Any advice appreciated. I've searched this forum and other sites but nothing has solved my issues. Forenza (2005) started missing and I got the 300 random cylinder misfire code. Changed the cam position sensor and it was good for 2 days then started back 0300 code again, so more research and found I did have oil around the plugs so changed them and replace valve cover gasket. Wires are only 3 months old. good for a few days then saw code once but not repaeated for a couple days but now it is every time I start the car. It will go away after a few miles but I hate to drive with it this way due to other damage that could be occuring. I have no way to test ignition coil or compression, with either of these two or possible the computer, what else is left? I hate replacing jus tto see although with all I've done , it is still cheaper than one trip to dealer. Thinking of replacing the coil next but at $100+ thought I would appeal here for wisdom. Thanks
Forenza Mis-Fire Frustration
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Hey there, looks like you did some good troubleshooting so far...
However... its starting to sound like it could *possibly* be your headgasket that is starting to leak. Many people have had that issue with the stock headgasket, and it usually starts out as a small leak that lets some coolant into one or more cylinders after the car has been sitting for a while. Then it misfires during start-up and the first few minutes of running until the coolant is cleared out of the cylinders. When it gets worse, it leaks more and you have more misfires more often until it becomes almost undriveable. Tell tale signs of this are mysterious coolant loss and possible overheating... Also you would start seeing burnt coolant/oil residue on the plugs...
Do you have any of those symptoms? How is your coolant and oil level? How do the plugs look?
However... its starting to sound like it could *possibly* be your headgasket that is starting to leak. Many people have had that issue with the stock headgasket, and it usually starts out as a small leak that lets some coolant into one or more cylinders after the car has been sitting for a while. Then it misfires during start-up and the first few minutes of running until the coolant is cleared out of the cylinders. When it gets worse, it leaks more and you have more misfires more often until it becomes almost undriveable. Tell tale signs of this are mysterious coolant loss and possible overheating... Also you would start seeing burnt coolant/oil residue on the plugs...
Do you have any of those symptoms? How is your coolant and oil level? How do the plugs look?
bingo!!! it is worse and I do have a large amount of coolant disappearing - I hate the amount of money I have wasted but sounds like I have a head gasket job looming - thanks for the replies. I will research that in other posts. Thanks again.
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Sucks, but at least you know what it is now..
In the meantime if you are driving your car still - please keep a close eye on coolant and oil levels! Do not let them get low as you will cause significantly more damage. Also - make sure when you check them there are no signs of cross contamination. If you see coolant mixing with oil (likely to appear as whiteish milky substance under the valve cover or in oil) stop driving it until you can have it fixed.
I verified and I guess it is much worse. I had just changed the oil and there was no water in it but now it is there. I should have known since I was losing alot of water and could not find the leak. But before yesterday there was not water in the oil; the dcar was pushed into the garage so I will begin the tear down. Any special advice? I've done it before on chevrolet's so I assume similar. I can't find a good tutorial for this car but I think I can handle it. Would appreciate any little tricks though as those nuggets can save you alot of headaches. I'll align and clamp the timing cogs if I can but I always mark them for backup. I sure dread the job. thanks again and you are right at least I know the issue......
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It is a fairly big job, but if you have done it before on other cars, then at least you have a good knowledge base.
I don't see how clamping the timing gears together would help you in this case... to remove the head the cams have to come completely out to access the headbolts.
As for "special advice" make sure you get ahold of the factory service manual to tell you the proper torque ratings and procedures... especially for re-installing the timing belt and tensioning it. Enough guys on here have messed that part up thinking it was tensioned and then started the car to end up with belt valves. The first time I did it, my exhaust cam was off by 1 tooth - no damage, but drove and sounded all weird. The way it gets tensioned on this car is just a little weird thats all.
Here's some pics from back when my stock headgasket went and I had the head ported...
Here are you can see where the stock HG was leaking coolant into 1 cylinder:
Cleaning up the surfaces:
Installing head with Cometic MLS HG and ARP studs:
For full details and pictures see my thread here:
http://www.suzuki-forums.com/forenza-reno-performance/34395-porting-flow-numbers-u20sed-head.html
I don't see how clamping the timing gears together would help you in this case... to remove the head the cams have to come completely out to access the headbolts.
As for "special advice" make sure you get ahold of the factory service manual to tell you the proper torque ratings and procedures... especially for re-installing the timing belt and tensioning it. Enough guys on here have messed that part up thinking it was tensioned and then started the car to end up with belt valves. The first time I did it, my exhaust cam was off by 1 tooth - no damage, but drove and sounded all weird. The way it gets tensioned on this car is just a little weird thats all.
Here's some pics from back when my stock headgasket went and I had the head ported...
Here are you can see where the stock HG was leaking coolant into 1 cylinder:
Cleaning up the surfaces:
Installing head with Cometic MLS HG and ARP studs:
For full details and pictures see my thread here:
http://www.suzuki-forums.com/forenza-reno-performance/34395-porting-flow-numbers-u20sed-head.html
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Also if you search on youtube you can find video tutorials on changing the timing belt, etc.
FSM here:
Daewoo Service Manual
FSM here:
Daewoo Service Manual
In summary, it took 2.5 days working around other jobs. Parts were alot more expensive than anticipated ~$700. They were cheaper on-line but I did not have time to wait - I did have to go to autozone, advance and O'Reilly's to gather all the parts. Largest time consumers were cleaning the mating surfaces for the head gasket. I only had one issue and that was I overtorqued one of the crank pulley bolts and broke it; so I had to drill it out and replace. Replaced all 4 to be safe. I did watch (or skipped thru) the youtube video series. It was excellent and had many nuggets to save time plus the torque values since I did not have the manual.
I replaced both can shaft seals but the inner cam shaft did not have to be removed to get to head bolts, only the outer had to be removed. Timing was not fun since the video shows the left idler sliding right on but my belt was too tight so I had to muscle it. Twice since I had the cams one notch over from the crank so off it came and re-aligned. I also had the two outer exhaust manifold stud to break. I have not replced them yet - need a 90 degree drill for that but I think it will be okay for a short time. Learned alot about the car so it was a good overall experience. Just wished I had save the $170 IAC and $50 Cam Position sensor cost before finding out it was the head gasket.
I poured new oil thru the engine to try to wash out the water - how long (miles) should I run the engine before I change the oil again. I figure a couple hundred. thoughts?
I replaced both can shaft seals but the inner cam shaft did not have to be removed to get to head bolts, only the outer had to be removed. Timing was not fun since the video shows the left idler sliding right on but my belt was too tight so I had to muscle it. Twice since I had the cams one notch over from the crank so off it came and re-aligned. I also had the two outer exhaust manifold stud to break. I have not replced them yet - need a 90 degree drill for that but I think it will be okay for a short time. Learned alot about the car so it was a good overall experience. Just wished I had save the $170 IAC and $50 Cam Position sensor cost before finding out it was the head gasket.
I poured new oil thru the engine to try to wash out the water - how long (miles) should I run the engine before I change the oil again. I figure a couple hundred. thoughts?
For future reference, you don't need to take the exhaust manifold (or intake manifold) off the head. Simply unbolt the manifold from the front cat and lift the entire assembly off. The YouTube videos are good but have you take off/apart a lot of stuff you don't need to if the head isn't being sent out for rebuilding or machining. About 6 months after fixing the hg on mine the rod bearing on the cylinder that was ingesting coolant started knocking. I guess the misfiring took its toll on it.
John
John
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Yep that sounds very plausible, bearings don't like misfires... also depending on how much that cylinder was ingesting it could approach the point of hydrolocking itself for example on the first startup after it has sat overnight and enough coolant has leaked in. Bearings also don't like extreme compression pressure with no oil pressure
Exactly what I was thinking but too lazy to type. I found that if I left the coolant bottle cap just loose enough that it didn't build up pressure it wouldn't miss on a cold start. I'm guessing that after shut own the pressure would slowly push coolant into the motor over the course of a few hours then it's miss on restart. Leaving the cap loose (I actually found it could be crossthreaded on) would prevent the pressure building up and therefore the coolant wouldn't be pushed in. Not saying this is the best or right way of doing things but it got me by for a bit until I was able to fix it properly. It'll help solidify a suspicion of a head gasket issue as well.
John
John
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Sounds like deja vu with my headgasket... lol
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