After having coldstart issues for quite awhile I have replaced the spark plugs with ngk platinums and checked all sensors with all good readings. So today myself and The Deacon ran a compression test and found some issues. Results: (psi) 1= 65 2=65 3=78 4=70 5=40 6=35 This test was ran today while the engine was cold with the throttle wide open. So now the question is should the motor start with these low figures? Cheers sean
wow. might be good to have a quick look for a replacement motor. dont know how all cylinders are so shot. you sure the gauge was reading correct? that motor seems really ****ed
new motor.. dont even bother working on this motor... a second hand na motor is about 500-600 depending on condition drop it straight in and dont worry about it anymore... or you can take some members advice on the forum and get the motor.. do a 100k,km service on the car then put it in (about another 600-800) but for 500-600 a motor... consumables.......
it runs pretty well. When it starts it runs really well like their is no problem with it amazingly... but its pretty rare for it to start lol
if those figures are accurate then that is amazingly low compression. suprised it will even run at all as said above. the motor is now a paper weight
Your readings are a bit low! Standard: 186 psi Minimum: 142 psi Results: (psi) 1= 65 - Compression LOST 121 psi 2= 65 - Compression LOST 121 psi 3= 78 - Compression LOST 108 psi 4= 70 - Compression LOST 116 psi 5= 40 - Compression LOST 146 psi 6= 35 - Compression LOST 151 psi You did have a fully charged battery for the test?
Maybe get the engine hot and try again if you can, maybe there's something causing the valves to bind at low temperatures? just throwing out some ideas. Also do the oil in cylinder test to see if its ring related or just heads.
dodgy tester or not, there's a variation of more than 40 PSI between the highest and lowest reading. that's already cause for concern. 5 and 6 in particular seem weak.
yea :/ Im quite amazed how low it came back, and yea I had the battery on charge before I ran the test :l Should a car with such low compression start intermittently? Im stumped
The Guage is a new snap on so I hope that it's a good one. The compression is what I expected given that you can hear it puffing when being turned over on the starter motor. I wanted the young man to post the result so he knows what strategy to adopt from here on. After doing checks prior and checking spark, fuel, cass, ptu, tps etc. I came to the conclusion that there may be a compression issue which we verified. The only thing is that the car had been sitting for some time and there may be the possibility that it needed to be taken on a big drive to see if that cycled the engine and possibly free up the internals, but that was wishful thinking given the results of the test. It is a bit disappointing given that it is his first car. However we all have stories about our first car. As a last resort we will drop some oil in the chambers and see if there is any positive out of the situation.
Simple tests first. When I got my Zed the first thing I did was a comp test and found one cylinder 40 psi dry and 160 wet so I know the rings are gone in the cylinder. I have learnt to do the simple tests first before jumping to complicated testing. MichaelZ
Yea thanks MichaelZ compression test doesnt lie haha, time for me to weigh up my options and possibly start my first rebuild. (Not sure if I should rebuild this motor or find a fresh one). Cheers sean
If it runs, drive it until it dies and then drop a new motor in. Since you now know it's rooted and not worth wasting money on, just wait it out. 2nd hand NA engines on here go for $500 for known working ones.
It wouldn't hurt... as a last ditch effort, to pour some seafoam in the cylinders and turn it over a few times, put in some more, and let it set for a couple of hours, restart it, warm it up, and test compression again. I had a seized turbo that was coked up real bad, took out the CHRA, soaked it for a few days in seafoam, and it freed up, went back on the car, and worked fine. It could be stuck rings, and if so, they might just free up.
Haha yea mate got it soaking at the moment.. we suspect the rings are stuck, if not ill get it running and give it a good reason to be stuffed lol :br:
Here's a tip! When you are purchasing a replacement engine, compression test it before you part with any money!
