View Full Version : car trouble (vacuum, exhaust or ?)

05-31-2002, 09:31 PM
I've got an 88 Chevy Beretta that just started running rough and obviously is in need of repair, I'm planning on taking it to the shop tomorrow AM. But I think I'd like to have a clue first of some possible problems.

The Symptoms:

Runs rough, like it is missing, and doesn't accelerate even when I depress the gas pedal.

A bit of Smoke was coming into the passenger compartment when I stopped. It was comming in from the console between the seats where the emergency brake is. I looked underneath and saw smoke coming from under the car in this area, it could have been the catalytic converter, but I think it was a bit further back.

Seemed to get high RPMs without shifting, in fact seemed to only be in one gear. Occasionally it would shift with a big "jolt."

I opened the hood and heard distinctive hissing of a vacuum leak, when I found the culprit line and jiggled it, the engine ran differnently, though I wouldn't say it was consistently better.

So I'm thinking I need to get the vacuum lines replaced, (I think cheap). Or maybe my catalytic converter is plugged (not so cheap). Or worse it could be something dramatic like the head is blown, or transmission (though, it runs rough regardless if i'm in park, drive or reverse.)

So before I take it to Midas and say fix it, I'd like to be more confident and tell them "I think I need the vacuum hoses fixed. or " I think I'm screwed."

Is this enough ifo for the teeming couple hundred to help with

Joey P
05-31-2002, 09:36 PM
As far as smoke in the passenger compartment, I'm not sure about that, BTW did it smell like exhaust or something else?
My guess would be a vacuum tube, since you said it was different when you jiggled it. It don't go compleatly back to normal because jiggiling it didn't compleatly seal the leak. Also you said it sounding like it was missing. I'm not sure about your exact cars but IIRC alot of cars do use a vacuum advcance distributor/rotor system, so that's probably what the deal is.

OTOH if it is your catalytic converter that's causing problems, you almost for sure have something else wrong. I remember hearing somewhere that CC almost never ever go bad all by themselves. If they go bad it's a sign of a problem further upstream.

06-01-2002, 01:27 AM
I've seen cats glow literally red-hot. It may be plugged. Like Joey P said, that would most likely be a problem upstream, maybe running too rich for too long.

A misfiring engine can cause unburned fuel to go through exhaust system, foul 02 sensor, etc. which in turn can plug your cat. A plugged cat can cause you to not have power like you described.

A vacuum leak can cause a higher than normal idle causing the 02 to read the fuel/air mix as being lean and start dumping more fuel.

What size engine is this? A 2.8? IIRC this engine doesn't have a vacuum advance distributor, that is all handled by the ECM by that year.

Misfiring...check wires for chafing, possible one is arcing to ground.
Check plugs, may be worn or porcelain insulation cracked.
Sometimes it's the coil, if it's the separate type coil packs...
Try running a cylinder balance test with a test light and vacuum lines between the plug wire and the coil pack (if you've never seen this then don't do it, you can get shocked--not fun).
Sometimes, it could be the ECM starting to crap out.

Are you stalling? Are you getting a "Check Engine" light?

I forget which particular motor it was, but the design was bad where the s/p wires would get chafed by the air filter horn, and it would start misfiring because it started going to ground through that route instead.

06-01-2002, 09:04 AM
friend sigene,

it was once my misfortune to own a 1985 s-10 blazer. it had the 2.8 liter engine, and we had an episode similar to your symptoms. it sounded like a vacuum leak and what little power the engine had before was drastically reduced.

our problem turned out to be a leak around the throttle where the throttle linkage enters the carburator. it required replacing the carburator.

when a drunk in a volkswagen jetta turned left in front of my daughter while she was driving the blazer we were momentarily concerned until we found that no one was injured. after that we considered the damage to the blazer as a mercy killing.

06-01-2002, 01:44 PM
IIRC the 88 Beretta has fuel injection.

Gary T
06-01-2002, 03:09 PM
Going into a shop and telling them what to fix is sometimes a recipe for disaster. If they simply do what you instruct, and your evaluation is wrong or incomplete (which is particularly likely in this case), you can easily be in the position of having spent money for work that doesn't solve your problem. And since they obligingly did what you asked, it's pretty hard to fault them for it.

It's analogous to going to a physician and telling him what disease you have and/or what treatment you want. You're really much better off letting the professional do the diagnosis.

It is important to deal with the right shop. There are, unfortunately, lots of problems in auto repair. They typically show up as unnecessary work done and work poorly done, and too often it is difficult at best to get these problems satisfactorily resolved. Most auto repair problems are rooted in lack of competence, sometimes aggravated by lack of accountability. The best approach is to choose a facility that knows what they're doing and deals honorably.

In my opinion, the chain auto repair shops are not the best choice for the type of problem you describe. They specialize in routine service items which can be handled by entry-level mechanics, and tend to train their personnel to make sales rather than to develop sound mechanical judgment. The top flight mechanics typically are at the dealerships and the better independent shops, not at the chains.

My suggestion is to direct your attention not at figuring out what's wrong with the car, but at finding a qualified, ethical shop to take care of it for you. Ask for referrals, not just from customers but from industry source, such as parts stores that cater to shops (e.g. Carquest or NAPA, not Autozone). Look for ASE certified mechanics (the new term is technicians--just semantics), ideally certified in most or all of the eight test areas, rather than just a couple. Look for membership in trade associations (ASA, ASP, ATRA, etc.). Check with the Better Business Bureau. Go to www.iatn.net and find a sponsoring member (name should be in blue) in your area. You're much more likely to be successful at finding a good shop than at engineering a good outcome at a poor shop, even with helpful information from this board.

Keep in mind that good work doesn't come cheap. The best shops can't afford cut-rate parts or mechanics who are willing to work for peanuts. Sometimes, the best bargain is paying a fair price for good quality. And sometimes, you'll spend less getting a proper evaluation and doing the right repair than you will on "cheap" repairs that don't help.

Chris Luongo
06-01-2002, 09:56 PM
Hey wow, Gary T really knows his stuff! As he said, Midas' strong point is that they can quickly replace known defective parts----if your muffler has a hole in it, there's no debate about what's wrong with the car. They'll have the new muffler in stock, and can get the car out of there the same day.

But as Gary said, you need a true mechanic, not a parts changer. They are hard to find, but if do a little research like Gary said, your chances will improve.

I should also mention that if your car has GM's distributorless ignition system--and if it's a V6, it likely does--they were problematic back then. The car would often still run, but it would make popping sounds, have low power...but no smoke as you describe.

If your catalytic converter is clogged, the car will probably run marginally better when it hasn't warmed up--does it?

Smoke coming up through the middle of the car could possibly mean that the cat is clogged, and exhaust is finding its way out through a small leak in the exhaust before the cat. (Or, the clogging actually caused the leak to happen.) If you suspect this, get look under the car while a friend hits the gas--do you hear a "psss" kind of sound from somewhere before the cat? What if you stuff a rag up the exhaust pipe and then try it? If so, that only means you have an exhaust leak, but the cat may still not be the problem--but it would still warrant some further inspection.