How it Works! Welcome to Auto 101

marsha7 · July 2005

Yeah, everybody talks about the heat out west..."yes, it gets very hot, but there is virtually no humidity and so it's a dry heat"...

Please remember...everytime I roast a chicken in my oven, I am doing it with DRY heat...consider yourself warned...

:shades:

sda · July 2005

Re: 95 Cutlass Ciera 3.1 v-6. Factory air 134-a. Needs recharge. Compressor doesn't engage when system is turned on. I imagine low pressure switch prevents this. Question: when I try to recharge system, will pressure from 134-a recharge can cause enough in-line pressure to disengage low pressure switch, ie allow compressor to turn back on so refrigerant can be received into system? Or is there a different way to activate compressor? I would hate to buy a recharge kit, only to find I can't get the compressor to turn on. Thanks!

Mr_Shiftright · July 2005

You can usually by-pass the switch temporarily with a jumper wire to briefly test the compressor, yes.

94_chevy · August 2005

hey i have a 94 silverado 1500 and my speedometer and tach dont work, but all of my other guages do. does anybody have any ideas on how to fix this problem?
thanks

gijoe3 · August 2005

I am having trouble removing the drum on the rear wheels of a 1999 Chrysler Town and Country LTD.. Can you give me info on this and how to replace the brake shoes.. Thanks, J. Lindsey

gijoe3 · August 2005

Need info on Drum Removal and replacement of brake shoes on 1999 Chrysler Town and Country

alcan · August 2005

If the drum doesn't move at all, it's seized onto the hub. A healthy dose of penetrating oil followed by a few taps with a hammer in the hub area should break it loose. If it moves but won't come off, there's a ridge built up at the inner edge of the drum that's catching on the shoes. Remove the rubber access plug in the rear of the backing plate and with a brake adjusting spoon or suitable sized screwdriver, rotate the star wheel adjuster to back the shoes off. Might be necessary to use a thin screwdriver through the access hole to hold the self-adjuster lever away from the star wheel while turning it.

When replacing shoes, do one side at a time and use the other side as a reference. Here's a blow-up of the parts:
http://www.autozone.com/images/cds/jpg/small/0900823d801a4c1a.jpg

rddaves54 · August 2005

I have a 1991 Chrysler LeBaron and the air bag light is staying on. When it does stay on the air conditioning does not work.

I disconnected the battery to clear the system and it only kept the air bag light off until I started it about after three miles. I have looked at the wiring on the engine and they all seem to be connected. Everything else seems to be working fine.

I do have a problem with the odometer not working and the speedometer working on and off. What is causing this?

Any and all help would be appreciated.

:confuse:
Thanks!

Mr_Shiftright · August 2005

Since this is a duplicate post I'll just give you a link to how air bags work as that is the purpose of this forum--this isn't for repair questions per se:

http://www.carcare.org/Safety/air_bag.shtml

gakor · August 2005

I have a Honda Odyssey, (not 2005 model), and my battery died. I replaced it without a problem, but my radio doesn't work. The radio asks for a security code, but my car dealers didn't give me one.

I need step-by-step instructions on how to remove the radio. Can anyone help me with this? I bought the car used, and its a factory radio. Thanks ahead

user777 · August 2005

yes I have a suggestion for what you seek:

go to the "honda odyssey problems and solutions forum".

at the top will be a big banner for H + A Accessories, a sponsor for the site.

click on it and select Honda (as opposed to Acura), then Odyssey, then the model year, and then Electronics (there are links for Internal and External and Maintenance, etc), and scroll to the model radio (or similar that you have). There will be a link for downloading the instructions for installation of the radio. that should be a good start.

before you do that though, is there an entry in your owner's manual or special anti-theft radio card which came with the vehicle?

good luck.

Mr_Shiftright · August 2005

To get to the forum recommended in post #218, here's the link:

Honda Odyssey Forum

Shiftright the Host

gakor · August 2005

Thanks alot, i really needed this. You helped alot

sloopjohnc · September 2005

I know next to nothing about cars except changing my starter and brakes on a 74 dodge colt I owned in college.

I recently went to work for a company that makes a device that monitors various engine performance parameters. Both consumers who want to check whether little Jimmy is drag racing the family Volvo and comm'l fleet managers buy this product.

The only problem is it shows just raw data and doesn't give context or meaningfulness. It's like showing the chords of A Hard Day's Night w/o explaining the social significance of the song.

For example, it gives RPMs of your car but doesn't say whether your car is revving too high at stoplights or getting onto the freeway.

Below are some of the parameters this device mentions and if anyone knows what these would mean re: a car's performance, I'd love to know. Some I'm more aware of than others, but that's okay.

RPM
Throttle Position
Engine Load
Fuel Pressure
Fuel System Status
Short-term fuel trim
Long-term fuel trim
Battery Voltage
Timing Advance
Coolant Temp
Air Flow Rate
Intake air temp
Intake manifold pressure
O2 sensor output voltage

Thanks for the help in advance

swschrad · September 2005

RPM is raw engine turns.

RPM balanced against throttle position doesn't give you much more info, but RPM against timing advance or intake manifold pressure might give you how hard the throttle was jammed, indicating hard driving. RPM and engine load might be used to calculate shift points, and there may be a way of developing a mathmetical relationship between them and the intake manifold pressure that could indicate if little Johnny was peeling out at the stoplight. most of the rest are service parameters which are useful to diagnose troubles.

throttle position just uses the TPS voltage to tell the computer how far the gas pedal is depressed.

engine load is a calculated internal number to the engine computer that should correlate to how much of the design horsepower is being generated. if you're towing and headed uphill, engine load will be high. similarly, if you are hammering the gas and burning rubber all the way down the road, engine load should be high.

fuel pressure may be a go/nogo or may be a linear curve. you have to have a certain fuel pressure at the injectors to get the right fuel/air mix to run the car. there should be some "slop" in the system that the computer can correct for, and this is probably the signal that allows the car to keep running as the pump and regulator age.

fuel system status may be about anything, I would suspect it's a go/nogo signal out, or a "low fuel" signal in from extra contacts on the sender in the gas tank.

short and long term fuel trim are the signals from the 02 sensors... short-term would be the manifold sensors, long-term the catalytic sensors... used to align the operation curve with actual performance, and adjust the fuel/air mix.

battery voltage is a linear signal, basically anything below 10.5 volts in run is likely to be a check light, because after the voltage regulators in the engine computer, the dropout of the regulators below 10.5 volts makes the computer iffy.

timing advance is probably an output signal corrected to degrees, generated from the crank position sensor and the computer's calculations on how to get the engine to do best right now dynamically. there is no "timing advance" conducted mechanically any more, but it represents when the computer kicks the coils to fire the plugs.

coolant temp is used to adjust the air/fuel mixture for better efficiency, and indicate when the computer can get off its fixed curve set and go dynamic, when the engine and all its sensors are warmed up.

air flow rate is from the MAP sensor, and practically ought to be similar to the engine load in determining how hard it's working. 17 parts air to one part gas makes the wheels spin.

intake air temp is outside temperature, probably used in cold weather corrections to the computer curve.

intake manifold pressure is actually going to measure engine vacuum.

02 sensor output voltage is raw input from the sensors, and when integrated over time should be similar to the fuel trim signals.

sounds like new software analysis functions for the CarChip in the future...

tiki2 · September 2005

ok was here awhile back got some really good info and tried to purchase a owners manual but alass cannot find one! I need to know if ANYONE knows how to work the cxomputer on the dash for milage and MPG ect. Also I recentlty put a NEW ECM BUT now i have a check engine light only when idling and an inspection lite.I know the check engine lite is certainly something I want to be concerned about but is the inspection lite just a lite that comes on after a certain amount of miles? AND if anyone can help me out with a manual I would greatly appreciate it Ebay is nil...Thanks all

TIKI2 :confuse:

sloopjohnc · September 2005

I think you're right. thanks.

napoleon · October 2005

has anyone ever opened up a dodge computer to do repairs? I have a 95 5.9L ram van 3500 with an electrical short in the ecm. is there a way to remove the resin goop that covers the components on the inside. it appears to be a simple fix if i can get inside without destroying it HELP!

swschrad · October 2005

that is moistureproofing and anti-tamper coating. if it's grey, the antitamper feature leads.

generally, epoxy coat can be dissolved out by pure methylene chloride, heat, and agitation. when that is done, both the anti-tamper and the components' epoxy cases are gone, and the guys who do that are looking to put the chips themselves under polarized-field microscopes, to look for failure mode flaws on the chips between metal and silicon layers.

that is a unit-replaced module, no repairs there. if there were, it's all surface-mount chips, and they don't carry real part numbers, but manufacturer-specific joke codes like "5E" and "2C." matching up these with real part types is not cool, you need the design data that dodge is not going to give you.

user777 · November 2005

FWIW:
While participating in another forum, the topic of Fuel Injection came up. I found the following link/page which might be of interest to those wishing to learn a little about the technology:
http://xantiaclub.net/techguide/

330xi2005 · December 2005

The other day I did a U-turn in my car and the next thing I know, my left front tire is not moving. Apparently, my tire axle was broken. The dealership has stated that the damage will not be covered under warrenty because they think it is from driving over a pothole or curb, bending the arm,and then severing during the u-turn. If that was the case wouldn't my rim or tire be damaged before the axle being bent? Any thoughts on what could have caused this problem? Has anyone experienced this problem?

comaroman06 · January 2006

can anyone tell me how to remove the shifter knob only on a 1998 dakota????????/

jfeisthamel · February 2006

How do I install a new hazard lllight switch on a 1997 Chevy Venture? It is a one piece unit with the directional lights. It has cruise control. It is located on steering column. Help!!!

alcan · February 2006

Requires disabling the airbag, and a special tool to remove the steering lock plate. Those switches are pretty reliable, what's wrong with it?

fear_hope · March 2006

Can someone help me?! I test drove a Pontiac Vibe with 22000 miles on it today. It is a 2005 and in great shape. However when we checked the tail pipe, wiping inside of it with a paper towel, we picked up a lot of black soot. It was not oily, just very black and sooty. My van is a 1999 and has no soot in the tail pipe, just very little light grey, more smokey than sooty. My husbands truck is the same. Is the soot normal for Pontiac Vibes or Pontiacs in general? Do you all have soot in your tail pipes also? If it is not normal are there any mechanics here who can tell me what would cause that? Thanks for the help!

Mr_Shiftright · March 2006

Visually is just guess work. You should have a shop "sniff" the tailpipe and see if the car is running too rich. Is your fuel mileage below normal? Do you take only very short trips most of the time?

fear_hope · March 2006

I do not own the car! We were test driving it and are considering purchasing it. Today we checked two or three other Pontiac Vibes, 1 used and 2 new. They all had black soot in the tail pipes. Of course the new ones had very little, but the used one had about as much as the other one we test drove. Can that be "normal" for these cars? Why would the fuel not be burning completely? Thanks!

Mr_Shiftright · March 2006

Oh test drives....yeah, it would be normal to be sooty in the tailpipe. The cars are running rich and not going very far.

carlisimo · April 2006

My friend dropped a nickel down the air vent that blows onto her windshield, in her '99 Corolla. So now I'm looking for diagrams of air ventilation systems to see how they work, where the tubes go, what safeguards there are...

The specific question is "can the nickel get anywhere harmful?" but now I want to know just what path air takes all the way to the vent. Any good place to start?

Mr_Shiftright · April 2006

Probably a blow-up diagram from the dealers' parts department microfiche or computer CDs.

But really, I don't think I'd worry about this if I were you.

smokey75 · April 2006

Anybody know an accurate method to determine with what force your lugnuts were installed? Will using a torque wrench & gradually increasing the torque setting until the lugnuts move work?

Mr_Shiftright · April 2006

iffy but not bad..problem is this doesn't account for the effects of long time weather corrosion or threads damaged during installation etc. But if the lugnuts were put on recently and didn't cross-thread, I bet you'd be within 5-10 lbs of installation torque, using your method.

smokey75 · May 2006

Thanks... just like to check after having tires installed & usually find them torqued signifigantly higher than they are supposed to be.

Mr_Shiftright · May 2006

You should ask that they be hand tightened.

sc00bs · July 2006

iluvfordz · August 2006

I just purchased an '03 F150 Lariat supercrew SB W/tow pkg. Upon going over the controls/functions, I discovered a small, round, black "rocker style" switch located where the front airbag switch would normally be, just below the vent adjacent to the climate controls, and I cannot, for the life of me, figure out what it's for. It must control something, because when I turn it on, the AM radio doesn't operate from electrical noise. Noone else seems to know.
Any ideas?

bdkinnh · August 2006

Does it have two fuel tanks? That could be the tank switcher.

stever · August 2006

There's a thread over in the Yukon group about fuel consumption while coasting, with one side saying no way can an engine operate without fuel, and the other side referring to ecu mod sites that say that fuel is cut off completely during coasting situations, like long downhills. Hits like engine overrun and (gas) engine vacuum pop up in searches too.

Here's the thread start:

elias, "2007 Chevrolet Tahoe/GMC Yukon" #1670, 21 Aug 2006 10:47 am

Steve, Host
SUVs and Speed Shop

jerrywimer · August 2006

One of the last messages posted in the other topic claims that it's impossible for an automatic-equipped vehicle to use fuel shut off during coasting because there's nothing directly connecting the rotating wheels and the crankshaft to allow the vehicle's inertia to keep the crankshaft rotating, unlike in a manual transmission vehicle that is in gear.

I had to do a bit of research, but I believe that this post is entirely incorrect- at least for vehicles with lockup torque converters when the converters are locked. I also believe this to be the case with the GM 4L60E transmission used in the 1/2 ton trucks and SUVs. This must be the case because otherwise my 2004 Silverado would have provided no engine braking when coasting down hills, and RPMs would have fallen off to idle levels from those obtained in normal throttle-on cruising at the same speeds (or, assuming GM is or was using fuel shut off during coast in the 04 Silverados, the engine would have died completely, as asserted by the other member posting that message).

Am I wrong?

wwest · August 2006

The torque converter does NOT have to be locked up in order to turn the crankshaft during coastdown periods. Some torque converters even have a one-way clutch incorporated for just this purpose. as we all know, or should know, torque converters are not very efficient for "conveying" engine compression braking, but they certainly do.

The whole discussion gets a little confusing because automatics cannot be push started. But that's because there is no way, absent a rear pump driven directly by the drive shaft, to engage any of the necessary clutches without hydraulic pressure.

And I rather doubt, strongly, that the "light" duty lock-up clutch would, could, ever be used to convey engine compression braking, keep the engine turning over during coast downs.

But it is a simple matter to test, just downshift and then turn the ignition off during a coast down time and then back on a little later and see if the engine resumes "running".

elias · August 2006

below are snippets about PCM from a university web page - note the repeated references to the zero-fuel decel condition. also, the point re torque converters are well taken. there's nothing much different here in the case of auto trans vs manual trans. the only reason i granted that might be a factor in the new tahoe v4/v8 was that there are certainly lots of techno things i don't know about that vehicle. it's funny that someone with a mech eng background cannot admit that an engine can run indefinitely downhill with zero fuel when even a lowly electrical-eng computer geek can figure it out! the condition is theoretically possible and empirically demonstrable with a diag laptop hooked up to the ECM - it will show fuel pump at "zero" in such condition.
for example, VW vag-com can show the condition on most any VW, i bet .

5. Deceleration  when a deceleration condition is detected the fuel delivery is decreased or completely shut off.

OPEN LOOP - the A/F ratio is controlled to provide the best driveability and minimal emissions under the following conditions:

A. Start-up - richer mixture
B. Cold engine operation - richer mixture
C. WOT - richer mixture
D. Deceleration - leaner mixture or complete fuel cut-off
F. Idle > some engines
G. Heavy engine load - determined from TPS & MAP or MAF

toronado455 · September 2006

You should ask that they be hand tightened.

I've tried to ask mechanics to do this in the past and I always get mean looks. Why do they hate doing this so much?

Also, I have an underslung spare with a nut-driven winder that tightens a steel cable that holds the spare up under the car (minivan). The owners manual says never to use an impact wrench on this and yet I cannot seem to get any mechanics to obey this rule. I even asked a mechanic who was using an air wrench to please stop and the owner of the shop was standing right behind him and told the mechanic to just continue using the air wrench.

Mr_Shiftright · September 2006

I guess I'm just old-fashioned...I have this (call it crazy) notion that if you are paying someone $75 an hour they should make a feeble attempt to please you now and then.

marsha7 · September 2006

simply do not understand why they should hand tork lug nuts is disgraceful...I have been to 3 different Goodyear shops and they all hand tork lug nuts as SOP...

I also get very upset at techs who will use an oil filter wrench to tighten and install and oil filter...where did they miss the concept that you HAND tighten the filter )after puting a thin film of oil on the gasket) but use the wrench to take it OFF???

0patience · October 2006

If they do not torque the lug nuts on today's vehicles, then I would look for another shop.
That is either incompetence or ignorance on their part.

Lug nuts that are run on with air wrenches can cause problems with the wheels and rotors.

Any REPUTABLE tire shop will torque ALL lug nuts.

marsha7 · October 2006

is that if they can't do something correctly as simple as tightening lug nuts or install and oil filter, probably the first thing one does when working on their own car as a teen, then what does that say for the remainder of their work???...and these are, I hesitate to say, pros...

0patience · October 2006

That is the problem with a lot of the newer mechanics coming into the field.
A lot of them start out in some lube place that emphasizes being fast. Get it in, dump the oil and get out.
Then they go into some shop paying flat rate and they get paid for what the book says, so if they can skip a step and shave .2 hour off the repair, they make money.

Now, don't misunderstand me, this happens less than folks would like to admit. But it still happens.

echota · November 2006

Not to get into the zero fuel thing...but on another note, I have pop started an automatic transmission vehicle. Actually, two different vehicles. It is dangerous because it has to be towed at about 40-50 mph....can be done, though!

marsha7 · November 2006

But putting a little oil on the gasket takes, oh, 5 seconds, less time than sneezing and recovering, and hand tighten is quicker than finding the filter wrecnch, wrangling it into the cramped space, and turning the filter 1/4 turn at a time because the wrench cannot make a full turn w/o hitting the engine...it is MORE efficient to do it right than wrong, altho hand torking the lug nuts will take about an extra minute...

sky23213 · November 2006

That's why I'm finally getting me a quality torque wrench for Christmas

. Will double check after every tire/wheel related repair performed outside my garage.
By the way, Discount Tire (America's Tire in some parts of the country) boast on signs in their reception areas that they hand-torque the tires. And you can actually watch the kids in the bay working on your vehicle.

How it Works! Welcome to Auto 101

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