Autonerdz Home Autonerdz FAQ Userís Comments Autonerdz Events Autonerdz Store Contact Autonerdz
 
  Welcome, Guest. Please Login or Register
Autonerdz - Since 2000, North America's Authority on PicoScope
 
  HomeHelpSearch Member Map Event CalendarRegisterLogin  
 
Diagnosing a misfire in NJ (Read 5,011 times)
Vin528e
Freshman Member
*
Offline


I'm an Autonerd

Posts: 3

Gender: male
Diagnosing a misfire in NJ
Jan 21st, 2015 at 1:30pm
 
I called this website's phone number to see how I could find out if there are any mechanics that use PicoScope in NJ and they said to post here and see. If anyone on these boards from NJ sees this and knows of one, please contact me.

I have a 2001 Hyundai Elantra and have a misfire on cylinders 1 and 4. The right coil pack controls these cylinders. The first thing I found was arcing at the spark plug wires and got them replaced under warranty. I did a fuel injector balance test, switched spark plugs around to see if the misfire codes would change but they did not. Compression was pretty much the same across all four cylinders. The Long-Term Fuel trim is -8% and out of the 6 mechanic shops I stopped at, the "ASE" mechanics at 5 of these shops didn't know what that meant. I have medium level mechanical knowledge but don't own any expensive scan tool equipment. I stopped at the 6th mechanic and he said that it was fore sure my coil pack. I asked how he would know if he didn't diagnose it so he assured me that it would fix the problem and that I didn't have to pay if that didn't fix the problem. Sure enough, that didn't fix anything and I took the coil off and didn't pay.

A few days later, the car lost power and shut off when I was driving. I had a P0355 crankshaft sensor code and P1372 segment time incorrect. I became restless and took it to the local Hyundai dealer. They said that "they THINK it's a problem with wiring and that I need a new engine wiring harness" and that "I should tow it home or junk it." When I asked if they got it started and actually hooked it up to diagnose it they said no and then told me they wouldn't charge me the $130 diagnostic fee.

I got the car home and now am becoming restless with this problem. I need someone who can scope the ignition system and also the crank sensor.

Any feedback or advice on what I should look for next? I am really tired of these certified mechanics who waste my time.

Back to top
 
 
IP Logged
 
jarvissamuel
Super Nerd
Picogroup
*****
Offline


I love YaBB 1G - SP1!

Posts: 1,154

Denver Colorado, Colorado, USA
Denver Colorado
Colorado
USA

Re: Diagnosing a misfire in NJ
Reply #1 - Jan 21st, 2015 at 2:32pm
 
A couple of options, there is a member map at the top of this site.† Find New Jersey and browse through, the members with Pico group might be what you want.

Another option is to use the shop finder on www.iatn.net† there are a lot of good folks there as well.

And if it is a budget issue you might want to try a community college there are several instructors that use Pico scopes.

I suspect your post did not intend to come across harsh but it kind of reads that way.† Sadly, most of the people in the automotive field get paid for what they get done, and there is no standards really in the US.† So, keep in mind when being asked for a testing fee it is not always a simple find.

With a misfire on cyl 1 and 4 I would be wondering about a wiring issue as well.† A local library might be able to allow some basic service information, a good start would be measuring the wires (not ignition) for continuity to the computer and testing to see if there is a short to power or ground.

Also, when was your last T belt?† Both Hyiundai and Kia's tend to tear up belts and destroy crank sensors if not serviced at the proper intervals.

Good luck, Sam
Back to top
 
 
IP Logged
 
Vin528e
Freshman Member
*
Offline


I'm an Autonerd

Posts: 3

Gender: male
Re: Diagnosing a misfire in NJ
Reply #2 - Jan 21st, 2015 at 3:16pm
 
Hi thanks for the response. I looked up members in NJ and did message a few of them so I will see if I can talk to one of them.

I wouldn't say I have a budget issue at all if the work gets done but my issue is I can throw all the parts at it myself.

Each coil has a power wire and then a wire that goes to the ECU. I tested the voltage wires for each coil and they tested ok with the key on engine off and also with the car running. Voltage is present at both coils with 12.30V at all of the wires to coils. Then with the engine running, the power wires had 14.40V and the wires to ECU both had 14.26V.

The two wires that go to the ECU are inside a shield wire with like a silver mesh wire covering them. That shield wire is connected to Ground according to the diagram I saw and that tested for 0.4 resistance (leads on multimeter touching each other are 0.4 also).

Anything else is outside of my realm as I don't know much about electrical testing. How would I test for a short to power or ground exactly?

Yesterday I also tested for voltage to the crankshaft sensor and it was 12.21V. The last timing belt was changed around 2,000 miles ago.
Back to top
 
 
IP Logged
 
jarvissamuel
Super Nerd
Picogroup
*****
Offline


I love YaBB 1G - SP1!

Posts: 1,154

Denver Colorado, Colorado, USA
Denver Colorado
Colorado
USA

Re: Diagnosing a misfire in NJ
Reply #3 - Jan 22nd, 2015 at 3:51pm
 
I am pressed for time at the moment, but an easy way to check is with BATTERY UNHOOKED, measure each lead to the positive cable and the negative cable.

So a ground should have continuity to the negative and no continuity to the positive.

Most likely a coil control (wire to PCM) unhooked from the PCM and the coil should have no continuity to ground or power.

Hopefully that makes sense.  That is not the best way to test but it is a simple way.

Sam
Back to top
 
 
IP Logged
 
top4
Senior Member
Picogroup
***
Offline



Posts: 222

Ellwood city pa, Tennessee, USA
Ellwood city pa
Tennessee
USA

Gender: male
Re: Diagnosing a misfire in NJ
Reply #4 - Jan 23rd, 2015 at 10:28am
 
  IMHO  If T belt was done just 2 K ago that is the first place I would look!   If all is not well with that how can you go deeper? That plus the codes should do it for someone.
Back to top
 
 
IP Logged