jbradshaw77

SUMMARY OF ISSUES:

- Poor MPG (12.4 mpg typically)
- Car must be started twice
- Smells of gas (heavily) upon exiting the car
- Bogging while going from one gear to the next
- Poor/slow acceleration
- Sulfur smell while heavily accelerating or going up-hill
- Very rarely, the car will turn off while sitting at a red light



Hello and thank you for taking the time to read my post.

I've had my automatic '86 V6 Firebird SE for about 9 months now, and bought it at 88,000 miles. The car purportedly sat in a barn for about 13 years prior, and by the look of it was very well-kept.

I live in North Florida, and the climate here is typically very warm.

Initially when I bought the car, the only issues relating to gas was the smell of gas after exiting the car, and low MPG. Those issues still exist -- I get around 12.4MPG, and I always smell gas when exiting the car. I do not smell it inside the car. I do not have a lead foot.

Going uphill or putting a lot of pressure on the gas pedal sometimes does give me a sulfur-like smell coming from the front of the car which I can smell on the inside. I would believe this to be my catalytic converter, and I was curious to know if anyone thought this was related to my other issues.

I only use 100% pure gasoline in the car.

The main issue now is that the car bogs during the first 45 minutes of driving it of the day. The issue does somewhat subside as the day progresses. The car always takes twice to start in the morning -- I put the key in the ignition, turn the car on, it sounds like it starts just fine, and then it just turns off (it's as if it hits a high rpm, and then just drops, within a few seconds). I wait a few seconds, turn it on again, and it holds steady, with maybe a slightly noticeable drop in RPM after a few seconds, but it does stay on. I never have to turn it on three times. And, I normally only have to do that during its first start of the day.

I pull out of the driveway, drive a little, and then stop at a red light. After being stopped, as I proceed to make a turn, the car hesitates, bogs, revs over and over and over, and then eventually lurches into second gear. This happens turning over to 3rd gear as well. It appears to happen mostly when I am turning, and especially when my car's nose is pointed downwards -- surprisingly, less so while going up a hill. It does still happen though.

The car feels as though it is not accelerating at a pace that it should be. I realize it is only a V6...but I always feel bad for folks behind me because I can just never seem to accelerate well enough.

I recently (within the last month) replaced my fuel filter with no change.

Very rarely, but on more than one occasion, the car has simply turned off while sitting at a red light for no apparent reason. It starts back up just fine with no other qualms.

My question is, what could it be, and does anyone have experience with this sort of issue and dealt with it with success? I have read through old forum posts here and understand that it apparently might be my fuel pump, fuel pressure regulator, sending unit, injectors, catalytic converter, ignition module, fuel lines, fuel tank, 02 sensor, throttle position sensor, base timing, charcoal canister, and who knows what else. I'd like to narrow it down or simply hear of other's similar issues to give me a better idea of where to start. I understand, however, that if it may indeed be any of these that I may just have to pick one and go from there.

Thank you again for taking the time to read this, and for any feedback you might provide.

brettr81

Ok, a car needs 3 things to run, and they need to be at just the right quantities or it won't run right. You need air, fuel, and spark.

It sounds like you are either not getting enough fuel or running really really rich. Check the fuel pressure, check the injectors (probably really nasty if you didn't clean out the tank after it sat).

If you didn't replace the spark plugs, that could be making the issues worse. I did know someone that their car would stall out and not run right because there was a mouse nest clogging the air filter.

What did you do to get it running, before driving it?

HitchDav

I had some similar issues. My car would start rough, if at all and usually better the 2nd time. At red lights it would often stall, and I was missing power that it used to have. I wound up changing the plugs (they were due), the entire distributor/cap/rotor, repairing vacuum lines, and DISCONNECTING the charcoal cannister. Up to the charcoal cannister, everything made minor improvements to the car's condition. Mind you, it did need the tune-up and distributor, but that was my own fault from a previous repair.

Bottom line, try the "free" fixes and checks first. Look for vacuum leaks and try disconnecting your charcoal cannister. If it is stuck open, it may be starting too rich in the morning and running fine after you crank it the 2nd time. It could also be messing with you ari:fuel ratio when idled. You can have autozone check your ignition module for free, ut call first as not every store does or has people trained to do it. Check you base timing to make sure it matches the manual/hood sticker. For my 92 V6 stock is 10* BTDC, which I believe to be the same for yours. I see many poeple on this board run a bit advanced at 12* instead though.

jbradshaw77

Thank you very much for the informative reply.

I purchased the car from a dealer (close to the family), and I humbly admit I don't recall what all they did to it beforehand. Perhaps it is safe to assume they did not change out any spark plugs, and I should just proceed with a complete tuneup.

Is there any easy way to check the fuel pressure? Or is that best left to a mechanic? Sorry, my knowledge of cars is fairly limited, but I have a basic understanding of things.




Thank you for your reply -- you know, when I first got the car my very first suspicion was that it was the charcoal canister. How did you disconnect yours? And, what's the best way to check for vacuum leaks? Your post was very helpful, thank you.

brettr81

Definitely take out the plugs and look at them. The condition of the plugs will tell you if they are due to be changed, you're running rich, or running lean. Pretty much, I'd start with looking at the plugs. Then I'd go with a fuel filter change (a lot of people and places don't change then. A clogged filter can lead to similar issues to yours).

Run some fuel injector cleaner through your tank as well.

HitchDav

Look around the forums for a charcoal cannister delete thread, there are plenty of them here. To do this temporarily as a diagnosis tool only, find the line which runs from your cannister to your engine(labeled purge), disconnect it, then take it for a drive. I suggest disconnecting it when you are done running the car for the day so you will know if it is causing your start issues as well.

Vacuum leaks can be tricky to find depending on their size. If you do a google/youtube search you will find just about every conceivable way to test for vacuum. Two of the most common ones I have seen are to VERY CAREFULLY spray brake cleaner on connection points and suspicious looking lines while the car idles. You will hear a change in engine speed if the line has a leak. Wait a few seconds between sprays, do this with EXTREME CAUTION as this stuff is very flammable. Personally, if you don't mind a cigar, you can smoke a cigar and either blow smoke over a line with the engine running to see if it is sucked in, or you can blow smoke directly into the vacuum system, such as the brake booster line (big line running to you brakes) and look for smoke exiting the engine/vacuum lines.

Testing fuel pressure: you will need a fuel pressure gauge. There should be a test port on the fuel rail. For my 3.1L it is located in the back of the engine under the upper intake manifold. You will need to own or purchase a fuel pressure test kit for this, just make sure it can handle 50psi or more. You should let the engine sit the the gas tank open a few hours to vent the line. Look around for instruction on this, but in general you will connect the tester, turn on your engine, read the pressure, turn it off, and watch for when the pressure drops. Look around for your engine, but ~40psi is expected. It should stay at this pressure for a while if you don't have any leaks in the line. Mine dropped from 40psi to 35psi after 30 minutes when I tested it.

Are you seeing a check engine light in any of this?

Galaxie500XL

iTrader: (1)

A scan tool would be invaluable.

Have you checked the coolant temperature sensor? If the ECM thinks the engine is cold, it adds fuel....could be it's reading way low, which is why after running for a long while, it seems to improve.

zs&tas

Hi, lots of answers here, but start at a basic tune up, look at the colour of the plugs when you remove them, they will tell you alot. My charc canister is fully removed , I just plugged the fuel line that goes to it, it got me mileage back and got rid of my fuel smell !

Not sure what engine you have but there is a cheap way to read computer codes on our cars with a paperclip, that will also tell you things that are not giving the computer correct readings. There is a port under the steering wheel, engine off use paper clip to join pin 5 &6 counting from top left. Turn ignition on and the dash light flashes the codes. Just count the flashes and pauses, a note pad helps.

jbradshaw77

Thank you all for the tremendously helpful and insightful responses. I promise to update this thread as I make attempted repairs and will be sure to include a solution, if I do find one.

How exactly did you plug the fuel line? I've read a couple of threads but I am not understanding the best way to cap it. Duct tape it perhaps? And would I need to get a vented gas cap afterwards?

zs&tas

Took the rubber hose off the hard pipe in the engine bay then got a sealant gun and put a good load of that down the pipe. Job done. Tanks vented anyway.

Hopefully stop your first problem when u got the car.
The running may take more time , coolant sensor will make it run crap like that.? Just got to systematically go through and check everything !

jbradshaw77

Interesting, okay. Thanks a bunch!

Follow-ups to come...