6.0 Swap now flashing check engine light

[Partsguy19]

just completed 5.3 to 6.0 swap on my 2001 Tahoe. Starts up and runs and drives great. First time on highway my check engine light started flashing for about 30 seconds and stopped. A few minutes later started doing it again and stopped. It seems to only do it on the highway.

I did put a new computer in it programmed for the 6.0. I haven't read the codes yet. Seems to run just fine. I don't feel any mis-fires. Suggestions??

 

[Tonyrodz]

Run the codes and let us know what you got. Could be anything.

 

[#1taho]

Flashing engine light normally is a emissions code. How are your cats and O2sensors.

 

[sumo]

Flashing engine light normally is a emissions code. How are your cats and O2sensors.

s

Yes it mean damage that is harmful to cats. Usually flashing means misfires

 

[Partsguy19]

Code is P0800 multi-misfire. I can clear the code and it will only come back when I get on the highway above 2000 rpm. Didn't have the problem before engine swap. Of course I put new plugs and wires on. 6.0 ran fine before I did the swap. My scan tool only gives basic info. Anyone recommend a scan tool that will give much better info maybe?

 

[#1taho]

Check conections and grounds. Recheck your work. Could be an over sight. What could did you use ?

 

[bottomline2000]

check all of the plug wires and make sure they are all securely connected. If they are and it doesn't stop the misfire, try unplugging them one at a time to see if the idle changes. the one that doesn't change your idle is your problem wire, plug and/or coil. found a bad coil that way on my son's Honda 6cyl accord..unfortunately the cat was already killed due to the cylinder dumping fuel on the cat. its a little harder on an 8cyl, but its a start and we were getting a random misfire code.

 

[Partsguy19]

Thanks for the help.. I'll keep trouble shooting and hope to figure it out. I had a "tunned" computer shipped to me for the 6.0 set-up. I might toss the old computer in and see what it does also. What gets me is it only comes on 2000 rpm or more (driving 70 on the highway). I don't "feel" a mis but...

Also, what the little black canister looking thing right behind the throttle body sticking up. Its real loose (wiggles around a lot).

 

[bottomline2000]

Vapor purge silenoid. Make sure its got an oring on the bottom where it fitsinto the intake. Mine moves around a little but it's snug.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[sumo]

That could cause it. Unmetered air. Since is not read by the maf, the ecu doesn't know how to compensate

 

[Partsguy19]

Ok.. got the truck scanned with a real scan tool. Cyls 1 and 6 are mis-firing above 2000 rpm. Don't feel it.. but the scan tool says different.

Now the other thing someone said was since I replaced the computer I have to re-time my sensors or something like that.. make any since? And how do you do that and why didn't my programmer tell me that?

Any thoughts?

 

[#1taho]

I would change the coils first and then check your wires and plugs. Check all conections also.

When I did my swap I used the 5.3 coils.

 

[iamdub]

Crankshaft position sensor (CKP) relearn? You may not actually have a misfire but if there is a discrepancy between what the CKP is saying and what the Camshaft Position Sensor is saying, the PCM could see this as a misfire. 2000 RPM may be the spot where the sensor is misreporting. Check all the basics first- solid coil connections, etc. But I think you should have a CKP re-learn and maybe an actual live tune performed. The live tune isn't really necessary if the 6.0 is stock and you're not interested in more power from it by way of tuning.

 

[bottomline2000]

What was the condition of the 6.0 when swapped? New, used, rebuilt, known history? I would start swapping plug wires, then coil packs and plugs in any order to see if you can make the misfire move. The misfire would follow the bad part obviously.

Short of loading a tune file on the pcm I didn't have to calibrate any sensors, but I did use an autocal. Your tuner should have done something similar with the 6.0 tune file.

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[Partsguy19]

The 6.0 came out of a rear ended Caddy which ran great. New plugs and wires and we did swap coils and same reading.

How do I get CKP relearn done? My PCM was programmed by Wait4Me performance and mailed to me.

 

[iamdub]

CKP relearn is a mode initiated by a scan tool or tuner. A competent mechanic shop or dealer can do it. It's a common and straightforward procedure that takes about 5 minutes.

 

[Partsguy19]

Thanks for all the help everyone. I'll get that done today and I'm sure it's going to fix the problem.

I was really impressed with the snap-on scan tool the shop used to diagnose. I can't afford something like that but does anyone recommend a "consumer grade" scan tool that will read individual cylinders and perform tasks like CKP re-learns?

 

[Partsguy19]

CKP RE-Learn fixed it!! Again.. thanks for all the help.

I would like recommendations on a scan tool that can do this in the future for me. And if possible include some links to maybe some eBay auctions or something. Thanks again !

 

[Chip18]

Thanks for all the help everyone. I'll get that done today and I'm sure it's going to fix the problem.

I was really impressed with the snap-on scan tool the shop used to diagnose. I can't afford something like that but does anyone recommend a "consumer grade" scan tool that will read individual cylinders and perform tasks like CKP re-learns?

Quickest and least expensive option is a Smart Phone a Diagnostic Port Interface and an App.


https://play.google.com/store/apps/details?id=org.prowl.torque&hl=en

http://topreviews.best/main-review/...vV9bmi5wDWeav6BW41odjbvsWh5uwihjqQhoCxdTw_wcB

They can read and clear codes you can't make "changes" to the engine parameters however ... it's not a "tuner."

If your having driveability issues and you are planning on making mods anyway ... then as has been mentioned BB appears to be the way to go.

http://www.blackbearperformance.com/faqs.asp

 

[Partsguy19]

Ive got the smart phone set up for reading codes. But i'd like to be able to see individual cylinders and such like the snap on did. Will the BB do that?