Ok so i have an 88 2.8 firebird and it has a few problems that i cant figure out if my life depended on it. First thing first when i start the car in the morning it dies, i can keep it running by holding the gas a little for about 20 sec then once i let off it revs up and down up and down until its warmed up. Second while the motor is cold car accelorates great but once its warm it seems to bog down really bad, but i can push the gas to the floor and it will overcome the bogging and take off like normal. Third every now and then it will backfire through the intake. Me and my dad adjusted the valves so they no longer tick (we did it while it was running so i know its pretty close to perfect). I dont think its my cat cause ive got plenty of flow out back. oh and i had a code for the egr so blocked it off till i can afford a new one. PLEASE help me guys this thing is driving me crazy!!

All sensors are newish oh and i have pacesetter headers with an exaust leak on one head (not to bad though)

 

Congratulations...I think your injectors have decided they want a early retirement and no longer want to work in environment of your 2.8 engine.Make sure your fuel pressure is within specs and pull the upper intake and ohm each injector..not sure on the specs for injectors on 2.8 but assuming they are the same for the 3.1 which is 12 ohms plus or minus 1 ohm.anything less is probably delivering more fuel then needed.Its also possible the O2 isnt working if injectors dump additional fuel the O2 is the next thing on the early retirement list..

 

Well thats the thing i just had new injectors put in, they were the ford injectors but not the disc type. Another thing i realized last night while cruising down the highway last night. While keeping a steady speed if i let off the gas and pop the trans (auto) into neutral the rpms jump up to about 3000 then drop to 1000 then go back up to about 2000 then back down to 1000 then back up to 2000 where it will stay until i put the car back into gear. Im thinking this might be the TPS but im at a total loss. Anyone else have any ideas????

 

If you think your injectors or fuel system is okay..then its possible you may have some sensor issues.One sensor or the wiring is working but only some of the time.This is a MAF car right? so without a scanner to read live data your going to get a lot of suggestions on what it could be.TPS/CTS would be my next check.I never messed with a MAF sensor other then tapping it while its running and notice the RPMS.Thats one reason I wanted a MAP car ..dont care for the MAF deal.Without a scanner your going to have to do a lot of checking each system and component..otherwise pull out your wallet and hand it over to the auto store and hope something you buy solves it?.You can check the TPS off the car with a DVOM or on the car backprobing the wires?..

 

Yeah it is a maf car. And im pretty sure the fuel system is ok but the injectors i put in were remanufactured so i guess they could be crap. Ill borrow my friends volt meter and check the injectors and tps. I really just want to get the car running right so it doesnt give up on me before i get my 3.4/3400 built. Another thing ive noticed is that the temp guage is showing that the car is never getting over like 130, i know there are 2 temp sensors but could this cause the car to think it still needs to warm up?

 

Its possible the t-stat is stuck open and never closing so the coolant never reaches operating temp.If the ECM sees that it doesnt reach a certain temp it could think its still cold and increase pulse width ..which is dumping more fuel.Theres is two sensors one is for the gauge itself which is at the front of the drivers head and the other is the CTS which is just in back of the t-stat neck its a two wire sensor.At the back of your passenger head is the fan sensor..3.1's use the ECM to ground the circuit for fan operation so theres no sensor there.Make sure that t-stat is closing if you take off the radiator cap (when its cold) and start the car up you should never see any water flowing through the cores of the radiator(make sure its full too) if so the t-stat is stuck open..

 

Everytime iv had the intake off i always say to myself "man i should change my t-stat" lol but i never have one with me. I think this weekend ill be getting a new one along with a new tps. How to i clean/reset? the iac?

 

First it sounds like your cold start injector isn't working. You have a 7th injector.

2nd that rev up and down on its own is normal when its not getting signal from the 02, it goes into loop mode. Once warm it get proper signal and stops that. 02 sensors don't work until warm. Why everything newer uses heated ones for a near instant signal.

3rd my 2.8 was the same, fun when cold but once hot it got sluggish and I was on it harder, till I got my temps under control.

A true cold air / ram air system. Fresh cold air from directly outside the car, directly into the engine. I removed all the non working AC junk and the AC rad to get more air. And put on a good air dam. Most get broken from curb grinds. [ $30 ebay, airdam]


Mine runs crisp and clean, rev's fast and hard to redline like it should all the time.

[I also don't use a fan, I turn it on maybe a few times a yr as its only neede when I sit still for over 2-3 mins. Once moving, even slow I get plenty of cooling.]

 

Dont know if you have an auto zone where your at but they carry a 5 dollar kit that includes a throttle body to plenum gasket,o-ring for the IAC,and gasket for the top cover on the throttle body(where the air passages connect to the IAC valve)I use a throttle body cleaner comes in a can and just clean the tip of the IAC dont try to push or pull on the tip just clean it and re-install it.Disconnect the battery if you havent already done it..and once you rehook it ..do a Idle relearn..that should reset or relearn the position for your IAC.

 

How do i do the idle relearn. I know i know how i just cant remember the steps.

 

Oh and GUMBY when i first start it and it revs up and down it will die the first like 5 times unless i keep my foot on the gas. Im gonna disconnect my coldstart injector and put the new egr ive got on and hopefully that will solve everything. Ill keep you guys informed

 

If its a auto ..you need to block the wheels..if its a stick just start it up and let it idle until the fan comes on.if its a auto you need to place in drive and wait till the fan comes on(all accessories off).Hopefully your water temp gets high enough to kick it on and your fan system is operating correctly.I think once it reaches operating temp you could call it good(dont know whats considered operating temp) but once you achieve that turn it off and wait minute or two and start it up again .place in drive if an auto and run it for an additional 4-5 minutes then your done.Unless you have a scanner that has the idle relearn feature then you could skip it all..

 

Well got the new egr put on, and installed new TPS, although i do not have a volt meter to adjust the tps so i just did it by ear. AND>>>>>>> Now its fixed!! no more backfiring or bogging down!!! Idle is still rough but i think thats because of a header leak and kinda weak coil. Thank you guys so so so much!!!!!!!!!!

 

Sounds like you have multiple issues ??...glad you got some of the things solved.You might want to put a fresh set of plugs in it..sometimes running rough ruins a plugs performance.It might smooth it out ...Especially if its been awhile since you replaced them.ANyway hope you work out the rest..

 

I finally got everything fixed. Turns out a heated O2 sensor did the trick. I guess the pacesetter headers were not letting the o2 get hot enough, plus my o2 was pretty dirty lol. But thanks again everyone that helped! And i would recomend anyone with headers get the heated o2, my idle is perfect now

 

That will do it, without a good 02 signal to read the computer is allot dumber then usual

 

HAHA Also any one that hates that anoying reving up in the morning until the car gets warm i recomend getting a heated o2. Got in my car this morning and it was awesome, I started it was nice to not see the rpms go up down up down up down lol. Another thing my temp guage started reading right again???? WIERD

 

Not to hijack this thread but what brand and or part number was your heated O2 sensor ? What did you tie it into for power ?

kaycee

 

The one i got was Bosch and it was a universal 4 wire o2 for a 3.8 firebird. One wire was for the signal, one for heat/power, and it had 2 grounds one of which were optional. I ran the power off of the ignition to coil wire and the grounded it on the firewall. So far i have not had any problems, although i have heard that some people are sceptical of bosch. Im sure their are a lot of different options with vering prices but this is just what i went with. GOOD LUCK

 

Just hit ebay for a uni 3 wire 02 sensor, they all use the same threads, if its for a honda or a caddy.