305 TBI to 454 TBI question?

[XxAdams14xX]

I have a 92 1500 2WD came stock with 305 TBI with 700R4 trans. It now has a 90 2500 454 TBI but still has the 305 computer and chip. The computer number is 16146299 with chip AWHC. With this setup the truck just isnt running correctly. It has what I would call a hesitation at low RPM's and like a surge. Once you get over 3,000 RPM's it seems to run ok. I unhooked the TEMP sensor just as a test to see if it was lean and it ran better. I'm thinking I need another chip or maybe even the whole ECM but not sure which one I need. Any help would be appreciated. P.S. This motor had a idle surge and after reading on the web I put a new ACDELCO pickup on it and set the timing on 12 Degrees with brown and black wire disconnected and it fixed the surge.

 

[MIHELA]

If you are using the 454 injectors the computer needs to be reprogrammed to take the increased flow rate into account. Also a few AE settings need tweaked to compensate for the larger inrush of air when you crack the throttle.

 

[XxAdams14xX]

If you are using the 454 injectors the computer needs to be reprogrammed to take the increased flow rate into account. Also a few AE settings need tweaked to compensate for the larger inrush of air when you crack the throttle.

Yes. It’s the complete 454 engine with its throttle body. What’s best way to go about this? Would it be easier to buy a ecm with chip for a 454 from a junkyard?

 

[Stokes1114]

I would have a look over at gearhead-efi.com. You really need to get a datalog and a new chip burned. But if you don't want to go through that, just find a chip out of a junkyard truck that had the same motor and trans and it'll run fine. You don't need a new ECM.

 

[XxAdams14xX]

I would have a look over at gearhead-efi.com. You really need to get a datalog and a new chip burned. But if you don't want to go through that, just find a chip out of a junkyard truck that had the same motor and trans and it'll run fine. You don't need a new ECM.

It has a 700R4 trans and none of the big blocks came with those. do you think a chip for Turbo 400 will work?

 

[MIHELA]

I misunderstood you, I though you had the 454 TBI unit only on a 305. What you need to do is run it with a 454 chip. The trans shouldn't matter since they are both non-electronic.

 

[Stokes1114]

Ok I see now. You'll want the chip for a 454 out of the same ECM,... I'm not sure on how to wire it for tcc lockup tho. I'm used to the electronic tranny's.

 

[wheelman]

I have a 92 1500 2WD came stock with 305 TBI with 700R4 trans. It now has a 90 2500 454 TBI but still has the 305 computer and chip. The computer number is 16146299 with chip AWHC. With this setup the truck just isnt running correctly. It has what I would call a hesitation at low RPM's and like a surge. Once you get over 3,000 RPM's it seems to run ok. I unhooked the TEMP sensor just as a test to see if it was lean and it ran better. I'm thinking I need another chip or maybe even the whole ECM but not sure which one I need. Any help would be appreciated. P.S. This motor had a idle surge and after reading on the web I put a new ACDELCO pickup on it and set the timing on 12 Degrees with brown and black wire disconnected and it fixed the surge.

 

[wheelman]

I have a 92 1500 2WD came stock with 305 TBI with 700R4 trans. It now has a 90 2500 454 TBI but still has the 305 computer and chip. The computer number is 16146299 with chip AWHC. With this setup the truck just isnt running correctly. It has what I would call a hesitation at low RPM's and like a surge. Once you get over 3,000 RPM's it seems to run ok. I unhooked the TEMP sensor just as a test to see if it was lean and it ran better. I'm thinking I need another chip or maybe even the whole ECM but not sure which one I need. Any help would be appreciated. P.S. This motor had a idle surge and after reading on the web I put a new ACDELCO pickup on it and set the timing on 12 Degrees with brown and black wire disconnected and it fixed the surge.

Why not use the 305 injectors.i think it will work.some of these trucks throttle body gasket goes bad.maybe sucking air.

 

[wheelman]

Use the 305 injectors and check and see if the base gasket has gone bad.most do.and they suck air.and act crazy.