Tune Port Engines

I own a 89 Pontiac Firebird Formula and in it, there is a Tune Port Injection engine.

In lamen ( aka idiot ) terms, can someone please give me a little background on this engine. Why everyone tells me its a sturdy engine? ( yet mine is considered 'tired' because its over 140,000 miles now ) What can be done to help make it less 'tired', ( tune up maybe? ) and the basics of the engine..

Remember guys... in stupid terms. I am a newb, but im willing to learn more about my car any day.

Well, to put in lamens terms like you said, TPI pretty much means you have an A$$-LOAD of torque, but your car will stop making power at about 4200rpm, and will be completely dead by 5k, maybe 5100k. BUT.. that's very fixable. A Holley Stealth Ram will be an awesome upgrade to your car.
Who ever tells you a 140k mile car is worn, is correct. That's why my 190k mile car would still chirp the tires in second gear w/ out me even trying, and would rapidly fill the speedometer. I just rebuilt the car this past winter. The intake manny was loose, carb was loose and WAY out of tune, the O2 sensor was shot making the car a little doggish and suck more gas, the air filter is absolutely BLACK, the car wouldn't run on anything less than 91 octane because the timing chain was so poorly worn there was about an inch worth of slack on EACH SIDE, the distributor was shot and was arcing like a mofo, the plug wires were worn and arcing, 2 of the spark plugs weren' even tight, and the exhaust manifolds were loose. Oh ya, and the Catalytic convertor was shot; it was melted shut almost.
Like I said; it would *easily* chirp second, and if I actually tried I'm sure I could hit third.
Do you have the 305 or 350 TPI?
Matt

First of all, you need to determine which motor you have. Being an 89 your either has an LB9 305 TPI motor rated at 220/230hp 290/300tq or you have the L98 350 TPI motor rated at 230/240hp 330/345tq. If your car is a 5 speed then you more than likely have the 305 because NO manual 3rd gens came mated with the L98, HOWEVER this does not mean the previous owner(s) could have done a motor swap. Either way, you have a pretty good starting point. As 85_305 said, TPI is great at making low end tq but hits a brick wall pretty hard in the upper RPM's. Tuned Port Injection is a system that uses tuned runners(hence the tuned part ;) ) to enhance torque output between 1500 and 3500rpms. Overall its not a bad injection system, especially when you overcome the "brickwall" problem. As far as waking it up a bit, first you should make sure everything is in good mechanical working order, then let the modding begin. Start with bolt ons, cat back, intake, headers, suspension, stall, good set of tires. The sky's the limit...goodluck and have fun!

I own a 89 Pontiac Firebird Formula and in it, there is a Tune Port Injection engine.

In lamen ( aka idiot ) terms, can someone please give me a little background on this engine. Why everyone tells me its a sturdy engine? ( yet mine is considered 'tired' because its over 140,000 miles now ) What can be done to help make it less 'tired', ( tune up maybe? ) and the basics of the engine..

Remember guys... in stupid terms. I am a newb, but im willing to learn more about my car any day.
Along with a general tuneup, the term tired may simpy imply that the rings, bearings, valvetrain, ect. have wear and the motor is not at its peak potential as the day it rolled off the dealer lot. A rebuild would be necessary to correct those problems and would be nothing I would rush to do at the second. I would however do as mentioned above and throw in some fresh plugs, wires, fuel filter, pcv valve, air cleaner, 02 sensor, and clean the throttle body.

wouldn't hurt to check your valve springs too...as they wear out they can cause bad valve operation.

350tpi

350tpi

Mmm.. me likes the sound of that :devil-grin:

Mmm.. me likes the sound of that :devil-grin:


Why is that?

Do a ground up tune up; brass insert cap & rotor, 8mm spiral-core wires, good plugs etc..
1)set your air-bleed or sometimes called idle
2)set your TPS sensor to .54v @ idle and 4.20v + @ WOT.
3)set timing a couple of degrees hotter...10-12* advance range, play with it, if it detenates back it off 2*'s..
4)Lose the weight, box, amps, spare tire, 1/4 tank or less fuel etc..
5)Let it shift itself...I've tried shifting but always had better runs in "D".
6)Run a 160* T-stat, no problems guarenteed..
7)Try a cheap afternarket PROM chip, it'll at least run cooler, (turns fans on sooner) but you may have to re-adjust your timing..(used on E-Bay cheap)
8) re-locate your MAT sensor to the filter box, on tpi motors just buy a new one, add extra wire to extend to the air box, drill a hole and screw it in.Stock valve springs do suck after 70-80K miles, replace them and the valve seals, always a good investment...but GET SOME GOOD AFTERMARKET ones, it'll pay you back almost immediately. :cool:
**Don't forget change ALL filter, especially the fuel filter.**

Why is that?

Why is that? Maybe because at the push of a pedal you have a raging 345 lb's of torque that will throw your a$$ into the seat without problem :cool: And if you wanna go crazy with it, the L98 will take to mods really nicely.