you get 25.6 miles to 28.8 miles per gallon. I filled up the tank for 4 years, once a week on average, and got these numbers. Believe the 400 kilometers was in the winter time and 450 was in the summer time.



All calculation are based on only 37 litres, to fill tank from when idiot light comes on (always equals 37 litres, give or take a few), so know its not a faulty gauge. And are based on city driving, with roughly same driving habits and outside temperatures, distances and roughly same number of trips.



On highway before all this happened a would get 550 kilometers per tank, or 14.9 kilometers per litre.

Convert that to miles per gallon you get 35.2 miles per gallon.



Do not know how many kilometers per tank I would get now, as I usually do not need to take it.



I did a vacuum test just to compare the difference from when I had the problem, see the comparision, as I do not know what it is telling me.

[media]http://www.youtube.com/watch?v=CTclQT5qdcY&feature=mfu_in_order&list=UL[/media] before ECM was replaced

[media]http://www.youtube.com/watch?v=vLOU6vs2JEk&feature=mfu_in_order&list=UL[/media] after ECM was replaced (at 10 seconds when I start to raise the RPMS the gauge starts to raise and drops a split second before raising again, plus there is still little viberation in needle at idle. Gauge was hooked up through PCV)

Thanks for any advice.



What should I try now?

 

If I read that properly, you lost ~20% of your fuel economy when they changed the computer? That sounds not great. First thing I'd do is secure the computer to the car properly. Wouldn't it be a kick in the nuts if a bad ground through the computer case was causing the poor economy? Check the part no. on the computer and make sure it's for your car, maybe it's tuned for the wrong engine?

 

Hmm. Good advice stocker. I'd also try re-fitting some of the old sensors as well, as these are the only other variables that seem to have changed here.



Either way, it would be worth checking your spark plugs. All that rough running might have fouled them. It won't solve the problem, but it would be good to eliminate that doubt.

 

any advice on the video of the vacuum test after the computer was replaced?

 

I can only say to search Youtube for how to read a vacuum gauge. No video on the superold laptop I'm reading on these days

 

could a partially clogged CAT cause excess gas consumption. While my car was running like crap, the CAT started smelling like rotten eggs. I know this usually means it is on it's way out. Ever since I got the ECM replaced the smell is no longer there. Could the CAT be clogged somewhat?

My only concern in thinking that, is if the CAT is replacing and my problem still persists. But my car passed the emissions test with flying colours. Now that being said the emissions test was done at the dealership. What are the odds that they used another car to do the test on and my car is not as good as I think.

Could this still be a problem? Should I still replace the CAT? if I remove it, I know the flex pipe will have to be replaced too.





Thought I would change the spark plugs today just to find out they replaced my plugs while the car was at the dealership. They put in old worn plugs (NGK). All have a rusted colour tip. Like, WTF. Don't like dealing with dealerships but come on. I knew I was going to have to change them the way the car was running before. I also found they broke a few clips that hold the wires in place. I think they replaced the wire harness from the ECM to the under the hood fusebox. Don't know what else they replaced. They said when I was there they were going to change the main relay first, but thats in the dash, is it not? But I do know that my wheel well in the drivers front wheel was removed. They hacked away the tape and plastic cover that surround the wires from inside the car and didn't even bother rewrapping them. A few other wire covers are missing as well. They snapped a bolt for a hanger that holds the wires in place by the firewall and f**cking just drilled a regular screw in to hold it. The wires should be covered right? to prevent breakage. Like I don't even know now what was replaced on the car. Nothing was said about the wiring and no my invoice there is no mention of replacing the main relay, not like they charged me extra. But really....so now I certainly have no idea what was done on my car to know whats causing the extra extra gas usage.



What should I do? Highly doubt the dealership will admit anything. Its been 2 weeks or so since the work was done. Didn't think I would have to check there work. Guess thats my fault. I should have, especially since I noticed the other few things when I got the car, with the hood release and whatnot. If only I wasn't strapped for time then. Send an email to Hyundai head office to tell them about it all. Could go back to the dealership but really don't want to go back after all this. God knows what they will do.