Question about 1985 Chevrolet Corvette

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1985 corvette no pulse to injectors

I hit a pothole engine quit. i have good fuel pressure and spark but no pulse to injectors

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  • bradgraybill May 08, 2009

    thank you for all your help

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4 Answers

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Very important that if you are not savvy of working on your Vette ...you would be better off - taking your car to a dealership for repairs on your trouble codes. However if you feel that you want to, First locate your car's alcl this component is located just below the instrument panel and to the left of the center console. Remove the plastic cover the first two slots to your right are the A & B slots.
The A slot is the diagnostic slot and the B slot is the ground slot. Insert the computer key into these slots if you do not have a computer key, a paper clip or wire jumper clip will do, (with the engine off) this is very important...now only put the ignition key to on ( not start !!!) the check engine light will display a code 12 which is one flash followed by two flashes. This code will be flashed three times ..followed by the trouble code stored in your car's computer.

What ever the code is it will be flashed three times. Have a paper and pencil ready and write down the code.

Code #12: Normal No Codes. 
Code #13: Open Oxygen Sensor Circuit. 
Code #14: Coolant Sensor Circuit Low.
Code #15: Coolant Sensor Circuit High. 
Code #21: Throttle Position Sensor High. 
Code #22: Throttle Position Sensor Low. 
Code #23: Manifold Air Temperature Circuit High.
Code #24: Vehicle Speed Sensor. 
Code #25: Manifold Air Temperature Circuit Low. 
Code #32: EGR System Failure. 
Code #33: Mass Air Flow Sensor High.
Code #34: Mass Air Flow Sensor Low. 
Code #36: Mas Air Flow Sensor Burn-Off Function Fault. 
Code #41: Cylinder Select Error. 
Code #42: Electronic Spark Timing.
Code #43: Electronic Spark Control. 
Code #44: Lean Exhaust indication. 
Code #45: Rich Exhaust Indication. 
Code #46: Vehicle Anti Theft Fault. 
Code #51: Faulty Mem-Cal. 
Code #52: Fuel Calpak Missing.
Code #52(1990-91 Corvette Only): Engine Oil Temperature Sensor Low. 
Code #53: System Over Voltage. 
Code #54: Fuel Pump Circuit Low Voltage. 
Code #55: Defective ECM. 
Code #62: Engine Oil Temperature Sensor Circuit High.

Please remember that if you have the computer key installed in the alcl and you start the engine (you will ruin the engine's computer) only put the ignition to on (not to start).

If you should get a check engine soon display.. you can use the above procedure and codes to buy the right part or at the very least to keep from getting taken for a ride and be made to pay hight prices for some inexpensive module that you could have installed yourself.

If your engine displays a trouble code ... your engine will go into limp mode ..it will still run but very poorly. You might be able to reset the computer if it will not start (just to get home) by disconnecting both battery cables and re-installing them ...this is not recommended ..but if you are stranded it might help unitl you get your car home or to a repair shop..good luck.

Good luck and hope this helps. 

Posted on May 08, 2009

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I don't know the connections for an 1985 Corvette, but on my '86 there are two fuses for the injectors, INJ1 and INJ2. These fuses supply 12V to the injectors through the ignition switch. Check those first. The '86 ECM fires all 8 injectors at the same time (they are connected in parallel), so the '85 is probably the same.

The description of the ALCL (now called ALDL for Assembly Line Diagnostic Link) has multiple errors. Terminal A goes to ground, terminal B goes to the ECM. You will not damage the ECM by starting the engine with A & B connected together. Code 12 is NO PULSES FROM DISTRIBUTOR (because the engine is not running), not "Normal no codes".

Posted on Aug 23, 2010

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  • Expert
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Sounds like you might have fractured a solder joint in the ecu, but before we can conclude to this check that there is voltage going to the injectors when the ignition is turned on. The pulsing comes from the ground side of the injectors and the only thing inbetween is the connectors and the ecu. So if you have your injector voltage e.g. get a test light or voltmeter and go between chassis and both sides of one of the injectors. If it lights up on one of the wires going to the injectors then it must be the ecu. If your game you could pull the ecu out and try and find the dry joint(s).
1985 corvette no pulse to injectors - dry-joint_small.jpg

Posted on May 08, 2009

  • Dudeman321 May 08, 2009

    You can't check the ground wire for the injectors, because it does not exist. If you read my earlier post you would realise that the computer on all ECU's sinks the current from the injectors e.g. it is the ground for each injector that is what switches them. It provides the ground pulse sequentially between each injector in the correct timing governed by the CAS (Crank Angle Sensor)

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  • Expert
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Check the ground wire for the injectors.

Posted on May 08, 2009

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Posted on Jan 02, 2017

  • 179 Answers

SOURCE: 91 corvette , Engine starts every time but dies like you shut off the key. I have checked the fuel pressure and it is good.

is it injected try new injectors

Posted on May 31, 2009

Molson02536
  • 3854 Answers

SOURCE: 1993 s10 2.8 tbi the fuel pump fails to pressurize

There needs to be 60 PSI of fuel pressure in the system to have the fuel injectors to work. There is also a fuel pump relay on the fire wall just left to the brake booster, There is two relays there, i just can not remember which relay is which but try switching the relays with one another. Also check the fuses to the fuel pump and ECM, and the fuel pressure from the shredder valve. Good luck and keep me posted, not a bad Idea to also replace the fuel filter, and that is located at the inside frame rail under the drivers side.

Posted on Jun 03, 2009

  • 6 Answers

SOURCE: no injector pulse

what vehicle? injector pulse controlled by computer. the computer recieves a pulse from crank angle sensor, or distributor pick up, etc.
then controls injector pulse. Mass air flow on some vehicles determines spray pattern

Posted on Jun 29, 2012

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Make sure that you're getting spark. A very common thing on these engines are coils going bad. If you can verify spark, check to make sure you have an injector pulse. As you rotate the engine, look inside of the throttle body and make sure that you see fuel pulsing into the engine. You can still have good pressure but you don't have an injector pulse, the fuel still cant get into the engine. You can use a test light as well to test for an injector pulse. One wire going to the injector will have constant power and the other will blink when the engie is rolled over. Does it start if you spray starting fluid into the throttle body? If it does, it's a fuel delivery problem. Again be sure you have spark from coil to distributor and plugs. You can remove the ignition module and take it to NAPA and they have a module tester. Have them test the module several times not just once. This will eliminate the possibilites of an intermitted problem. Let me know how it does. tiqautoperformance@live.com

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