Vortec 454 Revs up high then dies HELP!!

[Christian Steffen]

Well what injectors would you guys most recommed? I actually tried putting the stock injectors back in and now seem to be too short. links would be appreciated

Too short? Like the rail doesn't fit correctly now?

The ones Tom posted or these:

https://www.fiveomotorsport.com/bosch-454-j-code-024-blue-knight

If you don't plan to do any more for more power?

 

[Tachyon]

This sounds like a MAF issue or even an air leak behind the MAF.
I agree with Christian Steffen's advice to swap the factory MAF back in. At least temporarily for diagnostic purposes.
If the replacement MAF doesn't have the exact same flow to resistance curve it won't work right with the ECU.
Wouldn't hurt to check your IAT too.

 

[Tom P]

This sounds like a MAF issue or even an air leak behind the MAF.
I agree with Christian Steffen's advice to swap the factory MAF back in. At least temporarily for diagnostic purposes.
If the replacement MAF doesn't have the exact same flow to resistance curve it won't work right with the ECU.
Wouldn't hurt to check your IAT too.

Could you not also diagnose by disconnecting the MAF and letting the computer run it in speed density mode? My truck will run with the MAF unplugged.

 

[Christian Steffen]

That would also work yes. I just have my doubts about this actually being a MAF issue. There is a base idle air flow table that is used for startup, and then it should be using mostly the VE table for the low rpm stuff. The stock tune doesn't go 100% MAF until its higher in the rpm range.

That said, try it for the sake of it being an easy test.

 

[Brice Edwards]

I went ahead and ordered the correct injectors. should be here Thursday.

 

[Christian Steffen]

I hope that is the fix.

 

[Tom P]

I hope that is the fix.

X2... Keep us updated. Hopefully we can get a solution posted up.

 

[Tachyon]

Could you not also diagnose by disconnecting the MAF and letting the computer run it in speed density mode? My truck will run with the MAF unplugged.

It depends on the year. My 99 will not run without the MAF signal. I'm not sure what the cut off is for this change, but I suspect it was 97.

 

[SierraDully]

You can get MAF, IAC, TPS, etc. Readings from a $30 Walmart odb2 reader. it only gives freeze frame if there's a code, but you can monitor it through "live" data (not really instant data, but better than guessing) and always take a pic or vid with your phone if need be.

I know it's not as functional as some of the newer software out there but it will do the trick on the cheap.

I always have one with me driving around and bring one if I'm looking at buying anything. Last time I brought one with me to buy, it showed a cyl-specific misfire, passlock issues, emissions failures and other stuff that changed my mind on that truck (no cel on). Well worth the $30. Saved me from a bad flip.

 

[Brice Edwards]

New injectors and a healthy application of gasket sealer seemed to do the trick. Now it's just running real rich. Thanks for the help guys