Long initial crank

[LilTahoe]

So I just replaced the motor in my 94 2 door tahoe, its a mildy built 350 that dynoed around 350 hp (not sure on what was done I purchaced it from a local guy it was freshly rebuilt). Every part attached to the motor was replaced water pump tbi all that fun stuff. Well anyways my first initial crank bout mid day it takes about 5 or 6 seconds to fire up. But after it warms up it will crank right up no issues runs good. Now check engine light is on but I have no way to check it atm. I do have headers 02 isnt hooked up and i don't have the second filter on the tbi (breather box). Just wondering how i can resolve this issue.

 

[LilTahoe]

It also runs rich on start up.

 

[someotherguy]

If you have a paperclip, you have a way to check the codes.

O2 not hooked up is a huge mistake. Get one. Without it you will run in open loop, rich fueling...

Richard

 

[LilTahoe]

What could I do with the paperclip? And my headers are o2 sensorless unfortunately I can't spend the money on another set without my wife killing me already invest 3 grand to get it running and rebuilding the tranny.

 

[Smitty1021]

You use the paper clip to jump the top right two ports on the connector you would normally hook your scanner to under the dash below the steering wheel. Your check engin light will flash quick with long pauses indicating a number in which you'll references to a code. If you have Haynes manual it's on page 6-6,6-7 with instructions on how to check it along with every code.

 

[someotherguy]

Any decent exhaust shop can put an O2 bung in your exhaust, it doesn't go in the headers when you use a heated sensor. Your '94 should already be wired for a heated (3 wire) sensor, that goes in the pipe between the cat and the muffler. Since I doubt you have cats just pick a spot just past the collectors and they install the spot for the O2.

I'm not kidding, if you don't get an O2 in there and working you're wasting your time and anyone's that is trying to help you. No O2 = /thread

Richard

 

[98_k1500]

+1 on the o2 sensor. Just installed mine on my camaro. Bought a o2 sensor bung from a local exhaust shop for $3. drilled a 1" hole in the pipe, weld bung in, screw sensor in. Done. After that we may be able to help you.

 

[Horns]

Mine did the same exact thing when the o-rings in the TB were bad. It would drip fuel into the cylinders after the truck was shut off. Making it cranks a bit on cold start ups. It would also run rich at idle because of this. Haven't had any problems since I replaced them.

 

[LilTahoe]

I had already replaced all the o rings gaskets all that. Tbi was rebuilt I'll take car of the o2 sensor I'm straightpiped atm i dumped it half way through the truck. Ima just redo all of it.

 

[Chris6060]

I had already replaced all the o rings gaskets all that. Tbi was rebuilt I'll take car of the o2 sensor I'm straightpiped atm i dumped it half way through the truck. Ima just redo all of it.

The computer literally doesn't know how much fuel to give your engine without the O2.

The O2 senses your air to fuel ratio.

And its the only A:FR sensor in the whole system, so.

Get the bung installed as close to the collector as possible on the PIPE after the header.

Good luck man!