theCure

i just picked up an 87 gta 5.7 yesterday, needs a little bit of work, but what i want to start on first is why it acts cold natured. the car starts everytime, but i have to give it a little gas til it warms up some and then it will stay running. most of the time while its running if i turn the a/c on it will die and if it doesnt die, it will make a "surging noise" like a bad vacume leak. i'm not real sure where i should probably start. it does have the original cat on it so thats 20 years old probably no good anymore, plan on cutting it off since dont have to worry about emissions around here. any other advice? and also it idles a little low.....cant i adjust that at the throttle body?

thanks,
jon

swerve

When is the last time it had a tune up? Did you check the timing? Did you find any vacuum leaks? Check engine light on? Might be a sensor. O yea, I had a 305 tbi camaro that acted like that, once I cleaned the injectors it clear right up. Good Luck! The only thing I hate about a code scanner is that if the car is running bad it will give you codes for sensors even though there is nothing wrong with them. Anyways I would start looking at these places first.

theCure

well the check engine light "Was" but i just got the cat chopped off (dont have to worry about emissions around here) and now the light is off hehe.....it is definitly running ALOT better, but still idling too low......im gonna change the plugs and wires and see what it does and put a k&n filter in it. im suspecting a vacum leak, but i dont have any tools or know how.....on checking leaks.

Sonix

iTrader: (1)

Pull the codes anyway. O2 sensor, MAF sensor, etc could do that.

theCure

will do....gonna take it to a local parts store this evening see if they'll run the codes for me

Toehead

you can also read them yourself. Brb, let me dig up one of my old posts.


Q: How can I display the error codes from a Service Engine Light?
A: If your car does not have the 12 pin DLC connector, you may not be able to manually "flash" your trouble codes. The language "may be possible" appears to suggest that this method should work with most, if not all, 12 pin DLC equipped cars.
THE CONNECTOR
----------------------- | 1 2 3 4 5 6 | | 7 8 9 10 11 12 | -----------------------
DISPLAYING THE TROUBLE CODES
Run a wire/hairpin from Pin 6 to Pin 12 with the ignition off (although on later cars it should be from Pin 5 to Pin 6), then turning the ignition to the on position without starting the engine will flash the "Service Engine Soon" light in the following sequence: flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause Following this "12" code repeating three times will come any trouble codes stored, flashing each of them three times. If you do not see the "12" flash three times, your diagnostic circuit is defective. Some vehicles will display stored trouble codes, then "12" again, followed by energizing "most system controlled relays." The fuel pump relay will not energize. The idle air control valve will fully extend to enable checking minimum idle speed.
CLEARING THE TROUBLE CODES
Turn the keyswitch to the off position. To clear any trouble codes, disconnect the power feed for 30 seconds. If this is done at the battery, and your car stereo is equipped and programmed with a four digit pin code, you may have to re-enter that as well to use your stereo again. A better place to remove power is at the fuse.
TROUBLE CODES

12.No reference pulses to Electronic Control Module (ECM).
13.Oxygen sensor signal stays lean during warm engine cruise
14.High temperature indicated at engine coolant temp sensor
15.Low temperature indicated at engine coolant temp sensor
16.High battery voltage OR Direct inition system open or shorted to ground
17.RPM signal problem
18-20.N/A
21.High voltage at throttle positon sensor
22.Low voltage at throttle positon sensor OR Fuel cutoff relay circuit open or shorted to ground
23.Low temperature at manifold air temperature sensor OR Throttle position sensor error
24.Circuit fault in vehicle speed sensor
25.High temperature at manifold air temperature sensor OR Vacuum switching valve circuit open or shorted to ground OR High voltage at ATS sensor
26.Fault in quad driver module
27.Fault in 2nd gear switch
28.Fault in 3rd gear switch
29.Fault in 4th gear switch
30.N/A
31.Low voltage at manifold absolute pressure sensor OR Fuel injector OR Park or neutral switch OR CAM diagnostic OR Governor malfunction OR Wastegate overboost OR Wastegate eletrical signal open or shorted to ground
32.Fault in barometric pressure sensor circuit OR Fault in exhaust gas recirculation valve diagnostic switch OR Fault in electronic vacuum regulator valve
33.High voltage (low vacuum) at mass air flow sensor (or MAP sensor)
34.Low voltage (high vacuum) at mass air flow sensor (or MAP sensor)
35.Idle speed can not be set to desired RPM
36.Burn off at mass air flow sensor OR Problem in transmission shift OR Fault in direct ignition system OR Missing pulses in electronic spark timing signal
37.N/A
38.Fault in torque converter clutch brake switch
39.Fault in torque converter clutch circuit
40.N/A
41.Fault at cam sensor OR Cylinder select error OR Tach input error
42.Fault at electronic spark timing circuit OR Fault at direct ignition system OR Fault at fuel cutoff relay circuit
43.Low voltage at electronic spark timing circuit
44.Oxygen sensor lean
45.Oxygen sensor rich
46.Fault at vehicle anti-theft sytem OR Fault at power steering switch
47.Problem at Electronic Control Module (ECM)
48.Misfire
49.Vacuum leak
50.N/A
51.PROM error
52.Problem at Electronic Control Module (ECM) - Missing fuel calpac missing OR Analog to digital converter error OR Fault at quad driver module OR Low voltage at oil temperature sensor
53.High voltage at battery OR High voltage at exhaust gas recirculation valve OR Voltage reference error OR Problem at vehicle anti-theft system
54.Low voltage at fuel pump OR Low voltage at Fuel pump relay OR Output failure at quad driver module
55.Problem at Electronic Control Module (ECM) - ECM failure OR Serial bus error OR Fuel lean malfunction
56.Low coolant or corrosivity OR Fault in port throttle system vacuum sensor
57.N/A
58.Problem at vehicle anti-theft system
59-60.N/A
61.Oxygen sensor degraded OR Port throttle system error OR Cruise control problems
62.Gear switch input diagnostics OR High voltage at oil temperature sensor OR Fault in cruise control- vacuum solenoid circuit
63.High voltage at manifold absolute pressure sensor OR Fault in exhaust gas recirculation valve OR Fault at right oxygen sensor
64.Low voltage at manifold absolute pressure sensor OR Fault in exhaust gas recirculation valve OR Right oxygen sensor lean
65.Failure at exhaust gas recirculation valve OR Faulure at injector peak/hold diagnostic OR Right oxygen sensor rich OR Fault at cruise control position sensor
66.Internal reset of Electronic Control Module (ECM)
67.Fault at cruise control switch
68.Fault at cruise control switch
69.Fault at air conditioner pressure switch
70-87.N/A
88.Internal reset of Electronic Control Module (ECM)
| 1 2 3 4 5 6 |
| 7 8 9 10 11 12 |

theCure

hahahaha......youre not gonna believe this, just took the air box cover off to check the filter and there was a rag stuff up in the air opening and large pieces of paper in middle of the air filter.....maf screens are still on so hopefully nothing has gotten into the engine.......runs ALOT better no, but still idling too low.....isnt there a screw somewhere on the tpi throttle body that i can adjust the idle?

Toehead

Check the tech articles...


There is a procedure for setting up the "Minimum air" for idle.


Whil you are at it clean out the IAC and the throttle body passages.

theCure

whats the best stuff to get to clean it out? im about to run to the parts store and see if they have a kit to clean the fuel injectors and also im gonna switch to mobil 1 synth and suggestions on best weight oil and filter for a engine with a tad over 100k miles

thanks,
jon
----------
also checking out little things i noticed i have a screw missing on the top of the tps sensor so on that one i'll prolly have to take it to a shop to get the tps set right

theCure

alright got it running right now....BUT hooked 2 different scanners up to the car to check codes and will not respond....so im guess i will have to start looking for my car some new brains, huh?

babybear82lilj

yes u can adjust the idle at the throttle body it will help it stay running just watch it cause if u set it to high you will have to go and turn it down once it warms up i keep a torx driver in my arm rest for that i the cold nature i have no idea mine has been doing that for two years i have had no luck trying to fix it good luck if you figure somthing out give me a line

Sonix

iTrader: (1)

an ODB1 scanner? Hooked up right, and no response? That's strange... If the car runs ok, then i'd suspect some bad wiring at the ODB port. I'd try the paperclip. If nothing works, start checking wiring near the ODB port area.
I doubt the ECM is fried or anything, if the car will run.

babybear82lilj

maybe i have put too new ones in mine still does give check codes and is could natured

theCure

yeh we tried a couple of different OBD1 scanners and still got no response from the computer.....we set the TPS sensor the old fashioned way with a volt-meter so the car is no longer acting cold natured. its running PERFECT. start up everytime now without dieing. so its just whats the deal with the ecm now.