My 454 Rebuild

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.

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
I can't figure out how to open the file or post it. I have 2, they are .csv, .lgf Both of the same log file.
 

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
How does a guy check for a lower intake leak on the underside of the intake?
When i hook up a vacuum gauge i get 19in and is steady with no needle twitching at all as a guy would suspect from a leak.
Yesterday i changed the MAF and went for a short drive. Did not really change anything.
Today i went for about a 30 mile drive and LTFT was a little higher for the most part -17.85 and had usually been running around -15.XX with the old MAF.
As i was sitting in the driveway letting it idle for a few minutes the LTFT went up over -20.xx and tripped codes P0175 B2 and P0172 B1.
After having the upper intake off about 483 times messing with FPR's and injectors im absolutely positive there are no leaks in hoses or upper intake gaskets.
so i think that could only mean it is leaking on the underside?
Is there any other place i can check first?
 

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
Don't think it's a intake leak. If i plug the PVC and the engine breather tube it builds pressure at the oil fill tube.
I did find though my TPS is reading -0.4at idle and WOT it reads 84.3 percent.
 

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
Well i think after weeks and weeks and months of trying to fix this i give up.
Never have i ever had a engine i could not fix till this fkr and im tired of messing with it.
Time to move on to something else.
 

Mangonesailor

I'm Awesome
Joined
Apr 19, 2014
Messages
1,081
Reaction score
992
Location
Triad, NC
I can't figure out how to open the file or post it. I have 2, they are .csv, .lgf Both of the same log file.
You could just PM me your email and go
that route...

How does a guy check for a lower intake leak on the underside of the intake?
When i hook up a vacuum gauge i get 19in and is steady with no needle twitching at all as a guy would suspect from a leak.
Yesterday i changed the MAF and went for a short drive. Did not really change anything.
Today i went for about a 30 mile drive and LTFT was a little higher for the most part -17.85 and had usually been running around -15.XX with the old MAF.
As i was sitting in the driveway letting it idle for a few minutes the LTFT went up over -20.xx and tripped codes P0175 B2 and P0172 B1.
After having the upper intake off about 483 times messing with FPR's and injectors im absolutely positive there are no leaks in hoses or upper intake gaskets.
so i think that could only mean it is leaking on the underside?
Is there any other place i can check first?
Unplug TPS, then attach a long hose onto the working end of a propane torch (Without the torch lit!) And snake it under the intake.

Don't think it's a intake leak. If i plug the PVC and the engine breather tube it builds pressure at the oil fill tube.
I did find though my TPS is reading -0.4at idle and WOT it reads 84.3 percent.
I remember that being an issue on my own truck. I took the TPS assembly off and filed a little so it'd indicate actual 0% when closed. Come to find out though my IACV counts were too low too.

You may need a new TPS if you don't read 100%. Have you tried using an analog meter to check resistance and voltage feedback?

Well i think after weeks and weeks and months of trying to fix this i give up.
Never have i ever had a engine i could not fix till this fkr and im tired of messing with it.
Time to move on to something else.
OK, nevermind
 

BeXtreme

I'm Awesome
Joined
Jan 13, 2020
Messages
363
Reaction score
359
Location
Salem, OR
I would expect the computer to see an intake leak as lean and would have LTFT in the positive range, not negative.
 

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
@Mangonesailor I changed the TPS. It now reads 0-100%
@BeXtreme I just don't know anymore what to think.
All sensors i can read are reading in their normal range now. I replaced all the sensors with new that were not reading in the range specified. MAF, All 4 o2 sensors, Map, EVAP valve, Swapped EGR with a known good one, IAT is new, TPS is new.
2 Sets of injectors. The first set are 5o injectors less than a year old and ran perfect in the old engine. Replaced them with reman stock style injectors. I refuse to believe both sets of injectors are bad.
FP is 58PSI, I suppose the new FPR could be bad and leaking fuel into the intake or the little hose could have broke?
2 new sets of plug wires, New cap/rotor
I used a temp gun and measured the catalytic converter inlet temp and outlet temp. Both measured around 380F. If inlet and outlet are close to the same i understand they are working properly?
Compression is even around 160PSI
 

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
Forgot to mention this pooped up and is new.
You must be registered for see images attach
 

Spareparts

Supporting Member
Supporting Member
Joined
Aug 12, 2021
Messages
1,103
Reaction score
1,474
Location
North Idaho
If this posts it is worth saving!
 

Attachments

  • GM_20Class2_20mode_20$06_20data_20final_dm.pdf
    92.1 KB · Views: 18
Top