Ok guys, I have a 91 Camaro RS with a 305 TBI in it.

Basically about a week ago, I replaced my O2 sensor and since then the car has been doing fine. The previous sensor I had pulled out of the car was really bad, it was brown and crusted to the top. So anyways, I took the old factory one out and replaced it with a Bosch O2 sensor.

Things have been running great with the car, and I havent gotten a whiff of gas smell at all, and my fuel economy has increased substantially (I used to get 15 mpg previously, now I am raking in about 18mpg)

Until now, the car has been acting funny and the gas smell is coming back, not to mention the car still smells pretty bad from the exhaust. I dont know if my cat. converter is bad, or if something is wrong with my emmissions. I tried checking EECS filter but to no avail I wasn't able to pull out the filter to check it out. The hoses are tightly gripped on there. Anyway, I don't know what else I can do, I have basically done an engine tune up (I mean not the whole thing just partial stuff)

I changed out the spark plugs and I replaced the O2 sensor, everything else looks ok though....I am just worried about this gas smell, and fumes from the exhaust because this car needs to pass inspection in order for me to register.....

 

and not to mention, there is a slight ticking sound coming from whenever I accelerate the car.


This ticking sound, probably only started just about a month ago, but the white smoke on startup was always there before also.

I am really worried now because, alot of my friends suspect ts a blown head gasket which means my motor is pretty much going to be needing a rebuild or replacement.

The car still runs, and it runs great, I just done like hearing that ticking sound. It doesn't always do it, but about 60 percent of the time I hear the ticking sound upon acceleration.

I really need any info or input you guys might have, please

 

ugh please anyone I need an answer

 

91ChevyRS,
I'm going to try and help as much as possible without getting FLAMED by someone who knows more than I do.

You've described several different problems and I'm not sure but they COULD BE related to each other (Maybe not..). Let me try and help where I feel comfortable.

Head Gasket.
Just because you MAY have a bad head gasket doesn't mean you need to trash the motor. That should make you feel a little better. I've personally replaced several head gaskets on various vehicles and not removed the motor. The results were good in all cases.

IF the gasket is bad often (but not always) one will see water getting into the oil. Obviously oil with water in it doesn't lubricate properly hence the engine WILL become complete crap IF it is bad and you continue to drive it.
If your oil is milky brown - you definately have a problem and it is very likely a head gasket (although it could be a cracked block or head that's a bit less likely).
If you find OIL in the radiator/cooling system you definately have a problem and it is very likely a head gasket (although it could be a cracked block or head again that's less likely).
Since you see white smoke.... have you had to add coolant or water to the radiator lately? Normally, the system should be relatively sound requiring very rare additions. If you've had to add water it's sounding pretty good for the head gasket (again it could be a number of other items).
Has the car been running hotter?
Have you noticed any water or oil leaks? Where on the Motor?
Are your friends that think it's a Gasket skilled with engines?
Do you have any additional info?

Ticking sound
COULD be related to the head gasket as it could be a release of compression or that Milky Oil not proving proper lubrication to the lifters or other parts. I typically think of lifters or rocker arms when I hear the term "Ticking". Although without being there, it could be any darn thing. Whatever it is... It won't go away on it's own without some sort of repair.... It can only get WORSE.

Fuel Smell
I'm really almost making stuff up with this one as I have little experience with the TBI. A bad head gasket WILL screw up your ECM's input from the O2 and make it attempt to compensate. The O2 sensor is an integral part of the Emission Control System.... Probably the most important part.. If you've got a bad head gasket sending Oil or Water "Down-Stream" at/toward the sensor your ECM is going to be all screwed up trying to lean out and/or richen the mixture to make emissions right. Hence... FUEL SMELL!

You should probably take it to a shop and have the Cooling system pressure tested that can tell (almost definatley) if you have a bad head gasket.

You can also do a compression check and make sure that all the cylinders are very close to each other in compression.

Whatever is going on with that motor.... It's not going to get better without repairs. Your 60% of the time ticking sound will soon be 100%. If you WANT to replace the engine...KEEP DRIVING IT!

Try and provide some more information if possible. Maybe some of the other TGO Guys will chime in soon with some good advice. But....without being there to look, listen, and drive it, I don't believe anyone on this board can DEFINATLEY say to you ... IT's this "Gizmo" or that "Thingy" you need to replace or repair.

I hope this helps.... It's about the best I can do!
Kurt

 

Head gaskets are nothing, $50-75 in parts and easily a weekend job and thats cured.

 

Depending on the mileage on the engine there are couple other items you might consider replacing (i.e. Lifters) while you have the top-end apart. That COULD be considered optional depending upon how much $ is available.

Kurt

 

Hey 91Chevy

I had a similar problem on my first Camaro, the ticking noise turned out to be a leaky exhaust gasket, but like kboe said it could be a head gasket, I also owned a Ford truck that ticked and it was a exhaust gasket.

As for the rich smell, 83RedCamaro (whose is never one here) had a TBI car and it was a list or problems that we fixed to make it pass emmissions and get it to not run so rich. The tune up, and O2 sensor are the place to start, also like kboe said, have the cooling system tested and a compression test done to rule out internal problems. but with my buddy's TB it turned out to be a bad TB unit, it was dirty and clogged, as well as the injectors were out of spec when they were hot causing the car to run rich when it warmed up. if you want to test them your self, get a Ohm meter, multimeter, or DVOM and set it to Ohms, or resistance. then run the vehicle and get it up to operating temp, basically when the temp gauge in the dash levels off and goes no higher, a good 20-30 minute ride will get it there. then shut the car off, remove all the mess on top of the TB and then unclip the connectors to the top of the injectors(they should need to be squeezed ad pulled right off) then take one test lead and touch it to one side of the injector, and the other test lead to the other side or the same injector, and write down that number. Repeat with the other one.

!!!NOTE: DO NOT "PINCH" THE LEADS TO THE INJECTOR WITH YOUR FINGERS, YOUR BODY HAS NATURAL RESISTANCE AND WILL SCREW WITH THE RESULTS!!!

Now i dont have the specs in front of me but i can try to get them for you, otherwise search online, in a Chiltons/Mitchells/Haynes book(thats where i got mine from) or some one on here may chime in and let you know. But there is a range that they need to be in, and they CANNOT have more then a 10% difference between each other (it maybe 15%, go with 10% it is better). If they are out of spec (meaning that they has less resistance then normal) that is a good indication of a rich running car which maybe why your O2 sensor was gunked up. But if the resistance is higher then your are running leaner, cause then it takes more electrical "power" to operate the injector, and since it is a set voltage then it does not operate properly. either way it is off to the junkyard to pull a few sets to test or off to a parts store(which is A LOT more money to buy new), but other than that good luck and let us know!!

and if anyone sees my theory/understanding is off, let me know nicely!!

 

well I checked the oil today, and its...brown.

Now that you mention I have developed a slight oil leak under the car, and as far as I can tell there is no water anywhere in the engine.

However oil should be the color black and not brown as described before....


Personally I am a little pissed off, because this car is my only set of wheels right now. I think it is a blown head gasket, because on top of all the commotion, my SES light comes on every once in awhile (its becoming more and more frequent, once very three days now)

Well I guess thats that then, its most definitely a leaking gasket or blown gasket.

I guess I wont drive it......until I figure what the hell this car's problem is

 

How many miles are on it? Has the engine been rebuilt? Has the odometer been "rebuilt"?

 

109894 or something like that...

almost 110k miles, I am just angry, frustrated. I have done every thing that I could do to this car.


I changed out my spark plugs last month, switched out the O2 sensor this past week, I mean what gives..I dont even know where to start on a blown headgasket or where the hell it is on a TBI motor.

I'll leave it for tomorrow and take a closer look at it, maybe the TBI is bad, or clogged or something, or maybe I really do have a bad gasket. If I do have a bad headgasket, I CANT do it, the Haynes Manual I bought doesnt tell me where it is or how to pull it out and replace them, I might have to take it to a shop and then thats where I fall...the parts are always cheaper but then the labor hits me and then its going to be an expensive job...

UGh

EDIT: There was never an engine rebuild, the car doesnt have that many miles, its a damn 91 with 110k miles on it. Yeah its still a bit but....considering it an almost 15 year old car thats not bad at all.

 

Well here's a low buck suggestion. If the SES light is coming on the ECM is storing fault codes. Swing by Auto Zone/ Advance auto etc. and have them read the stored fault codes for free. Report back with the info. Unless you're like a lot of guys here and love to tear down an engine, spend a little more time troubleshooting instead of pulling heads off / buying injectors that might be bad.

 

the Autozone here only does the SES light for 96 and newer vehicles...

 

Sounds like they need to be recalibrated.
If you have a paperclip you can read them yourself.
Instructions are HERE as well as some other usefull info.

 

91ChevyRS,
Don't get too discouraged. Everybody on this web-site started somewhere and we didn't wake up one morning and know how to change a head gasket.
I know how you feel! Really!! I've rebuilt a dozen motors++ and have been doing auto repairs on cars, motorcycles, snowmobiles, and my friends machines since I was in High School (almost 30 years ago). Yet a few months ago I was at my wits end with my Son's CCC-Carb. I didn't know ANYTHING about setting up a CCC-Q-Jet and now I think I'm pretty knowledgeable, and the car runs GREAT!

A Head Gasket Change will take a few decent hand tools, a little time, some reading, and help from friends. You can get a great deal of help right here on TGO. Maybe one of your home town friends that told your head gasket was bad can lend a set of actual hands? I've done a lot of repairs for a handshake and a good Steak dinner, maybe your hometown friends are the same?

You don't sound like your skill level (today) could get you through a head gasket alone. If you feel brave a lot of guys here at TGO will help a great deal!! That Haynes Manual MUST have a decent set of instructions you should read it 10 times!

Here's a photo of where the head gasket is located. Basically, you have to remove everything from the top of the engine. Replace the gasket. Put it all back together. A very skilled mechanic could do the whole job in a day, easily. With help from a semi-skilled friend and TGO Guys you should be able to do it in a long weekend without much trouble.

If you feel brave I'm willing to help as much as possible. I know a bunch of other TGO guys will help also!!

Sincerely,
Kurt

P.S. Where the heck are you located? Ya' never know.... Maybe someone here at TGO likes steak dinners and is from you neck of the woods!

 

Kurt, I must pay you my utmost thanks in all respect, you have truly contributed enough to me...

I will definitely take a look at it this weekend and see whats up with the car. Its still driveable, it still goes, even with all the crap its going through, it never left me stranded on the side of the road, or blew up straight in my face. Its just all of the little nicks and nannies here I dont like bother me a little much and I really want this car to run at its utmost best.

However, since mine is a 305, would the head gasket still remain in the same place? I will look through the manual tonight and see what tips I can get from gaskets and the lot.

I have quite a few friends here who are mechanic car junkies and they are basically, my main source for information and what not. They have helped me a great deal getting to know my engine, they helped me change my spark plugs but I did the O2 sensor by myself.

I'll definitely have a look through it though, by the way one last quick question....

IT is bad if the oil is colored brown right? The oil should be black straight from the dip stick right? Because as you stated it is milky chocolate brown almost. I will decrease my driving habit and will only use the car if totally needed.

 

head gasket will be in the same place - and also your oil should NEVER be black black. Light caramel to a medium brown is all it should ever be. Black oil means it's way past time for the oil to be changed. If you're that worried about the color of your oil - compare it to the color of a known good car. Colors should be close to identical.

 

91ChevyRS,
ALL Small Block Chevy engines are the same basic configuration; 305, 350, etc. The real differnces are in the INTAKE System. That's the area between the heads. The TBI and Carb as very very very similar. The TPI Tuned Port Injection is the really different one and once you get the Intake off it's the same as all the rest of the SBC (Small Block Chevy) motors!

If your oil looks like A Chocolate Milk Shake. YOU really must stop driving it. Rent, beg, or borrow another vehicle or even a damn bicycle. Right now you have probably $75 work of parts you need. If you keep driving it, the motor will be TOAST and you will be screwed! That oil CANNOT lubricate properly!!

Sincerely,
Kurt.

P.S. You have a PM (Private Mail)

 

hmm,

being the devil's advocate here for a second, when I read your original post of the problem, you may have been on a decent track of diagnosis to elimainate a possibility.

You mentioned you were trying to get at the charcoal conister filter right? That still wouldn't be a bad idea especially because of the gas smell you mentioned. You should be able to just remove the hold down bolt, pull it up out of it's hidey hole and turn it upside down to get the filter without disconntecting anything. The most I've ever had to disconnect was the solenoid wires and a vacuum line once or twice, never the hose(s). But if it is indeed the cause of the gas smell, I don't think a filter is going to remedy it, it will probably need replaced.

AND, if the canister is indeed experiencing problems and filled with gas, MAYBE the ticking sound is you A.I.R. system tyring to work overtime due to this?

It's worth a shot before you go tearing into the motor, to wich I'd say a compression test to first. If your oil ends up o.k. it probably an intake leak, what does your coolant look like? I had a leaky throttle body gasket cause me grief becasue I opened my radiator and saw air bubble in it when I was blowing white smoke. And I almost started ripping it apart thinking I was 99% sure the heads were gone. Well voice of reason told me to look into the other 1%, did the test, and saved myself a lot of time.

White on start up only could also be a leaky vacuum modulator diaphragm on the tranny too.

 

Think I'm gunna play devil's advocate as well.


two words should do it for yah "exhaust leak"

The ticking sound can come from an exhaust leak. The burning rich can come from an exhaust leak (it tricks the O2 sensor into thinking that the car is running leaner than it actually is, so it dumps more fuel in).


As for your oil being brown and not black. Brown is good. Chocolate milky is BAD. Black is bad too! If you have black motor oil, then you had better get it changed cuz it's way over due


What you should do is get some seafoam from the auto parts store. Then take off a vacuum line (not a major one), then with your motor on, put the vacuum line in the seafoam and let the motor drink it up. It should start to smoke. If it doesnt, then move onto a bigger vacuum line.


What you are going for with the smoke (out the exhaust) is that you will find out exactly where the exhaust leak is, so that you can patch it up, and be on your merry way!


Honestly, I've read maybe 1/2 of the posts here, so I'm sorry if this is a repeat.

 

false alarm guys.....nothing wrong with the head gaskets, everything is functional.

I went to the good folks at a local motor shop and I had the guy take a quick look at it. He said the oil is just fine, there's no water in your engine, and he scanned my car for free and told me all I needed was a new EGR valve, and I believe something called a new EGR sensor or solenoid....one of the two needs replacing as well.

Apparently this is what is causing my car to smell bad, and if I get this fixed it'll take care of the SES light and the fumes so my car will be breathable around without a risk of getting a terminal virus....

I must say I got a little worried but all is well, apparently the TBIs are far more stronger than I thought they were. I dunno if the ticking sound is related to the EGR valve but I checked up on the Haynes manual and looked up pinging or knocking engine sounds during acceleration (which is what my car does) and they said one of the problems can be a faulty emmissions system.

I tried doing the EGR myself but my work space is far too limited for me to even attempt at nabbing it.

Hopefully all will be well, and this car will be back in its prime running condition.