Engine won't start

I just put my engine back in after an overhaul and I can't get it to start unless I have something plugged into the OBD2 port. Just the cable no scan tool.

 

Without taking a look at diagrams, I’d suspect a ground issue possibly.
Most OBDII scanners bridge the grounds. So, possibly you are missing a ground.
That is , is as you say, it starts only when the scanner is plugged in? Which is very odd.

 

I added a new fresh ground from the block to the chassis and it didn't make any difference. I do need to go back through and make sure I have good clean grounds on the factory spots. I had the scan tool plugged in and I didn't have any codes and as soon as I unplugged it the truck would die. I tried just plugging in the cable without the scanner and it's started fine but as soon as disconnect the cable it dies. I think i made a gremlin

 

I don’t have the location for the EB ground on a 1999.
But the 2000 Manual shows it next to the throttle body.

You can see the 2 grounds in on the DLC (OBDII port) in the diagram below.
Pins 4 and 5. I’d check them for ground.

 

Best picture I can find, gona be a bunch of brown wires going to one or more eyelets most likely.

 

Here are a couple of ground locations circled in blue. Just did a head swap on a 2.7. Hope the best for ya.

 

Yea bottom picture is EF, I'm pretty sure I see EB in the top picture (circled in red below).

 

Thanks for helping me out guys.
I was hoping one of you had better material. 99 and 00’ diagrams are hard to come by.

My 99 diagram also showed EB2, but not EB?

 

The truck I worked on was a 2001.

The OP claims base model. Was there a base model that came with 4x4? Thought all 4x4 were 6 lug (prerunner/sr5/ etc).

 

Yes Mitchell info doesn't have much electrical info either for a 99.

He probably meant base as in no options (crank windows, manual locks, etc).

 

I don’t know for sure.
But depending on what Toyota dealers website I’m on, I have to click “Base” to get my truck.
Your options are Base, PreRunner, and xRunner. But I’m a 2nd Gen. So that information might not be relevant to the 1st Gen?

 

Did you document anything along the way? Pictures of wire connections and where they were for reference? I also suspect a compromised ground. The problem lies where the power dies. If I were you I would go over everything you touched that you still have reasonable access to.

 

I did document a little but its very evident to me now not enough. I do have a subscription to the diy alldata website but I haven't found anything yet that has gotten in the right direction. I think the ground in the photo with the power steering pump i might have missed. I need to check that one after work. I want to say thank you for all the help!

 

You guys nailed it, it was the ground in the intake right behind the power steering. Got it all buttoned up and it works perfect. Thank you guys for the help.

 

Nice

Thanks for the update

 

Sweet! Thanks for reporting back with your success.