First start up, on first swap had some troubles
 

So I started my 5.3 LM7 for the first time. This is also my first LS swap. The engine fired right up, but it wasn't without some problems. It seems like it doesn't want to idle too well, but runs OK with some throttle. After a short time running it starts running roughly and wants to die. Then I can't keep it running.

It threw a code P0650, MIL Control, Circuit Malfunction. From what I can tell, it doesn't appear to have anything to do with the way the engine runs. Any thoughts are greatly appreciated.

I don't have a fuel pressure tester, but I do plan to buy one. Once I get it, I'll check to make sure I have good fuel pressure with key on and running.

I ran the issue by my harness builder who thought maybe the problem was from using Dakota Digital's BIM-01-2 OBDII interface module with my RTX gauges. Apparently there have been some poor running problems associated with using this module. I reset the code and this time didn't connect the DD BIM module and it made no difference. Still starts good, but after a short period runs rough and then dies.

Re: First start up, on first swap had some troubles
 

What aftermarket parts or changes have been made? Intake/exhaust?

It sounds like it will cold start and idle with help, then after it heats up it either moves into a different part of the idle table, maf table, or it goes into closed loop. Either way at that point the fueling is off too far and it wont run.

Re: First start up, on first swap had some troubles
 

It is a stock 5.3 with no modifications. It's using the stock intake. I'm running Speed Engineering short headers (#25-1021). I don't have exhaust system installed yet. The O2 sensors are installed in the collectors of the headers. Maybe that has something to do with it? I wouldn't think it would be OK as long as I had the O2 sensors installed?

Re: First start up, on first swap had some troubles
 

How close are the O2's to the end of the collector? Probably pretty close? Could be getting really lean readings since there's no pipe to protect them?

Re: First start up, on first swap had some troubles
 

I had the same issue until I put exhaust on my truck. It also fouled the plugs out within a few tries of getting it to stay running. I ended up putting a long piece of pipe on the end of the collector so I could get it to the exhaust shop.

Re: First start up, on first swap had some troubles
 

Hey Dan, firing it up for the first time is very exciting .
When I started my sons truck it was same as you, headers and no exhaust and it didn't run to well until I added some pipe to the collectors.
The hulk build I had the exhaust completed and it started right up with no real problems.
Try adding some exhaust pipe to the collectors and try that.

Re: First start up, on first swap had some troubles
 

I'm assuming you have the MAF hooked up? Almost sounds like when it goes into closed loop that it has issues, which leads me to believe that the above posts are correct, that it is getting skewed readings.

As far as the MIL issue, it must be wired up incorrectly. It sounds like the PCM is seeing an uncommanded ground on this circuit. Check to make sure the correct wires on the correct pins at the blue/green PCM connectors and that the check engine light is wired correctly. It won't affect the way the engine runs, it's just an issue of the check engine light functioning as it should.

Re: First start up, on first swap had some troubles
 

Good Luck! I will be ecstatic if mine even fire first try...

Re: First start up, on first swap had some troubles
 

Yes I have the MAF hooked up.

I am running Dakota Digitals BIM-01-2 OBDII interface module, which should read the check engine light signal from my PCM. I contacted DD tech support and they said maybe the open wire for "Check Engine Light" I have from my harness is causing this issue. They recommended I connect the harness check engine light wire to their main module (and not leave it open). Then go into the settings of the BIM-01-2 module and turn off the "ENG" in there. This will avoid any conflicts between the BIM module and PCM check engine signal. I guess I'll give that a try.

Re: First start up, on first swap had some troubles
 

My O2 sensors are right at the end of the collectors. It sounds like that may be the issue. I may have to buy some 2-1/2" 45-degree bends and some straight pipe to make up a temporary exhaust. Right now I'm not sure. I have a tilt trailer with a winch and I may just load it up and take it to my exhaust guy that way knowing that this could be the problem.

Re: First start up, on first swap had some troubles
 

Keep us posted after you install the exhaust. I am having similar issues as you. My truck is basically configured the same as yours.

Re: First start up, on first swap had some troubles
 

How many O2 sensors do you have in your system?

Its usual to find one before and one behind CAT on each exhaust manifold unless you have had the ECM flashed with a different tune to exclude the down stream O2 sensors....

P0650 is an error generated when the POST fails to see a complete MIL (Check Engine Light)...this too can be turned off in the ECM...

Seeing you have an open MIL wire in your system, the P0650 makes sense, but it would not cause the stalling issue.

:chevy::chevy::chevy:

Re: First start up, on first swap had some troubles
 

I have two O2 sensors in my system. I'm assuming the harness builder flashed the PCM to exclude the downstream sensors... However, you know what happens when you assume. Maybe I should check with them.

Based on the installation of the Dakota Digital BIM-01-2module, the check engine light should be controlled through that. Even Dakota Digital thought it was odd that I would have this error code.

Re: First start up, on first swap had some troubles
 

I had a similar issue on my truck - though it did keep idling, once it hit warm idle, it idled very rough and hunted, sometimes coming close to stalling then suddenly idling very high.

My issue was missing a cap on a vacuum port I wasn't using on the intake. The large 3/8" port on the top of the intake. I also had similar issues with failed (or failing) O2 sensors - though mine did eventually trip a code, it doesnt sound like yours is running long enough to get there.

I also have a P0650 but its because I don't have my MIL wired in yet. As others have said, it does not at all impact the truck at all and drivability is good now that I've got two new O2 sensors and the vacuum ports plugged.

Re: First start up, on first swap had some troubles
 

I contacted Dakota Digital and they told me how to get into the BIM-01-2 and toggle off the ability for it to read the check engine light. I connected the open check engine light wire to my DD main module. I haven't started the engine yet, but the check engine light appears on the DD gauges now. Hopefully it shuts off when the engine is running. :lol:

I hate to keep starting the engine because as it runs for a bit, it starts to run rough. I looked into getting a couple of 2-1/2" 45-degree elbows and some straight pipe or adapter fittings to make up a temporary exhaust, but the elbows alone will cost $50 for the pair. I don't want to spend extra money just for an experiment and to cut it off and throw it away later. I'm just going to wait until I get the exhaust system installed to see what happens. Fortunately I have a tilt trailer and a winch, so I should be able to get it to my exhaust fabricator. I'm planning to get this to him in the next week. I'll update this thread once I know more. Thanks for all your input.

Re: First start up, on first swap had some troubles
 

I didn't forget to update this thread. It's just that I ran into a major problem with my build. I was getting ready to send out the truck for exhaust when I noticed a crack in the housing of my 4L60E. I had to remove it and send it back for rebuilding. This was a major set back.

Re: First start up, on first swap had some troubles
 

Damn, so sorry to hear about this setback! I know something like this can be soul crushing and devastating to your motivation. Hang in there! I have never seen a tranny cracked in that location before, what do you think caused this?

Re: First start up, on first swap had some troubles
 

That is a real bummer. Can they weld it or is it new/used case time? Must taken a pretty good hit to crack case.

Re: First start up, on first swap had some troubles
 

Sorry to hear that. My 700r4 had a huge crack in the bellhousing when I got it at the junk yard for $50. I was going to rebuild it myself so I gutted it and had it welded. It has held up through some serious abuse for over 20 years now. I also totaled the truck once and it is still alive and kicking.

Re: First start up, on first swap had some troubles
 

The transmission was rebuilt by Bowtie Overdrives. They are awesome people to work with. Nikki was very helpful and went out of her way to make this right. They paid to have the transmission picked up, rebuilt, and returned to me. Round trip shipping could not have be cheap from Buffalo, NY to California and back. They rebuilt it using a different transmission housing. They performed the turnaround work almost instantly once it arrived in their shop. It took longer for shipping then it did for the re-rebuild. Shipping was about 8-days each way. I have no idea what could have caused this crack, and neither did they.

Here is the timeline:

1. I pulled the transmission on Jun-10.
2. Bowtie Overdrives arranged for pickup on Jun-11.
3. The transmission arrived back at their shop on Jun-18.
4. Rebuild was completed and shipped out on Jun-22.
5. It arrived back at my place on Jun-30.
6. I installed it on Jul-1 and had everything buttoned up by Jul-4 weekend.
7. On Jul-7 I delivered the truck to my fabricator for custom exhaust.
8. I should have the truck back around Jul-17th.

Re: First start up, on first swap had some troubles
 

4 days to vroom vroom!!! lol What mufflers are you installing??
Post a video when you can!!!

Re: First start up, on first swap had some troubles
 

I got a great deal on four Corsa Db mufflers from a dealer friend of mine. I plan to use two on this truck and two on my 71 swb. They better sound good lol. I don't know how to post videos, so any help is appreciated.

Re: First start up, on first swap had some troubles
 

My exhaust fabricator just informed me that they sent the wrong material. Was supposed to be 304 polished SS, but they sent him aluminized steel. Looks like another minor setback. Ugh!

Re: First start up, on first swap had some troubles
 

If you have a YouTube channel you can post a link. I hope you can post as I never heard of those mufflers before.

Re: First start up, on first swap had some troubles
 

Well I got my truck back from my exhaust fabricator and you guys were right. Not having any pipe downstream of the O2 sensors definitely caused the poor running problem. So now that the exhaust is completed the truck runs much better. As I mentioned in an earlier post, it would start fine and then seem to run rich and the want to stall out. The problem was the O2 sensors being so close to the ends of the collectors with no exhaust pipes downstream. Now that there is a complete system, it runs great!