I need a scanner to set timing

VegasJen · February 24, 2018

Hey all.

I searched "Vortec timing" but none of the results matched my needs.

This is actually my '99 Suburban, but it has the old 5.7 Vortec. Anyway, when I got it, it didn't run. Found the gears on the distributor were worn off so the engine came out and a complete tear down/overhaul. It's a budget build "going down the road" motor but I did it as right as my budget allowed. I rebuilt everything, stabbed the motor back in and got it running (because, ya, I can do that) but I have the dreaded P1345 fault. It actually runs pretty well. Idle sucks but above idle it pulls strong and smooth. I can clear the P1345 fault and it will stay clear as long as I'm driving the truck, but comes back on the next restart. This is the first Vortec (but not the first SBC) I've built. I had no experience or idea about the distributor on these. So I need a scanner or some kind of program that will allow me to set the ignition timing to 0* +/-2*. I already have a pretty decent OBD2 scanner so this timing will be just about the only thing I need it for. Kind of like to keep it budget friendly.

Any recommendations?

barry G · February 25, 2018

I had same question, I got gadgets and blue tooth, lap top, scanners..

no retard cam timing.

this one is on ebay.. it is just one of many a guru can save money with.

crp 123 scanner

Sigma.40 · February 25, 2018

I have no experience with any scanners other than Snap On. I have a Modis Edge that works wonderfully but was highly expensive. You might be able to find an original Modis for just a few hundred dollars on EBay. I've seen them as low as $100. Just make sure it comes with the cords and keys. They can't be updated anymore and theyre a Littleton slow compared to a newer scanner but it would serve your needs very well.

east3021 · February 27, 2018

DashCommand and CarGaugePro are two android apps that can read the CMP retard. I think they’re around $20 or so. You’ll need a Bluetooth OBD adapter (maybe $40) and a cheap android tablet if you don’t have an android phone. I use a $30 Walmart RCA tablet.

Here’s a link...

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

The app (or scanner) doesn’t actually set the offset. You do that by loosening the distributor hold down screw and turning (rotating) the distributor until the offset is correct as read by the scanner. RPM has to be around 1100-rpm. To compensate for a positive reading, rotate clockwise. Counterclockwise for too negative of a reading. It doesn’t take much, you’ll eventually just be barely bumping it to get it to specification.

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Logan Lanfear · February 27, 2018

1 hour ago, east3021 said:

DashCommand and CarGaugePro are two android apps that can read the CMP retard. I think they’re around $20 or so. You’ll need a Bluetooth OBD adapter (maybe $40) and a cheap android tablet if you don’t have an android phone. I use a $30 Walmart RCA tablet.

Here’s a link...

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

The app (or scanner) doesn’t actually set the offset. You do that by loosening the distributor hold down screw and turning (rotating) the distributor until the offset is correct as read by the scanner. RPM has to be around 1100-rpm. To compensate for a positive reading, rotate clockwise. Counterclockwise for too negative of a reading. It doesn’t take much, you’ll eventually just be barely bumping it to get it to specification.

Sent from my iPhone using Tapatalk

You cant rotate the distributor at all on these trucks. Once it goes down into the intake, theres only one way it fits. If its off, then you have to be off a tooth on the gear or on the computer. You need a proper scanner to change the timing.

east3021 · February 27, 2018

I think that that I’ve heard of the 4.3L having a fixed hold down clamp preventing rotation (I’m not sure as I’ve never had one) but on the 350 vortec you stab it and then have to rotate the upper housing to get the CMP offset within spec before tightening down the hold down clamp.

You won’t be physically lifting up and going from tooth to tooth, it’s just the cap and rotor housing that you are turning.

Here’s the diagnostic for P1345 (for a 1998 K1500) in case it is something else causing the code.

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Logan Lanfear · February 28, 2018

20 minutes ago, east3021 said:

I think that that I’ve heard of the 4.3L having a fixed hold down clamp preventing rotation (I’m not sure as I’ve never had one) but on the 350 vortec you stab it and then have to rotate the upper housing to get the CMP offset within spec before tightening down the hold down clamp.

You won’t be physically lifting up and going from tooth to tooth, it’s just the cap and rotor housing that you are turning.

Here’s the diagnostic for P1345 (for a 1998 K1500) in case it is something else causing the code.

Sent from my iPhone using Tapatalk

So what you posted here says that if you can spin your distributer when its in the block something is wrong. I recently "timed" my truck when I did the intake manifold gasket. You definitely cant move the distributor more than 1 degrees when its in the block.

VegasJen · March 1, 2018

That's odd. I easily have 20* of rotation in the distributor. When I originally dropped the distributor, I was a tooth off. Barely got it running but the distributor was hitting the manifold. Redropped one tooth over and got it running pretty well. Idle is a little low but off idle power is good. It just constantly throws that P1345 code.

Not looking forward to needing an app. I can rebuild a SBC in my sleep but I've managed to make it to 2018 without ever downloading an app. Don't even know where to go or what to do. I am truly a techno-idiot.

So do I need to get a cable to go from the OBD port to my phone? How does that work?

east3021 · March 1, 2018

The connector uses Bluetooth to communicate with the phone/tablet. I used BAFX model 34t5 on my two 98 models. It came with instructions for setup.

The link that I posted showed the steps for getting the CMP offset reading in CarGaugePro. You’ll either watch the reading and rotate the distributor while the engine is running or take the reading, stop the engine, adjust the distributor and repeat.

Here a YouTube video on it using a scanner, same principle with the app...

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VegasJen · March 5, 2018

Wow. You really overestimate my technical savvy. Don't get me wrong, I can spin a wrench with anybody. But you start talking about blue tooth and blue ray and blue sky or whatever and I'm lost. Seriously, I have no idea what you're talking about.

But that's largely irrelevant at this point. I was feeling confident in my work so Friday I decided to trust it enough to take the truck to a dental appointment. Had to cancel the appointment.

First strike against the truck.

septaric · June 28, 2019

Please disregard.

Edited June 29, 2019 by septaric

TW97C1500 · June 29, 2019

On 3/5/2018 at 10:42 AM, VegasJen said:

Wow. You really overestimate my technical savvy. Don't get me wrong, I can spin a wrench with anybody. But you start talking about blue tooth and blue ray and blue sky or whatever and I'm lost. Seriously, I have no idea what you're talking about.

But that's largely irrelevant at this point. I was feeling confident in my work so Friday I decided to trust it enough to take the truck to a dental appointment. Had to cancel the appointment.

First strike against the truck.

You know where you plug in a code scanner beneath the dash? What he's talking about is they make a little doohickey that plugs in there and communicates with a smartphone or tablet or laptop computer by Bluetooth (radio broadcasting / "wireless").

I've been told by a couple of mechanics I thought knew what they were talking about that you don't / can't adjust the timing on the 96-98 (holdover 99) Vortec engines. The distributor goes in and is either right or wrong. The computer fine tunes timing. Of course, now people post these Youtube videos of people adjusting it, so I guess those yahoos were wrong.

edit: I was also told by one of both of those guys that the distributor has a little bump on the bottom of the mounting flange that goes into a hole in the block and that's where it is supposed to be. I have 2 distributors from bad motors I've bought and neither has a bump there. I don't recall if the blocks have a hole.

Pretty much, the plug wire ports on the cap need to be pointing straight out to the sides. This assumes the cam is aligned the same as a factory original.

Edited June 29, 2019 by TW97C1500
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TW97C1500 · June 29, 2019

I watched that video and it seems that maybe if you want to be precise, what they are doing is "properly positioning the distributor", not "adjusting the timing" like you, I, and other pre-computer people think of it. So I say on yours, check that the plug wire ports on the cap are pointing straight out to the sides, then see what it does. (disclaimer about cam alignment applies)

I guess in computer controlled engine lingo, the computer does vary the timing up and down, so when you look for "setting the timing" or "adjusting the timing" you get all sorts of answers saying you can't do it.

wreckdiver230 · June 30, 2019

check out south main auto on youtube , he replaced a distributor on a suburban a while back , maybe it can help

VegasJen · June 19, 2021

Holy crap! I did a search on how to set the timing and didn't realize I posted a thread about this three years ago!

Anyway, I still have the truck. It still runs, but I have never been able to set the timing correctly. Fast forward to this week and my uncle has loaned me his Tech 2 so I can finally set the timing properly. I've done some research and everything says I need to find the reading for the Camshaft ****** Offset. I have gone through almost every parameter I can find in the Tech 2 but I don't see anything about the camshaft offset. I figure I have to be missing it somewhere. Can anybody point me in the right direction?