misfire on cylinder 5 - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 12 (permalink) Old Jul 11th, 02, 01:11 PM Thread Starter
 
Join Date: Jul 2002
Location: Sebastian,FL.
Posts: 4

I have a 97 V6 with a misfire on one cylinder. I hooked up my obd scanner and the only other thing it shows is the O2 sensors and EGR valve did not pass which could mean they might be bad?i already changed the plug and wire and still have sputter when accelerating. It's like everything is off timing but it's not I replaced the plugs and wire reset the computer and all it says is misfire on cylinder 5! But there is no miss, no vavles clinging engine sounds fine until you accelerate and it hesitates and sputters. Would a bad O2 or Egr vavle cause that? I only have 45,000 miles on the car and take great care of it!!
WykedRyk is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old Jul 11th, 02, 05:03 PM
Senior Tech
 
Join Date: Apr 2002
Location: puntagorda fl u.s.
Posts: 122
look were your egr is mounted in relation to the #5 cylinder. if the egr is stuck open it could be causing the miss. also do a compression test on that cylinder and how did the plug look. A o2 sensor is easy an cheap to replace an has a lot to do with how the car runs. keep us posted
storman is offline  
post #3 of 12 (permalink) Old Jul 12th, 02, 11:23 AM Thread Starter
 
Join Date: Jul 2002
Location: Sebastian,FL.
Posts: 4
Thanks for your reply. When I removed the plug it appeared in good shape still grey in color. The O2 sensor is right next to the plug and the EGR is in front of cylinder 1 on the same side of of cylinder 5. The weather has not been cooperating with me here! And I only have weeknites to try and figure this out! My girlfriend is laughing at me with her Tiburon running without fail! I just got a compression tester so I guess I'll know if it's the EGR or O2 sensor then. I'll keep you posted. THANKS again
WykedRyk is offline  
 
post #4 of 12 (permalink) Old Jul 12th, 02, 07:37 PM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Could be a lot of things, but I'd do a dynamic compression check first to rule out a mechanical breathing problem with the engine. The static comp test just checks the engine sealing ability. The dynamic check will tell you each cylinders ability to take in an intake charge and expel it without restriction. If you need info on how to do this I can post it, it's fairly simple, there are a few precautions on modern FI and direct fire ignition style cars.

I have a 2.8 V6 that started out this same way, a miss on the #5 cylinder only when under a load. It got worse quickly and the dynamic check proved the #5 exhaust lobe was gone on the cam. Apparently Chevrolet still has some problems with cam hardness after all these years. Once they start to go they'll go fairly quickly if that's what it is. I hope this isn't your problem. By the way mine would idle fine when in nuetral and fairly well in gear, but at around 2500 under a load it would backfire through the intake pretty badly.

Dave

[This message has been edited by SY1 (edited 07-12-2002).]
SY1 is offline  
post #5 of 12 (permalink) Old Jul 12th, 02, 08:01 PM
Senior Tech
Don
 
ZZ_430's Avatar
 
Join Date: May 2001
Location: Houston, Texas
Posts: 4,491
It sounds like you may have to start throwing parts at it.

What kind of scanner are you using on it?

My money is on the coil pack or module.

I doubt it is mechanical.

Is it still under the 5/50 emissions warranty? Depending on the delivery date, and with that mileage, it may be covered.

------------------
Don~ ZZ430DropTop
~~~~and~~~~
70 RS/Z28
67 RS/SS Convertible, 70 RS/Z28




[This message has been edited by ZZ430DropTop67RS (edited 07-12-2002).]
ZZ_430 is offline  
post #6 of 12 (permalink) Old Jul 13th, 02, 12:25 PM Thread Starter
 
Join Date: Jul 2002
Location: Sebastian,FL.
Posts: 4
Thanks for all your replys it is definetly helped me narrow this down. I have a Actron obd 2 scanner. The only other thing this thing tells me besides the misfire is the O2 and EGR have not passed which the menu on the scanner tells me there may be a problem the computer cannot record. I don't have any backfire it acts like the catylatic converter is clogged. If that's ever happened to any of you, About a year ago almost the same thing happened and I replaced all the plugs and wires and everything was great!! This time I'm not so lucky. I did a compression test with and old gauge someone had I couldn't tightened it all the way so it wasn't completely accurate but I had at least 75 psi on #5 cylinder. I have no smoke just a bad exhaust smell, and I noticed a little more condensation coming from the exhaust. Would a bad EGR or O2 sensor cause a misfire??
WykedRyk is offline  
post #7 of 12 (permalink) Old Jul 13th, 02, 07:09 PM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
75 is quite low, you'll need to try to get it tightened for your readings to be usable. I'd expect 170 or better for a static (cranking) compression check. Then record all the cylinders static compression readings and run the dynamic check. It will tell you if you have restrictions on your intake or exhaust systems. Remove the schrader valve to do the dynamic check. Once the engine is up to temperature put the test gage in each cylinder and run the engine at idle, record the readings and compare them to the cranking compression readings. The dynamic readings should be about half of wha the static readings were. Also do the snap test this really shows the ability of an engines individual cylinders to breath. The snap test is simple, just after recording the dynamic reading quickly snap the throttle linkage, NOT the gas pedal you can not do it quick enough, and imediately release it. You are trying to snap it wide open and release it without the engine accelerating, this is forcing the engine to take in a big gulp of air, but you need to do it quickly so the engine doesn't actually accelerate. Snap reading should be 80 percent of what the static readings were.

If the snap reading is much below 80 percent you have a restriction in the intake, for example severely carboned valves, worn intake lobe on cam, rocker arm problem ect.

If the snap reading is much above 80 percent you have an exhaust restriction like a worn exhaust lobe, bad lifter or clogged cat converter if they are all high.

This really does work, I found my worn #5 exhaust lobe using this method. It'll at least rule out a number of mechanical problems without much work.

Remember when working with computers and OBD systems including OBD2 you still have to decide if the sensors are at fault or if they are indicating correctly an out of limit condition caused by another mechanical problem with the engine. they're a great tool, sounds like you have the same OBD2 tool as I do, just be careful how you interpet the data so you're not throwing $$ at it based on what the reader reports.

Don't forget to ground out the plug lead so you don't damage the ignition modules or coils during the tests. On port injected cars disconnect the fuel injector too if it's accesible.

Hope this helps,
Dave

[This message has been edited by SY1 (edited 07-13-2002).]

[This message has been edited by SY1 (edited 07-13-2002).]
SY1 is offline  
post #8 of 12 (permalink) Old Jul 13th, 02, 07:14 PM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Forgot to add as far as ignition goes, when a coil goes on the GM system usually you'll have two cylinders not firing. This is because each coil fires two cylinders and doesn't ditinguish between the exhaust or compression stroke, they fire every time those cylinders come up on top center, including on the exhaust stroke. Anyway normally you'll have two plugs reading bad. They don't always fail this way, they can fail internally so the connection to an individual cylinders output is lost and not it's mate for that coil. But normally you lose both. Still something to look at.

SY1 is offline  
post #9 of 12 (permalink) Old Jul 13th, 02, 07:22 PM
Senior Tech
Don
 
ZZ_430's Avatar
 
Join Date: May 2001
Location: Houston, Texas
Posts: 4,491
That's a good description of the secondary ignition, I brought up the module possibility because I had a 2000 Monte with a similar problem, the module was bad.

------------------
Don~ ZZ430DropTop
~~~~and~~~~
70 RS/Z28
67 RS/SS Convertible, 70 RS/Z28
ZZ_430 is offline  
post #10 of 12 (permalink) Old Jul 13th, 02, 07:28 PM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Droptop,
The coil and module are both good candidates. I've seen both fail myself as well as had bent pins cause problems. The modules are located on some modules in not very easy to reach areas and sometimes you end up working just by feel. It's easy to get a connector on and bend a pin and not know it. I hate to admit it, I've done it myself.
SY1 is offline  
post #11 of 12 (permalink) Old Jul 16th, 02, 01:27 PM Thread Starter
 
Join Date: Jul 2002
Location: Sebastian,FL.
Posts: 4
I just wanted to say THANKS to everyone who helped me out!! Ended up being a bad #5&2 coil!! Now she's purring like a kitten again! And I can continue to kick those little rice kites off the streets!! No offense to anybody, I enjoy all types of cars and respect anyone who can get more horsepower out of anything these days!! THANKS AGAIN!!
WykedRyk is offline  
post #12 of 12 (permalink) Old Jul 16th, 02, 02:37 PM
SY1
Senior Tech
Dave
 
Join Date: May 2001
Location: Michigan
Posts: 2,920
Droptop,
You nailed this one right on the head! Good call.
Dave
SY1 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome