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iATN Review: Newsletter for Members
Second Quarter 2010 EditionWorld's First & Largest Network of Automotive Professionals
Table of Contents
Powerful New Features
Cherokee Cluster Solder Joints
100 Tips for the Young Tech
When is TDC not TDC - In Cylinder Testing
05 Volkswagen Passat 1.8L Poor Idle Quality, MIL On
Mechanical Misfire Diagnosis - Let's Talk
Prospect or Suspect?
Free Marketing
Fly-by-Wire Throttle Body Exposed!

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Powerful New Features
Scott Brown

Welcome to the second iATN Review for 2010! We have many great articles to share in this issue including tech tips for the younger techs, as well as general time-saving tips everyone should read. You'll want to click through to read the entire discussions, as many related tips can also be found in the follow-up discussions.

As we continue to develop iATN for today and tomorrow's service professional, we would like to take this opportunity to provide some insight into what we've been working on lately.

We've just released an extremely powerful new feature called Related Documents & Media. You'll see it at the bottom of every closed TechHelp request, near the replies. If you expand this new box, we'll search all of iATN for other fixes, forum posts, and files tied to related vehicles (based on engine package). It will also perform similar searches based on the related DTC's and/or symptoms associated with the TechHelp you're currently viewing. You'll instantly see what is available, and sponsors can link directly into those search results. We'll be using this kind of relational information in more and more areas of iATN. You really need to try it yourself: read through some recent fixes.

We recently released a video on our homepage that aims to provide a very brief overview of iATN for both consumers and automotive professionals. We'll be incorporating more video into iATN as time goes on, both automotive-related, as well as videos designed to help you get the most out of the iATN website, such as the ones found here.

Speaking of video, the new multi-file uploader released last quarter has provided us with a foundation to accept more file types, including support for video uploads, set to be released in beta test very soon. Get ready to share and discuss video of live waveforms, scan data, video diagnoses, and repair techniques with your peers on iATN.

The fastest way to learn about new features as they're beta-tested or released is to stay tuned to the iATN Development Forum. If you're using Facebook or Twitter, you can also follow us on those services at and, where we post occasional updates as to what we're working on or beta testing.

We hope you enjoy this issue! Feel free to pass it around to your friends and co-workers.

Scott Brown
iATN President

Full Article

Cherokee Cluster Solder Joints
Technical Tips Forum
Gene from Texas

Another shop brought me this Jeep complaining the CEL came on at each start cycle, the odometer kept saying "no bus", and it had a misfire. The codes were P0700, P1694 & P0303. That was just the ones coming back after erasing. The other original codes were P0432, P0320, P1687 & P1698. After exhausting the forums, I decided to pull the cluster just to check. Sure enough, some of the solder joints at both plugs were cracked. I kind of expected it to be a futile effort, but it looks like it paid off. I took the cluster home with me last night and re-soldered all 20 pins. Today, the odometer states the mileage (207K+), no CEL, no codes, no problems. Even the misfire is gone. I can't really explain that, but it's gone nevertheless. I guess since the Caravan and associated ones have that problem, it can be somewhat concluded that all Chrysler products of that era are susceptible to the same thing. The joints weren't cracked as bad as some I've seen. It took a closer visual inspection to see some of them. It doesn't take much to kill a bussed line, though. I just finished one drive cycle and no problems yet. ;)

Time (and another drive) will tell. Hope this helps someone.

Full Article

100 Tips for the Young Tech
Technical Tips Forum
David from Michigan

I'm thinking it might be a good idea to put some tips in here that are probably well known by many but certainly cannot be known by all. I'm also thinking that there may be a reluctancy to post here tips that are of this nature. Most of what I see here in this forum is often very neat or tricky stuff. Because we expect to see that, I feel we are cautious about posting something that might not be very useful.

The most important thing we learn in this profession is that none of us knows it all and keeping the mind open to new ideas or ways to do things is prudent. I have worked at 6 different shops over my career and every new place I worked or different tech I worked with, taught me something new when I watched how they do things.

I'm hoping a bunch of you will share some tips also without censoring them. Think of the things you would show a young guy to help him get the job done faster or safer. I'm willing to bet that a lot of simple tricks don't make it into this forum because they appear too simple. But often the simple things can be the most profound and are overlooked by many. Here are a few from me to get this started.

1. When you pull a brand new serpentine belt out of it's sleeve you will find it has bends in the belt that are there from the belt having been bent in it's packaging. Use these preformed bends to your advantage when you install the belt. I often use a part of the belt stuck into a tight loop as a starting point to get the belt onto the crank pulley from up top. You can often put that tight loop right onto the crank and it will stay there because of it's shape. You can either fight with the shape of the belt or work with it.

2. Many specialty tools can be used for more uses than what they were designed for. Watch the experienced guys in your shop how they do things and of course search the forums here for great tips. I'll give a example;

I use a old 13mm distributor wrench to remove the thermostat housing bolt on a 3.1 L GM. The bolt that has the exhaust manifold crossover in the way. The Distributor wrench goes under the manifold and takes the bolt out with ease. Tricks like these save tons of time.

3. When pouring liquid from a rectangular bottle, always turn the bottle so that you pour with the larger flat sides (front and back) facing up and down.

Full Article

When is TDC not TDC - In Cylinder Testing
Technical Tips Forum
Harvey from British Columbia

1996 Chevrolet S10, Engine/Propulsion waveform2000 Jeep Cherokee Classic, Engine/Propulsion Waveform
Recently, I received the latest edition of iATN Review (Feb. 2010), good job Scott and staff. This edition contained a couple of articles on transducer testing. The post authored by Kevin from Manitoba caught my eye. Here is the link to the post: []

In that post, this is the capture that caught my eye. The notes in that capture stated, and I quote "The secondary ignition pattern has shifted over to the right from TDC (indicating timing out of sync)."

That comment seems to be in error to me, the data is being misinterpreted. If the spark timing is based off the crank sensor and the crank sensor is fired off the crankshaft, how can the timing be shifted (relative to TDC) when the timing chain jumps? The crank sensor and TDC is being controlled by the same item, the crankshaft. While the cam or valve timing is off, the spark should be firing at the proper time, at or near TDC.

If we agree that the timing doesn't shift and that TDC is occurring at TDC (piston position), then the logical answer is that the peak pressure of the in-cylinder transducer is NOT happening at TDC of the piston. Again, the spark timing is NOT shifting versus TDC of the piston.

To help prove the point, I have uploaded a couple of captures. All these captures are made with the new Pico transducer and an inductive probe. I chose to use a Pico scope due to peer pressure. :-)

This first capture is of cranking compression versus spark on a known good cylinder from a 2000 Cherokee with a 4.0 litre inline 6 cylinder. Notice that the spark is occurring at approximately TDC.

The second capture is of cranking compression and spark on a known bad cylinder. Check out the compression pressure and where the spark is occurring. It "appears" to be late. However, this is a DIS ignition system and these 2 cylinders that I am showing are companion cylinders.

Here is a capture with both good and bad cylinders together with spark. You can see the differences a lot easier. Again, the spark is not shifting, the peak compression pressure versus TDC is. This occurs when there is a leak in the combustion chamber.

Because this is a DIS ignition system and I am scoping companion cylinders, the coil firing is the same coil for both of the cylinders. One can argue that there is a possibility the sensor that controls the spark timing could be off slightly and that is causing the variance in the timing versus TDC. For those, I have uploaded this capture showing the good cylinder and bad cylinder with equally spaced cursors. The cursors are evenly spaced between the 2 good firing towers. You will notice that it is offset about the same amount as ignition firing.

My point I am making with this post is: With a leak in the combustion chamber, you cannot trust that the peak pressure from a in-cylinder transducer is indicating TDC. Be careful that this doesn't lead you to the wrong conclusions, especially if you are scoping ignition versus peak pressure. You may see that the timing is late and assume that the timing chain has jumped when in fact the combustion chamber might have a leak.

While the author of the other post that I referenced, did make the right call even though he misinterpreted the data, he had an obvious case of a jumped timing chain. I can see instances where you may be trying these techniques when the problem isn't so obvious and get burned.

Transducer testing is full of pitfalls, keeps your eyes open for them. Feel free to reply with the pitfalls you have seen with these methods of testing.


Full Article

05 Volkswagen Passat 1.8L Poor Idle Quality, MIL On
European Driveability TechHelp
Jay from Texas

I have this Passat come in idling real bad and check engine light blinking.

Pulled codes and initially found misfire codes on all cyl's and lean code bank 1. Customer previously had been at VW dealer and they diagnosed as 4 bad coils. They installed new coils and symptoms were gone temporarily. Cust unhappy with dealer so she brought it here. I pulled plugs out of all cyl's and found they were leaned out - super white. Checked gap and they were very much worn. Installed new plugs. Installed air filter (nastiest I've ever seen), and changed oil using 5/30 synthetic. Car ran good for about 5 minutes and then started running poorly the way it did.

Cust had to have her car that day, but brought it back today (did these repairs 2 days ago). Pulled codes again just to check, and found same misfire codes, no lean code, but found a new one, P1297 connection turbocharger, throttle valve pressure hose.

At this point I am scratching my head. Found TSB about re-flashing ECM if misfire codes and this P1297 are stored, but I have no way to be sure that is the problem. Ohmed out injectors and all ohm out at 13 ohms. Pulled new plugs I installed and they look okay, not white like the old ones, but I don't smell fuel on them either. Pulled oil cap off and have suction when engine running - good thing?

I have been reading other tech help requests but am unsure about some things. One tech help had almost exact same symptoms and related repairs, but his fix was a new throttle body. This car is a drive by wire. Checked throttle body, does not look too dirty. I do not hear any vacuum leaks, but I am going to smoke test intake after I finish this request. I am also going to try a fuel filter and intake cleaning to see what happens next. Any ideas would be greatly appreciated.

(You can read the full article, 7 replies and FIX here.)

Full Article

Mechanical Misfire Diagnosis - Let's Talk
Technical Discussion Forum
Scott from Missouri

Poor Sealing ValvesWorn Valve Sealing
Some of you will remember my previous post alluding to mechanical misfires. This post is an offshoot of that post with a little different twist. If you don't like long posts, then you can go ahead and close this one now. I'm not sure, but this could possibly be the longest post in iATN history. As I started typing, I just felt compelled to include all the pertinent data in one place so as to support my point as well as possible. I can assure you I have not given you even half of it.

My goal in this post is two-fold. The first approach is to present a case that there are misfires out there caused by mechanical operation of the engine that cannot be easily diagnosed. I will go so far as to say that you will NOT diagnose (or prove) them using normal non-intrusive diagnostic procedures. They require tear-down sometimes in order to even confirm their presence. Some can be confirmed with the advent of some more stringent failure criteria for the current mechanical testing. The advent of pressure transducers will make some of this easier, but is not for the unlearned. The ultimate goal here is to elicit some evidence from those who may have fine tuned their procedures that can help eliminate common shortfalls in current mechanical testing methods, by providing new insight, methods, or tolerances for testing.

My second goal is to elicit some responses on new potential uses of these higher end sensors and how they can be used to "prove" where the problem exists, if that is possible. Or to shine the light on common misuses of "normal" diagnostic processes in isolating mechanical misfires.

For those of you who refuse to believe that they do exist, that is your prerogative. If you have run into one of these and you have developed a way to prove their source, then by all means chime in and help us all learn how to do it. If you haven't run into one of these, and your only response is that they do not exist, then please save the bandwidth and do not reply. I won't negate the potential that difference in tooling will affect the results of testing procedures as well. Please respond in kind with any useful information.

If you had told me two years ago that it took longer than 30 minutes to isolate and prove a dead miss, I would have told you that you were an idiot (well, not TOLD you, but I would have thought it anyway) and didn't know what you were doing. But since we have seen 3 of these in 2 years, my thoughts have changed. Now when I see those posts or tech-mail regarding diagnosing a misfire, I have a lot more respect or at least empathy for some of them.

The type of misfire that I am referring to is NOT electrical in nature. It is NOT the intermittent bump or jerk on the highway or under load. The type of miss that I am talking about is the one that misses in the bay. They will miss mostly at idle and may, or may not diminish or disappear (or appear to) at higher rpm. The miss will be nearly consistent in nature and may be called a "dead" miss. The affected cylinder may have zero power contribution or low power contribution. Isolating this misfire to a specific cylinder is not hard. Either misfire monitors or cylinder kill, preferably both, can be used to isolate the exact cylinder causing the concern.

I will state that while I can and do use a scope to help diagnose this type of problem, secondary analysis is not my strong suit. I use it mainly to identify a cylinder and potential electrical problems, and then resort to mechanical tests. I have begun using pressure transducers, but my diagnostic ability on analyzing the waves is very new and extremely wanting. I was hoping to be able to use them to verify what is causing the problem, or at least prove a mechanical issue to warrant teardown. I also have never used a gas analyzer. Mark Warren has written about them recently, and I am interested in them, but have zero experience or availability of their use.

So let's get started in diagnosing this misfire at idle. We have verified which cylinder it is. We pull the plug and move it to another cylinder, as well as the wire. The misfire stays the same on the same cylinder.

You install a vacuum gauge on the engine. The hose should be centrally located and be as short as possible, with no restriction in the hose, such as a cone on the end of the hose. The cone is a restriction that can dampen any oscillations that might appear. The vacuum gauge is rock solid. It might float slightly/slowly if rpm is not steady, but it does not pulse at all. You snap the throttle and watch the gauge drop to very low, then very high on deceleration, then settle back to where it was before and no pulsing is present. You rev the engine to about 2500 rpm for a minute or so, then bring it back to idle. The vacuum gauge never pulses...

(Click here to read the rest of this post and replies)

Full Article

Prospect or Suspect?
Shop Management Forum
George from Nebraska

I did a Webinar last week for AMI and my good friend and fellow Instructor Margie Seyfer sat in on it. The subject of the Webinar was handling price-shopper phone calls. I've done extensive research on this and have found that a substantial percentage of shops are more concerned about cautioning the caller about all the possible things it could be and things that could go wrong and all the extra charges there may be to the point that many callers will just go to the next place to call.

Margie said my approach was interesting and asked me if that many shops really do regard the caller with that much trepidation. She called me the next day to tell me she had consulted a very prominent shop owner for his own opinion on the price shopper. She asked him point-blank, "Do you consider the price shopper phone caller a prospect or a suspect?" He replied with no hesitation, "Suspect".

Do we really get burned that often or do we just remember that one in 6 months that drove us nuts?

Is this the same fear of the public that leads us to put up stupid signs, like "No out of town, 2-party checks". Well, duh!

Could our overt fear of covering certain body parts actually result in them not being exposed at all, since the caller gives up pretty quick in most cases and finds another shop to call?

I've always looked at that phone as the key to my bank account and welcomed every single ring as the sound of opportunity.

My position is that far too many of us mis-identify too many price shopper callers as true price shoppers when I believe that a substantial percentage of them aren't really shopping for the low price at all, they just don't know how else to talk to us. They don't really have a clue what's wrong with the car, either. We're so sick of dealing with people that we happily dismiss them, hang up the phone and then complain about how bad business is lately.....

Maybe if we learned a few tips about selling, understood that not everybody out there really does want the cheapest possible job and decided to look at the phone caller as a reflection of our own marketing efforts, we'd feel better about some of this.

It's our marketing that projects our image, you know.... ;o)

Full Article

Free Marketing
Shop Management Forum
Steve from Florida

Marketing booth
Over the years the best marketing I have done has been to avoid mistakes in marketing. Mostly by not doing any marketing.

I have done a bit of TV, a bit of direct mail, a tiny bit of newspaper, and an advatorial or two. Add in some variations of the above and that has been about all.

I have noticed though that some of the best marketing of my competition has come from their participation in church, social clubs, local government functions etc. My partner was able to do this to a point, but I am just not a mixer. My partner did it most through his wealthy Harley buddies and their extended community.

My second generation folks, my partner's daughter and her husband are a significant force in this arena and as service writers are a huge part of why we were up 19% last year and why our parking lot is double parked every day.

Heidi just emailed me a picture of the display booth she designed and set up at the local mega health/fitness club. Both Heid and Darren (our service writers husband and wife) are members there and are the socially mobile types that can really make an impression. This health club is huge and is a recognized fixture in our community. They have set up a free business networking function where members can share their products with other members and hopefully give them a break (I really hate the word discount).

Tuesday night they had a gathering (don't know the exact word for the event) where each business was given a table and allowed to display their wares. Here is the picture she sent me: [Marketing booth]

The brochures laid out on the table were Bosch Service Center directories and a one page front and back folded piece that Heidi produced. I give her an A+ for both content and effort. I don't think one can buy such employees. She obviously is doing this because she will some day own it, but if they can find a way to replace me they will really have a great future.

BTW, the title of this post stated free marketing. It actually took a lot of effort and really can't be bought. As I stated above I think this kind of relating to the community is the best marketing.

Full Article

Fly-by-Wire Throttle Body Exposed!
Technical Discussion Forum
Robert from Florida

2008 GMC Sierra 1500 SL, ECM/Inputs/Outputs Photo2008 GMC Sierra 1500 SL, ECM/Inputs/Outputs Photo
Today I replaced a throttle body on this truck and decided to look for the failure. This one failed with TP sensors 1+2 disagree. While performing a throttle sweep test KOEO, it would fail and default every time around 75% throttle. Once it failed, it would not move until a key cycle, and sometimes it would require a code clear before it would move again.

I found it interesting and thought others might also.

TAC throttle body

motor, gears and butterfly

Closeup of TP arm and potentiometer

You'll note 2 terminals to the motor, yes 12V will snap it open or closed :) Didn't see anything visibly wrong with the tracks, although there was definitely a problem there. If you look closely, you'll see where a strip runs all the way around the outermost track and connects to the opposite end of track 2. Pretty simple really.

Full Article
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