Swino Posted September 17, 2017 Share Posted September 17, 2017 Been trying to get to the bottom of my problem after some help please guys car drives fine for the 1st 3-4mins then get major hesitation/back fires on pull off and any gear below 3000rpm after that drives normal until I try to apply boost can creep up the rev range fine swapped every sensor can think of and spent countless hours searching internet for things to try until I did compression test which wasn't good news just took manifold off to look at exhaust valves as people seem to have the valve guide slip took pics if anyone could look at them and point me in the direction to go next as all look fine to me Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted September 18, 2017 Share Posted September 18, 2017 Is id down on compression and if so on how many cylinders ?Are the first pair of exhaust valves the same colour as the second pair ?As the 2nd look darker to me , if so compare the plug colour of both cylinders too. If its a fair bit darker that could indicate a misfire (unburnt fuel) hopefully a cheap fix .or if its oily residue , bad news like a bore or valve oil leak [emoji57] Sent from my SM-G930F using Tapatalk Quote Link to comment Share on other sites More sharing options...
Swino Posted September 18, 2017 Author Share Posted September 18, 2017 All cylinders are down on compression three at 100-110psi and cylinder closest to turbo is 60psi the last 2 are different colour they look burnt it's been misfiring like a pig under 3000rpm but I've got no smoke coming from exhaust and I've not lost any oil and plugs are clean changed them couple weeks ago think I've got to take engine out and inspect the heads not looking good but good time to upgrade I suppose Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Tidgy Posted September 18, 2017 Share Posted September 18, 2017 sorry to say mate but engines got serious issues, 40% down on compression is a big problem, as in engine rebuild problem :( Quote Link to comment Share on other sites More sharing options...
Swino Posted September 18, 2017 Author Share Posted September 18, 2017 That's what I've been thinking been trying to put it off but just picked up some v3 sti heads and going to get engine out in couple days and inspect it Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Swino Posted September 18, 2017 Author Share Posted September 18, 2017 Just strange how it starts up idles fine and drives fine at 1st and it's not using oil or smoking Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
savage bulldogs Posted September 18, 2017 Share Posted September 18, 2017 If the compression test was done correctly those results are full rebuild symptoms [emoji852]Even if the stripdown shows valve or gasket damage ,as cylinder number 3 is way down on compression. Sent from my SM-G930F using Tapatalk Quote Link to comment Share on other sites More sharing options...
Swino Posted September 19, 2017 Author Share Posted September 19, 2017 I wasn't 100% confident in the gauge that was used as it's old but did it again with engine cold and and 3 of them were 85-90psi and cylinder 3 was 50psi both tests were done twice and with throttle open was going to do a leak down test today but decided to just rebuild now get it over and done with :) Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Tidgy Posted September 19, 2017 Share Posted September 19, 2017 test it again if your unsure, if they all come back the same with one down again you know theres a fault Quote Link to comment Share on other sites More sharing options...
Swino Posted September 22, 2017 Author Share Posted September 22, 2017 So the rebuild has began and noticed a few things the timing is off by one tooth on the right side of the engine could that have caused the problems I've been having couldn't see any problems with the head on that side exhaust valves looked burnt but no cracks not got the other side off yet but pistons look fine no movement with them and the cylinders walls are very clean think it was rebuilt not that long ago I have some v3 sti heads to put back on will it start and run with them Ill be booking in for a map once it's built Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Swino Posted September 22, 2017 Author Share Posted September 22, 2017 Sent from my iphone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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