smog help

I'm doing a engine swap in a 87 Suburban 4x4 (Suburban came out of Colorado where they in force emission laws ), I bought a 4month old GM TBI crate engine that was in a 90 Chevy 4x2 p/u for those 4 mons, I bought it to replace the bad motor in the Suburban. I got the complete engine from the 90 P/U plus the TBI & flex plate, torque converter, exhaust manifolds, serpentine belt system and all the accessory's. I have the bad motor out of the Suburban and it has 6 holes in the oil pan, I will post pics of it when I get it on the engine stand, pics of b4 and after tear down.




I'm wanting to put headers on (I've got the headers) I will install the O2 sensor. theres no emission testing here in the sticks of Nebraska, but there is a smog pump on The Suburban that ties into both the exhaust manifolds & pump. the serpentine belt system on Suburban is called (I think) mini serpentine belt system. it has a serpentine belt plus 2 other belts, one of witch run the smog pump. so removing the pump & belt won't cause any problems that way.

My Question:

can I remove the smog pump and belt if I plug the vacuum line to the pump with out causing a check engine light or any other trouble ?

my other question is, what all else should I do or replace in a engine swap ? I'm putting in a new oil sending unit, T stat & plugs & plug wires and front tranny seal, new water pump and gaskets, new alt, and new starter, the radiator was just done by a radiator shop. and headers & 2 1/2 exhaust to the rear bumper.

Mustangsaly

7 lookers and no help ? I know someone here can help me.




I wish I had another engine stand so I could hang this engine and get pics and tear it down and take pics of the inside too. I was told this Suburban got hot and the owner did a complete top end, new heads cam redone radiator ect. witch everything looks new. but the frost plugs every where including in the rear of the block behind the bell housing area look new. I'm thinking it got hot and someone not knowing what they were doing rebuilt the complete engine, and thats why it came apart. looking in the pan holes when I had it hanging on the cherry picker. I can see 1 rod that came apart at the cap and one rod looks like it broke in two above the big end.






Mustangsaly

Taking off the smog pump won't turn on the check engine light.

Make that 8 lookers. On a Benz, low air injection flow WILL throw a code and bring on the light. Dunno 'bout a suburban though.
Are you talking 2 1/2 inch single or dual? 2.5 in dual will kill low end on a 4500 lb sbc cruiser.
seeya, Ian.

on two other boards it was told that I can remove the smog pump & plug the vacuum line with out throwing any codes. I'm putting my O2 sensor in the header collector so it will get warm fast and read oxygen at where all 4 cylinders come together at the closest area where they all turn into one.


my plan is 2 1/2" duals from headers to rear bumper with a H pipe and a turbo muffler on each side.



anyone else think 2 1/2" exhaust is to big with a stock tbi GM crate engine with headers on a 87 Suburban 4x4 with a 2" to 4" lift with 31" to 33.5" tires ? I might have to adjust my gear ratios.


Mustangsaly

If there is enough money in the budget you should get a later model 3-wire (heated) O2 sensor. It can make a big difference at idle especially with a free flowing exhaust. You just have to wire one of the heater wires to ground and the other to a switched ign. hot source.

it's doubtful that a 1987 ecu is "smart" enough to notice an increase in NOx emissions - i'd say removing the smog pump would definately NOT throw any codes. OBD2 ecu's have a 2nd O2 sensor located at the catalytic converter which would probably throw a code if something was wrong with the emissions system... but your truck doesnt have that.

Thanks,

Is a full 2 1/2" exhaust system with a H pipe from the header to the rear bumper to much exhaust ?


Mustangsaly

depending on what motor you have (305, 350, 454 or the 6.2L diesel), i dont think a 2.5" dual would be too big. maybe a little big for the 305... but i think you have the 350 (the only tbi in 1987). you might want to check with your local smog laws to find out if you CAN put true duals on there. as far as i know, in cali, if it didnt come with true duals from the factory it isnt road legal to have (for offroad use only). some smog testers will fail it visually.