5.3 engine swap won’t rev past 1500 RPM

[MotorheadDT]

Did a 5.3 Motor swap, won’t rev up past 1500rpm, Idles like shit and when MAF unplugged It dies.

just replace fuel pump too. Any ideas ?

 

[Rick Flair]

What codes is it throwing? Sounds like it’s stuck in limp mode.

 

[MotorheadDT]

It only has a MAP code, and the signal on the MAP is within spec. What is the limp mode? how would I know it’s in it? thanks

 

[MotorheadDT]

What codes is it throwing? Sounds like it’s stuck in limp mode.

It only has a MAP code, and the signal on the MAP is within spec. What is the limp mode? how would I know it’s in it? thanks

 

[jordankier]

Are you running a factory harness and ecu? Oem map sensor?

 

[Rick Flair]

It only has a MAP code, and the signal on the MAP is within spec. What is the limp mode? how would I know it’s in it? thanks

Odd, there is something else going on. Maybe a shorter wire. Limp mode all modern, CPU controlled engines go into to protect themselves when it senses something out of parameter so it shuts things down to keep you from melting things down.

Sorry, a full engine swap is complicated and if you used a companies harness, call them. Otherwise, nobody can know what you have going on.

 

[MotorheadDT]

So just had a buddy check it, limp mode is off. Working on figuring it out now. Just stumped.

 

[Jerry Bransford]

Sure sounds like a timing issue. I know nothing about the 5.3, could there be a timing issue between the crankshaft and camshaft position sensors like can happen with the 4.0L?

 

[Bill M.]

Sure sounds like a timing issue. I know nothing about the 5.3, could there be a timing issue between the crankshaft and camshaft position sensors like can happen with the 4.0L?

Jerry's advice is where I would start, first make sure your are getting a good signal form the CPS and CKP and then do a relearn.