Simsy 0 Posted October 29, 2008 Well, this morning i noticed a bit of blue smoke and some misfiring (didn't take long for something to go wrong!). Naturally i thought perhaps the valve seals are leaking overnight enough to cause misfire and blue smoke out the exhaust. But i also got a bit paranoid about the health of the engine altogether as it doesn't really feel that quick to me (poss because my last car would have torn it a new arsehole) Anyway, i did a compression test (dry, engine warm, throttle open) Cyl 4: 175 PSI Cyl 3: 175 PSI Cyl 2: 170 PSI Cyl 1: 180 PSI Do they seem overly high, it doesn't look to have a had the head off from what i can see (indicating HG change or similar and a skim). In any case, they are even enough so i'm happy with that. I've changed the plugs today too and the old ones looked good, if a little white/grey rather than tan? I've wound the dizzy on a bit and it turns out the marking on the head/dizzy where it was set is spot on (just off DBL) so the timing was spot on and is spot on now again. BUT there is this cold misfire thing and the occasional misfire when ticking over, hardly noticeable in the car but obvious with the bonnet up. The only ignition system component i haven't changed is the Coil and the amp thingy on the n/s wing. Thoughts? Share this post Link to post Share on other sites
Simsy 0 Posted October 29, 2008 Fine to me! Coolio, any ideas regarding the cold start misfire / inability to idle. I removed the SAD and cleaned it but its just the same. Idles fine when warm. New SAD (expensive i don't doubt!) Share this post Link to post Share on other sites
grandos 16 Posted October 29, 2008 (edited) I'm pretty sure you can check if the SAD is working correctly and adjust it a bit if necessary. It descibes how to check it works in a Haynes Manual (electrical side of things) I also believe that if the SAD switches off too early (air gap closes to quickly) that the engine hasn't warmed up enough and it then stalls. The length of time the SAD is open can be adjusted to suit. This is easiest off of the vehicle with a 12V supply. Edited October 29, 2008 by grandos Share this post Link to post Share on other sites
Simsy 0 Posted October 29, 2008 Where is that covered in haynes? I can only see vague instructions on to remove the SAD. Share this post Link to post Share on other sites
welshpug 1,657 Posted October 29, 2008 (edited) SAD doesnt "switch off" at all, its a simple valve with a heater element inside it that heats a Bimetallic spring, which in turn rotates a disc that has a hole in it, the 12v supply is constant with ignition feed. The SAD is also bolted to the thermostat housing, and gets additional heat that affects the aforementioned spring, so if your engine heats up quicker than the 12v supply closes the valve, it'll close earlier. I didn't think the SAD could be adjusted at all, certainly doesn't state so in the manuals. The slight miss may be caused by running a little rich, if the idle speed is correct and the ignition timing set I would get a garage to check the emissions levels when its warmed up. Max is 3.5%, they run best at around the 1.5% mark (you adjust the idle CO% by the screw in the AFM.) Edited October 29, 2008 by welshpug Share this post Link to post Share on other sites
Simsy 0 Posted October 29, 2008 SAD doesnt "switch off" at all, its a simple valve with a heater element inside it that heats a Bimetallic spring, which in turn rotates a disc that has a hole in it, the 12v supply is constant with ignition feed. The SAD is also bolted to the thermostat housing, and gets additional heat that affects the aforementioned spring, so if your engine heats up quicker than the 12v supply closes the valve, it'll close earlier. I didn't think the SAD could be adjusted at all, certainly doesn't state so in the manuals. The slight miss may be caused by running a little rich, if the idle speed is correct and the ignition timing set I would get a garage to check the emissions levels when its warmed up. Max is 3.5%, they run best at around the 1.5% mark (you adjust the idle CO% by the screw in the AFM.) Aye, i need to sort the mixture still, but an analyser is needed for that, which my next door neighbour may break out of his garage if i ask him nicely Share this post Link to post Share on other sites
Simsy 0 Posted October 30, 2008 I didn't think the SAD could be adjusted at all, certainly doesn't state so in the manuals. It has a 7mm nut that seems to lock its start position, i've tried to slacken and move it but its made little difference. Might check the resistance of the coolant temp sensor when i re-visit the area to adjust it (i think moving it all the way to the right opens it more?). Share this post Link to post Share on other sites
