They want money!

[Anonymous]

Hi Richard, I read your post on mechanics. Yup, I agree with what you said. Most ppl don't have an understanding of how all the controls work together on the newer cars. I'm an Assistant/Manager for an Auto Tech sight. ( Pro Autotech) in Msn Groups. It's for techs to trade info. You forgot to add the air temp sensor that works with the water temp sensor. :wink: Info to the ECM, info out, eh? Like a tree with branches. Sending info to the trunk. Every tech on the sight are hard working ppl trying to keep up with all the new things thrown at them. I have been in the sight for about 2-3 years & all I have talked to, just trying to do the job as best as they know. Good ppl. Another sight we have is for ppl that ask Q called Auto Techs Online-> MSN Groups. For the ppl that aren't techs to ask & we try to help them, Dave P.S. Any one in the GS group can ask a Q & remember the more info we get, the better answer you get. Not trying to steer anyone to a sight as I'm not trying to spam. I'm really glad I found this sight as a wealth of info here to read on my 82 GS650E. Trying to get tires for it & any info on where to buy & what would be helpfull.

 

[Anonymous]

Stuff..

Stuff..

Loco:
Lets' not forget the three different processors (computers) in todays cars : the ECU (Engine computer) PCM (Transmission computer) BCM (Body control computer) and last but not least lets talk about the concept called Multiplexing whereby lets say dozens of control signals are going thru a single wire to be decoded at the different devices independently.
(Trust me its' a real mess out there folks)
Rick.......

 

[duaneage]

Re: "work on it yourself!!!!"

Re: "work on it yourself!!!!"

While we are on the subject:

I went to a local shop with my 93 VW Jetta because the e-brake was sticking. This has happened before, it's a stupid cable design- nothing to do with the calipers at all, just a corroded cable. The cable costs about $38 from the dealer, so I'd replace it every year myself. Well now I have a real job that I commute to, a house with a big lawn and a wife to deal with, so basically I don't wanna do this kind of work myself. Even though it is a 30 minute job, I take it to a local brake shop. They tell me I need to replace all the calipers (back and front- hey wait, didn't I just come in here about the e-brake which is only attached to the rear calipers?) and that it will be about $1200 for this job to make the e-brake work correctly. I tell them to forget it, I have been through this before, it's just the damn cable, but they insist I am wrong! So I came to pick it up and of course they have parked it with the e-brake set even though I have told them not to pull the e-brake handle cause it will stick! So now I have to drive for 18 miles with the e-brake engaged until I can get home and push the cable with a pair of pliers. In the end I bought a cable for the $38, replaced it myself and wasted an hour dealing with the idiots at the brake shop.

Everyone who drives a car should have to work on it themselves so the mechanics are forced to be more ethical.

SO.....You all wanna work on your own cars Huh????
Let me rattle off some devices & you tell me how they interact with each other, how they pertain to performance, drivability, economy & emissions

Throttle position sensor
Mass airflow sensor
Bank 1 upstream O2 sensor
Bank 1 downstream O2 sensor
Bank 2 upstream O2 sensor
Bank 2 downstream O2 sensor
Crank position sensor
Coolant temp sensor
Intake air sensor
EGR Valve
EGR Feedback Solenoid
PCV
Purge Control Solenoid
.........I'll stop here (Theres' more)
Todays modern cars are far too complex for most of you all, Ive been at this for twenty years now & I can barely keep up with it all.
Ive seen the results of customers trying to do this themselves & they usually mess it up royally & I have to decipher what their intentions were & backtrack to fix what was originally wrong.
Rick.......
Cam position sensor

No problem..

Throttle Position Sensor - Relays opening angle of throttle to computer
Mass Airflow Sensor - uses either a heated wire or vane to determine amount of air entering engine after the filter
o2 sensors ( various locations) measure oxygen content in exhaust to allow proper fuel air mixture of 14.7 to 1 under cruise. downstreams measure after the converters to make sure convertors are working
Crank Position sensor determines engine position relative to reference point and is responsible for setting initial timing
Coolant Temp Sensor tells computer engine temp is high enough to permit closed loop operation using the O2 sensors for feedback
Intake air sensor check air temp so the Fuel injection can compensate
EGR valve sends exhaust gas back into the engine to cool combustion, it is carefully metered and controlled by the EGR valve feedback solenoid that reads the exhaust pressure using either a peizo element or a diaphram
PCV vents crankcase gases into the engine to be reburned
Purge control valve vents the gases in the gas tank into a charcoal canister and reburns them into the engine as soon as the engine hits warmup temperature

I am not a pro mechanic, i just picked up a book or two and learned how it all works because I don't like getting loved by mechanics. A/C is the only thing I take a car in for anymore ( also front end alignments) because I don't know any that play fair. Most tell customers they need the fuel injectors cleaned, new wires and plugs, cap and rotor, various sensors, etc when the computer in the car actually will pinpoint most problems for you. New cars are even more specific with OBD II scanners you can buy for about 150.00, less than one repair in most cases.

Most mechanics are not any different than the rest of us, they just have garages and plenty of tools. Car companies make it easy to find the problems so they so they don't spend too much on warranty work, hence the computers. BTW the US Gov. required computer diagnostics years ago, and the OBD II standard was implemented so they are all the same now

 

[Anonymous]

parts

parts

head sensor, ambient air sensor, egr-poteniometer, fuel pressure regulator, MAP sensor, frequency valve, vec. speed sensor, several types of injectors. $5000 in Snap-On scanner soft ware, another $15,000 for a cheap exhaust analyzer, and the BIGGIE 15% of your gross earnings for insurance, plus every 2-3 years upgradeing your smog licence and school fees

 

[Anonymous]

Re: parts

Re: parts

head sensor, ambient air sensor, egr-poteniometer, fuel pressure regulator, MAP sensor, frequency valve, vec. speed sensor, several types of injectors. $5000 in Snap-On scanner soft ware, another $15,000 for a cheap exhaust analyzer, and the BIGGIE 15% of your gross earnings for insurance, plus every 2-3 years upgradeing your smog licence and school fees

You'd think that with all the training mechanics undergo the local national repair chain shop wouldn't have tried to sell my wife $600 worth of work she didn't need when she inquired about a small necessary job (I sold the car years later without any of that work being performed, despite them telling my wife the car wasn't safe and/or would break-down). She was especially perturbed to be assured the engine oil was "black, and thick as molasses" when she questioned the need for an oil and filter change described as essential: In fact, we had changed oil and filter two days previously, and the vehicle had 10km (6 miles) on it since.
I have many such personal-experience stories. Savvy motorists know when they are being ripped-off! By the way, I'm tired of hearing "they all do that" and "it wasn't anything we did" before I'm forced fix the (sometimes exacerbated) problem myself. Why do dealership mechanics have to do expensive diagnostic work and unnecessary repairs on the way to discovering the actual problem, when I can usually jump on the internet newsgroups/forums and learn that the problem is a well-known defect common to the particular model? You should have seen a Chrysler dealer roll the dice repeatedly when I broke down out of town. After investing $200 without resolution, I limped home (all night) just to learn that one in three of my model suffered the same symptoms/problem/ultimate fix.

Don't get me started! And how about those flat rate jobs: My brother works at a m/c dealership. They charge flat rate on every occasion that the job takes half as long as book value (often), but charge more than flat rate when anything occurs to cause the job to go long (rarely). Too, the service manager treats customers in a most surly and rude manner, smirking openly at their perceived ignorance (my brother is the service manager).

 

[duaneage]

Re: parts

Re: parts

head sensor, ambient air sensor, egr-poteniometer, fuel pressure regulator, MAP sensor, frequency valve, vec. speed sensor, several types of injectors. $5000 in Snap-On scanner soft ware, another $15,000 for a cheap exhaust analyzer, and the BIGGIE 15% of your gross earnings for insurance, plus every 2-3 years upgradeing your smog licence and school fees

You'd think that with all the training mechanics undergo the local national repair chain shop wouldn't have tried to sell my wife $600 worth of work she didn't need when she inquired about a small necessary job (I sold the car years later without any of that work being performed, despite them telling my wife the car wasn't safe and/or would break-down). She was especially perturbed to be assured the engine oil was "black, and thick as molasses" when she questioned the need for an oil and filter change described as essential: In fact, we had changed oil and filter two days previously, and the vehicle had 10km (6 miles) on it since.
I have many such personal-experience stories. Savvy motorists know when they are being ripped-off! By the way, I'm tired of hearing "they all do that" and "it wasn't anything we did" before I'm forced fix the (sometimes exacerbated) problem myself. Why do dealership mechanics have to do expensive diagnostic work and unnecessary repairs on the way to discovering the actual problem, when I can usually jump on the internet newsgroups/forums and learn that the problem is a well-known defect common to the particular model? You should have seen a Chrysler dealer roll the dice repeatedly when I broke down out of town. After investing $200 without resolution, I limped home (all night) just to learn that one in three of my model suffered the same symptoms/problem/ultimate fix.

Don't get me started! And how about those flat rate jobs: My brother works at a m/c dealership. They charge flat rate on every occasion that the job takes half as long as book value (often), but charge more than flat rate when anything occurs to cause the job to go long (rarely). Too, the service manager treats customers in a most surly and rude manner, smirking openly at their perceived ignorance (my brother is the service manager).

I bet your "cry" sler had a crank position sensor go bad. I know four different people that had this same problem and mechanics with all the latest gadgets could not find it. Coil packs, computers, wire harness, etc and the answer was on the internet in a user group. I found a post in 5 minutes that pointed to the CPS. Maybe instead of all the afore mentioned equipment most garages should just buy a computer and get on the internet once in a while

 

[Anonymous]

Throttle position sensor - resistance type usually. Position of throttle determines resistance measurement. Manual will usually give you a check value.

Mass airflow sensor - Similar to the TPS - Must work smoothly and freely since intake airflow sets it's position, and therefore output resistance. Manual gives you a value.

Bank 1 upstream O2 sensor - Measures exhaust conductivity. If you got alot of miles on your car - could be cause of problem. Usually quite reliable and fails gradually.
Bank 1 downstream O2 sensor - similar to upstream - they sense O2 in 2 places. This may be after the catalytic converter. See miles comment.
Bank 2 upstream O2 sensor - See above.
Bank 2 downstream O2 sensor - see above.
Crank position sensor - sounds like a "hall" sensor - used for timing? This "sensor", if a hall, can be checked since it is a "coil". Need right manual to get specs.
Coolant temp sensor - yeah - take it out - put it in a hot water or coolant on the stove and measure it's resistance at a certain temperature. If OK - go to the next thing. If not working - may affect mixture richness.
Intake air sensor - Measures temperature of air intake to determine "fine tuning" on mixture adjustment. Can be checked also.
EGR Valve - Exhaust Gas Recirculator Valve - they plug up sometimes. Not sure of details, but if defective, NOX is usually too high.
EGR Feedback Solenoid - OK - an on/off switch for the port or hose for the EGR valve. If defective, NOX can be too high.
PCV - Positive Crankcase Ventilation - a little anti backflow valve which lets crankcase vapors breath into the intake but not the other way. They can gum up. Easy to replace- may affect idle.
Purge Control Solenoid - Duh.

Anyhow - a factory manual tells you how to check many of these items properly with a volt ohm meter in many cases. I had a VW golf. Had missing at heavy throttle loads. Factory manual said all kinds of scary horrible things that could cause it. One item was-check the fuel pressure regulator. It was a diaphram type. I determined the diaphram had a leak (easy to check). ...so replaced it. My car was happy again.

If it had been the fuel regulator - well ..try the cheap item first.. Since I could tell the diaphragm had a leak (just suck on the vacuum line. Should hold pressure) I was able to be positive about the problem.

I encourage the DIY'er to do do their own work...but get a factory manual and do what is within your limits. Then STOP if you cannot fix it...but....yes...modern cars can be checked to some degree....and yes...they are more complicated. You should know how each item works and what its impact is on emissions from a qualitative standpoint when diagnosing. Yes there is interaction between components...but factory manuals tend to have diagnosis charts.

Keep track of what you checked, the data you record, and bring along to the mechanic. If at any rate....if you do a proper test or inspection, the mechanic will be able to tell if they can rely on your information and it should speed diagnosis and repair.