oh man... i have some major problems going on with the bird. i've had three mechanics look at it and no one can fix the problem or even find whats causing it.

the car: 1991 firebird trans-am WS6. 305 TPI LB9 with 700R4 tranny. 99,xxx miles.

the problem: my car starts and runs half decent when cold but try starting it up hot and its a no-show. when it DOES start up after that, a cylinder or two is missing and i belch unburnt fuel out the back of my car. gas mileage is terrible. the car is slow as hell. the whole car shakes bad because of the problem.

the background: 4 days ago i replaced all 8 spark plugs and wires with AC Delco parts. spark plugs meticulously gapped at 35. fresh oilchange with 5W30. ran through injector cleaner for three tanks three weeks ago. replaced o2 sensor myself (which might i add was a b**** ). my girlfriend's dad and i set the timing back to 6 degrees just yesterday. after all of this the problem persists.


the car was running EXTREMELY rich and i was getting at best 2 miles to the gallon.. ugh. when it started getting warmer out, the car started missing and then two cylinders or so just ceased to fire. car wont start when hot. ever since i bought the car it's just going down hill. even after all of this work it's still running like crap.



is there anything anyone can do to help me trace where this is stemming from? anyone with a similar problem? this sucks too because i'll be going on a roadtrip with my friends this friday

 

sounds like an igniton coil to me. they work fine when cold, but then get hot when the engine warms up and start acting up, this would also explain your no-hot-start condition. if nothing else after 100K you probably need a new one anyway.

i hope this fixes your problem.

 

Ignition coil / ignition module are definitely worth checking. Are your sensor's all function correctly? I'd check the temp sensor, CTS, IAC just for the hell of it. Might as well measure the injector resistance since it's so easy.

 

firebirdjosh:
this injector resistance check... what does it indicate? i have never heard of this before.

 

I can't recall the exact ohm rating, something like 14 or 16 ohms, but it shows the solenoid is the proper specs. It doesn't guarantee that the injector flows properly, but it is a quick way to test if the electrical part is working. It's a fairly common (and easy) test.

 

I'm also feeling a distributor/ignition problem. Take your dist. cap off, and look underneath at the terminal ends. Look to see if they are clean, and there are no signs of carbon tracking. Also check the rotor button in the middle of the cap, and that it is not worn down. I doubt a fuel injector problem, since you say it ends up running real rich. That tells me plenty of fuel is being delivered, but not enough combustion. If the distributor cap and rotor button look ok, then take the ignition module to a parts store to have it tested. Good luck!

 

yeah, it's definitely something electrical related... and narrowed down to the distributor and ignition coil. tomorrow i'm going to take a ride [limp] down to the auto store and pick up an ignition coil. i'll also have to look at what pneumatictire recommended, tomorrow as well. thanks you guys, you'll be hearing from me soon.... off i go

 

now i'm gettin kinda mad.. i just replaced the ignition coil. it didnt help at all.

so far ive: replaced and gapped all spark plugs to 35 with ac delco units. replaced all wires with ac declo. replaced the ignition coil. did an oil change. set the timing back to 6 degrees. every cylinder is getting spark. everyone is getting fuel because it runs pretty rich.. no more pluming black smoke, it just misses REALLY bad when the car gets to running/hot temperature. the car runs at its hottest 220 and the fans kick in when they should be. im going on a roadtrip this friday and NEED this car to work... what the hell


anyone else have any suggestions? i'm also looking to sell this car because i'm fed up with the poor body work and half-a$$ed engine work. it LOOKS really sweet but it doesn't do me any good with a poorly running car that wont start when the car is hot.



anyone??? ahhhhhh

 

After a good cold start - does it continue to run good even after it warms up as long as you don't shut it off?

 

Did ya replace the ignition module under the cap on the dizzy? They are the cause of a lot of hot start/drivability problems.

 

no, after a good cold start (by good i mean it runs and takes maybe 3 seconds to crank. it still isnt running perfect but isn't missing cylinders like crazy when its hot) the car when it warms up, begins to miss and become extremely slow and shakey from the misfire

i havent replaced the ignition module... only the coil, plugs, wires, and o2 sensor. if i had more time to do this, i wouldn't be so pissed but man prom is tomorrow and friday morning i leave. i've been working out this problem for a little around 2 weeks

 

Id say it's a sensor I believe it's the IAT - inlet air temp. or the temp sending unit sounds like it running with the choke closed so to say. I know there is not a choke on a tpi but it sounds like your computer is keeping you car running like its cold. dumping the extra fuel and such..

 

You can also check that with an ohm meter.


I would say it may be that or the ignition module. Does your tach also jump around like crazy?

 

You have GOT to take that ignition module out and taken to autozone to test it with their stupid little machines. (Make sure you get someone who at least REMOTELY looks like they know how to do it). I also agree with the above, check out the tach in the car when it is running, and rev it up, watch and see how much the needle bounces around. If the ignition module test out ok, its time to be thinking about that whole dizzy itself, but don't just go guessing and replacing parts anymore. Test first, look for the obvious. If the ignition module and dizzy both end up being ok, do a compression test on all 8 cylinders. Verify they are withing 10% of each other. (IIRC 10% is the general rule of thumb for balanced compression.) Good luck, you'll get her figured out.

 

Umm...My car did that when the O2 sensor was not hooked up..You double checked that wire and installation..

 

Did you check the resistance of the injectors? When two of my (stock) injectors shorted out, (at around 100k miles) the car ran dead rich. They were stuck open.

 

I second checking the injectors.

Anything below 12 ohm is junk.

17 is stock

When they drop low they overheat the drivers and cause them to shut down.

Start there first, someone should have been able to do that easily, if no one was smart enough to, I would find 3 new mechanics.

later
Jeremy

 

well, i'm on mechanic four and i've suggested testing all of those for me and just replacing them on the spot (i know the guy and trust him) if anything is shot. only time will tell... if i got it back before 6 tomorrow id be the happiest guy alive. it's my prom wheels and jersey shore transport.. blasted car

 

My car behaved the same way when the coolant temperature sensor went bad. It was telling the computer that the engine was ice cold and causing the engine to run super rich. The CTS is the sensor on the front of the engine, next to the "U" shaped coolant hose. It cost $12 and took 10 minutes to change. Give it a shot if you are out of other ideas

 

I'm thinking CTS or MAP. Good luck.

 

yeah come to think of it, 3 mechanics couldnt figure it out? lol. They didn't think to check basics like injector resistance? Not hard to do, and it's also not hard to hook up an OBD1 scanner, and view the datastreme. That way you can see what temp the CTS is reading, if the o2 is doing its job, IAT reading, etc. Wow, good thing you are on number 4, hope he has a little more brains.

 

would a sensor with the coolant really cause the car to run so poorly and miss like crazy and be rich? i'll look into that..

and yeah lol first person who looked at it was a typical firestone "tune-up mechanic", the next was a friend of my father's friends who i thought was promisable because he used to be a mechanic but i think he was just drunk.. and the third was my girlfriend's father. he at least knew what he was doing, he looked it over for a half hour and fixed my timing but we were working in a rush. i'm sure if i gave him more time he could have found out, the guy rebuilt his 69 camaro SS and 71 chevelle himself so i know he knows his stuff more or less. oh well, it's now at a garage and we'll see whats to make of the problem.. i should be hearing back from them today, i'll put it up here when they figure it out- hopefully before 6 today! she's my prom wheeeels

 

Yes, the CTS can cause the problems you are describing.

If the CTS has failed dead short (or open -I do not recall which way) and is giving a false indication that the engine is very cold, like absolute zero cold, the computer will add fuel for the "cold" condition - A lot of fuel. The engine may still start cold, but will run way too rich. The warmer the engine gets, the worse that the overly rich condition will get.

On my car, when the CTS failed, the engine was missing and blowing black smoke so bad that it would barley move under its own power, I had to floor the gas to keep it running. It ran best for the first minute or so when cold, then rapidly got worse. However, I did get a code.

Basic troubleshooting would eliminate the speculation. Is your engine light on? Did the "mechanics" scan the sensors? A ruptured fuel pressure regulator may cause a rich condition without throwing a code. You could pull the vacuum line off the regulator and check for gas.

 

Again.... I'm with formula pilot on this one. If you follow his advise on this one, I bet you'll find your Gremlin..

 

I got word on the problem... here goes.

Distributor is bad, cap and rotor. And the oxygen pump went as well, and then he mentioned something about gas leaking somewhere it shouldnt be leaking but I can't remember it at this point. The car wont be ready for a while... No prom in the 'bird and no prom weekend jersey shore trip for the 'bird either... ****...

i appreciate everyones help SO much, pointed me to many routes to go and helped me single everything out. what does the oxygen pump even do?

 

Oxygen pump??? I would imagine it's the air pump for emissions he's talking about. Never heard about that causing drivability problems before. And as for distributor problems it's always been bad if they are bad, from startup hot or cold. I hope this guy is treating you right!!! Ask him about your blinker fluid & muffler bearings... AS for the gas leaking, I imagine that would be your fuel pressure regulator, which could be the root of all your problems. If you replace it get a adjustable unit..

 

well, my two cents says to hook up a fuel pressure gauge and see what is shows before starting the car with the ignition set to run. if it tests fine, start the car up for a while till its a normal operating temp. leave the car and tester alone for maybe an hour or so. check the tester after that. if its dropped, im gonna say the diaphragm in the regulator is shot. happened to my car and it sounds exactly the same as your describing. do you have to hold the accelerator down to start the car after driving it for a bit? and do you smell fuel in the upper intake manifold?

 

check the fuel pressure, the diaphram ripped in my regulator and the car ran like crap, pull the vacume line off the regulator to the manifold and see if it is sucking gas into the manifold through that vacum line if so then the diapghram is ripped inside the regulator

 

UH oh! First case EVER of a "oxygen pump" causing the car to run poorly! Are they sure your Kaneuter valve is good?

 

Too...funny.....

 

Update? Did the oxygen pump fix it? Seriously though, did you get your car fixed? Curious to know what was the real problem.

 

i was away the past two days. the car still isn't fixed. the car wont even start now. the only lead they had for me was that my "gas looked rusty brown, not golden like it should be".... i got ripped the **** off. by oxygen pump i figured they were referring to my vacuum pump, i dono. i was in a frenzy for prom and prom weekend and wasnt paying much attention. good thing they replaced my oxygen pump though, maybe now i can get that oxygen in there in line with my exhaust pump and get all that exhaust out of my cylinders...? i'm going down there with a crow bar and three of my other wop friends tomorrow afternoon and i'm going to have a chat with some of them.


they replaced my distributor, checked all the work i did, checked something else (who knows if they did) but tomorrow i'm going back down there because i didn't just get charged $330 for the car to now, not even start at all. carmine's going to have a stern talking-to with them... no one jerks me around.


if something ever gets figured out, i'll tell you all

 

being Italian kicks ***.



this plate (and my last name associated with it) has gotten me out of a ticket once.

for the uneducated
http://en.wikipedia.org/wiki/Gambino_crime_family



in regards to the car, i am with formula_pilot, check on the temp sensor after you get your car back. THIS is why i never take my car to mechanics. you spend WAY more to have them do nothing then you would to just throw parts at it until it works.

 

a wikipedia link to explain to me who the gambinos are!? cmon my name is carmine dominick and i live in northern NJ. as a matter of fact, in one town next to me (east hanover) at a pizzaria (godfathers pizzaria.. best around), the gambinos and lucchese were busted opporating a huge gambling ring involving millions and more pot and coke you could shake a stick at... happened just last week. you can look it up on dailyrecord(dot)com. the italian flag in my rearview mirror might've helped me a few times.

regaurdless... we went down there and it was a misunderstanding. they replaced my iac valve, not my oxygen pump lost in translation i suppose... we all laughed. even though the car doesnt belch black smoke anymore with the work they did to it, it's still missing horribly so i'm trying somewhere else as another last resort. jesus

 

This probably wont help much but heres what caused mine to do whats going on with yours

When I first first got my TA it was running horrible and was shooting out raw gas also like yours.

The previous owner had put in what they thought was a performance chip for the car, well turned out it wasnt even for the right engine. Later testing found that the computer itself had gone bad.

By replacing the the "performance chip" and the computer with a stock manufacturer one fixed the problem.
I would say check those two? You never know, that may be the problem.

 

I've been having a rough idle problem myself lately.

I do know a few things: The O2 sensor is broken and not in the exhaust - the remainder of the sensor is still there, plugged up.

I found a vacuum check valve that was literally falling apart - was electrical taped up. This one ----> Cruise/HVAC Check Valve

So - I pulled that Valve from the car and the 'vented' vacuum hose it was attached to, as I did, pieces of the hose and valve were just falling everywhere, lol.

In any event, I put a new hose on the Plenum where it was attached, capped with a bolt... and for a bit... it purred like a kitten. After it warmed, it seems to start idling rough again. Perhaps that's just a result of the O2 sensor, maybe - but for a bit, it was running top notch - I think I was even drooling for a second there... (or maybe that was the girl jogging by in the pink shorts... who knows, lol)

I pulled a spark plug outta curiosity and although the plug wires look 19 years old, the plug was surprisingly clean.

Still more bad vacuum hoses under there... But it was a very small leak and obviously it had a lot to do with the rough idle.

Why's it's idling rough again? If I had to guess... I'm thinking the lack of a leak on that hose, caused another one in poor shape somewhere in the engine to start sucking air... lol

I bought 8 foot of each size vacuum hose I had under that hood and I think I'm gonna need more, I'm pretty much at the point I'm going to replace all the hoses and belts, period.

But... you might wanna just go under that hood when you aren't stressed, and just look carefully and see if you can find weak or rotting hoses or connectors. It don't cost a thing to give it another look over, and even if you just start pulling and replacing vacuum hoses - heck, that's not expensive and never can really hurt at all.

It might be something insanely simple - I find a lot of times, when a problem is real hard to track down, it's because it was so simple, you didn't think to look.....