Quote:
Originally Posted by venomtail
I have no reason to suspect there have been any mechanical damages from the timing belt snap. The replacement was done by a Volvo mechanic who's done it for several decades, checked to make sure it was alright, ran smooth with no weird noises after the timing belt replacement and taken to the Volvo dealership themselves who checked twice that it's done properly and given the all clear.
Sure, I can have a look if nothing's damaged visually but I would likely mess up something if I played with the timing mechanics myself, that's why I don't dabble with it and let the specialist do what they're qualified to do.
An oscilloscope might be a bit above my understanding let alone having one. I've got noid lights and a multimeter but that's about it. Remember a guy a while ago telling me how to test injector signal readings with an oscilloscope but I'm afraid I might need a bachelor's degree to understand and follow what he was explaining to me.
If I can't test it with the 2 items I have, that will be a dead end for me. Might have to sell it... any offers?  |
If you've tested every injector with the NOID lights and they all show as working, you've already got a visual go/no-go on whether they're working or not, assuming the injectors actually function, something else i believe you've already checked.
Without being rude but picking up on your self-confessed limited technical ability, how competent are you at removing the rocker/valve cover?
If you're ok with that, i'm fairly sure you can identify the valves and their springs and observe their movement as you turn the engine over by hand using a socket and ratchet drive on the crank pulley bolt, obviously in the normal direction of rotation. The firing order i believe is 1-2-4-5-3 with #1 on the right hand end, usually timing belt/crank pulley end. However you know where #4 is as that's the one giving trouble if memory serves so please excuse the teaching to suck eggs! That said, turning it over by hand you should see all the inlet vales open in the same order as the firing order and ~1.5 turns later the exhaust vales should open in the same sequence as the inlets. In other words, as you turn it over, if #1 inlet valve opens, about 1.5 turns from when it starts opening #1 exhaust valve will start to open but the other valves will all be doing what they should at various times throughout the turning over of the engine.
What you're actually looking for is that all inlet valves open a similar amount and that all exhaust valves open a similar amount. If any (probably on #4) aren't opening as they should, look for a problem in the corresponding valve train between the camshaft and that valve. Could be a broken rocker, a dished follower or even a bent valve or broken valve spring - the last one won't allow full compression so power will be down as a result.
If that reveals nothing then i suspect it will be a top end stripdown to ascertain the cause of #4 not firing as it should.
Either that or as you suggest, sell it and cut your losses, someone may amke a good offer and have the bits to fix it cheaply enough to make it worth their while and gives you the opportunity to find one that does run as it should.