setting timing marks on 97 Silverado w/5.7
I had my 5.7 rebuilt in a shop and installed it back into my truck a couple months back. Since then the service light has come on for a few days at a time then goes off. I had the codes read at the local auto parts store and it says: Bank one sensor two malfunction. one of the fixes is to adjust cam retard timing. When I checked my timing, the marks were way off and when I tried to align them by turning dist. The truck knocks, sputters and dies. Could a faulty o2 sensor cause this problem or is there something else I'm missing? Also, on the print out from code reader there are approx. 2 pages of possible fixes. I really hate to just start replacing parts- especially when the 3 o2 sensors alone cost over $200. Any ideas to narrow it down or reason why I cant get timing on mark?
Thanks! Jim E.
you need a snanner to set ignition timing cam retard should be 0 degrees was the truck missing or roughing smooth when the check engine light came on? Before u messed with it
It would pop occasionally and I have poor mpg approx. 12 mpg, but it runs fairly smooth. I tried to set it back where it was but I dont think I'm at the same spot on dist. cause its running a little rougher now.
need to get timing set right and running properly before diagnosing O2 sensors .
Your vehicle has an electronic advancement inside the distributor. To properly set the ignition timing there is a plug that has to be separated. On the late 80s and early 90s it was on the firewall towards the passengers side. Brown or dark tan wire with a similar color plug. Follow the wiring harness from the distributor you can't miss it. If you leave this plug hooked up the engine will constantly try to adjust the timing and you will never get it set right. Once you get it set to 0° shut it off and hook the plug back up. The ecm will constantly adjust the timing sometimes up to 20° or more so that's y it looks off. After u get the timing set post what is happening
john you're way off . this is an OBDII system , the only way to set the timing is to use a scan tool, there is a procedure to follow , if it's not done the right way it will never be right.
It has a DISTRIBUTOR there for the DISTRIBUTOR has to be set to 0° for the electronics to do their job properly. You have obviously never replaced a distributor on an OBD II vehicle. Its just like replacing a distributor on an OBD I. Even the 2000 and newer Honda's have to be set properly when the distributor has been replaced. Yes there is a procedure to be followed but the timing has nothing to do with a computer. I explained the procedure ask any mechanic and they will tell you if the vehicle has a distributor whether its carbureted, TBI, MPFI, or SFI the timing is adjusted by turning the distributor till its flashing cylinder 1 (or 6 on a GM) at 0° with the electronic advancement wire unplugged.
yeah ok !
He even said he changed the timing and now can't get it back to where it was. If you don't know what your are talking about then don't include yourself in the discussion. Its guys like you that have made cha cha a worthless service. You think because you know how to check your fluids, tire pressure, and read a car magazine at a dentist once that you're now an expert.
John is absolutely correct. This sets baseline.. This is the procedure to a tee. I know if you don't unhook this wire timing will drift as it is then being contolled by the advance. I believe John's reputation speaks for itself.
Never could find the wire John refered to. I did a tune-up recently though and noticed on the inside of dist. cap that it was firing just at the side of the pronge (or what ever they're called, where the coil sends the spark to the plug?). I assumed it should be hitting the middle so I advanced it a little. It doesnt run bad, it just doesnt get the mpg I thought it would after rebuilding it, as I was getting 12-14 in town and 15-17 on longer trips before I had it rebuilt, so I thought I would get at least that? Maybe its still going through a brake-in period as I still only have about 7k miles on the rebuild. I appreciate your input and advice, but need to ask for a favor? Let up a little on the dumby trying to fit in even though he was giving incorrect info. Thanks again.
The number one reason for a check engine light on is a loose gas cap or a bad one.
John is correct with the obd1 however on a 97 obdII, that distributor should not be adjustable, unless someone cut the tabs off the plastic dist body. There also is not a wire to unhook on 96 or later to set timing. The hold down bolt goes thru a slot in the dist and you can only adjust the dist by about 2-3 degrees, just the slop in the hold down bolt to the slot. These are difficult to set because of that, trying to seat the dist gear and the hold down slot at the same time because the distributor will twist as the dist cam gears mesh. YOU MUST USE A SCAN TOOL TO SET TIMING ON VORTEC 5.7 Here at our repair shop we have the factory GM tech2 scan tool. You will be able to read the timing degrees with that. If the timing is off by more than 2 Degrees it will set a check engine light. Once you have the timing correct, you MUST do a procedure called (cam crank variation re-learn). You MUST DO THIS WITH A SCAN TOOL. In the function with the scan tool, with the engine running, scan tool will tell you to quickly rev the engine to 4000rpm basically flooring it in park, and immediately let the engine back down to idle, and then if completed correctly, it will display that on the scan tool. Even if your timing is correct, you must do the cam crank variation re-learn if it has not been done yet. If you ever touch the dist once the re-learn is done, you must do the re-learn again. Sometimes it takes a few times to get the variation re-learn to accept, but also be carefull because sometimes, during the relearn the rev limiter is disabled to allow the engine to rev high enough for the relearn. If you put your truck in park and are able to rev it up past 3500rpms, then your re-learn IS NOT done.
im having the same problem by the book n Chevrolet say the mark needs to hit the 8 imprint I done tried n tried nit wont it ,it will get close to it but I start the truck and automatically the check engine light comes on sayn crank n cam corillation ,,n im all out of ideas!!!!!!!!!!!!!!! what kinda scan tool are u talking about cus I have a 230.00 one n it doesn't give me that option!!
snap on .
TEch2 is the factory GM scan tool and that is what we use at our shop. That $230 is a code reader and nothing more. There is a reason that snap on, cost 2500-3000+ along with tech2 or other scan tool.
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