1993 Chevy Lumina 1993 Lumina starting problem

Tiny
MATT29
  • MEMBER
  • 1993 CHEVROLET LUMINA
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 125,000 MILES
I have a 93 lumina with the 3.1L engine and about 125k miles.

I have had trouble starting the car, especially in the morning after sitting all night. It always cranks, but sometimes it cranks and loud noises like it is backfiring comes from the engine side. When it begins to catch and start running, it backfires or pops from the engine, stutters and lags.
When I finally get it running a little, I have to mash the gas and it stutters, pops and is real sluggish, then takes off.
What I have done so far is replace all the spark plugs, replaced the IAC and the TPS. In the process of replacing the TPS and the IAC, I cleaned the throttle body of all the carbon in it.
Any ideas on what is goin on here?
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Thursday, August 7th, 2008 AT 7:11 PM

6 Replies

Tiny
MERLIN2021
  • EXPERT
Check the timing, it may be off, if it checks out, compression test the engine, you might have a worn cam lobe, And test the fuel pressure. Your last tune up was?
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Friday, August 8th, 2008 AT 4:39 PM
Tiny
MATT29
  • MEMBER
It has been about a year since I last had the car in for a tune up. I have done the oil and the sparkplugs myself within the last month.
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Friday, August 8th, 2008 AT 4:45 PM
Tiny
MERLIN2021
  • EXPERT
If the service engine soon light is on read the codes, as shown below!


http://www.2carpros.com/forum/automotive_pictures/62217_GM_DLC95_Older_19.jpg



http://www.2carpros.com/forum/automotive_pictures/62217_GM_Jumper_Key_2.jpg


Cross these two terminals as shown, then turn the key on. Count the flashes, a 22 will flash as 2 flashes then a short pause, then 2 flashes, if more than one code is stored, the pause will be longer. The codes will display three times and end with 12. Write them down and post here. This connector is right under the middle of the dash...
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Saturday, August 9th, 2008 AT 5:50 AM
Tiny
MATT29
  • MEMBER
Ok here is the codes I got this morning started with a 12, next was 14 then a 22, then a 35 and last was 12 again.
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Saturday, August 9th, 2008 AT 9:45 AM
Tiny
MATT29
  • MEMBER
Ok, disconnected the battery, pulled the IAC out, the plate the IAC was attached to cleaned the plate and the part it was attached to with carb cleaner, pulled the TPS back out.
Put everything back on and now only have trouble codes 14 and 22. Code 14 im not worried about right now. But I just put a new TPS on the car last week.I didnt unplug the battery when I did it last time, could that have messed the TPS up? It seems simple enough to install, is there any trick to it like maybe the throttle has to be in a certain position? It only has two screws with no room for adjustment there, just screws back on.
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Saturday, August 9th, 2008 AT 12:23 PM
Tiny
MERLIN2021
  • EXPERT
CODE 14 - COOLANT TEMPERATURE SENSOR (SIGNAL VOLTAGE LOW) 1. Code 14 indicates control module has seen low coolant sensor voltage signal (high temperature) at control module terminal for a precalibrated period of time. This checks if conditions for Code 14 still exist. 2. This tests for grounded sensor signal line between control module and coolant sensor. Diagnostic Aids After engine is started, temperature should rise steadily to about 190 F (88 C) and then stabilize when thermostat opens. At normal operating temperature, signal voltage at control module terminal should be 1.5- 2.0 volts. Check sensor for shifted calibration by using sensor TEMPERATURE-TO-RESISTANCE VALUES table. When Code 14 is set, control module will turn on electric cooling fan(s) if equipped. CODE 14 ECM TERMINAL & CIRCUIT WIRING IDENTIFICATION TEMPERATURE-TO-RESISTANCE VALUES (1) Fig. 4: Code 14 Schematic (Signal Voltage Low) Coolant Temperature Sensor Fig. 5: Code 14 Flow Chart (Signal Voltage Low) Coolant Temperature Sensor NOTE: This chart assumes engine cooling system is functioning properly (not overheating). Test numbers refer to numbers on diagnostic chart. Application ECM Terminal Wire Color 3.1L "J" & "L" Bodies CTS Signal E16 Yellow CTS Ground B6 Purple 3.1L "W" Body (Exc. Calif.) CTS Signal C16 Yellow CTS Ground C10 Black 3.1L "W" Body (Calif.) CTS Signal A31 Yellow CTS Ground A17 Black Temperature F ( C) Ohms 210 (100) 185 160 (70) 450 100 (38) 1800 70 (20) 3400 20 (-7) 13,500 0 (-18) 25,000 -40 (-40) 100,700 (1) Measure resistance across sensor terminals. Page 1 of 1 TESTS W/CODES - 3.1L -1993 Chevrolet Lumina 8/9/2008
CODE 22 - THROTTLE POSITION SENSOR (SIGNAL VOLTAGE LOW) 1. This test checks if code is result of a hard failure or an intermittent condition. 2. This test simulates conditions for a Code 21. If control module recognizes change of state, control module and wiring are okay. 3. This simulates a high signal voltage to check for an open in TPS signal line to control module. Scan tester should recognize this signal and display high TPS voltage. Diagnostic Aids A scan tester displays throttle position in volts. Closed throttle voltage should be low. Voltage should increase gradually to about 4.5 volts at a steady rate as throttle angle is increased. If code is intermittent, see INTERMITTENTS in TESTS W/O CODES article in this section. CODE 22 ECM TERMINAL & CIRCUIT WIRING IDENTIFICATION Fig. 13: Code 22 Schematic (All Models) Throttle Position Sensor (Signal Voltage Low) Fig. 14: Code 22 Flow Chart (All Models) Throttle Position Sensor (Signal Voltage Low) NOTE: Test numbers refer to numbers on diagnostic chart. Application ECM Terminal Wire Color 3.1L "J" & "L" Bodies TPS Signal F13 Dark Blue TPS Ground B5 Black TPS Reference A5 Gray 3.1L "W" Body (Exc. Calif.) TPS Signal C15 Dark Blue TPS Ground C10 Black TPS Reference C12 Gray 3.1L "W" Body (Calif.) TPS Signal A30 Dark Blue TPS Ground A17 Black TPS Reference B31 Gray Page 1 of 1 TESTS W/CODES - 3.1L -1993 Chevrolet Lumina 8/9/2008
Try resetting the IAC: IDLE SPEED 1. Idle speed is ECM-controlled. Resetting of IAC valve pintle is the only possible adjustment. To reset IAC valve pintle position, turn ignition on (engine off). 2. Using a jumper, ground ALDL diagnostic test connector for 5 seconds. Remove jumper from ALDL diagnostic test connector. Turn ignition off for 10 seconds. Start engine, and check for proper idle operation. Refer to underhood emissions label for idle specifications. Clear any trouble codes. NOTE: Idle mixture is controlled by Electronic Control Module (ECM). Adjustment is not possible. NOTE: Incorrect idle speeds are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly. Page 1 of 1 ADJUSTMENTS - V6 -1993 Chevrolet Lumina 8/9/2008
Your TPS is not adjustable, so the only thing you can check is for voltage as you operate it by hand, low reading at idle to 4.5 volts at wide open.
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Saturday, August 9th, 2008 AT 4:30 PM

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