Kawabuggy

iTrader: (1)

Like the title says-we swapped in a rebuilt 5.3L engine into my sons 2002 Silverado that came factory with a 4.8L. Engine will not fire. So far we have done;
1. Compression test (185 PSI average)
2. Coil test
3. Verified crank signal using scanner and tach moves when cranking
4. Verified 12V+ getting to each fuel injector by using voltmeter
5. Fuel pressure is exactly 58
6. Engine will start if we spray starting fluid into the intake plenum but then stalls shortly when the fluid burns off.
7. NO codes. No pending codes. No history codes. NO codes in any of the different places you would normally look and expect to find one.
8. No check engine light.

I'm open to any help that you guys can offer! I have spent two days on it trying to get it running.

TXjeepTJ

iTrader: (8)

VATS disabled? Make sure all grounds are connected/super tight, make sure there are no huge vacuum ports open that would cause a 'vacuum leak'

Kawabuggy

iTrader: (1)

No programming, or tuning done at this point so no, VATS has not been disabled. I wanted to get it up and running, and all fluids topped off BEFORE my tuner came out. I did not want him to show up and the engine not start, or have some other issue that would prevent him from programming and then driving.

I have found the VATS relearn sequence on-line. I am attempting that now. The only issue is that when I turn the key to the "run" position, the security light is not illuminated. Only "battery" is lit up in the DIC (drivers information center). So, not sure it's a VATS issue, but it is possible.

I'm doing the on for 11 minutes, off for 30 seconds, cycles right now as I type this. I'm hoping that's what it turns out to be. Is there any other method to bypass VATS short term just for testing? Does VATS also disable the coils? I ask because it will run if we provide an alternate fuel source.

TXjeepTJ

iTrader: (8)

How did you check injector voltage? Did you check while cranking or key on?

Kawabuggy

iTrader: (1)

I checked the voltage side both ways. While the key was in the run position I had 12V+, and also while cranking it had 12V+. When I tested the other side for continuity to ground, we only tested it while cranking the engine and it was not pulsing regularly. It's like when you first turn the key on and crank it it will provide a ground path for the injectors but only ONE time. After that one time, you get nothing from the PCM in regards to a ground on any of the injector wires.

While cranking I can watch the ENGINE RPM screen on my Snap-On Solus and see if the engine speed so I believe the crank position sensor is working.

I'm going to perform the test again just to verify that I am giving you good data. I will test both sides of the injector wiring, both static, and while starting.

Kawabuggy

iTrader: (1)

I had a spare PCM laying around from a '00 Silverado so we tried that yesterday. It does the same thing, but now that PCM is setting codes for VATS issues. Engine starts, but then instantly dies.

I'd like to put the original PCM back in it but need to figure out the problem. I DO NOT have the original key for the vehicle as we bought it used. I do not have the GM key fob that I assume came with the vehicle. The vehicle does have an after-market alarm that we have the fob for and we are able to disarm that alarm but the non-running engine issue persists.

Do you guys think this is a VATS issue? Other than deleting through programming, is there any other way around this issue?

Kawabuggy

iTrader: (1)

Okay, I performed another test. I pulled an injector out, kept the wiring attached, and then put a compressed air gun with rubber tip against the "IN" side of the injector. I had my friend hit the key to crank it.. It fired two squirts of fuel, and then stopped pulsing.

I know FOR SURE that this is a controls issue. I have a tuner coming out on Monday to delete VATS. I'm just hoping that this is what is wrong with it. I have NO SECURITY light on at this time though so I'm just not certain what else it could be.

I've used my Snap On scanner to attempt to access the Anti-theft programming but I keep getting a "cannot establish communication with module" error message. I can go in through the BCM and see that the status of Anti-theft is 'off", and condition is "normal".

This is so frustrating. I HATE computers when they cause more problems than they solve.

Kawabuggy

iTrader: (1)

tuner is here this morning. He has disabled VATS still NO START. Ignition coils are working but the computer will not fire the injectors. I am at my wits end.

Grounds have been checked and verified that they are all in place, and we even tested them at the blue & red connectors at the PCM to be sure they were grounded throughout the harness.

We have tried a second computer and still the PCM will NOT FIRE the injectors.

Since this is a core engine that we built, if it has the 58X reluctor ring on the crank, and the trucks computer should be paired with a 24x ring, could this be the problem? The 5.3L core engine we rebuilt was supposed to be a 2000 year engine. Is there a way to verify with a scanner what reluctor ring is on the crank? Or is there any way to verify with the engine still in the vehicle?????

I don't think that is the issue as I can spray gas into the intake and it will run, but I'm grasping at straws here trying to get this figured out.

If anyone can PLEASE offer any help I would really appreciate it!!

Thanks!

Dalton Burton

Did you ever figure this out? Im not having any luck

YoungDart75

any word on the fix?

Dalton Burton

I pulled the intake on mine and cleaned the ground going to the back of the motor right above the bell housing. It will start now and run fine but its intermittent on the start with a cam sensor code

hamann

Having the same issue with the new Gen V l83 swap. will run on ether but no injector pulse, checked every forum and their solution. Harness and computer from psi. Have gone through literally everything from injectors to grounds. Weird thing is when i connect the battery the DBW TB will not respond to the pedal when key on. It will twitch and that it. code P0650. any help appreciated

Jimmy_d

iTrader: (3)

Any answers? Having exact issue with a s10 and bp automotive harness

detcop2007

Hello, I am having the exact same issue. By chance were you ever able to figure it out?

detcop2007

were you able to figure out the problem

Kawabuggy

iTrader: (1)

Since everyone is asking, and I keep getting notifications of people posting here, I thought I would finalize this post with what fixed my situation. When we pulled my sons 4.8 engine out, the truck sat for almost 2 weeks while we were building the 5.3... In that short two weeks the cat-**** gasoline that is now being sold at ALL of the gas stations dried up inside the injectors and froze them such that they were stuck internally. The pintle valves inside them were locked in place.. What I had to do was remove all injectors from the fuel rail. Set them up in a vise, fill them with brake cleaner, and then apply compressed air to the fuel inlet while applying 12V+, and a ground, to the injector to try and cycle it electrically. In this manner, I could free them all up. When I got all 8 cleaned and flowing, I put them back in and the truck started right up and I had no additional issues. We got it tuned (because the 5.3L had a bigger cam, and we went to LT headers, and better exhaust). Apparently the lack of injector pulse is a common thing if the engine does not start right away, the PCM stops pulsing the injectors... I have no other explanation as to why when we used the noid lights that we were not getting an injector pulse while cranking.. Cleaning the injectors of the cat **** gasoline solved the issue immediately. Keep in mind... it only took two weeks of sitting for all injectors to essentially freeze up. I think had I kept the fuel rail full of fresh gas instead of draining the gas from the rails that this would not have happened.

Mcwauto

I swapped 6.0 for 6.0, and I had the same issues. But it was about 2 weeks in between with the fuel rail sitting out for me too. And in the Pheonix heat, maybe the gas dried up in mine as well. Going to pull the rail tomorrow and see what happens. Been pulling my hair out for 3 days checking and rechecking. Everything is connected, will start with spray but no start otherwise. So its a fuel problem. The rail has plenty of pressure on it. Im sick of computers tho. Im selling everything I have and buying stuff made before 1980 from now on. The computer stuff is incredibly aggravating. Even aftet working on cars 35 years now, computers are still a royal PITA.