My wife's Saturn SC2, 232K, bought it new in '02. Recently, it has failed to start so I'm trying to diagnose the issue. Replaced the fuel filter and did find the input side of the old filter to have some rusty looking fuel come out when I dumped it out. Checked fuel pressure at the rail, 60 psi. Checked spark, good. Replaced the plugs, old plugs were nasty especially #s 3 and 4. I have yet to ohm out the coil packs but that is where I'm looking next. Once it does start, it runs well and restarts easily. Bore scoped each cylinder and noted nothing out of the ordinary for an engine this age, still has cross-hatch on the cylinder walls. Any advice will be greatly appreciated.

 

I had an intermittent no start problem with my 97 which turned out to be a flaky crank position sensor. The issue was more likely to occur when the engine was cold too.

 

Is that 60 PSI at the rail with the vehicle running or with key on only?

If the CKP goes open circuit, it kills spark and inhibits the fuel injectors. If you're seeing spark, CKP is not the issue.

Have you ever changed the ECTS?

 

What is the ECTS? Engine coolant temperature sensor? The pressure value is at the rail with the key on, brief fuel pump run. I will check pressure if I ever get it running again.

 

Compression Check Results: All right at 190 psi. Fuel pressure with the engine running, 65 psi. Going to pull the coils and test.

 

Coils test good. Cleaned up the coils and ICM, contacts and housings. Thought I would never get the bolts out as they were Loctited in place. Luckily the blue product. Wire brushed the bolts and chased the threaded holes with a tap. M6X1.0 in the event someone out there is interested. Reinstalled everything and then pulled the CPS. It tests open on the bench but will generate a few millivolts of current if I spin a bolt over it. I have parts coming but they will not arrive until tomorrow. Going to try the CPS first. Wiring to all this stuff is old looking as it is over twenty years old. Hope I don't get into replacing a harness!

 

I believe the spec is 43. Running. What do you have in there for a fuel filter? The fuel regulator is inside the filter on the 3rd gen s cars.

Then you say below it is the same pressure running. I don't believe that to be the case. If it is, it may be part of the problem.

Have you actually tried to verify spark when the ckp (not cps) reads open? The ckp going open circuit when hot after the vehicle is turned off as a well-known phenomenon on the S cars. Takes a few hours to cool off enough for the coil inside to become continuous again.

It's a lot easier for us to troubleshoot when you include all obviously useful information up front.

Never did answer the question about ects change.......

 

According to my Haynes manual, fuel pressure for the 98 and later models, should be 65 to 94 psi. As I stated, I'm seeing 60 psi at the rail just from the initial key on/no start cycle. With the car running, I'm seeing 65 psi. I have yet to check the engine coolant temperature switch. I'm checking the crankshaft position sensor on the bench so, obviously it is out of the car. From what I've read, this sensor does not inhibit spark but a false reading can lead to an either very lean or very rich fuel mixture making starting difficult. I'm learning here as I go so maybe some grace is in order. Everything I'm sharing is as I perform the tests. Today, if I get the parts, I will first replace the crankshaft position sensor. If I still experience failure, I will check the engine coolant temperature switch. This morning I bench tested the "ckp" again and getting .380 m Ohms so I'm satisfied it is bad.

 

The ckp inhibits spark and fuel when it goes bad because the vehicle does not have a physical cam position sensor.. there is no alternative physical means to figure out where the crank is in its rotation. Therefore it will not allow spark or fuel because it doesn't want to fire at a random point in the engine's rotation and shall we say wreck stuff badly.

The sensor that can cause the feel next to become overly Rich to the point that the car cannot start easily is the ects. This happens because if it goes open circuit, the ECM sees that as a reading of minus 30. It therefore richens the mixture, sometimes to the point that you can't start the vehicle.

When examining ects issues, replacement sensor should be constructed fully of brass.In your case change the pigtail to which the sensor connects. They build up corrosion and in some cases retain coolant that has leaked through the original sensor design. The circuit is a low resistance circuit and therefore any significant corrosion mimics a higher resistance than should be there. There is an approximate resistance versus temperature curve somewhere on the site. I think it is in the general tech help section. You can measure across the two pins of the ects with the sensor in the car. Then compare to that table. Keep in mind that this is the sensor whose temperature, presumably the coolant temperature, is used to control the auxiliary fan under the hood. The fan should always turn on when you engage the AC button provided the compressor is engaging. the fan should also turn on probably somewhere around the three quarter to 7/8 position on the temperature gauge, in order to cool down the coolant flowing through the radiator when the car is sitting still or on hot summer days. Without a properly functioning ects, the fan may never engage based on coolant temperature because the temperature inferred by the PCM is incorrectly low if the sensor has gone open circuit.

As mentioned by someone else on this thread, and myself, the ckp is prone to intermittent open circuit behavior. I've only ever seen this happen when the vehicle heats up after it's turned off, but someone else posted most of their issues were when the vehicle was cold. I believe them, and therefore apparently it can happen under any conditions depending on where and how the internal coil or external connections are damaged.

Neither the ects nor the ckp seem to ever throw a code when bad in the s Series cars. -30 is a valid temperature, and for the ckp, I honestly don't know why it doesn't pop a code.

That should hold you information wise for a couple of hours after you receive your parts.

Apologies if I was a bit snippy.

 

Be aware that the connector on the ECTS is a squeeze type. If you go yanking or pulling on it, odds are pretty good you'll break it or crack it. It's HIGHLY recommended that if you replace the ECTS to replace the pig tail connector while you're at it. Solder the wires and use some heat shrink. Don't half-*** it and twist the wires together and use electrical tape. You do it right the first time, you won't have to do it again.