1993 LT1, No Spark

[norwegianvette]

Hi. Yesterday i went for a spinn and the engine felt a bit rough. Idle rpm went up to 1300 and then it stopped. Have no codes yet but there is fuel pressure but no spark at all. Any ideas out there. Have a new coil and opti in the garage for the comming winter project. Also a new water pump, spark plug wires and spark plugs are in the house for replacement as all the engine is original from the Bowling Green. Only have 60 000 mileson the clock. Last time i used the car it was raining heavely (fyi)

Thanks and regards,
Steve

 

[John Robinson]

Start by cleaning the ground wires. Also check the connector on top of the opti for corrosion in side of the wireing plug.

Was the car in storage for a while before you started it this time? If so check for chewed wires under the hood or a rodents nest.

The high RPM and rough running then dying sounds exactly like what happened to me and in my case it was a bad TPS which did not code

Hope this helps.

 

[norwegianvette]

Stored 4 weeks only, no animals in the garage Had it towed to a garage and there are no spark at all. It turns but dont think about fiering:I Had a bussy day today, i go to the garage tomorrow to check for codes. No lights came on, just died. Tried to start it and the 3 first times it ignited and stopped. After that no ignition.

Steve

 

[norwegianvette]

Replaced the coil, no good. Ordered a new ignition module and have the garage to install an MSD opti with new MSD plug wires and new spark plugs. Also have the waterpump replaced with a high flow unit, ad all parts in the house due to this should be my winter project but no i have to pay a mecanic to do it:W Have a MSD AL6 left in the garage now so my project this winter is down to that, replace shocks and brake pads. Guess that gives me plenty time to polish

Codes:
The car threw every code in the bookad Fuel pump, fuel pump relay, ignition and so on.

 

[93Rubie]

Are you sure you have adequate battery voltage? I have seen many a car throw tons of codes due to inadequate battery voltage.

I like to think that diag. time is better than paying someone to shotgun some parts at a car. For me Diagnostics is more fun anyhow.

 

[norwegianvette]

Battery is new and it crank easily. Problem is that since it stopped on the road i had to have it towed to a garage. If it happened at home no problem.

 

[John Robinson]

Another piece of the puzzle

Hope this sheds some light on the tps for you

​

Throttle Position Sensor (TPS)
Copied from 1993 Service Manual​

The Throttle Position sensor (TPS) is a potentiometer connected to the throttle shaft on the throttle body. It is a potentiometer with one end connected to 5 volts
from the ECM and the other to ECM ground. A third wire is connected to the ECM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately .5 volt). As the throttle valve opens, the output voltage should be approximately 5 volts.

By monitoring the output voltage from the TP sensor, the ECM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent burst of fuel from the injectors and cause an unstable idle, because the ECM detects the throttle is moving.

If the TP sensor circuit is open, the ECM will set a DTC 22. If the TP sensor circuit is shorted a DTC 21 will be set. A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the ECM will use a default value for TP sensor, and some vehicle performance will return.

A personal note, when my TPS failed it DID NOT set a code other than to tell me the ECM was bad.

I used a couple of straight pins through the wires to hook the meter on

​

 

[norwegianvette]

Update on this.

Had the car back from the garage and it was the opti which failed. It now has a new MSD vented opti, new MSD coil, new ignition module, new high flow water pump, 160 degrees thermostat, new spark plugs and new MSD plug wires. I have the 6AL in the garage and will install that during the winter together with Bosh III injectors and the fuel filter.

That opti only have 50K on it and i did not wash the engine down. It just died.

Regards,
Steve