Unclejake Posted July 5, 2011 Share Posted July 5, 2011 Sorry Jase - but you are wrong, the throttle IS best to be held open Oh, I totally agree that an open throttle is best, but a closed throttle does not invalidate the compression test.As you point out, the only difference a closed throttle makes is the volume of available air, and that will stay constant on a single carb. You will get bigger numbers on an open throttle, but a significant difference between cylinder readings doesn't seem likely to be the result of a throttle setting (unless it had ITBs - which this motor doesn't)..... or am I missing something? Quote Link to comment Share on other sites More sharing options...
coldturkey Posted July 5, 2011 Share Posted July 5, 2011 i've done cold compression tests before, good for detecting major defects like blown head gaskets, cracked head etc. Not so good for measuring how worn an engine is, but then a compression test never really is, all it can tell you is that one cylinder is more worn than another. A compression test is normally a good indication of where problems lie, it is certainly not a definitive diagnoses of an engine. -Oh and make sure that if you are doing it cold that the engine cranks over nice and quick, and that the battery doesnt die halfway through. Quote Link to comment Share on other sites More sharing options...
Shandangles Posted July 6, 2011 Share Posted July 6, 2011 sell the G4 and buy on of those 4age ignition controllers (forget the name, but plug into where the dizzy wiring goes, runs standard dizzy and 11 degrees base timing iirc) for like $250. instant $1000 minimum profit. Quote Link to comment Share on other sites More sharing options...
slacker.cam Posted July 7, 2011 Author Share Posted July 7, 2011 sell the G4 and buy on of those 4age ignition controllers (forget the name, but plug into where the dizzy wiring goes, runs standard dizzy and 11 degrees base timing iirc) for like $250. instant $1000 minimum profit. I've heard bad things about those ignition controllers. The guy I bought the car off had one on it before the Link and it blew up (I think while trying to jump start the car). I spoke on the phone to another guy who runs an AE86 in the series and he also used to have one before it blew up and now he runs a MSD6AL. I have two megaquirts lying around that I can use to replace the Link if I want to make a quick buck. Either that or sell the carbs and swap to EFI. Either option should net me over a grand which is sweet. Thanks for mentioning it though. If they didn't blow up I'd most probably go down that route! So to update on this. I now have the car (I'll start a project thread shortly). I just pulled it off the trailer and tried to start it. And..... IT STARTS!!! I don't know what the guy was going on about but it definitely frikin starts and runs, albeit rather roughly. It kinda sounds like it's running on 3 but not quite. This is a huge bonus in my eyes. I can now diagnose the issue with a running motor rather than pulling it down and hoping I correctly diagnose the issue. I can check for cold exhaust primaries, drop spark to one cylinder at a time and shit like that. Oil pressure is still excellent so I'm not too concerned about running it in the state it's in. It's not making any terrible noises either. Shit yeah! Quote Link to comment Share on other sites More sharing options...
slacker.cam Posted July 7, 2011 Author Share Posted July 7, 2011 Here's the link to those ingition controllers for anyone who's interested: http://www.erd.co.nz/products/toyota.html Quote Link to comment Share on other sites More sharing options...
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