99 Saturn SL2 engine hesitation, now won’t start

[ForceEdge]

I was driving and the engine started hesitating almost feeing like it was going to stall. So I pulled over and turned the car off. Now it won’t turn back on. Car turns over but never starts.

Any idea what the issue could be?

Having it towed to house now with AAA

[SRGW]

Two things to check: 1 Do you hear the fuel pump run for 3 seconds when you turn key on?
Check fuel pump relay for 12 volts. 2 Possible CPS [crank position sensor] bad. Check if plugs are wet with fuel. Check for spark remove 2 plug wires from 1 coil and crank no spark jump CPS is bad.

1995 SL1 236,300 2005>2018
1997 SL1 78,600 2014>????
CHECK YOUR OIL!!

[ForceEdge]

Originally Posted by SRGW

Two things to check: 1 Do you hear the fuel pump run for 3 seconds when you turn key on?
Check fuel pump relay for 12 volts. 2 Possible CPS [crank position sensor] bad. Check if plugs are wet with fuel. Check for spark remove 2 plug wires from 1 coil and crank no spark jump CPS is bad.

1995 SL1 236,300 2005>2018
1997 SL1 78,600 2014>????
CHECK YOUR OIL!!

Okay I will check fuel pump that’s an Easy one it sounds like.

If the plugs are wet with fuel that means the CPS is bad?
Also, so I have to remove one spark plug wire from a spark plug and see if there’s a spark when I try to turn the engine on? Maybe I’m not understanding this correctly?

[Waiex191]

With no CPS signal there will be no spark and no fuel, because the ECM can't tell the motor is spinning.

[fetchitfido]

The fuel pump will still prime the system for the first 3-5 seconds of KOEO, the PCM just won't fire the injectors. There's a test port in the IPJB to probe with a 12v light which will light up when the fuel pump is commanded on.

Checking for spark usually takes 2 people, one to turn (and hold) the key to 'start' and another one to hold the side of a removed spark plug (plugged back into the plug wire) to an unpainted metal surface on the engine. You could run a 16awg wire with an alligator clip on both ends from the purple wire on the starter to the + on the battery and just leave the key in run if you don't have a second person.

[Waiex191]

You can also use a spare plug, connect the wire, and use a jumper cable to both make ground and hold the plug so you can see it under the hood.

[fdryer]

^ Caution warning. That setup with hand holding a spark plug to the engine block to test for spark can result in a....... shocking result. Up to 40k volts is the specs given with electronic ignition systems. It might be better to note plug wiring before disconnecting all four plugs from the ignition coils and observe for spark jumping across both coil towers as someone cranks the engine. Safer without learning how high voltage electric shock affects first timers. There's a reason powerline workers wear long rubber gloves and use 'power poles' when they have to perform maintenance on live powerlines.

If im not mistaken, Saturn EFI systems initialize fuel line pressure for about two seconds during KOEO (key on, engine off) cycles. Just enough time to pressurize the fuel rail then shut off if the engine isn't started. The fuel rail test valve is the easiest place to check for fuel and pressure right after turning on ignition if one can't hear the faint hum/hiss sounds of a fuel pump. Depressing the valve stem on the fuel test valve after removing the plastic dust cap should result in a fuel spray (cover loosely with a rag to contain fuel spray). All this does is verify the pcm operation to cycle the fuel pump. It does not say anything of injector operation. If fuel sprays out the test valve, the pump is fine. The fuel system retains fuel pressure for many minutes before bleeding off pressure.

[ForceEdge]

Originally Posted by fdryer

^ Caution warning. That setup with hand holding a spark plug to the engine block to test for spark can result in a....... shocking result. Up to 40k volts is the specs given with electronic ignition systems. It might be better to note plug wiring before disconnecting all four plugs from the ignition coils and observe for spark jumping across both coil towers as someone cranks the engine. Safer without learning how high voltage electric shock affects first timers. There's a reason powerline workers wear long rubber gloves and use 'power poles' when they have to perform maintenance on live powerlines.

If im not mistaken, Saturn EFI systems initialize fuel line pressure for about two seconds during KOEO (key on, engine off) cycles. Just enough time to pressurize the fuel rail then shut off if the engine isn't started. The fuel rail test valve is the easiest place to check for fuel and pressure right after turning on ignition if one can't hear the faint hum/hiss sounds of a fuel pump. Depressing the valve stem on the fuel test valve after removing the plastic dust cap should result in a fuel spray (cover loosely with a rag to contain fuel spray). All this does is verify the pcm operation to cycle the fuel pump. It does not say anything of injector operation. If fuel sprays out the test valve, the pump is fine. The fuel system retains fuel pressure for many minutes before bleeding off pressure.

Can’t I just do this?

https://youtu.be/vpUy8TeUgi4

[Waiex191]

Yep! Of course you can.

[ForceEdge]

Originally Posted by Waiex191

Yep! Of course you can.

Okay so I had someone try to start it and I hit the throttle a bit and it kind of started to run for a second but VERY rough and then it started to smell by throttle body maybe like gas? But not to sure.

Haven’t don’t the test on the spark plugs yet but I’m testing now.

What do you think the above could mean so far?

[ForceEdge]

Originally Posted by Waiex191

Yep! Of course you can.

Okay tested spark plugs. There is a spark. So I’m guessing no crank shaft position sensor.

Decided to start it up again and give it a lot of gas.

Car stayed started and stayed on but was very hesitant. To be honest it really sounds like something with the exhaust. Exhaust is shaking like crazy I’m going to go under and check it now.

[ForceEdge]

https://streamable.com/8p6uw

Video of exhaust and what car sounds like

[Waiex191]

I'd check the ECTS. If it is the original resin tipped one it could have failed. You can do the Erik Tande check - pull out the inlet air temp sensor from the airbox and plug it into the ECTS harness.

[ForceEdge]

Originally Posted by Waiex191

I'd check the ECTS. If it is the original resin tipped one it could have failed. You can do the Erik Tande check - pull out the inlet air temp sensor from the airbox and plug it into the ECTS harness.

Okay and if I do that what should essentially happen?

And what would it tell me

[ForceEdge]

Originally Posted by ForceEdge

Okay and if I do that what should essentially happen?

And what would it tell me

Also where is the air box sensor

[ForceEdge]

Originally Posted by ForceEdge

Also where is the air box sensor

Found it. It’s not even close to long enough to reach the ECTS sensor location

[ForceEdge]

Originally Posted by ForceEdge

Found it. It’s not even close to long enough to reach the ECTS sensor location

At this point I think I’m going to bring it in to a mechanic and get it diagnosed

[fdryer]

Normally, the couldn't sensor sends temperature signals the pcm needs to determine correct air/fuel ratios. When the original sensors failed (virtually all of them), cold engine starting results in extra fuel with some engines flooding. The sensors failing sends incorrect signals, telling the pcm the engine's freezing so it runs extra rich fuel all the time. One quick test of a failed sensor is holding pedal to floor during starting - this tells the pcm to shut off injectors and if the engine's flooded the lack of any more fuel during starting should result in a sputtering startup. Flood clear mode. Useful in flooded engine starting on occasion. We've all become accustomed to instant starting since EFI engines are the mainstay of every vehicle driven.

[Waiex191]

Originally Posted by ForceEdge

Found it. It’s not even close to long enough to reach the ECTS sensor location

Pop it out, connect it to the ECTS harness and let it dangle. If the car starts and runs you have found your problem.

[ForceEdge]

Originally Posted by Waiex191

Pop it out, connect it to the ECTS harness and let it dangle. If the car starts and runs you have found your problem.

Popped it out and car still struggles hard. Car stalls a couple seconds after sitting in park. Have to give gas for it to stat started.

After pulling out service engine light came on