►3C Intelligent Induction Cleaner
• eBOB DLC Breakout Box
• eSCAN Mode 6 Decoder
• eSCOPE PRO
• eSCOPE ELITE4
• Resistance Decade Box
• Capacitance Decade Box
• eCOP Induction Pickup
►Ruggedized Notebook PC
Proud to be a U.S. based company.
iEA (EMISSFIRE) TRAINING
Cam Gear Boogie - 2002 Dodge Stratus 2.7 Vin R
Bob Powell - Bob Powell's Auto Repair
A local shop brought this car in after a remain engine was installed. The complaint was that the car would not start unless the Cam sensor was unplugged. Otherwise, it ran OK. They figured that much out but were unable to pinpoint the cause of the fault.
The first thing I wanted to do was see if the cam and crank sensors were in sync. I was able to start the car with the sensor unplugged, then plug it back in and get some signals. Here is what I saw (Figure 1) Note the cam waveform pattern is 1-2-3-2-1-3 which will be important information. I could not find any known good patterns that matched my cam and crank signatures so at this point the jury was still out.
Next I decided to hook up a pressure transducer in one spark plug hole on each bank to verify whether or not the cams were physically in sync. The patterns indicated that things were in proper sync mechanically. (Figures 2 & 3)
OK, now I'm getting somewhere. The engine is mechanically synced so I must have a sensor problem. The crank sensor reluctor on this car is on the flywheel. The tech told me the same flywheel was used from the original engine. I next asked him about the cam gear reluctor. This is where things got real interesting. He informed me that the engine came with new chain and gears in a box and had to be installed. I asked if he had the original gear. He did and agreed to drop it off at the shop so I could inspect it.
The original reluctor slot pattern was 1-2-3-1-3-2. This did not match the cam pattern I saw on my scope. At this point I knew the problem was an incorrect cam gear for this application. I instructed the tech to install the correct cam gear/ and his problem would be solved.
One week later he comes back and says, "I replaced the gear but I have the SAME problem". I can't believe it so I hook up my scope again to see what's what. Here is what I see from the cam sensor now. (Figure 4) Big chunks of the signal are totally missing. Time to quiz the tech again. After some discussion and checking, the "new" problem was discovered. I found if I took the cam sensor hold down bolt out and tilted the sensor toward the reluctor ring, the car would start and the cam signature was correct.
This picture tells the story. (Figure 5) Rather than put a new correct gear on the motor the customer ground off the rivets from the original gear, took the reluctor ring off and put it on the new gear that came with the motor. Because it was not centered properly it rotated in an elliptical pattern that caused it to move away from the cam sensor every 180 degrees. That's why the cam signal was missing lots of pulses. This is what the proper cam and crank sync looks like for this motor. (Figure 6)
The tech had installed all the mechanical components correctly but unfortunately he did not understand the significance of the slots in the relutor ring. After some show and tell with the scope he now understands completely.
Automotive Test Solutions is a multi-national award winning company for innovative thinking that produces patented tool solutions for the automotive industries. ATS currently holds 22 patents with over 25 patents pending. All of the tools produced at ATS are designed to allow technicians to quickly and accurately diagnose the modern vehicle. ATS tools offer unique solutions to help technicians where it counts, in your service bays. Established in 2001, ATS manufactures; oscilloscopes, ignition analyzers, OBD II scan tools for advance engine diagnostics, misfire detection systems, advanced engine mechanical testing using pressure transducers, pressure transducers, advanced leak detection systems, tailpipe emission gas analyzers, fully articulating borescopes, engine simulators, carbon removal solutions for induction systems, oil and fuel pour-ins to serve the automotive technician.
ATS is proud to be a U.S. based company.
Copyright © 2019 Automotive Test Solutions, Inc.
515 Wyoming Blvd. SE Suite A
Albuquerque, NM 87123
Mon-Fri 8AM - 5PM Sat - Sun Closed
Sign Up for Email Updates
For email marketing you can trust