Some drivability issues. Unknown history.
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From: Miami, FL
Car: 1986 Trans Am
Engine: 5.0 LG4 4BBL
Transmission: T5 5-Speed
Axle/Gears: 3.23
Some drivability issues. Unknown history.
Hello everyone . First post. Been browsing the site for a long time . You guys sure help us first-time3rd genowners. Hoping for some advice.
I have an 89 Firebird LO3 engine700R4. I purchased the car unseen and was led to believe that the vehicle was100% stock. It turns out it is anything but 100%stock.
I have found so far an Edelbrock Performer TBI intake,headers of some sort, what i believe is a3inch y-pipe with the same 3 inch tubing all the way to a huge muffler and no catalytic converter.
I also estimate 4.10 or 4.11 gears based on the number of rotations from the drive shaft. To top it off i can't verify it's the factory engine because although it surprisingly still has the factory intake tubing and enclosed air cleaner set up, i can't find the stamped letters or numbers on the block.
Of course, these arent bad mods and the car feels very strong down low, but throttle response is uneven and abrupt and there is bogging at low RPMs. Throttle opening and acceleration doesn't seem to correspond with pedal pressure. I've yet to drive it over 20mph
Frankly I don't know where to start because I'm not sure what else might not be stock. Wouldyou guys recommend just starting to replace all normal items (ignition, filters, fluids, etc) and check timing? What would you recommend for the inconsistent abrupt throttle?
Thank you folks.
Carlos
I have an 89 Firebird LO3 engine700R4. I purchased the car unseen and was led to believe that the vehicle was100% stock. It turns out it is anything but 100%stock.
I have found so far an Edelbrock Performer TBI intake,headers of some sort, what i believe is a3inch y-pipe with the same 3 inch tubing all the way to a huge muffler and no catalytic converter.
I also estimate 4.10 or 4.11 gears based on the number of rotations from the drive shaft. To top it off i can't verify it's the factory engine because although it surprisingly still has the factory intake tubing and enclosed air cleaner set up, i can't find the stamped letters or numbers on the block.
Of course, these arent bad mods and the car feels very strong down low, but throttle response is uneven and abrupt and there is bogging at low RPMs. Throttle opening and acceleration doesn't seem to correspond with pedal pressure. I've yet to drive it over 20mph
Frankly I don't know where to start because I'm not sure what else might not be stock. Wouldyou guys recommend just starting to replace all normal items (ignition, filters, fluids, etc) and check timing? What would you recommend for the inconsistent abrupt throttle?
Thank you folks.
Carlos
Last edited by Carlos89; Sep 6, 2018 at 07:01 PM. Reason: Misspelling
Senior Member
Joined: Apr 2016
Posts: 517
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From: Perth Western Australia
Car: 1987 Z28 Camaro
Engine: 305 LG4 4bbl
Transmission: TH700R4
Re: Some drivability issues. Unknown history.
Check if it has oil, water and trans fluid. Check the tyre pressure the go and enjoy it for a while. anything worth noting will popup pretty quickly...
Joined: Dec 2004
Posts: 16,747
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From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Some drivability issues. Unknown history.
There might have been a cam swap with the other mods. Datalogging with tunerpro rt would be a good idea so you can see your fuel trims. The mask is known as $61 this is the adx file you would need to use with tunerpro.
http://tunerpro.net/
http://www.moates.net/aldu1-and-cabl1-p-127.html
http://tunerpro.net/
http://www.moates.net/aldu1-and-cabl1-p-127.html
Re: Some drivability issues. Unknown history.
................ throttle response is uneven and abrupt and there is bogging at low RPMs. Throttle opening and acceleration doesn't seem to correspond with pedal pressure.
Frankly I don't know where to start because I'm not sure what else might not be stock. Wouldyou guys recommend just starting to replace all normal items (ignition, filters, fluids, etc) and check timing? What would you recommend for the inconsistent abrupt throttle?
Frankly I don't know where to start because I'm not sure what else might not be stock. Wouldyou guys recommend just starting to replace all normal items (ignition, filters, fluids, etc) and check timing? What would you recommend for the inconsistent abrupt throttle?
That says it all , you very rightly said you know nothing about this particular car and it's time for you and it to start building some history together . Yes indeed , first up is to do ALL of the filters/fluids/etc to give it a fighting chance (everything from the engine's oil pan to the differential , and then everything in between) , and then the second thing I'd be doing would be a series of tests before I bought any parts to chase the poor running (that you don't yet know the origin of) . A compression check , vacuum check , and fuel pressure check would be the first three checks I'd do , the compression check and vacuum check will tell you volumes about the condition of the engine and could be very telling with regards to the poor running .
It takes guts to play what I call "Automotive Forensics" , having to become "Mr. car Detective" to figure out what someone else screwed up , kudos to you for taking on such a project
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