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Username Post: L31 Vortec Timing        (Topic#350605)
Doomsayer88 
Poster
Posts: 13

Loc: Colorado
Reg: 04-11-18
04-13-18 06:16 AM - Post#2730847    

Hi Thanks for reading, first time blogger!

Im rebuilding an old 97 Tahoe that I picked up on craigslist. New crate L31 and new tranny with paperwork on motor (30,000 miles or less) Pro comp 4x4 stuff everywhere I paid $3000 and im having some issues as far as the timing when I changed my distributor to an aftermarket billet. (kinda tight on funds...my wifes going to deliver my son in a few weeks.) Im assuming the timing chain and cam are ok due to I have the paperwork on the motor.
HERES THE ISSUE:
Im at TDC and the distributor is pointing roughly towards cylinder #1. Turns but Still no fire. No backfire either, which made me think its a fuel issue as well. So i replaced the fuel pump and every fuel line. I tested the connector on the old pump and 2 of the prongs were dead soldiers so I replace that, also a few of the wires in the pump connector were burnt. Looks like a small electrical fire/heat happened. All the wiring is new now

Also Replaced all vacuum lines out of boredom waiting for online parts.

Went through the electrical system, ohms tested with a fluke and everything seems to have a good connection since all that aftermarket crap is gone.

The Tahoe also had 3 different old 4x4 electric fuse in line type things that went to no where. I took those out to decrease as much draw as I could. All three wire groups were just hacked off one side and attached to the battery on the other.

Waiting for a ride to go get some gas and a fuel filter but other than that is should start right?? If not what did I miss?

-Christian
Thanks!



Edited by Doomsayer88 on 04-13-18 06:42 AM. Reason for edit: No reason given.

 
454cid 
Valued Contributor
Posts: 3026

Age: 45
Loc: West Michigan
Reg: 02-18-12
04-13-18 12:32 PM - Post#2730871    
    In response to Doomsayer88

The Vortec distributor isn't like other distributors. Look at the cap. The contacts don't go straight through the top of the cap.

You actually need to put the rotor so that it's pointing to an "8" on the distributor body (or whatever mark the after market company used). Assuming cylinder #1 is at TDC when you do that, it should be good enough to start. Then you need to adjust the distributor, at at least 1000rpm, while watching cam position retard with a scanner. Have someone shut the engine off, when you get it where you want it, because if you let go it will travel on you. Then tighten the bolt down all the way, start it up, and check it again to verify you got it. You want it between -2 and 2.

You're not actually adjusting the timing. The computer takes care of that.

99 K3500 RCLB


 
Shepherd 
Frequent Contributor
Posts: 1550

Loc: Lake George, NY
Reg: 11-11-15
04-13-18 12:34 PM - Post#2730872    
    In response to Doomsayer88

Welcome to CT. Plenty of sharp folks here. Got spark at the plugs? Check fuel pressure at the port? You switched the accessories from your old engine this was just a long block?



 
Doomsayer88 
Poster
Posts: 13

Loc: Colorado
Reg: 04-11-18
09-14-18 08:56 AM - Post#2746142    
    In response to Shepherd

Thank you for the responses and yes there are some very sharp folks on here. I couldn't have gotten my truck running without them. Also I feel I have a whole new understanding of timing after that experience. Its taken me a while to get back on here because this construction season has been more than crazy. I'm having another issue with the truck now too. I was going down the highway at about 80 mph and the motor stalled. Just like that. Running fine (occasional rough idle but other than that fine) then stall. The fuel tank was empty when i tapped on it on the side of the highway and crunched in from vacuum i'm guessing. Called AAA and got a tow to a gas station, put $25 worth of premium in tried to start it with no avail. Checked the fuel pressure and it seemed weak or non existent at best. At this point im assuming it is the cheap ebay fuel pump I put in it (my wife was overdue with my son at the time so I was working with what i had.) this fuel issue ive been dealing with for to long. ive replaced all the plastic stuff on the lines with AN fittings.
What throws my theory off a little is I scanned the codes using ScanXL Pro and got 2 codes.
P0140-HO2s Circuit Insufficient Activity Bank 1 Sensor 2.
That one doesnt surprise me because my entire exhaust is one big leak. The next one was more concerning
P1345-Crankshaft Position (CKP) Camshaft Position (CMP) Correlation
Pulled the Crankshaft position censor and it does look like its the original part. The truck has a crate motor with 40,000 roughly on it. But would this cause the engine to stall on a highway and not start again? Or maybe the combination of that and the cheap fuel pump? Possibly running a cheap fuel pump dry in the tank?






 
Guy named Guy 
Poster
Posts: 36
Guy named Guy
Age: 27
Loc: Grand Prairie, TX
Reg: 07-31-13
10-10-18 06:04 AM - Post#2748326    
    In response to Doomsayer88

If you are getting P1345 it means that the cam/crank sensor correlation is off.
Either the cam sensor or crank sensor or both could be faulty or if you have the distributor advanced more than 2 degrees or retarded more than 2 degrees. These vortecs need to be around 0 to function correctly, not like TBI's that you can advance up to 12 degrees if you like.

What I do when installing a new distributor in a Vortec is eye it getting it as close as possible to the original distributor position and I usually get it spot on, but on the occasion that I don't and I get the P1345, I advance the timing a little (and I do meant a little, not even 1/8 inch), grab my OBD2 scanner and clear the code with the engine running. If it comes back, Advance it a little more - clear the code, if it comes back then just a little more. If it still comes back then go the other way retarding it. just keep playing with it moving it a little and clearing the code you'll find the sweet spot.
I know it's a little shadetree but I've done this several times and it always works.
The distributor itself could be the problem as well.




Edited by Guy named Guy on 10-10-18 06:10 AM. Reason for edit: No reason given.

 
454cid 
Valued Contributor
Posts: 3026

Age: 45
Loc: West Michigan
Reg: 02-18-12
10-10-18 02:17 PM - Post#2748354    
    In response to Doomsayer88

  • Doomsayer88 Said:
Possibly running a cheap fuel pump dry in the tank?



I know this is late, so maybe it's taken care of already?

Sounds like a good theory. Try whacking the bottom of the tank with a rubber hammer right where the filler neck is, and try starting it. If it still doesn't start check fuel pressure.

The CMP retard doesn't need to be in spec to run, and I don't think it's common for the distributor to cause a truck to die...usually more of a no start issue.


99 K3500 RCLB


 
Old Buzzard 
Contributor
Posts: 412

Loc: Madison, GA.
Reg: 10-13-07
10-12-18 05:26 AM - Post#2748499    
    In response to 454cid

"The fuel tank was empty when i tapped on it on the side of the highway and crunched in from vacuum i'm guessing."
If it was crushed by vac, the vent is plugged off.
Pulling a vac at the pump inlet will cause the fuel to boil, cavitating the pump. This will kill it.

Chuck
Hotrodding and dragracing since 1955..
Injector inspector, and certifiable EFI nut.
Back to 55, again, for the 6th time.


 
someotherguy 
Senior Moderator
Posts: 28799
someotherguy
Age: 48
Loc: Texas
Reg: 08-01-03
10-12-18 03:15 PM - Post#2748530    
    In response to Old Buzzard

Fuel cap may be bad. They're not supposed to allow vapor to escape, but they should allow air in as needed.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
454cid 
Valued Contributor
Posts: 3026

Age: 45
Loc: West Michigan
Reg: 02-18-12
10-12-18 03:29 PM - Post#2748532    
    In response to someotherguy

  • someotherguy Said:
Fuel cap may be bad. They're not supposed to allow vapor to escape, but they should allow air in as needed.

Richard



Hmm, this has me wondering if this has something to do why mine died... I kept hearing the tank oil canning periodically. I replaced the cap. I wonder if the vent line or charcoal canister is bad. I haven't noticed if the tank is still oil canning or not with the new pump.


99 K3500 RCLB


Edited by 454cid on 10-12-18 03:31 PM. Reason for edit: No reason given.

 
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