What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Need replacement TBI

vegasblazer90

vegasblazer90

Registered Member
 Premium
Joined
Mar 25, 2008
Posts
53
Reaction score
30
Location
Turlock, CA
My 90 K5 failed her Smog test in spectacular fashion, so much so that she is now a gross polluter. evap test also failed. turns out the top of the fuel pump had a crack so that got replaced. A smoke test also resulted in lots of smoke leaking from the TBI unit. My buddy looked at it and said there is an actual crack in the unit so it’ll need to be replaced.
Rockauto has an AutoLine FI9000 unit for a decent price.
any opinions on these or suggestions on something else that won’t break my wallet?
 
I have a TBI off a 350 that has some of the go-to mods done. It was gone through and had new injectors when it was pulled off, but that was a few years ago. Like 5 or something.
I actually have the entire TBI system laying around. Every single component was new, except the wiring harness.
 
I'll pm you tomorrow. And I'll take a couple pics.
 
ktmoutfront said:
They disappear here the day the truck is put on the line.

Put an add in the "wanted" section of the classifieds here.
Click to expand...
At those "pick you own part places" what I notice is instead of taking the entire TBI unit they take only the injectors because they are small enough to put in your pocket, and steal them without having to pay for them.
 
1-ton said:
At those "pick you own part places" what I notice is instead of taking the entire TBI unit they take only the injectors because they are small enough to put in your pocket, and steal them without having to pay for them.
Click to expand...
yes thats been happening for a long time- i cant understand why though - ive NEVER had a problem with a TBI injector!
 
vegasblazer90 said:
My 90 K5 failed her Smog test in spectacular fashion, so much so that she is now a gross polluter. evap test also failed. turns out the top of the fuel pump had a crack so that got replaced. A smoke test also resulted in lots of smoke leaking from the TBI unit. My buddy looked at it and said there is an actual crack in the unit so it’ll need to be replaced.
Rockauto has an AutoLine FI9000 unit for a decent price.
any opinions on these or suggestions on something else that won’t break my wallet?
Click to expand...

sorry to hear this- ive always been amazed at how bad the allowances are for the TBI 5.7, and how WELL all of mine have passed the tests...
are you SURE your TBI is cracked? Have you been hammering nails with it, without letting it cool down first after taking it out of the oven????

Ive not hooked up the "man's vape" smoke machine to mine yet- but i could see a lot of potential "leaks" from the tbi unit- whether that is directly past the throttle valves, or an IAC valve that is not seated and closed perfectly when the power is off??? cracked rubber elbows on the vacuum lines?


also one thing ive run into a few times (thankfully in between smog tests) is finding the passageways under the EGR completely blocked with carbon. If the motor is kinda old and tired, or just old and the valve stem seals are brittle- pcv valve not working correctly? -that carbon is diamond hard, but CAN be chipped out. I've done it a couple times.
 
one thing I ALWAYS DO here in CA, is make sure the gas tank is 100 percent full of clean fresh gas, and only take my truck to get the smog test when the truck is fully warmed up- even when your favorite smog guy is right down the street- go take a 10 min drive down the freeway and back, and I DONT SHUT THE TRUCK OFF WHILE WAITING MY TURN TO GET SMOGGED. let it idle in the parking lot if need be - the smog tech can shut it off when they pull it in and put it on the dyno... make sure that motor is warm, and the CAT is hot!

I forgot to do this once - and the Owner of the shop came over and said "you failed" as he chuckled... started telling me about how clean it was running 2 years ago, and 2 years before that... and I only put 10-15 thousand miles on it... laugh laugh...

I thought he was joking- he was not. I had barely failed one of the parameters. he said "oh, don't worry... i see cars like this pass and fail in the same day- go change the oil, put fresh gas in the tank, and come back- we will test it again for free. I did all those things- passed the test like a BRAND NEW TRUCK. the technician was giving me funny looks, and later wanted to know what I had done to make such a huge difference. The truck had been sitting for a while. He didn't want to believe that the oil change and fresh gas could make such a drastic change, but it did.

My current K5 is a manual trans, and i have a few other things to worry about on a smog check. when the truck is on the dyno- the technician needs to hold the RPMS in a certain range, and also the wheel speed within a certain range for 30-40 seconds. they do a low speed, and then a high speed test. Problem I have is that with the 465 trans, and with the tires size/ gearing... there is quite a bit of overlap. They can do the low speed test in 2nd gear, but the RPS are towards the high end of the range they have to maintain... some of the guys want to shift into third, but then the RPMS are at the bottom end of the RPM range, while the wheel speed is similar to where it was before.
I worry that if they are lugging the motor, its going to fail the test somehow- always ask them to keep it in 2nd for the low speed, and then shift into 3rd for the high speed. NO actual problems with this so far, but I worry it could make a difference.
 
You must log in or register to reply here.

Latest Posts

Top Bottom