94 park avenue 3.8

Larry CAN.

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94 park avenue
Will turn over but not start, sometimes first start but not always, could take multiple times. When does start runs great. Checks on fuel and ignition all as required. Does not mater whether hot or cold. When u get it running u can shut off and will start every time. Need help.
 

Larry CAN.

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94 park avenue
Did you check the crank position sensor for corrosion?
Yes and no problem. Cleaned anyway, reinstalled no diff in problem. It’s as if something has to warm up. Does anyone know where to find a description of relays as there is none on the cover. It has the max center under hood on left side by heater fan with big fuses on top and relays under them. Going to check grounds as well. Thanks Larry
 

Again

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Magnetic Hill, New-Brunswick, Canada
2016 Encore
Yes and no problem. Cleaned anyway, reinstalled no diff in problem. It’s as if something has to warm up. Does anyone know where to find a description of relays as there is none on the cover. It has the max center under hood on left side by heater fan with big fuses on top and relays under them. Going to check grounds as well. Thanks Larry
Did you remove to clean or you just cleaned the connector tabs?
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Larry CAN.

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94 park avenue
No
Will turn over but not start, sometimes first start but not always, could take multiple times. When does start runs great. Checks on fuel and ignition all as required. Does not mater whether hot or cold. When u get it running u can shut off and will start every time. Need help.
 

Larry CAN.

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94 park avenue
So no check engine light? Does that old thing have an EGR or a purge valve? I'm thinking maybe it's stuck open and the fumes from the tank flood the intake overnight. Next time it won't start try putting it to the floor to see if it makes a difference.
No light, all lights work properly. Not sure on the EGR or valve. Today did all connections and grounds. Still takes 2 or more times to start after 5 or 10 min. In the process of switching relays as I don’t know which is which. Thanks
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Larry CAN.

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94 park avenue
No light, all lights work properly. Not sure on the EGR or valve. Today did all connections and grounds. Still takes 2 or more times to start after 5 or 10 min. In the process of switching relays as I don’t know which is which. Thanks
Well checked all relays and all good. Tried to start and same problem. Did a few more start at at 10 min intervals. Started up a couple of times. Did a 20 min test and would not start. As soon as it fires it quits. I’m thinking ignition switch now because of the way it fires on start but then quits when on run. Any help on getting to the switch would be great. Thanks.
 

Again

Active member
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Magnetic Hill, New-Brunswick, Canada
2016 Encore
Something that might give you an oh-oh moment.

Ignition System Modes of Operation

Anytime the PCM does not apply 5 volts to the ignition control module bypass circuit, the ignition control module controls ignition by triggering each of the three coils in the proper sequence at a pre-determined dwell, with spark advance fixed at 10° BTDC. This is called Bypass Mode ignition.

When the PCM begins receiving 18X reference and 3X reference pulses, the PCM applies 5 volts to the ignition control module bypass circuit. This signals the ignition control module to allow the PCM to control the dwell and spark timing. This is IC Mode ignition. During IC Mode, the PCM compensates for all driving conditions.

In the IC Mode, the ignition spark timing and ignition dwell time is fully controlled by the PCM. The ignition control module is responsible for proper ignition coil sequencing during both Bypass Mode and IC Mode. IC spark advance and ignition dwell is calculated by the PCM using the following inputs:

• Engine speed (18X reference or 3X reference).

• Crankshaft position (18X reference or 3X reference and camshaft position PCM input signal).

• Engine coolant temperature (ECT sensor).

• Throttle position (TP sensor).

• Knock signal (Knock sensor).

• Park/Neutral Position (trans range switch or park/neutral position switch).

• Vehicle speed (Vehicle Speed Sensor / Trans Output Speed Sensor).

• PCM and ignition system supply voltage (PCM ignition feed voltage).

Once the change is made to IC Mode, it will stay in effect until one of the following conditions occurs:

• The engine is turned OFF.

• The engine quits running.

• A PCM/IC fault (DTC P1350 or DTC P1361) is detected.

If a PCM/IC fault is detected while the engine is running, the ignition system will switch to Bypass Mode operation. The engine may quit running, but will restart and stay in Bypass Mode with a noticeable loss of performance.

Diagnosis
If the 18X reference signal is not received by the PCM while the engine is running, a DTC P0336 will be set and 3X reference will be used to control spark advance under 1200 RPM, and Bypass Mode will be in effect at under 400 RPM. The engine will continue to run and start normally.

If the 3X reference signal is not received by the PCM while the engine is running, the PCM will use the 18X reference pulses to calculate RPM and crankshaft position. The engine will continue to run and start normally, but DTC P1374 will be set.

Poor engine performance and possibly a MIL with no DTC can be caused If the Reference Low circuit is open or connected to ground at the PCM.

The IC output circuitry in the PCM generates IC output pulses anytime crankshaft reference signal input pulses are being received. When the ignition system is operating in the Bypass Mode (no voltage on the bypass control circuit), the ignition control module grounds the IC pulses coming from the PCM. The ignition control module will remove the ground from the IC circuit only after switching to the IC Mode. The PCM commands switching to IC Mode by applying 5 volts on the bypass circuit to the ignition control module. The PCM monitors its own IC output, and expects to see no pulses on the IC circuit when it has not yet applied 5 volts on the bypass control circuit. When the second 3X reference pulse at the start of crank is seen by the PCM, it applies 5 volts to the bypass control circuit and the IC pulses should no longer be grounded by the ignition control module. The PCM constantly monitors its IC output, and should detect the IC pulses only when commanding the IC Mode. If the IC circuit is open, the PCM will detect IC output pulses while attempting to start the engine (in the Bypass Mode) due to the ignition control module not being able to ground the IC pulses. Three things will occur:

• DTC P1350 will set.

• The PCM will not apply 5 volts to the bypass circuit.

• The engine will start and run in Bypass Mode.

If IC circuit is grounded, the PCM would not detect a problem until the change to IC Mode is commanded by the PCM. When the PCM applies 5 volts to the bypass control circuit, the ignition control module will switch to IC Mode. With the IC circuit grounded, there would be no IC pulses for the ignition control module to trigger the ignition coils, and the engine may falter. The PCM will quickly revert back to Bypass Mode (turn OFF the 5 volts on the bypass circuit), DTC P1361 will set, and the ignition system will operate in Bypass Mode until the fault is corrected and the engine is stopped and restarted.

If bypass circuit is open or grounded, the ignition control module cannot switch to IC Mode. In this case, the IC pulses will stay grounded in the ignition control module, and DTC P1361 will be set. The engine will start and run in Bypass Mode.

The following information will list important considerations to aid the technician in servicing the ignition system.

• The ignition coils secondary voltage output capabilities are very high - more than 40,000 volts. Avoid body contact with ignition high voltage secondary components when the engine is running, or personal injury may result!

• The dual Hall-effect crankshaft position sensor is the most critical part of the ignition system. If the sensor is damaged so that the CKP 18X or CKP Sync crank sensor pulses are not generated, the engine will not start!

• There are 4 circuit wires connecting the dual crankshaft position sensor to the ignition control module. If there is a problem with any of the four, the engine will not start (no spark and no injector pulses). The circuits are descibed as follows:

- The 10 to 12 volt sensor feed for the Hall effect switches from the ignition control module.

- The CKP 18X pulse signal to the ignition control module.

- The CKP Sync pulse signal to the ignition control module.

- The sensor ground circuit for both Hall-effect switches.

• If the CKP Sync pulses stop while the engine is running, the engine will keep running. However, it will not restart after being shut OFF.

• If the CKP 18X pulses stop while the engine is running, the engine will stop running and will not restart.

• Crankshaft position sensor clearance is very important! The sensor must not contact the rotating interrupter rings at any time, or sensor damage will result. If the balancer interrupter rings are bent, the interrupter ring blades will destroy the sensor.

• Ignition timing is not adjustable. There are no timing marks on the crankshaft balancer or timing chain cover.

• If crankshaft position sensor replacement is necessary, the crankshaft balancer must be removed first. The balancer is a press fit onto the crankshaft; removing the serpentine accessory drive belt and balancer attaching bolt will allow its removal with special tool J 38197.

• When reinstalling, torque the balancer attachment bolt. This is critical to ensure the balancer stays attached to the crankshaft.

• If a crankshaft position sensor assembly is replaced, check the crankshaft balancer interrupter rings for any blades being bent. If this is not checked closely and a bent blade exists, the new crankshaft position sensor can be destroyed by the bent blade with only one crankshaft revolution!

• Neither side of the ignition coil primary or secondary windings is connected to engine ground. Although the ignition coil packs are secured to the ignition control module, it is not an electrical connection to ground.

• Be careful not to damage the secondary ignition wires or boots when servicing the ignition system. Rotate each boot to dislodge it from the plug or coil tower before pulling it from either a spark plug or the ignition coil. Never pierce a secondary ignition wire or boot for any purpose! Future problems are guaranteed if pinpoints or test lights are pushed through the insulation for testing.

• The ignition control module is grounded to the engine block through a ground wire to the ignition control module bracket mounting stud. If servicing is required, ensure that good electrical contact is made between the ground and the mounting bracket, including proper hardware and torque.

• A conventional tachometer used to check RPM on a primary ignition tach lead will not work on this ignition system. To check RPM, use either of the following items:

- A tachometer designed with an inductive pickup, used on the secondary side of an ignition system. These tachs are identified by a clamp that goes around a spark plug wire. Set the tach to 2-cycle operation. The 2-cycle setting is required because spark plugs on this engine fire every time the piston is at the top of its stroke. If a 2 cycle selection is not available, divide the indicated 4 cycle reading by 2.

- A scan tool.
 

Larry CAN.

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94 park avenue
Oh-oh is right. Good info but I’m not sure how to use it. When it starts it runs great and can be restarted. Yesterday after doing all checks it started after the 10 min delay. It wasn’t until we did the 20 min delay that it wouldn’t start. All lights are working as required. Will fire initially but won’t run. That’s leading me to ignition switch because of the initial fire on start but when it goes to run mode quits. Thanks
 

Larry CAN.

New member
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94 park avenue
Oh-oh is right. Good info but I’m not sure how to use it. When it starts it runs great and can be restarted. Yesterday after doing all checks it started after the 10 min delay. It wasn’t until we did the 20 min delay that it wouldn’t start. All lights are working as required. Will fire initially but won’t run. That’s leading me to ignition switch because of the initial fire on start but when it goes to run mode quits. Thanks
Any thoughts on how to access ignition switch ? Was told it could have loose or burnt wires. Thanks.
 

Larry CAN.

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94 park avenue
Did you spray clean the connector at the PCM? I believe if your HVAC fan motor turns in the ignition "ON" position it means you have engine run voltage.
No I did not spray clean pcm connection. And I’m sure the.Fan turns on. You thinking that switch is not problem , because of fan coming on?
 

Again

Active member
267
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Magnetic Hill, New-Brunswick, Canada
2016 Encore
Well now that I look at that switch, it's a funny contraption. The amount of switches for sale on ebay and the stock amounts at RockAuto makes me think you might be onto something. #12 in the break down diagram. My service manuals doesn't show how to replace this switch for a 1994 but I assume it's within the steering column by the looks of it. GM#1990163


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Couldn't you find help in the Buick Park Avenue Forum ?
 

Larry CAN.

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94 park avenue
Well now that I look at that switch, it's a funny contraption. The amount of switches for sale on ebay and the stock amounts at RockAuto makes me think you might be onto something. #12 in the break down diagram. My service manuals doesn't show how to replace this switch for a 1994 but I assume it's within the steering column by the looks of it. GM#1990163

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Couldn't you find help in the Buick Park Avenue Forum ?
No help as yet. That’s ok though. Buddy just brought me a chiltons 93 to 97 and it shows switch in lower column. Pretty involved. Used for dimmer switch, turn signal switch. Right down to using drill bit for adjustments if installing new one. Going have a look see. Hopefully just wires. Thanks
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Larry CAN.

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94 park avenue
Well manual don’t help! Surprise! Not sure where the switch is now. Anybody know for sure let me know. Thanks
Well manual don’t help! Surprise! Not sure where the switch is now. Anybody know for sure let me know. Thanks
Well found switch, what a shitty place to put it and can’t see anything wrong with it. Don’t want take it out as it is a bugger to replace and adjust. Not sure if it can be tested in place as big bundle of wires out of it and not sure what they all do. Guess I’ll spray it and put back together and pray. LOL. If that ain’t it I’m stumped. Thanks for all the input.
 

Larry CAN.

New member
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94 park avenue
Well found switch, what a shitty place to put it and can’t see anything wrong with it. Don’t want take it out as it is a bugger to replace and adjust. Not sure if it can be tested in place as big bundle of wires out of it and not sure what they all do. Guess I’ll spray it and put back together and pray. LOL. If that ain’t it I’m stumped. Thanks for all the input.
Well still stumped. Checked for switch continuity and checks out fine. The Vats system is working according to what I have read. I’m thinking what is happening is the fuel to the injectors is being shutdown after startup because it starts for a couple of seconds. Any ideas would be appreciated. Thanks Larry
 
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