Christopherson

Hello everyone,

This is my second LS swap, but I am having some problems. I was hoping to get some suggestions of what I can try next.

The engine is a 6.0l from a 2011 GMC Savana w/ 6L90E. It has a E38 PCM which was programmed by lt1swap.com.

The engine is to the point where it turns over, fires doesn't get to idle speed before it dies.

Currently I have all the swap relays "jumped" to always on whether cranking or not.

- I have Minimum of 58psi at the rails while cranking.

- Engine seems to keep running when firing small amounts of ether into the engine.

- Noid light flashes while engine is dying

- Have disconnected pedal & MAF with no change

- I cannot find any vacuum leaks

- I intermittently get about 4 codes related to the pedal:

- P0122 Throttle/pedal Position Sensor A Circuit LOW input
- P0123 Throttle/pedal Position Sensor A Circuit High input
- P0223 Throttle/pedal Position Sensor B Circuit High input
- P2122 Throttle/pedal Position Sensor/switch D circuit LOW input

I have confirmed in a 2012 van w/6.0l that it starts fine without the pedal connected.

Does anyone have any idea where I should start diagnosing this thing?

Thank you
Chris

psiconversion

iTrader: (5)

What is the part # of the pedal you are using ?

JoeNova

I don't know how the newer ECUs are, but the older ones would kill the engine if they detected any issues with the DBW.

Make sure that the throttle is getting power/ground.

Christopherson

Hello,

The pedal came out of the donor vehicle, part numbers:

6PV 933 902-26
20827131

3/19/10 * hard to tell if the 19 was actually 19

As far as the pedal goes, if it was wired wrong I think the vehicle would still start as a 2012 van with the same engine combo started no problem with it disconnected.

Thank you

JoeNova

And the engines will typically start without a MAF, but won't start with a bad one.

psiconversion

iTrader: (5)

Here is how your pedal should be wired, hope this helps.
pos. 1 tan
pos. 2 white/blk
pos. 3 dark blue
pos. 4 brown
pos. 5 purple
pos. 6 light blue

Azryael

Hopefully you get this resolved! Mind throwing up some photos of this beast?

Christopherson

Thank you for the replies!

I will try and get some pics up tomorrow!

I think I may have some stuck injectors. It wants to fire, but doesn't seem all cylinders are. I checked the headers for heat and found only some cylinders were warm. I pulled 2 plugs to find one covered in fuel and one almost dry. I will be investigating tomorrow some more!

Cheers

Lsxford

iTrader: (6)

Ive seen this issue a few times with engines that have sat for a while, its like the injector stick shut. Pull the rail up and spin it over to see if theyre all spraying, id bet the majority are not.

If that is the issue ive seen people clean them kinda ghetto style. Im sure an internet search would show how to do that. The best way, again if this is your problem, is to either get different injectors or have them professionally cleaned and flowed.

I have to ask im sorry, why the hell are you building an ambulance? Lol business related is my guess. It is def unique, im ready for pics,

Edit- I have also seen first hand a vehicle set some of those codes when the engine would not start. Its usually from folks pushing the gas pedal up and down trying to get it to start, this confuses the pcm and sets the code. Then again there really could be a problem somewhere. My $.02

Christopherson

Hi Guys!

So after a long day I am almost no closer to getting it running.

- Today I pulled the injectors and cycled them all with a 9v battery and blew compressed air through them.

- Swapped pedal with known good unit
-----Confirmed continuity at each pin between pedal & ECM


- Swapped MAF with known good unit

None of these have changed anything. I also picked up a Autel 802 scanner. Noticed the IAT is -40 degrees F. So I used a jumper between the 2 wires for the IAT sensor built into the MAF and it spiked to 300 degrees, telling me its at least connected to the computer.

Does anyone have any ideas what to look for on the scanner? I am still getting the same codes on the scanner even with swapping pedals & confirming continuity.


I have also swapped the throttle body from a 2009 5.3l with no changes.

My throttle position sensor stays at 31% when not running. Does that matter?


Sorry for the long text and no pictures yet! It is such a mess from tearing into it!

Cheers
Chris

Christopherson

The ambulance will be converted into a RV type vehicle! It came with a 6.0l Powerstroke that put a rod through the block. So we got it super cheap! We also already had the 6.0l chevy sitting in the shop. One thing led to another.....

Christopherson

I checked continuity to the throttle body from the PCM, everything is connected as is. Tested the throttle body, and it seems fine.

Strangely I tried to start the engine with out the throttle body and it seems like it ran similar to with it installed. It also did not throw any additional codes to the ones it has been reporting from the start:

Codes:

- P0122 Throttle/pedal Position Sensor A Circuit LOW input
- P0123 Throttle/pedal Position Sensor A Circuit High input
- P0223 Throttle/pedal Position Sensor B Circuit High input
- P2122 Throttle/pedal Position Sensor/switch D circuit LOW input

Christopherson

I blocked the throttle body with a piece of aluminum sheet metal and it fired right up. I cannot for the life of me figure where the vacuum leak would be from?

Any suggestions?

Project GatTagO

iTrader: (7)

Did you swap intakes or anything like that? Are all the ports plugged up?

Andrew

Lsxford

iTrader: (6)

Maybe the big plug on back of intake?
its where the brake booster hooks on some applications, the trucks with hydroboost has a plug here. Top back of intake, its like a quick connect air line style

Christopherson

As far as I can tell there is only 1 port, and I have plugged it. The port on the back of the manifold is plugged, it came from a van with hydroboost. It is the original manifold. I guess Ill have to get the ether out? Maybe the manifold is cracked. When I received the engine it looked like it had fallen on its side as a couple coils were broken along with the valve cover bent...

Lsxford

iTrader: (6)

If itll run with the TB blocked you could spray it with something flammable and see if it changes sounds. Its alot easier to monitor the O2 sensors and watch for them to change while you spray it.

For it to run with the TB blocked , it must have a big *** leak. Thats pretty weird, cant say ive ever seen that before. Im still wondering about the TB, if everything is good it shouldnt set a code. And it sounds like when you clear the codes they come right back which is a hard fault.