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What could be causing this starting problem with my '99 Saturn SL1?

I know that there’s no way to 100% accurately diagnose a problem over the internet, but I’m hoping to get some sound advise so that I can decrease my chances of being taken advantage of by a mechanic that I’m unfamiliar with.

For the past few weeks, my '99 Saturn SL1 has been having starting issues. This typically only happens in the late afternoon/evening after I’ve already started and driven it 2 or 3 times in the day. It always starts up fine first thing in the morning. However, later in the day, it simply won’t start. The engine turns as long as I’m turning the key, but it won’t fire up. Sometimes the engine finally fires up after about 3 tries, but most times I have to give it about 30 min - 1 hr to wait. I try it again after waiting, and it the engine starts just fine.

Also, this only seems to happen once a day. After finally getting the engine to start, I can turn it off and start it a dozen more times, and there will be no problems.

I’ve already had the electronic temperature sensor replaced, and the problem persists.

No warning lights come on when I drive, and an Autozone employee tested my battery and alternator and said they were fine. This has only happened for the past few weeks, so I haven’t noticed any other major symptoms, although there could be something I’m just not paying attention to.

Thanks for the help! I know I always wind up paying more than I should mechanic shops because I just don’t have enough car knowledge to know any better, so I need all the advice I can get!

When it fails to start, turn the key off and press the accelerator to the floor and hold it there for 30 seconds. Then while still holding the pedal to the floor, try to start the car and see if it fires right up. If it does, you have a flooding problem.

Not sure why you replaced the ECTS, a lot of Saturn owners/mechanics jump right on this, but you have to use a GM ECTS, aftermarket ECTSs are notorious for not working well in this engine for some reason. The aftermarket ones have some plastic piece in them that is brass in the GM version and that makes a difference somehow. Personally I have not changed the ECTS in my Saturn SL1 and it has over 265k on it.

One more question, when you are just idling after the engine is warmed up, is the idle a nice steady 750 rpm or is it over 950 rpm. If so, I can tell you what the problem is. Also, do you have a Service Engine Soon light on and if so have you had the codes read and if so, is the code a P0507?

Hi, Keith! Yesterday when it failed to start, I tried turning the key while pumping the gas pedal (I read that somewhere), and it started right up. I’ve only had the opportunity to try that once, so I can’t say with confidence if pumping the gas was the solution or if it just coincidentally started up on the third try while I was pumping. However, I’m going to try it again next time it happens (probably this evening).

A mechanic told me to try replacing the ECTS since it was a quick, inexpensive fix just to see if that solved the problem. It didn’t.

When the engine is idling, it’s always below the 1,000 rpm line (not sure of the exact number because I’ve never paid that close attention). I’ll make a note of the rmp and update this thread later. As far as lights, no lights whatsoever are on. The thing just won’t start once a day.

Thanks for the input!

It sounds like the mixture is overly rich on warm starts. Whatever gives the car extra gas on cold morning starts – on this car it may always giving extra gas. How this works varies from car to car. On my Corolla there’s a cold start injector and a coolant temp sensor that does it indendent of the ecm. On other cars there’s no separate cold start injector and ecm simply senses the coolant temp and decides how much gas to inject on the next start. Something is amiss in all that I expect. Best of luck.

Pumping the gas doesn’t really do anything on a fuel injected car except to add extra air. It’s not like a carbureted car where it adds gas. Try my way.

Now, about that idle speed.

Update: This evening when it wouldn’t start, I tried holding the accelerator down like you said, Keith. The car still wouldn’t start, so I think the incident of me pumping the gas pedal and the car starting the other day was pure coincidence. However, I did take note of the rpm when it was idling today. It generally stays between 750-800.

Just like always, after today’s incident of the engine not starting, I waited about an hour and tried it again. Sure enough, it started like there was nothing wrong. It’s like the car throws a temper tantrum every evening, and I’ve just got to wait it out and try again.

Holding the accel down allows air into the engine, and if the mixture was too rich for the engine temperature, the extra air would lean it out enough that it might make it possible to start. Since that isn’t working, the problem probably isn’t an overly rich mixture on warm starts. Well, at least you know that now. Some progress at least. hmmm … well, for a car without major mechanical or timing problems to start it only needs spark and gasoline. If this were my car the next time it didn’t start, I’d have all the pending codes read, then check for spark. And if spark was ok, and no code to guide the way, I’d measure the fuel pressure (at a time when it wasn’t starting.) I’m assuming all the routine maintenance is up to date and a careful visual inspection reveals no connectors undone or vacuum hoses adrift. And the engine runs and idles fine after it starts.

OK, there are a number of steps you can try in order to help isolate the problem.

Next time, try my trick again and if it doesn’t start, then stop cranking while you are still WOT (wide open throttle). Then take your foot of the pedal and try to start with closed throttle. If it starts up, then repeat the test each time it doesn’t start to see if the results are consistent.

If it doesn’t start, get an old spark plug, your mechanic should be able to provide you with one. It doesn’t have to be the one for your car, any spark plug will do. When if fails to start. open the hood and pull the spark plug wire off the #2 cylinder, that is the second from the left as you are looking at the front of your car.

Stick the old plug into the connector at the end of the spark plug wire and lay it on your valve cover where you can see the tip while cranking the engine. With the hood up, you should be able to see the top of the engine from the drivers seat. Otherwise you may need some help with this.

Crank the engine and look for a spark across the tip of the old spark plug. Then repeat this test but with the #4 spark plug wire, that is the one on the right as you look at the front of the car.

If both produce a spark, then the ignition is good. If only one produces a spark, then you have a bad coil, just remember which wire did not have the spark. Tie a small piece of tissue or a small rag or a piece of colored tape around the spark plug wire.

If the spark is good, then next time you go by an auto parts store, drop in and get a can of either, aka starting fluid. Now looking at the engine, you will see a rubber tube about 1/2" in diameter and about 6-8 inches long that goes from the end of your valve cover to the large air duct that goes to the throttle body. That tube is pretty easy to pull off from the air duct.

On the next no start, pull this tube, put a shot of either into the big air duct and plug the hose right back in. Then as quick as possible, jump in and crank it and see if it catches for a second or two. It may not run, but at least it lets us know if it is fuel related. If it doesn’t catch, have someone crank the engine for you while giving it a shot of either through that tube.

If it still doesn’t start, retest the ignition with the used spark plug. If you have ignition, then the engine should start on the either. If you have spark and it won’t start on the either, then the CPK is intermittent. The CPK controls your ignition timing and if you have spark and it won;t start with the either, then the spark is getting there at the wrong time.

The problem might be with the crankshaft position sensor.

This mounted on the side of the engine block. And if this sensor fails the engine won’t start. I actually have customers who know when this sensor is starting to fail on their GM vehicles because the engines won’t start and they bring the vehicle to me to have it replaced.

It’s not fun removing this plastic sensor from the engine without breaking off. And take hours of twisting and turning with penetrating oil before it’s removed from the engine.

If I were to have kept every crank sensor I’ve replaced from GM vehicles over the years, I’d have a bushel basket full of them.


Tester, have you ever replaced a CPK on a Saturn? They are a ***** to remove and replace.

Yep! My daughter had a Saturn where the CPK sensor had to be replaced.

Like I said, these sensors can be hard to access, and when you get to it, you just don’t remove the bolt and the sensor just slides out of the engine. It’s been in the engine for a long time. So gum and varnish has built up on the sensor body. So the sensor has to be worked back and forth with a penetrating oil until the gum and varnish has been disolved to where the sensor can be removed without breaking off.

One of the happiest days of my life was when the daughter got rid of the Saturn and bought a Honda. The next happiest day in my life is when the wife got rid of the Jeep Cherokee and bought a Honda.


Wow! To be honest, Keith, I really don’t know what anything under my hood is or what it does. I actually avoid even looking under my hood because the entire mysterious workings terrify me, and I don’t know what I’m looking at anyway, so there’s typically no point in looking. I think of it all much like string theory in quantum physics.

However, I will research what spark plugs, throttle bodies, cylinders and valve covers are and where they are. Surely I’ll find some photos or YouTube tutorials that will be helpful, and maybe I can do what you suggested.

Tester, regarding the crankshaft position sensor, sometimes the engine will not fire at all and I have to wait it out. A few times, though, the engine will finally fire up after about 2 or 3 tries cranking it without having to wait an hour and come back for another try. Could the crankshaft sensor still be the culprit if the engine fires up after 2 or 3 cranks?

Thanks for the advice! I really appreciate someone taking the time to offer it!

Update: My mechanic looked at my car this morning and replaced the crank position sensor. I hope that solves the problem! Hopefully, if the starting problem doesn’t crop up in the next few days, that will be a positive sign that everything has been fixed.

Thanks for all the advice, everyone! I really appreciate it.!

Nicki, if the problem still persists, show your mechanic my post and ask him to show you how to do each item. He will be helping himself by doing this for you.

Tester, I have has less trouble with my Saturn in 265k miles than with my wife’s Honda at 188k or her previous Honda 80k miles or my daughters Corolla 180k miles or any other vehicle so far.

I am having this same issue but my 99 sl1 will start with wide open throttle and I cant figure out the issue. KEITH what could be causing a flooding problem it will drive but run ruff and wants to die

Suggest you re-post this problem as a new topic @Wyatt32 , you’ll get better results here. Click “maintenance/repairs” above left, then “new topic” above right.

Do you have a check engine light? What is the code or codes stored? If no CEL, I’d look at the intake manifold gasket around the front upper corner, under the power steering pump for a vacuum leak. Spray something like WD40 or better a little grease over this spot and see if you get temporary relief.