Those of you following my 3rd gear and trap MPH woes...
Thread Starter
Member
Joined: Oct 2001
Posts: 425
Likes: 0
From: Central Jersey
Car: 1992 Z28
Engine: Stock L98 with bolt ons.
Transmission: Stock rebuilt tranny with 2k stall and cooler.
Those of you following my 3rd gear and trap MPH woes...
I check the plugs are some full throttle runs and shutting the car off and rolling to a stop here is a pic which if you cant see looks lean if Im correct so this Sat I will be messing with the Holley AFPR I added so I can try to tune in my combo.

For the hell of it I put the scan tool on the car again and this time I got 24 counts of spark and 3 degrees of KR at 2980 RPMs but I didnt have any info above that so I will have to try it again. I did however take some quick footage of my tach to show you what exactly happens when the car shifts into 3rd and bogs or labors. The footage isnt great but noticed how the RPMs jump up in 2nd (from a 45 MPH roll) then hit 4k and kinda slow up but pull thru to 5200 RPMS (tranny is shifting on its own), THEN it shifts into Drive and shortly after it hits 4k like its a steel wall and then actually if you look close drops some RPMs all the while its under WOT and stays put basically until I shut it down. I didnt want to get too crazy with the speed, I need help with the car but Im not lunatic. Im wondering if I shouldnt for the hell of it put a new knock sensor on the car since its nearing 100k miles now and may or may not need it. Either way Im biting the bullet and Im gonna have another shop look at it since I dont know WTF Im doing or looking for anymore. Lets see if this helps anyone who has given me advice in the past, heres the clip...
Tach

For the hell of it I put the scan tool on the car again and this time I got 24 counts of spark and 3 degrees of KR at 2980 RPMs but I didnt have any info above that so I will have to try it again. I did however take some quick footage of my tach to show you what exactly happens when the car shifts into 3rd and bogs or labors. The footage isnt great but noticed how the RPMs jump up in 2nd (from a 45 MPH roll) then hit 4k and kinda slow up but pull thru to 5200 RPMS (tranny is shifting on its own), THEN it shifts into Drive and shortly after it hits 4k like its a steel wall and then actually if you look close drops some RPMs all the while its under WOT and stays put basically until I shut it down. I didnt want to get too crazy with the speed, I need help with the car but Im not lunatic. Im wondering if I shouldnt for the hell of it put a new knock sensor on the car since its nearing 100k miles now and may or may not need it. Either way Im biting the bullet and Im gonna have another shop look at it since I dont know WTF Im doing or looking for anymore. Lets see if this helps anyone who has given me advice in the past, heres the clip...
Tach
Thread Starter
Member
Joined: Oct 2001
Posts: 425
Likes: 0
From: Central Jersey
Car: 1992 Z28
Engine: Stock L98 with bolt ons.
Transmission: Stock rebuilt tranny with 2k stall and cooler.
I just had the plenum off to add a Holley AFPR and I dont believe there to be any vaccum leaks, I even tested with carb cleaner and no effect on idle whatsoever. As for ignition it has newer plugs (few months at best, wires are after market 8.8s about 2 years old Im guessing, NEW coil and coil wire and almost new cap and rotor. Control module died and was replaced last year and I have a MSD-6al set up. I even by passed the MSD box to run factory ignition, still the same problems. With a fuel gauge the PSI holds at 48 PSI under WOT BUT I did record 3 degrees of KR this time at 2980 but not on that run in the video. Im thinking of replacing a knock sensor for the SLP Event for a shot in the dark, if that dont work Ill let another shop take a crack at it but damn how annoying and I know if I can get past this the car will see better times than 13.521, its just a matter of isolating the problem which I havent nor have trained mechanics been able to do so far, talk about frustrating!!
Senior Member
iTrader: (1)
Joined: Jul 1999
Posts: 578
Likes: 0
From: Cincinnati
Car: 1987 GTA
Engine: PT88 Turbo DART 406
Transmission: th400
Axle/Gears: 9" ford
GEEZE dude you have the same problem I do....Im still replacing stuff...Mine is not fuel related..Im getting tonds of fuel But when I hit third it really FALLS on its face...IM getting huge amounts of knock retard...Mine seems to be ignition related..But Ive replaced about everything there is...
If you find the problem plese post back...Ill let you know If I ever track mine down....
Did you check the PICK UP COIL????
If you find the problem plese post back...Ill let you know If I ever track mine down....
Did you check the PICK UP COIL????
Thread Starter
Member
Joined: Oct 2001
Posts: 425
Likes: 0
From: Central Jersey
Car: 1992 Z28
Engine: Stock L98 with bolt ons.
Transmission: Stock rebuilt tranny with 2k stall and cooler.
It was replaced awhile ago and even when the brand new replacement distrib went in the car ran just like it did after replacing the blown intake gasket a bad injector and replacing a shot distrib. I threw $ at it for so long I quit but it doesnt mean I like it or forget. Its been so long since the car revved smooth or idled perfect I dont know what a healthy motor feels like. If I ever trace it down Ill be sure to post about it, good luck with your problem as well...
Thread
Thread Starter
Forum
Replies
Last Post
eightsixseven
Tech / General Engine
2
Dec 16, 2024 01:50 PM
ambainb
Camaros for Sale
11
Apr 25, 2016 09:21 PM




