Setting distributor timing without $$$$ scan tool? 1999 5.7 Suburban

[redfishsc]

I'm in the process of swapping the intake gaskets on my Sub. I know better than to just yank the distributor out without marking it's position, but of course, I pulled it out just as I realized that I hadn't marked a damn thing. Either way, pretty stupid move. Morning coffee hadn't kicked in at that point.

Anyhow, while the JB weld is curing up in the one pit in my intake surface, I pulled all the plugs and rotated the engine to #1 TDC and know how to align the rotor to the right position.

My question is this. How driveable is this rough setying going to be, in order to get to a shop that can use a scan tool to read the cam retard ?

Second, are there any scan tools that can read this that are reasonable price, even Android or iPhone compatible with a Bluetooth OBD2 scanner? I have a Bluetooth scanner and Torque Pro, but cam retard is not available on it.

 

[kennythewelder]

I have had my distributor in and out of my truck about 10 or 12 times. If #1 piston is on TDC on the compression stroke, and the rotor is pointing to #1 spark plug wire, once the distributor is stabbed and seated all the way down, you can clamp it in place. The ECM will make all the final adjustments. There is no need to time the engine with a timing light or a scan tool. I always put the rotor so it is just making contact on #1 plug wire prong on the cap.

 

[redfishsc]

Thanks Kenny, that's encouraging. When you say you alight the rotor so that it is "just making contact", do you mean that the rotors electrode is simply centered on the #1 plug electrode?


Also, does it matter what angle the distributor is sitting before tightening the dist nut? I ask this because the videos I've seen of people tweaking the cam retard showed them running the engine at 1000rpm and gently twisting the whole distributor a bit until the scan tool reads a -2 to +2 cam retard.

I love this truck but am learning that the Vortec 5.7 is an odd duck.

 

[kennythewelder]

If you center the rotor on the #1 plug electrode as you said, this would be fine. The ECM will make timing adjustments as it needs to. As for the distributor nut, once the rotor is pointing to #1, you can tighten the nut down. There is nothing else to set, or do, because the ECM will do it for you. As long as the truck starts, and runs good, you are good to go. The Vortec 5.7L (350s) are the last of the original Chevy generation 1 small block engines. These engines, started there life in the 1950s with the first ones being a 283 CI engine, The same basic engine block. Gas millage is what killed the 5.7L, but the 4.3L is a 6 cylinder version of the 5.7L or 350, and although the 4.3L has been through many changes, it is still made today.

 

[east302]

Second, are there any scan tools that can read this that are reasonable price, even Android or iPhone compatible with a Bluetooth OBD2 scanner? I have a Bluetooth scanner and Torque Pro, but cam retard is not available on it.

I used the DashCommand app for Android with a BAFX 34t5 Bluetooth OBDii connector to read the CMP retard on my 98 350. The app is $10 and the GM PIDs another $10 through the app. Connector was around $30 on Amazon.

You can also use that connector with Car Gauge Pro at a similar price.

In theory, the DashCommand works on iOS devices using the Palmer Performance OBD connector, but I had trouble getting mine to work. A cheap $40 android Bluetooth tablet from Walmart worked fine.

http://www.gmt400.com/threads/car-gauge-pro-can-read-cmp.35275/


Sent from my iPhone using Tapatalk

 

[jvthundercat]

@kennythewelder you must have a one off Vortec. The computer does not "adjust" to it. You have to scan it as there is not even a timing correlation to it.
0 to +2 and that is it. We just did mine yesterday at the dealer, and at +3 it was throwing the code. Have the Distributor all the way against the plenum just to keep it at+2.

 

[kennythewelder]

@kennythewelder you must have a one off Vortec. The computer does not "adjust" to it. You have to scan it as there is not even a timing correlation to it.
0 to +2 and that is it. We just did mine yesterday at the dealer, and at +3 it was throwing the code. Have the Distributor all the way against the plenum just to keep it at+2.

I have had my distributor out 10 or 12 times. Every time, I put my engine on TDC on compression stroke. When I stabed the distributor back in place, I always make sure the rotor is pointing to #1 on the cap. I have never had an issue. No CELs. The truck runs good. Also if the ECM doesn't adjust timing, then tell me why when you do an ECM tune, they throw more advance at the timing. Are you saying that the timing at idel has to be adjusted, and the ECM has nothing to do with this ? If so then all you need is a timing light. I know what I have done, and what has worked for me. I have never had to have anything scand to set the timing at idle, but that's just what I have done some 10 to 12 times.

 

[kennythewelder]

The OP pulled his distributor because of a leaking intake gasket. There was no issues with his distributor to start with,soas long as it is stabbed properly there should not be any reason to need to use a scan tool. Allthe times I have had mine out, I nevernees to use a scan tool to get thw truck to run rite but like the OP I was using a good distributor or the OE distributor.

 

[Dr.Zoom]

I watched a YouTube video with a guy that cut inspection holes in a cap to use to set the distributor. When the spark was vertical it was within spec and didn't throw the code. When the distributor was a few degrees off, the code was set and check engine light would come on (the spark could be seen to be at an angle).

I'm thinking you may be wrong kenny.

I'd think you could line it up spot on 10+ times doing it the way you did.

I'd like to know what's right, I've read that the ecm would learn and I've read it has to be set. I've figured it had to be set and the learning may be some other vehicle that someone has introduced into gmt400 mythology.

 

[kennythewelder]

Like I said, I know what I did and it worked for me, 10 to 12 times. The reason I had the distributor out so many times varies from intake maniflod leak to broken ears on the plasytc distributor housing to swaping to a billet distributor. Like I keep saying , that is what I did,.and it worked for me.