Hey Group back again

I have an 88 Firebird Formula with the 5.7L 350 TPI. Just had all of this redone after it was sitting for 3 years. It was run every now and then but never any long driving.

Battery, Alternator, IAC, TPS, Fuel Pump, Radiator, Thermostat, Oil Pressure gague switch, Valve Stem, and All fluids were flushed and replaced with new.

Right now it is starting up great, it will Idle at 900-1000 rpm for about 5 min then drop to about 650-750 rpm. I will be driving and once I come to a stop the RPMs will drop and the engine will go dead. Turn the key and she starts up, but at every stop It feels like its gonna die. On another note when it is in park it will be idling around 650-750 rpm and I can push both window switches and the RPM's will drop down low and it I mess with it enough I can get the car to die. Again, turn the key, she starts up. Engine runs very strong when driving except for at low Idle

With an electric draw there shouldn't be a drop in RPM's. What could this be? It is blowing my mind! HELP HELP HELP The weather is finally nice and I need to be on the road again.

 

spark plugs...pull one, if its rounded tip,replace em...you'll thank me later...easy to do..happened to my 91z..thought it was my hypertech chip..i was wrong...learning the hard way really is the BEST way...

 

The only thing that really clicks is the IAC but you said you changed it.

 

change your cap/rotor too..easy to check..if you see white/flaky, or carbon-charred,you got your answer..all cheap parts,may have got overlooked..specially since its been sittin'...

 

I really appreciate the quick responses. I will check the plugs, rotor, cap. Probably just upgrade them all now instead of waiting. What should the normal Idle speed be on this car? It does have up graded Throttle Body, MAF, Headers, exhaust, under drive pulley.

Also should I reset the IAC? or is it at the right idle

 

im pretty sure one of my suggestions will get you back running just fine...almost too obvious..thats why it gets overlooked...try and get cap with brass contacts,not aluminum...no real price diff....

 

oh yeah, just read you got pulleys too...got rid of mine..was rollin' thru alternators all the time..hated em...went back to stock....not sure bout your idle, but guesstimate at 800ish,steady, in park...

 

Alright guys, Changed the distributor cap, carbon all inside dirty overall. Running sharper but did not fix the problem.

I did not get a chance to look at the plugs yet, do they need to be torqued down when i put them back in? Also does the car need to be lifted to replace all of them?

Check the videos let me know what you think:
first one is at idle, running about 20 min, started at 1000 then dropped to where it was and the drop in the idle is from drawing power from the window up switches.

http://www.youtube.com/watch?v=SO9ZlimgJEk

Second I have the engine revved and the same thing happens even at higher RPM's with more fuel being added from the gas pedal. Then lay off the gas and let it idle and rev again

http://www.youtube.com/watch?v=7idQZzvXTcM

 

One more thought could the under drive pulley be causing this since the alternator would not be spinning as fast?

 

i can tell when you do windows by looking at your tach..losing that "parasitic" power loss..The pulleys are worthless,and making your alt/bat work harder..you replaced the dist cap...didja also do the rotor?...cheap,its inside your cap(fyi)...not sure how savvy you may be,no insults intended....change your plugs..do you remember when you changed em last..no?,,replace..No#6(i think) may be the hardest(i have headers)..these parts need changin anyways..do it,get back to us...we gotta know!!..PS..Hows the "safehouse-bar?...

 

one more quick Q..when you go out and drive,and come up to red light,and brake hard,does your car act as if it wants to die?..or come close to it?...

 

Hahaha the safehouse is an interesting place, good novelty but not a usual place to hang. Have to go at least once.

Noticed O'Hare on your profile, i grew up in Chicago and then lived in niles for high school years.

I am taking out the under drive pulley tomorrow. Everything I have been readying says bad idea. I am not looking for a strip car and can get more HP with other upgrades later that won't f*** with my electrical system. On another note I picked up the car in March and the previous owner had done these mods (yes he put side pipes on it to witch are going to come off). Thankfully he left me with the old pulley (and full 3" exhaust) just need to pick up a new belt and put the pulley on.

I did the cap and rotor, picked up the Accel one with Brass tips. I have edelbrock headers on there too. Can all the spark plugs be pulled from the top, only reason i'm asking is if I need to make a trip to Chicago to pick up my jack stands. If it is possible I would like to save the trip lol. Also do i need to to torque those down?

Its just like the issue in park, the longer it goes the more it wants to do it. Then will just give out and the battery meter will be around 8. turn it off and give it a sec and it fires back up. Fast RMP drop it wants to die hard.

 

yeah,im in park ridge..not sure if plugs can all be removed from above..i thought the "difficult ones" were pulled from behind front tires(remove them for access,i think)..after this car sat for X amount they need replacing..quit chasing tail,replace plugs,gap em properly..yes should be torqued,but common sense applies too,and can be tightened with socket..use plug grease on your boots too...if its worth doin', do it right,will save time..and money down the road...have a set of car ramps i could sell ya,if you come this way..if interested...case of spotted cow,and theyre yours!!!..for real!

 

Doing the plugs tomorrow.

Anyone know where to get stock pulleys for 5.7L 350? The idiot I got the car from ended up giving me the wrong ones and I didn't notice untill last night after cleaning them they had ford stamped on them.

 

Get the car up off the ground using a floor jack so that you can get two jack stands up under it in the front in the proper locations. Using a floor jack you can lift the car from the k-member (so long its the stock k member). This is by far the easiest and most time efficient way of changing the spark plugs. Otherwise, you'll find yourself angry and cursing the car if you don't. I learned the hard way when I first changed the plugs. Good luck!

-T

 

Oh and the gap is .035, if you didn't already know!

-T

 

New spark plugs in, gap at .035, plug grease on threads and caps. All in and engine is running sharper. Still having the idle issue. Feels like it is going to die when I am at a stop light and in park very low idle, seems to bounce a little as well. End up pulling up to a stop with feet on gas and brake. But over all engine sounds better and is running sharper, tons of power at high rpm's, also turning over easier when heated up.Also ordered a new crank pulley to get rid of the overdrive. Possible new coil?

Help me het this back to normal.

Drove it more today, engine seems to be at 700 rpm's and now only drops to about 600 when i pull some power. Not nearly as bad as before. What if i set the idle higher on the car?

 

Are you running the TPI set up? If so, then check all your vacuum hoses because overtime they develop small cracks that can disrupt the the various vacuums they are suppose to keep normal. Also check your EGR valve. This valve is also known as the exhaust gas re-circulatory valve. It circulates exhaust gases back into the engine so when under load the pistons do not ignite early from the intense heat. When your EGR valve goes out it simulates a bad vacuum leak. It simply becomes stuck open from built up carbon. Hopefully this is a step in a good direction. Good luck.

-T

 

Also, even with a normal intake manifold you should probably check the vacuum lines and EGR valve. Anything that has ever thrown off my idle and caused the car to die when slowing down or putting in the clutch was related to the EGR valve and/or vacuum lines.

-T

 

Yes it is a TPI. I am not familiar with the vacuum hoses. Which are they, are there any good threads about them (checking and replacing)?

 

Oh its fairly simple. There are rubber hoses and plastic elbow hoses right around the plenum and runners for the TPI system. They are a cheap fix and if you spend some time and work through it, you wont have any trouble. Just take your time and jot some stuff down that you notice. Measure the hose diameter and go to your local auto parts store, or take a piece of the hose with you and have them give you X amount of length. Also, consider a new EGR valve or check to see if it even moves. You can do this by putting a finger underneath and pushing up on the valve. It is a bit trick with the TPI system to replace. I am going to be taking mine apart here soon because I am pulling the engine and rebuilding it. In the process of doing that I can take photos of how to properly uninstall the EGR valve. Just remember if you do it yourself, take your time because you don't want to break stuff. The car is older and parts are frail. Best of luck.

-T

 

Also noticed when i lifted up the car the last owner really did a great job (not) of putting on the exhaust. It looks like it is just sitting against the header and not even really connected and there are crazy 90 degree angels. Think this could be a problem too with losing back pressure?

-John