Best way to set timing on 99 5.7 Suburban ? When lining timing marks do I leave distributor in but lose or pull distributor completely out?
Here is the key part: For the V8 5.7L-- After setting distributor, Then connect a scan tool. Monitor the Camshaft Retard Offset value. Important: If the Malfunction Indicator lamp is turned on after installing the distributor, and a DTC P1345 is found, the distributor has been installed incorrectly
While looking I found this post by Tom, the Tom that is the all-time heavyweight undisputed champion points leader here, and deservedly so, Just substitute Suburban for Tahoe, it's the identical 5.7L engine: "In the Tahoe the distributor does not control timing. It controls the synchronization of the cam sensor and the crank sensor. The only way to set it accurately is with a class 2 scan tool. There will be a PID in data for cam/crank offset. The distributor has to be turned until this reads 0. Any more than 4 degrees off and it will set a P1345 code and run rough." End quote
thats what i was meaning relearn cam /crank sensor without scan tool
Don't turn the motor with the dist out or you will miss align the oil pump shaft. There isn't a way to do it without a scan tool unless you mark it before you pull it out and line it back up the exact same way.
Teeny bit of misinformation here . . . First of all, there is a way to do this with an affordable scanner that just clears codes, and secondly, a P1345 code does not always indicate an improperly installed distributor, so try a couple things before you start yanking your distributor. It could just be 8-10 degrees off. Anything more than +/- 2 degrees from spec will trip the code. If you don't want to buy the $1000 2-way scanner, or don't want to pay a mechanic $250 to do this adjustment, here is what I did. Old school. You will need a scanner that can at least clear codes. Get the blue-tooth scanner/adapter (amazon) and pay the $2.99 for the "torque" app (the free one is lame) and you can get some basic real time info and reset codes etc. all for way under $25. First of all, if your distributor is 180 out, or a tooth or 2 off it won't run for shit or at all, and is another whole post. So let's focus on this specific situation: Reasonably installed distributor, running well, still throwing the 1645 code. Clear the code. Start the truck. Start a timer to see how long before the code is thrown. 4-6 seconds equals too far advanced. Loosen the hold down. Back it off 2-4 degrees at a time, repeating the code clearing/restart procedure. You will quickly find that there is a correlation between the quickness the code is thrown and how far advanced it is. As you back off and restart, it will take longer to throw the code (ie 8-12, 12-16 seconds) then voila, you will find the sweet spot. If I had the $1000 snapon scanner, I would be able to rotate the distributor in real time @ 1000 RPM and get it into spec (within -2 to 0 degrees I think). The above took me 15 minutes and now the 1645 code is gone forever. On down the road!
Thank you chopper 7718 I'm going to try that now
Chapper, will a miss aligned distributor cause an occasional backfire while starting? I have tried the crank position sensor and it still does it. However, I haven't had the best luck with auto store sensors.
Short Answer, yes. Long answer requires more info: Is it throwing codes /making your check engine light go on? When was the last time you changed your cap and rotor, and did it happen before this? Have you adjusted the distributor? Don't be afraid to try this, just make sure you mark with chalk or that yellow engine marker where it was, so you can get back there. If not, you will end up with a 2-ton boat anchor in a hurry. I got back fires while starting it up for the first time after redoing the head on one side. Advanced it a bit and it fired up fine. If you haven't changed your cap and rotor in 3-4 years, do it, and carry a new one under your seat. When they go bad it's game over, and they do go bad. This was a horrible degins by Chevy, the knuckleheads. They used a hard plastic base that strips and wears out etc. They put the thing way back in the compartment so you have to climb a ladder and have long Orangutan arms just to get to it. Then they make the hold down screws Torx 10 and way down there. I must have 13 Torx screws that I have dropped down to my bell housing doing this. We can't change most of this, but there are improved versions of the actual distributor that use an aluminum base. Also moisture gets in there and causes crossfire and corrosion. Don't even try to clean up a used cap and rotor and reuse. You will see some corrosion, and think this makes sense, but just buy a new AC Delco cap and rotor. The end. Sometimes the aftermarket ones still look great after a year and your truck won't start. $40 on Amazon. Is the $14 you save going with another brand worth 39 hours of pain troubleshooting, absolutely not. Good Luck!!
Chapper7718 Multiple Scanners on Amazon which do you suggest?
I have a 1999 Tahoe and just backfired and shut off while running! I’ve changed the cap n rotor, timing chain, crank sensor and just turns over! It’s getting fire and fuel but can’t figure it out! The only code was for the crank sensor and replaced with new one. Any suggestions?
Squirt a bunch of starting fluid into the intake and see if will start. This will rule out fuel delivery. Sounds like you have already done this. If you haven't pulled the distributor, don't, just make sure the compression stroke of cylinder 1 is lined up with the correct position on the rotor. There are youtube videos that can help with this. Top Dead Center etc. One more thing, there is no "keying" inside the distributor to keep you from installing the rotor 180 degrees out. I couldn't believe this when I found it out the first time. Which GM genius designed this? Could they make a harder to maintain distributor? No. So try swapping it 180 degrees. Don't drop the ridiculous small Torx bolt into your engine cavity. Magnetics can help here . . . Double check your spark plug wire order, and try another cap or even the old one. When they go bad, it's game over, and I've had cheap cap and rotors (ie the 19.99 special) that are sketchy out of the box. If you know one is bad, destroy it forever so you are not tempted to use it again. The failing happens internally with arcing between the rails and you can't really see this. There's an awesome youtube video of someone putting serious voltage through one of these and identifying the ones that are arcing together. He had sparks going all over the place. Lots of free time on his hands! Not to take you down a bad path, but if you are saying that it backfired and died while running, you may have bent or burnt a valve. Try all of the above, but a burnt or bent valve will show up as low or nonexistent compression in one of the pistons. Take out all of your plugs and borrow a compression tester from a buddy. It doesn't have to be fancy, but take your time screwing it in and out so you don't strip the spark plug holes. The reason you take them all out is that you will have zero compression on your other cylinders and it will turn over much faster, and not kill your battery 14 times. If this is a giant pain in the @$$, just do them one at a time and have some free time and a battery charger handy. They should all be in the normal range, even a little low isn't the end of the world on these engines. It will still run. Burnt or bent valves will give you zero compression, then you are looking at cylinder head r&r. Good Luck!!
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