|
Lights, Camera, Action!
By Scott Brown
Welcome to the fourth quarter edition of the iATN Review. The last edition of the iATN Review newsletter was our 15th Anniversary issue, which featured many great articles posted to iATN over the past several years -- and now we're going to play catch-up. In this issue, we are featuring highly-rated messages posted to the network over the past two quarters.
This is the first newsletter published since the official release of our new video upload and sharing system. You know what they say about images and a thousand words -- well, video can say even more! We have had many members take advantage of this new feature by sharing unique experiences in and around the work place, and some of those are featured here today.
We hope that you find this edition of interest and if you want to see any of the previous editions, you can find them here in the Resources section. If you have a colleague who is not a member, please feel free to forward them a copy.
As we close out this year, the iATN staff wishes you all a prosperous fourth quarter and a happy new year as we move forward into the new decade!
Regards,
Scott Brown
iATN President
Using Headlight as a Short Finder
Technical Discussion Forum
Robert from Florida
Hi TDF,
Had some fun with this vehicle, I know this little trick has been covered before.
First job Monday morning, "we saved an intermittent short for you". (I was late, and nobody else wanted it :) Complaint says "every 2 weeks the ECM10 fuse blows and truck stalls. Gas station couldn't find problem. Tow In". So I walk out to the truck with a testlight and 10 amp fuse, found the ECM fuse (#15 position) missing completely, install my fuse, check all other ECM/Ign fuses and go to pull the truck in. As soon as I put the truck in gear, it stalls. Yep, blown ECM fuse. So now I get my headlight and put it in place of the fuse, truck starts and runs, filaments glowing very dimly. As I put it in gear and begin to move, I see this:
[Using Headlight as Short Finder]
What's next? Is there a better/quicker way to find this short?
Toyota RF Axle Shaft Installation
Technical Tips Forum
Wesley from Massachusetts
Simple tip for installing the clip that secures the right axle shaft to the motor mount. Use a cable style hose clamp tool [2003 Toyota Avalon XL, Transmission Photo] to compress the clip, then keep the clip compressed with a wire-tie. Once the axle shaft is in place [2003 Toyota Avalon XL, Transmission Photo] just cut the wire-tie and let the clip snap into its corresponding groove.
Can You Fix This With Factory Information?
Technical Discussion Forum
James from Florida
This vehicle has been in 3 times without being repaired. Now it's my turn. The vehicle in question is a 2009 Suburban with just about every option that you can order from the factory. It has no aftermarket equipment installed.
The complaint is that the customer gets into his truck after sitting overnight and finds the battery stone dead. This may happen several days apart. The vehicle was in before and checked for draws, every applicable bulletin was checked and the battery was replaced along with the negative cable, both positive cables and the mega fuse.
I first saw it when it was towed in. The battery was dead and measured 3.5 volts. Nothing was turned on in the vehicle. I charged and tested the battery and checked for key off draw. 10 ma. I saw no evident problem with the truck. It sat in the shop for 4 days. Every morning I checked the battery and found it fully charged. The 5th morning, it was dead and measured 3.5 volts again.
I charged the battery again and put a Fluke on it in min/max mode for 2 days. It never went above 12ma draw. Every morning the battery was strong. After 7 days, it was stone dead again. Where would you go from here? Is there any factory information to help you diagnose this puzzle?
Another Compression Waveform
Technical Discussion Forum
Mark from Ontario
Hello Group.
I have this 2000 blazer that has misfires on number 3 cylinder. The ignition waveform looks like this. [2000 Chevrolet Blazer LS, Ignition Waveform]. Here is the compression waveform of number 3 along with the number 3 secondary. [2000 Chevrolet Blazer LS, Engine/Propulsion Waveform]. The compression pressure is low at idle which is 28 psi. Here is a more detailed view of the same number 3 cylinder.[2000 Chevrolet Blazer LS, Engine/Propulsion Waveform]. This is from the number 5 cylinder and is known good. [2000 Chevrolet Blazer LS, Engine/Propulsion Waveform]. The compression is above 90 psi at idle.
The low compression cylinder is low but I don't see in the waveform a problem in the exhaust valve or intake valve opening or closing. Does anyone see a problem with the valves here? If there is not a problem of valve sealing then whats the cause of the low compression? Thanks for your comments.
The Prius 'B' Mode
Technical Theory Forum
Phil from California
Friends,
I have hopefully learned to be careful about making dogmatic statements about complicated cars, like the Prius hybrid. But I was sitting in a brake class a couple of weeks ago and the instructor told the group that the Prius B mode increased regeneration to a higher level to add vehicle braking. I kept my mouth shut even though this ran counter to what I had observed previously, mostly because the information is not terribly significant when it comes to fixing a car. But, I decided to see if I could prove it. Now, I think I have.
What I did was flog my car up a fairly good grade to get the state of charge down to a level where I knew that the THS would be trying its best to recover to its comfortable levels of 50-63% SOC. I was able to punch the SOC down to 36% which is not easy to do without going way over the speed limit (I think I hit 79 mph going up hill in order to accomplish it.) I then did a U-turn and went back down the hill. I recorded a ten minute recording on the Techstream and then zoomed in on a flagged area where I had shifted into "B" mode on a pretty steep downhill. [2004 Toyota Prius, Engine/Propulsion Scan Data] As you can see, the battery SOC had already recovered up to 52% just by coasting. I think I saw as high as 60 amps of regen without applying the brake, which I presume was being supplied primarily by MG2, though since I didn't capture revolution and torque on the two motors I can't say for sure. But, beyond any doubt, the B mode actually is drawing massive amps (82) out of the battery pack in the process of reving up the ICE rpm to accomplish the B mode braking. It is definitely counter-indicated for fuel economy. As you can see here [2004 Toyota Prius, Engine/Propulsion Scan Data] after I have shifted back into drive (at the flag; there is a bit of a delay before it actually happens)we get a pretty good regen, once again only by coasting.
So, it is my conclusion that the B mode is using the electric motors to transfer more load back through the power splitter (planetary gear set) to the gas motor in order to slow the car down. It kind of makes sense if you realize that the battery pack and its life are really important to Toyota. Force feeding it high rates of amps for the purpose of slowing the car on a long hill is a bad idea. I tried to duplicate this test on Saturday, but I waited too long going down the hill and I heard my battery fan kick on high blow. Even though battery SOC was only at 65% (on a cool battery pack I've reached just over 81% on a long down grade) the hybrid system shut down regen entirely, no doubt to protect the battery, so I couldn't prove anything with the B mode.
It is dangerous to make dogmatic statements about the Toyota hybrid system and how it behaves. I did not know till yesterday that it may not be possible to push SOC to the max on a long hill if battery temp went too high. I just never tried it under ambient conditions of 105 degrees. So, we go on learning...
Pressure Tranducer Testing at Fuel Pressure Regulator
Technical Theory Forum
Mark from Ontario
Hello, lately I have been doing more testing at the fuel pressure to compare and to recognize problems. However, I am getting some mixed results on interpreting the waveforms. For instance I was working on a 1996 Windstar with a rough idle. Here I just want to discuss this waveform with transducer at fuel pressure regulator. [Waveform] In this waveform, a=synced from cylinder 2 (2ndary) b=first look at pressure regulator seeing injector pressure drop. 1996 ford Windstar 3.8. This engine fires sequentially 142536 (waveform shows 253614) bad injectors? I have a parts van with same engine and changed out all injectors and the pattern didn't change much. Is this pressure testing at regulator not a very solid test to do?
I checked another car that did not have any driveability issues.
2001 Altima with 2.4 engine. Taken at idle with 1st look transducer. Sync in red is from number 1 2ndary. The 1st look sensor is in fuel pressure regulator with vacuum plugged. Here is the waveform. [2001 Nissan Altima GLE, Waveform]. I cannot make any diagnostic decision form this. 2 more from same car instead I am using the Pico transducer. [2001 Nissan Altima GLE, Waveform] This is from the same recording but what in the world is happening here? [2001 Nissan Altima GLE, Waveform].
Is this testing method not a consistent valid test?
GM Cluster Repair
Technical Tips Forum
Kevin from Manitoba
I am sure we all have seen these GM clusters where the speedometer or one of the other guages sticks,jams,or doesn't work.I am going to show the procedure how to replace these old stepper motors with a new one.
First let me show you the customer complaint. [2004 Pontiac Montana, Video] Now that we have verified the complaint, you must remove the cluster and take off the black plastic covers from the back and front of the cluster. Once you have the gauge needles accessible... perform this task [2004 Pontiac Montana, Video] Then you need to separate the front cluster board from the main circuit board as shown here [2004 Pontiac Montana, Video]. Once the circuit board is separated then we can see the old binding stepper motor [2004 Pontiac Montana, Video].Here is a video of the new motor and part # [2004 Pontiac Montana, Video] .
Here is video showing the 4 small contacts that need to be de-soldered as so we can remove the old stepper motor [2004 Pontiac Montana, Video] This is the soldering iron I like to use when doing soldering. [Soldering Iron] Once the de-soldering is done we can see the old stepper motor removed from the board [2004 Pontiac Montana, Video] Then next we need to install the new motor and slightly bend over the tabs to lock the motor in place for soldering [2004 Pontiac Montana, Video] Now here is the new motor installed after being soldered in place [2004 Pontiac Montana, Video] Here is a video of the completed soldering.[2004 Pontiac Montana, Video] Now we must re-install the gauge needles [2004 Pontiac Montana, Video] and finish assembling the rest of the plastic covers.
Now its time to Test the repair [2004 Pontiac Montana, Video]
If you need to calibrate the needles for positioning you can use the scan tool to compare the vehicle speed to what the cluster indicates. (Same applies to the other gauges). Or one could even use a GPS which shows current speed for comparison.
In Cylinder Pressure Transducing Revisited
Technical Theory Forum
Jeremy from Kansas
This vehicle is a 99 Ranger with a 3.0L. I am dabbling with in clyinder pressure transducing. I have saved known good wave forms not enough but I am working on it. I have one in my bay right now with an issue. Has a misfire, has audible vavle train noise, and on accell it pops back through intake. I have narrowed it down to cylinder #2. So I hooked up my fluke PV350 and Snap On Vantage pro and this is what I see while running [1999 Ford Ranger XLT, Engine/Propulsion Waveform] here is a video of it as well [1999 Ford Ranger XLT, Engine/Propulsion Waveform]
IMO it looks like I have no vavle movement at all.
I have other waveforms from another vehicle that is fixed I want to use this thread for discussion as well. I know some of this is in the archives, I have researched them as well.
Another Failure To Communicate
Technical Discussion Forum
James from Florida
Here's a new victim, similar to one I just posted but with a different failure and a different diagnostic path.
2005 Trailblazer. Customer states that after driving for 20 minutes of so, all the warning lights in the IPC illuminate, the radio goes dead and the A/C stops working. If the vehicle is shut off and restarted, the problem usually goes away. If the vehicle is left running, the problem corrects itself after 5 minutes or so.
Scanning the control module system, I have over 50 Class 2 communication codes set as history in all 13 modules. Sounds familiar. Obviously a data bus or module concern. Luckily, it stays failed for a while. Time for another home made tool.
[Splice Connector Diagnostic Tool]
I made this tool just for Class 2 communication problems. The main SP205 splice connector under the dash has 12 possible terminals. If you remove the comb and insert the terminals into all available connectors, you can unplug any or all modules at will without disturbing others. How does this help? Read on....
I plugged in my tool and connected my DVOM to terminals 2 and 5 in the ALDL. With the engine idling, I saw 1.2 to 1.8 varying volts...normal class 2 communications signals. I took the truck for a test drive. After about 15 minutes, the cluster went crazy and the radio and A/C shut off. I pulled over and left it idling. My DVOM read 4.05 volts and steady. Looks like a short to voltage on the class 2 bus.
Next, as I watched the DVOM, I unplugged modules from the connector one at a times, starting with non-crucial modules such as the RADIO, COMM to SP306, HVAC and DRR. My DVOM did not move. Next, ATC, SIR and IPC. Still 4.05 volts. Then I unplugged the EBCM. The voltage instantly dropped to the 1.2 - 1.8 range and varying. I plugged the EBCM back in and it went back to 4.05 volts and steady. I plugged all the data lines in and wormed my arm under the truck and unplugged the EBCM directly. My data bus came back to life and every module except for ABS came back on line. I left it unplugged and drove back to the shop.
Back on the lift, I checked power, ground and pin fits. I installed a new EBCM and sent the porter out for a 40 minute test drive. All modules on line, no codes set.
What Did You Fix With Your Scope This Week Part II
Technical Discussion Forum
Zach from Ohio
Back by popular demand, let's see what you did this week with your scope. Rules are, keep it clean and no hitting below the belt :)
Pretty uneventful scope week for me. Found and repaired a bad fuel pump on a TBI Camaro. [1991 Chevrolet Camaro RS, Fuel Supply Waveform] Pump turning 3700 rpm and pulling 1.8 amps. New pump [1991 Chevrolet Camaro RS, Fuel Supply Waveform] turning 8683 rpm and pulling a touch over 3 amps. Customers complaint was lack of power. Fuel trims where way positive and fuel pressure was 10 psi at idle and would fall off on acceleration O2 would would fall to 0v at WOT. New pump solid 13 psi. I have a FLS valve issue on a 2000 Mitsubishi I will post later I will post later.
| |
