backfiring problems

teaguespeed · Post by **teaguespeed** » Thu Apr 03, 2003 2:22 am

My '91 turbo is confusing the hell out of me. I'll start out at the beginning. When i first test drove it about 6 months ago, it was having back firing problems. When i gave it a sudden punch of the gas it would downshift (its an automatic), shooting the rpms up as they do, but it would not want to go over about 3000 rpm. There was an audible sputtering sound and i could also feel it at the gas pedal. The dealer fixed the problem, and said it had happened because there was some water on the spark plugs or something like that.
After that it ran perfect. A week later (now i owned it), the exact same problem returned. I took it to the mechanic and he fixed the problem, and said that the dealer had put the wrong kind of spark plugs in and had not spaced them properly. Once again, ran perfect.
Now the problem has returned. it wasnt nearly as bad as before. Sometimes, though not consistently, it would backfire at about 4000 rpm and not want to run the rpms any faster. this was not very often. So i took it to my mechanic today. When i picked it up he said it was running good, that he had just found a little gunk in one spot, though i didnt ask if it was on one of the spark plugs, which he checked, so i'm sure they are clean now. Unfortunately,on the way home, the problem returned, even worse than before i took it to the mechanic today. Once again, it didnt want to go over 3000 rpm, same sputtering and feel at the gas pedal.
Have any of you had this same problem? Any ideas on how to solve it? Is this the same thing you guys are calling "hesitation"(keep in mind my knowledge of cars is very limited)? could some better spark plugs help? Should i switch mechanics?
thanks for your time, Teague

vrg3 · Post by **vrg3** » Thu Apr 03, 2003 3:00 am

Are you sure you're talking about backfiring? Not misfiring? Backfires are very loud as the explosion travels up into the intake manifold. Misfires are when the spark just doesn't ignite the air/fuel mixture.

I'm gonna assume you're talking about misfire.

First thing - is your check engine light on? If not, does it come up when you first put the key in the "ON" position (along with all the other lights in the gauge cluster)? If it doesn't come on with the others when you first turn on the ignition, that means the bulb is burnt out or not connected right, and you should get that fixed so you can see if the ECU is throwing a trouble code.

A bad sensor could cause this trouble.

Another possibility is a bad coilpack or ignition wires, if they weren't replaced with the spark plugs. Maybe even the igniter. If it comes to it, I think I have an extra igniter and coil pack you could have cheap.

It could be a weird leak in the intake system, too.

You could take the car to another mechanic for a second opinion, I guess... Ask him the check the above things in addition to just the plugs.

Post by **Legacy777** » Thu Apr 03, 2003 3:01 am

Have you replaced the spark plug wires recently? What plugs are in there......you can check them yourself.....they're not too hard to get at and put in.

teaguespeed · Post by **teaguespeed** » Thu Apr 03, 2003 3:30 am

well your write i didnt know exactly what backfiring is, and that sounds kind of strange. I'm no mechanic though. Backfiring is the term my mechanic used. It definitely isnt happy doing it, slows down the car. I was talking to a guy who said backfiring is often caused by a worn out timing belt. And when i got home i think i did hear a bit of squeeling. What do you think? My check engine light is working fine and not giving me any codes.
Thanks, Teague

teaguespeed · Post by **teaguespeed** » Thu Apr 03, 2003 3:32 am

the spark plugs have been replaced, though im not sure when, im not sure of which spark plugs they are.

vrg3 · Post by **vrg3** » Thu Apr 03, 2003 4:12 am

Sounds like misfire.

Even if the spark plugs are in good shape, if the spark plug wires are bad, the engine will run poorly. Make sure the wires are in good condition and are properly connected to the ignition coil and to the plugs (you should hear a "click" when the connectors make full contact with the plugs).

entirelyturbo · Post by **entirelyturbo** » Thu Apr 03, 2003 5:20 am

Yup indeedy, I learned that the hard way. I replaced spark plugs very often but car would never run any better. DUH!!! The wires needed to be replaced, so I replaced them with Magnecors...

Those are great wires, but as has been posted before, they're tough to get on the plugs and coil. So I didn't install one right and it arced for months! I ruined the wire and coilpack...

So now I have a new coilpack and factory wires, runs great...

teaguespeed · Post by **teaguespeed** » Thu Apr 03, 2003 6:43 am

theres no clicking when i take off or put the cables onto the plugs. i have always thought it was kinda strange how easy they come off the plugs. the mechanic didnt mention it though.
Teague

vrg3 · Post by **vrg3** » Thu Apr 03, 2003 6:55 am

If there's no clicking, either 1) fix the terminals inside the spark plug boots by pulling them out, reshaping them, and pulling them back in, 2) replace the terminals on the wires if they're good wires, or 3) replace the wires.

Magnecors are hard to get on because many of them come from the factory mispositioned; see my post titled "Magnecor installation tip."

Magnecors are great; I've got the 8.5mm ones, and in the long run they're cheaper than normal wires because you don't have to replace the wire portion, but a simple $20 set of wires from AutoZone should be about as good as OEM. If you get new wires, try plugging them onto spark plugs not in the engine to see what the clicking is supposed to be like.

teaguespeed · Post by **teaguespeed** » Fri Apr 04, 2003 1:06 am

my wires are ngk, and as hard as i've tryed i haven't been able to separate the wires from the rubber connector housing sort of things, i dont think they are supposed to come off.

vrg3 · Post by **vrg3** » Fri Apr 04, 2003 3:54 am

I guess it's possible that the NGK wire insulation and boots are single pieces, but in general it's really hard to pull the wires through the boots. Think about it... the boots are rubber and the insulation is rubber. Rubber against rubber is a very high friction situation. :)

Can you make the wires click onto a spark plug in your hand by pushing the plug all the way in?

teaguespeed · Post by **teaguespeed** » Fri Apr 04, 2003 4:35 am

maybe i'll try a seringe(spelled wrong) and some water

Post by **Legacy777** » Fri Apr 04, 2003 2:50 pm

try soapy water

teaguespeed · Post by **teaguespeed** » Sun Apr 06, 2003 4:23 am

i solved my problem! I never got the cables seperated, but i did take my trusty xacto blade to 'em, and it did the trick. But i never would have figured it out without you guys. You'd think my mechanic would have discovered something so simple. $75 wasted! From now on its you guys, then the mechanic.
Thanks, Teague

entirelyturbo · Post by **entirelyturbo** » Sun Apr 06, 2003 7:19 am

Well, then, how much is our going rate of advice, guys???

J/k glad you figured it out. Now you know they're on right and don't hafta worry about it...

-K- · Post by **-K-** » Sun Apr 06, 2003 7:26 am

Well advice is free, but good advice might cost

The hard thing is some poeple just say what they have heard as truth, and don't realy know what they are talking about.

vrg3 · Post by **vrg3** » Sun Apr 06, 2003 3:32 pm

Teague, you mean you just shaved off a little of the end of the spark plug boot?

I tried doing that to my Magnecors but I messed the boot up... That was before I realized the other fix. So now my car has three Magnecors and one Magnecor with a generic Beck-Arnley boot. :)

teaguespeed · Post by **teaguespeed** » Mon Apr 07, 2003 2:20 am

actually, i shaved off the sides, the boots had stoppers incorperated, so that they would seal the little hole that the spark plugs are in. these were not letting the wires go in far enough and make a good connection.
Teague

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backfiring problems

backfiring problems