My Caprice is broken! HELP

I am 16 and this is my 2nd car. I love this car dearly it is a 1991 caprice classic with a 305. I love everythin about this car and want to keep it forever. Thats how much i love this car. Well since i bought the car i have had minor problems. It has 160000 miles on it but ran like a champ. The car would hesitate wen i would hit the gas. So i put some injection cleaner. After the cleaner it hesitated only alil bit now. Every time i would turn it would act like it doent want to go Any suggestions on wat it may be??

Well this morning in chicago it was about 10 degrees out and i stroled to my car to go to work. I turned her on and she was shaking a bit. i hit the gas and she didnt want to go so i let her warm up a bit more. The car wouldnt heat up for nothin i was freezing! Wen i started driving i was hitin the gas and it tried shutting off. When i hit my first stop sing and hit the gas it shut off. IT was hesitating and wasnt even going this time. WHATS WRONG HERE? ANYONE KNOW? i need some help please. After that the car over heated. But wen it was in the process of overheating it was driving a little better.. Please help a 16 yearold. thanks

You will find a plug mounted under the dash on the drivers side. This is where the dignostic computer is hooked in to the car to see if any fault codes are showing on the ECM. It has 2 rows of pins. The top right hand side pin is pin A, the one right beside that is pin b. With the car off, put a paper clip or wire in both a and b pin to jump them. Turn the ignition to on but do not start the car. The service engine light will blink. The first blink is the first number and the second blink is the second number.

For example: The first number to blink should be 12 which means the ecm is working properly. The engine light will blink once, short pause, and then blink twice for 12.

A long pause will follow the second number and the same code will repeat twice more (each code shows three times). After code 12 shows 3 times then it will show the fault codes. After all the fault codes are shown it will blink 12 again.

Make sure to turn the ignition off before removing the jumper wire or clip from the plug or you risk damage to the ecm.

Take note of the fault codes and then look them up on the internet to get an idea of what you are dealing with. Here is a site with code listing. Scroll down for fault codes.

http://www.montecarloss.com/SSThunder/gmcodes.html

Hope this helps. Good luck.

Is your antifreeze in good shape, a 50/50 mix of water and antifreeze, or a 40/60 water to antifreeze ratio, which would be even better for cold weather? If the coolant froze, it would not flow, and would cause overheating.

Vacuum leaks also make it hesitate/shudder and die at stop lights/signs.

You also want to make sure you have a thermostat installed, and if you do have one (like you're supposed to) - make sure it's installed correctly.

At 10 degrees, you should really be plugging in a block heater. These cars don't like cold.

Ok.... 5 hours later i tried that thing with the pins and the service engine.. 2 b honest i was amazed it actually workd. Thanks 88CCBLS ..now i know for the future. Does that work with all cars the 2 pins on the top right? and since i know how to check the computer will i ever have to go and do a diagnostic test if i know how to decode it?

So now that thats done im going to just buy the 50/50 antifreeze mix from the store.. When i drained the antifreeze last time when i went to put more in i guess there was still some water in the system from the summer which made it freeze this mornin..

What im still scared about is when the car acts up how it regularly did.. Ill give more symptoms.
1 For one everytime i would turn onto a new street the car would hesitate. and still does unless the car is cold.

2 When i would reverse it would hesitate constantly. everytime i park i have to hit the gas a bit to get it to reverse and sometimes it would hesitate to the point where it would shut off.

3 sometimes when i would make a sharp turn like a u turn it would shut off.

4 When im driving in traffic driving really slow usually when i would hit the gas and let it go fast the car would get quiet then i would hear soemthing from the rear end of the car kinda like hit into place.. I think it may b the differential that is makin that noise.

5 when im driving at a total constant speed usually in the ally 10 mph- 15 it would like like the flow of gas would go stop go stop go stop. its not that the whole car would stop it would still drive at that constant speed but i would hear it go stop go stop like the flow of gas is opening and then closing

6 and final wen i hit the gas i hear a gust of wind from my vent. just for a seconed.

Alright guys. These are all my problems with my car. All the other ones like the shocks/ springs ill worry about.

Thanks I was so mad today i was thinking bout selling my baby and buying another caprice an older model thoe but i figured hey it turned on and ran good wen it got warmer outside maybe the guys from automotive forums can help me out so i know wat to get fixed and dont get ripped off. Thanx again!!!!

o 1 more thing about how much would all of this cost if u guys know..
and what is that heat block? what does it heat? how much does it cost? and is it safe to keep during the summer?..
Thanks again

Sounds to me like your TPS (throttle position sensor) is acting up. While driving at a constant low speed, my car would buck like that. I also had a loping idle problem. It didn't throw any codes.

What I did to correct the problems in mine was to clean the IAC (idle air control) valve, and I changed the TPS for a new one (since you can't clean it). Be carefull when re-installing the IAC on the TB (throttle body). If you over tighten it, it will snap, leaving you with the threads stuck in the TB. I made that mistake, and had to remove the TB to get the pieces free. I ended up rebuilding it for the hell of it.

A block heater is basically a heating element that screws into the block. You plug it into a 110 wall plug to keep the oil warm overnight. In the summer, tuck the wire away until you need it in the winter next year. I'm up in Canada and I have a block heater, but have never had to use it. However, I am glad it's there just in case.

I would suggest picking up an antifreeze tester (only a few bucks) to make sure that you have the proper ratio of water/prestone. It's cheap insurance against cracking your engine block.

Can i clean the idle air control by myself? If so where is it and how would i clean it?
How much would the Throttle position sensor cost? And how much would that heat block cost?
I cant wait to fix all these problems. Everyone talks about my car so much. The cars body only has 1 dent at the rear right passenger door. and needs a paint job..NO RUS or nothing just a pain job and ppl are always sayin i have a p.o.s
Thanks

Hey Blue, Iv'e been reading your threads and this is what I think may be going on. Have you checked your catalytic converter for restricted flow? The reason I ask is you said your car overheated, your car hesistates when speeding up coming out of turns, you hear a hissing sound when the throttle is punched, and the car runs fine cold and gets worse as it it driven - all symptoms associated with a flow problem (restriction) in the catalytic converter. What happens it exhaust gets backed up in the manifold pipes and and instead of leaving the car it comes back into the intake through the now forced open egr valve. This screws with internal engine pressure i.e.- mass air flow and tps try to accomodate for the abnormal air/fuel mixtures and the fuel delivery is inconsistent. If the converter is plugging or plugged, you probably have noticed a pretty sharp decline in fuel economy.

So, how do you check the cat con? You can remove an oxygen sensor and put a backpressure gauge in the hole. Usually it should remain below 12 pounds. You can also take the exhaust pipe off, ram a crowbar repeatedly into the rear opening of the converter until the guts blow out (wear safety glasses and a mask). If the converter was plugged the car will run just fine after you gut the casing. As long as there are no sensors past the rear of the cat con, it should be perfect to drive. Of course, to be legal, you will need to replace the converter eventually. Be sure to use only a GM converter. GM cars and aftermarket cat cons are a bad combination.

ok so im going to break the back of my catylytic converter tomorow...... u said where is the air flow sensor... and get the back pressure gauge and put it in the hole when i find where it is lol... is that gauge the gauge that u check them tires with???,
O the reason the car over heated that day was because my antifreeze froze.. i had 2 much water.. more water than freeze. im gona put new freeze in soon.. thanks...

I am having the exact same problem today. It is -10 below zero. My car (1991 Caprice Classic) has been hesitating off the line. Today it started and idled fine but when I left it died on the first turn. After waiting 15 minutes, it started and roughly reversed back into my driveway. Now it starts and idles but when you press the accelator, it is still choppy. I am trying a fuel filter first with some gas treatment. Do you know where the fuel filter is? How did your car work out, did you finally find what was wrong with it?
Thank you,
Don Pedlar
www.choiceblades.net
www.skysubmit.com

Blue,
The IAC is on the TB sticking out of the side. It's pretty big, you'll probably need an adjustable wrench to remove it. You can clean it with TB cleaner (spray).

PoppaBrasco,
Your fuel filter is underneath the car on the inside of the framerail, in front of the rear wheel, on the passenger side of the car. It should have quick release tabs and one bolt holding it to the chassis. Make sure you have some rags and a container handy. It's a big enough filter, and will drop a lot of fuel when you remove it.
:2cents:

ok im going to clean the tb monday its 5 degrees out here in chicago today........ quick question when u say its on the side of the throttle body is the throttle body the top of the engine??? sorry im trying to learn about working on cars so when u say throttle body im thrown off... sorry... apreciate your help..

and so after i find the throttle body i can clean the idle air control valve with throttle body spray.

The TB is located at top of the engine. Remove the air filter housing completely. You'll see something that looks like a carburator.

The IAC valve is sticking out of the left rear side of it. There is a four pin electrical connection going into it. Remove the elec. conn. from the IAC. Remove the IAC using a 1-1/4 inch wrench or an adjustable wrench.

Take the old gasket off and replace it with a new one. Make sure to clean it with TB cleaner, NOT CARBURATOR CLEANER. Carb cleaner can remove the film from the metal and screw things up for you later on.

The IAC will have a pintle sticking out of it (kinda looks like a pin with a spring around it). Measure from the gasket to the tip of the pintle. It should not be out more than 1-1/8 inches. If it is longer than that, you'll have to push it back in until it is sticking out less than 1-1/8" or you can damage it putting it back in.

Put the IAC back into position with a new gasket, making sure not to overtighten it. They are very easy to snap with such a big wrench. Reconnect everything that you removed.

The car might run funny for a few minutes while the PCM adjusts to the change.

If you are at all uncomfortable with doing this, pick up a 'Haynes Repair Manual' (I don't think 'Chiltons' has one for these cars). It has troubleshooting tips, specifications, step by step instructions and illustrations to help you along your way. At the very least, you will learn more about your car from reading through it. Ask your local parts store where you can get one.

With that said, I hope you find all the gremlins that are keeping you from enjoying your car. I'm sure that everyone here is willing to help you learn more.

Get greasy, and have fun!

Good point burnM, the throttle body gasket could be torn, that would also screw up the fuel/air mix. If its torn, it makes the car stall under throttle on/off conditions due to the PCM not being able to react quick enough to the changes.

After it runs ok, go scab some used tires, get a video camera, smoke em' till they blow and send it to all your "skeptic" friends.

Incidently, after I broke the remaining guts out of my broken converter, my car ran great.

thanks burnm im goin to go get that book... for sure.. thanks for telling me all that info. but i got a real question.. my catilytic converter is in the middle of my car... i still dont know how to gut it out........ lol plz help... thanks

Take the bolts off the back of the cat (you may have to use a torch to heat them up, or cut them off with a grinder/Dremel etc). Get a large crowbar/prybar and stick it in the back of the cat, hit the bar with a hammer until you feel it break through the guts. Keep doing it until it gets all the guts out. Bolt the exhaust back on. (if you cut the factory bolts, you can drill out the factory nuts and put your own nut and bolt through the drilled out nut. Get some spares so whem your muffler or tailpipe goes bad, you can simply cut the bolts off, drop the exhaust and bolt the new stuff back on.

It helped me to have the car running so the guts would blow out of the cat. Wear a mask and safety glasses, it's messy.

so when i take off the bolts on the rear of the cat its going to kind of come off a bit? from there take the crowbar and hammer away.

Or you can do what I did, and just replace it with a piece of exhaust pipe, and hope that nobody looks under your car.....

lol ill gut it out lol thanks thoe. you guys have been the most help to me.. this is the best forum ive ever been on.. thanks yall

this is odd but i came here to ask the same question.my car shakes bucks hesitates when i get on it.goin slower is fine but if i floor it it starts to buck 1 time it even turned off,and when u floor it i hear a popping sound,not a back fire but sounds liek almost a exhaust leak i guess.so this is why i think im gonna hollow out the cat?i live in pa so its cold here.in the summer it never did it.and also it doesnt do it all the time only for alil while.i dont drive it alot and it doesnt run everyday.so im thinkin my cat is blocked or gettin blocked up then clearin out after some time?is this possible? or maybe the fuel filter? i dont knwo its has 90 k 305 v8. sounds liek alot of ppl are havin this situation.my heat does work good tho.but i didnt check the antifreeze which iwill today. anybody have anythng else to add why this could be happening?

FEUL PUMP sending unit

Is it possible to read the ECM codes using the same method on the older model Caprice? I've got an '87 and I've seen the plug under the dashboard.