nicats

Ok a month ago we put on a new water pump and opti. I left in the car Friday night and it wasn't running right, I came back home and by the time I got to the back door it was overheating like crazy. We check the thermostat and it was ok it was open but assumed the water pump went bad so we have replaced. It still runs the same. As far as overheating I am not sure because it has no power when you try to bring the RPM's up it chokes out. It doesn't even sound right like there is no exhaust noise coming from the back but sound likes a roar in the front of the motor. We have run the code reader and we are not getting any errors. Really at a loss and need some help from someone who may have had the same problem. I will try to answer any questions you have for me if I have the answer.

My car is a 94Z with the LT1 motor. Thanks millions.

Injuneer

Are you sure you got the Opti's splined drive shaft indexed correctly? It may appear that it only goes together one way, but it seems like about 10-15% of the Opti installs end up with it indexed incorrectly?

Did you spill any coolant on the new Opti when you were installing the water pump, and refilling the coolant?

Did you follow the very specific procedure required to fill the LT1's "reverse flow" cooling system, and eliminate all the air from the system?

nicats

Yes the opti is right. Its been running great for about a month.
No did not spill coolant on opti
Yes did the reverse flow right.

ChickenScreamer94

blocked cat?

I am just throwing out ideas.

Do you have a scan tool that reads live data? If would be nice if you could see what the computer sees.

nicats

No we dont have a live scan tool, though someone might have an idea what to look for...

nicats

i know we were getting a Code 29 Secondary Air Injection (AIR) pump circuit didnt know if that could be a problem or maybe an o2 sensor? Just dont seem rite with the noise comming from the front of the engine when you press the gas.

jasonface

Did you put the splined connector for the water pump back in?

nicats

Yes everything is back in...was running good the this

Injuneer

I think the suggestion above regarding the "blocked cat" was worth considering...... no sound out the exhaust, strange sound "comming (sic) from the front of the engine".

ChickenScreamer94

I haven't been in this forum since I totalled my 94 Formula (EDIT: that was in 2004), it's good to see Shoebox and you still sticking around.

OP: Did you get any further with this issue?

nicats

Well after waiting out monsoon season and a little dry time. We punched the brick to make a straight away for air to flow. Started it up and amazingly enough it sounds just like it should.

We find it odd there was no advanced warning. Ran fine one minute and the next no power.

So we are working on breaking and blowing out the rest of the brick with out cutting up the cat housing. Will there be any other issues I should be on the look out for? We were thinking of replacing it when we get a chance with just a piece of straight pipe or should we leave the gutted cat on?? We don't have emissions here so that is not a problem.

Thanks for all the great troubleshooting help.

Fatdog2

If I read this right,problably not,but if your cat exploded,then all those pieces are now in your muffler,clogging up the system.Beer time.My02.