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Originally Posted by Cymrych
Last week, my wife's Bravada (4.3L Vortec, W-Code, 125k miles) died on me, but thanks to AF, I determined that the CPI was the most likely cause of the problem. The car had all the symptoms: Over a period of a few weeks, it went from running and starting fine to having to hit the key three or so times prior to it starting, to having to hit the key countless times before it may or may not start. It had plenty of fuel making it to the rear of the plenum, and all kinds of spark, etc.
So, with the assistance of some really fantastic pictorials here on AF, I decided to swap that bad boy out. Sure enough, the regulator side of the plenum was completely washed. I swapped out the CPI and Nut Kit, buttoned everything up, then cranked her over. After the car fired up, and after waiting for the crap to burn off that was fouling the plugs, I took her for a test drive. Everything seemed fine. It started right up when cold, and even seemed to be running better than it had in about 6 months.
Until yesterday. When I got home from work, the wife told me that she had to crank the engine a couple of times before it started, both before going to work in the morning as well as before coming home in the evening. Then this morning, it failed to start at all.
Any ideas of what I may have missed? I freely admit that I am a Ford guy myself, and a pre-computer Ford guy at that, and I know that there is a bunch of stuff on these new(ish) engines that I just don't fully understand. But it still seems to me that if there is fuel flow and spark, there should be a running car (or at least a car that seems to be TRYING to start, but I only hear and feel the starter winding away.) I think I must be missing some obvious check here, but I'm fresh out of ideas.
Speaking of missing something, but on a completely different issue, I decided after "fixing" the CPI problem to check the initial timing on this Vortec, but for the life of me, I cannot locate the timing marks or plate, which should of course be somewhere down near the damper on the crank (at least, that's where they were on every other vehicle I've worked on.) Did GM do away with the timing marks all together, or am I just blind? I know that the advance timing is all computer monitored and controlled, but I figured that the initial timing would at least still be adjustable. At the very least, I would think the timing marks and plate would still be on the engine somewhere, if for no other reason than for finding TDC during a major engine overhaul. Any ideas where these timing marks might be hidden?
Thanks in advance for any suggestions. I hope my status as a non-GM guy doesn't dissuade any one from helping!
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