TBI 454 problem

[71blksuper4x4]

Hey guys, we recently took out the original tbi 454 in our 87' K30 w/ a sm465/205 combo. We installed a running tbi 454 out of a 89' K30 w/ a th400/205 combo. My question is, since installing the motor, we have been having problems with the motor "loading up". It is fine in 1st and most of the time in 2nd, but when you hit 3rd, it seems to get to much gas and smells like it's running rich. Do you guys have any suggestions where to look? We didn't know if it was tbi related, TPS related, or CPU issue. We left the original 4 speed cpu in the truck but the tbi is the one that came with the automatic truck. We just are trying to rule things out as we use the 87' as our hauling truck. Thanks Trevor

 

[4X4HIGH]

I would definately get the proper prom for an auto trans to start with.

 

[eagle mark]

I'm just wondering how you smell rich in third gear? And if the truck still has a Cat you should not smell rich, you could smell HOT or see the cat glowing red...

TBI unit should be the same. Since the TH400 has no electronic controls the 4 speed ECM should work although there is a differant broadcast code for auto and manual. Swap the ECM and see if it makes a differance but I doubt it will help rich. May help idle.

Have you checked for codes? Look at the Sticky at top of this forum for instructions.

 

[71blksuper4x4]

Is it required when switching engines? We didn't think it would matter since all we switched was the engine and nothing else. I would have figured it to be plug and play. We did not change the tranny or transfer case, just engine. We just took an automatic 454 and put it in front of a sm465. Trevor

 

[71blksuper4x4]

Thanks eagle mark, I did not realize about the different codes in the ecm. Trevor

 

[eagle mark]

Like I said the chip broadcast code is differant from manual to auto and to auto with electronic connections like the 700R4. But since you are talking about a TH400 with no electronic hookups it will run fine.

 

[71blksuper4x4]

Changed the coil pack and it runs good. One question though, the choke light is always on though. Is there something to be checked? Trevor

 

[eagle mark]

Since an 87 K30 came fuel injected it shouldn't have a choke light? So yes, big problem...

 

[71blksuper4x4]

Mark, does that mean it's a check engine light? We swapped in a factory tach dash in it, so thus why there is a choke light. Trevor

 

[eagle mark]

Possibly! check the wire from the ECM A5 tan with white strip. If it goes to the choke light then to keyed on power it will work as Check Engine or SES light. Use the instructions in troubleshooting sticky to read codes and see what's there.