OK ill start from the begining, i bought a 91 camaro rs that had recenlty had a 350 tbi put into it. now for the problems the car had a high temp reading and the ses light was on, so i ignored the ses for now and replaced both of the temp sensors to get everything up to par, well i still was reading way hot so i took it to a shop and had them read the codes, the first was fuel pump relay, the second was ecs something, and the third was something to do with the temp sensor(i think i dont remember but it show -41 degrees) so i start soing research and found about what to do when you swap the engines, now i have an ecm with the # of 16127501 with a hyperteck 305 chip in it. also the guy said i have the 350 injectors and ks. all i want to do is to get the car running right i just need some guidance plz any info on what i need to do wouold be greatly appreciated

 

I'm no ecm expert, but I'm pretty sure you need a 350 TBI prom in the ECM when you swap to a 350 motor.

You also need a 350 knock sensor installed as well.

If the PO didn't change out the ECM prom, doubt he changed the knock sensor either.

ESC is electronic spark control. The knock sensor senses engine knock way below what the human ear can detect, and changes timing in the computer controlled distributor accordingly to end the spark knock. Thus why I think you need the correct 250 TBI knock sensor installed.

TBI computer does not take into account the temp readings of the coolant. There should be only two coolant-related 'sensors' - 1) the fan switch in pass side head that turns on electric fan (has a mushroom connector), and 2) the coolant temp sender in driver head that feeds the gauge (has a single spade connector). So, given the ECM code for temp readings being off, again I suspect that is because of having an improper chip installed.

Get a 350 TBI chip from a truck or Caprice and install into the ECM, and get a 350TBI knock sensor, and see what happens then.

Also, these gauges on a good day never show very accurate - they are for "looks" more than anything - never assume you car is too hot unless it's boiling over.

*edit - just realized the PO "says" it has the 350 knock sensor in it, might just be an issue with the ECM prom then - a 305 ECM won't properly read a 350 knock sensor. Change the ECM out to a proper 350 TBI prom.

 

well the temp guage pegs out and is my ecu one of the 746s where do i get a normal chip just to get it going

 

If the gauge pegs as soon as car started, then the sender isn't hooked up - it's a dark green wire, goes to sender in driver side head between #1 & #3 plugs. If it does it slowly, maybe be bad sender, maybe be bad gauge, etc.

Anyway, your car is NOT overheating until it boils over - many folks think their car is too hot because of the gauge, take it to a shop and have them hit it with the infrared gun to see real temps - unless it's over 250 it's not overheating.

 

If the person that put the motor in did not hook up all the grounds on the back of the heads you will have this problem also. The coolant sender for the computer needs a ground to reference. You can use a ohm meter on the coolant sending unit. Check to see if the black wire is grounded.

 

ok heres an update i went and bought a ecm out of a caprice and put the chip in my ecm and i guess it ddint like it the # on the ecm is 16136965 and the # on the chip is batj 5900 i need help guys i dont know much about this i just want my car to run right