OP
OP
bigfootchiro
Full Access Member
Ooooh I see what you mean now! Yeah I doubt having only 3 will make a difference lol
Vortec 454/4L80e HD swapped 1999 Tahoe OBS
- Thread starter bigfootchiro
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Ooooh I see what you mean now! Yeah I doubt having only 3 will make a difference lol
OP
OP
bigfootchiro
Full Access Member
Riddle me this gentlemen...
Short term fuel trims are out of wack (mostly driver side), and Long term on the passenger side being 25%. Saw on the scanner that the AC relay was Off, even with AC on. Jiggled the connector at the low pressure switch on the accumulator, AC compressor kicked on and short term fuel trims stabilized. Jiggled it to make it turn off, and they went off again. Jiggled to make it turn on and they stabilized. How is this connected? Would the connection cause a short in the system? Is the AC system connected to the vacuum system of the engine somewhere?
Short term fuel trims are out of wack (mostly driver side), and Long term on the passenger side being 25%. Saw on the scanner that the AC relay was Off, even with AC on. Jiggled the connector at the low pressure switch on the accumulator, AC compressor kicked on and short term fuel trims stabilized. Jiggled it to make it turn off, and they went off again. Jiggled to make it turn on and they stabilized. How is this connected? Would the connection cause a short in the system? Is the AC system connected to the vacuum system of the engine somewhere?
OP
OP
bigfootchiro
Full Access Member
Right after takeoff, you’ll notice the dip in RPMs. That is under consistent throttle with no change in position. Also, I can let off the throttle at times and the RPMs will rise once load is off the engine. It can happen under WOT runs too.
OP
OP
bigfootchiro
Full Access Member
What makes you think that? And are you saying upper intake leak?
kbuskill
***CAUTION*** I do my own stunts!
I say that because that is my guess as to your issue. My grandfather had an '88 GMC crew cab dually with the 454 and you would be driving it and all of a sudden it would bog down like it had no power and you could floor it and it wouldn't accelerate much at all and then all of a sudden it would kick in and go back to the normal torque monster that it was... turns out it was an intake manifold gasket that was leaking intermittently.
Now his was a TBI injection model and yours isn't I don't believe but the theory is the same... plus you said your fuel trims are screwy.
Now his was a TBI injection model and yours isn't I don't believe but the theory is the same... plus you said your fuel trims are screwy.
Last edited:
OP
OP
bigfootchiro
Full Access Member
It’s definitely worth a look at. Thank you! I’ll spray some brake cleaner around the intake and see what happens with the fuel trims.
OP
OP
bigfootchiro
Full Access Member
No hydroboost yet fellas. Forgot the steering pump at home. Still stops better than before though lol
kbuskill
***CAUTION*** I do my own stunts!
I know you are going hydro boost but...
Just FYI... you can install the rear wheel cylinders for a 1 ton pickup on the rear end and get a little more braking power. The wheel cylinders on the 1 tons are a bigger diameter piston.
When I had my first gen Escalade I did that along with swapping the master cylinder over from the newer gen trucks because they run a bigger diameter cylinder inside the master as well. It only required one adapter where the brake line screwed onto the master as the newer trucks run a different size fitting on one side than the older trucks.
The newer style master gets rid of the spongy/soft brake pedal feel the older trucks had.
Just FYI... you can install the rear wheel cylinders for a 1 ton pickup on the rear end and get a little more braking power. The wheel cylinders on the 1 tons are a bigger diameter piston.
When I had my first gen Escalade I did that along with swapping the master cylinder over from the newer gen trucks because they run a bigger diameter cylinder inside the master as well. It only required one adapter where the brake line screwed onto the master as the newer trucks run a different size fitting on one side than the older trucks.
The newer style master gets rid of the spongy/soft brake pedal feel the older trucks had.
OP
OP
bigfootchiro
Full Access Member
Wow, that’s great to know! I love little nuggets of knowledge like these
