it starts and runs fine till I try to drive it. It pops and spudders when I try to accelerate and when I floor it, it sounds like the d/shaft is hitting something but its not. The timing, plugs, wires have all been checked. The motor ran fine in the burb. No cel or codes. Iam lost and have been messing with this for the last month

Massive vacuum leak, Check all the hoses, TBI to manifold bolts etc.

I sprayed the top of the motor with carb cleaner while it was running and felt around already, nothing happend

ck'd fuel pressure?

I just replaced the fuel pump when I put the motor in, but it did have bad gas so mabey it fed up the new pump

Have you checked the distributor and/or distributor cap?

In tank rubber line from pump to hard line rots out.

fuel pump replaced again. the cap, rotor, pick ups and plugs all cleaned and checked, still no differance.
TBI no rubber lines

Maybe I should put the parts back on the burb, nevermind I rather sell it all for scrap

Fuel filter? Replace all the vacuum hoses?

0kay.....how about if you feed a little carb spray in as you manually throttle it up (to substitute fuel)..... does it then throttle up properly? (be careful it doesn't backfire thru the TBI tho).....if not, probably not fuel related. Did you try a different coil? The coil itself could be going bad as well.
Also, was the fuel pressure rating different for the burb vs. the blazer, and did you order the pump for the engine/computer that you are using? Probably the same, but just in case.....hard to know without putting a gauge in place of the filter and seeing how much fuel pressure is actually present. Try adding "fuel" in the TBI and see if that allows it to rev up smoother. At least that should help isolate it to a fuel or ignition prob. You may want to scan it too, you may have an in range failure of a sensor that will goof things up. Could be a glitch in your TPS causing it to stumble. Double ck all the engine grounds too. Or a bad map sensor...make sure the vaccuum lines are in the correct location as well. Hard to diagnose through a computer, it's too bad you live so far away!

dleroy43 wrote:

fuel pump replaced again. the cap, rotor, pick ups and plugs all cleaned and checked, still no differance. TBI no rubber lines Maybe I should put the parts back on the burb, nevermind I rather sell it all for scrap

TBI has a short little hose that connects to pump to the hard line inside the tank.

the little hose was replaced with the fuel pump

reving the motor and adding fuel to it works fine, its only while I drive that couses the problem. I am going to go through the wireing agein today, mabey removing the abs, auto trans and cruise screwed up a signal somewhere.

vatozone doesnt have a fuel press tester for loan

I checked a lot of the wire and they are what they should be.
If I snap the throttle pretty wide, it back fires through the tbi.
Adding cleaner through tb kills the motor
Injectors seem to be dripping fuel at idle but spray when I rev it.

If it throttles up fine when you give it a little "extra" fuel, it sounds to me that you have either the wrong pump, ie not enough pressure, or perhaps a bad fuel pressure regulator diaphragm causing your pressure to be too low, something is causing your pressure to be too low. I think they run on 9-15psi. There's no chance you pinched one of the steel lines during the swap over is there? The symptoms you are describing are lean fuel. Leaning out can def. cause backfires through the TB, and will also cause the popping and lack of power under load that your dealing with.

That sounds like a direction to go. The gas did go bad in the tank, so it probly clogged the lines somewhat and burned out the first fuel pump. I will pull the lines clean them and the tbi as well.

I pulled the injectors out and there was a bunch of rusty crap in there and in the regulator. The lower O rings were stretched out too. I rebuilt the throttle body and had a mislabled plug wire. It runs good now.

Thanks for all the help

To celebrate, I shall burn it to the ground before it couses anymore problems

dleroy43 wrote:

had a mislabled plug wire. It runs good now. Thanks for all the help To celebrate, I shall burn it to the ground before it couses anymore problems

Don't you hate it when that happens.

Good Deal!

Glad you finally got er' straightened out! Now to play!