2006 Saturn Vue 2.2 Crank but no start

[barriosl]

Hello everyone!

I have a puzzling issue. My Vue cranks but does not start. It's hard to give a full picture, but I will do my best. I am very vigilant in my maintenance of the car. I do my own oil changes every 5,000KM (as recommended by the manufacturer). Change my plugs once a year for good measure. All mechanic parts are in perfect order. Always put the best Michelin tires on with an alignment once a year. Anytime I get a check engine light, I change sensors/parts according to what the issue is. I even did the entire timing chain kit a few weeks ago, including the upgraded oiler that came with it < I did this only because I am approaching almost 300,000kms & I don't know the complete service history of the vehicle before 200,000kms.

With all that being said, a couple of weeks ago, the car started randomly cranking but not starting. I would drive to go drop something off at work, for example, then go back to the car after 5 minutes - wouldn't start no matter how much effort I tried. I had the car towed home, then it started the next day with no intervention.

A few days later (after lots of driving in between), I went to pick up some gear for my bike and came back outside, car would crank but not start. Had it towed home, this time, it took 3 days, but it started again. Again, no intervension.

Took a long trip (about 8 hours both ways) to pick something up, and left the car running just to be safe, no issues there... car ran smoothly on the highway. Then just today, again, crank but no start.

I changed the coil pack + plugs today - crank but no start. The fuel injectors are fine, and the fuel pump is fine. Both working as intended.

The last thing I can think of is, maybe a bad crankshaft sensor, or maybe a starter. Although, there are no funny noises or anything coming from the starter when I'm trying to crank it over.

There are no codes, it doesn't run rough at all (when it does work). The fuel economy does seem to be down 15 or so %.

I'm puzzled!

[ArtVandelay]

First suspect would be a heat sensitive crankshaft position sensor. When the problem occurred, did you notice if the fuel pump turned on before the starter cranked the engine? The ecm won't run the pump with a bad CKP signal.

When ignition is turned on, the ecm should run the pump for 2 seconds if the engine isn't started.

Another possibility - it looks like your problem began about the same time as your timing chain replacement. Possible camshaft alignment problem? I wouldn't suspect this if the engine drives ok and has the same amount of power.

[barriosl]

Originally Posted by ArtVandelay

First suspect would be a heat sensitive crankshaft position sensor. When the problem occurred, did you notice if the fuel pump turned on before the starter cranked the engine? The ecm won't run the pump with a bad CKP signal.

When ignition is turned on, the ecm should run the pump for 2 seconds if the engine isn't started.

Another possibility - it looks like your problem began about the same time as your timing chain replacement. Possible camshaft alignment problem? I wouldn't suspect this if the engine drives ok and has the same amount of power.

I did just replace the crankshaft position sensor the other day. It didn't change a thing.

The timing chain (kit) was replaced probably 2/3 weeks before this started... sorry for the confusing timeline. So I'm not sure if it's possible for that alignment problem with the chain to happen a couple of weeks later. Whenever the car did start randomly, it ran fine. Same power, no idling rough or anything.

Whenever I start the car, I always listen for the fuel pump to do its 2 second prime thing. So, yes I noticed the fuel pump turned on before.

[ArtVandelay]

Staying with the symptom that your gas mileage is worse, I'll give you a couple of other possibilities:

1) Even though you say they are fine, one or more fuel injectors may be leaking down. I used to have a 2.2 Vue and the factory service manual, but I don't any more so I don't have the details of the factory test procedures (which require a scan tool and fuel pressure gauge). One was a fuel pressure stability test and the other was what they called a balance test. With the miles you've got it may be justified to just go ahead get the injectors cleaned and tested.

2) Bad coolant temperature sensor.

[barriosl]

I had my mechanic come over today to take a look at everything. I do what I can for the car, but it gets to a point where I need the experience.

So we tested the plugs, no spark. We tested the old ones, but nothing. We tested the new ones, but nothing. So, I think the issue is probably there. There is no spark.

We tested the connector that goes into the coil pack - it has power & ground. There are a few more wires there, but, I couldn't find any wiring diagram on what they're supposed to be.

Bad coolant temp sensor will 'cause no spark?

[barriosl]

What about a bad ECM/PCM? I'm not really sure how you would test that, but, it's not hard or expensive to replace.

[fdryer]

Replacing crank sensor (be sure its seated all the way in), ignition coil pack and plugs suggests a faulty ignition control module (the finned aluminum box sitting in one side of the coil pack). Ignition control modules tend to fail more than coil packs. A search of 2.2L problems here and in other GM models using the same 2.2L engine should show this.

A simple way to tell for fuel pump/injector operation; after failed starting attempts, spark plugs should be wet with raw fuel. A faulty coolant sensor will not interfere with spark or fuel injection. During engine startup, the coolant sensor detects cold coolant and sends signals to the pcm. The pcm automatically enriches fuel mixtures so a no start condition should reveal wet spark plugs if spark doesn't occurs. Remove plugs to verify fuel pump and injectors are operating; the crank sensor timing signals during starting and running allows the pcm to operate; fuel pump, injectors and ignition for spark.

[barriosl]

I replaced the ECM/PCM today. It still just cranked, but no start. However, after the 3rd time, it finally started. Check engine light was on, service engine light was on, power steering didn't work, it wouldn't go over 4k rpms. It wasn't great.

I put in a brand new battery thinking maybe the voltage wasn't right, or with all the cranking I've done, I somehow killed the battery. It wouldn't start after I put the new battery in, until the 3/4th try. Still ran like crap with all the check engine lights.

I plugged the old computer back in, all the engine lights went away & it is running very smoothly... I'm really at a loss. Sometimes it wants to start, sometimes it doesn't.

[barriosl]

Yes the plus are wet. After having the issue again today, the car left me stranded after a family day out. I spent probably a good hour (on & off) cranking, but not start. My poor starter.

However today it did something different. It cranked & started, but shortly after I buckled my little guy in his car seat, it just died while idling. Wouldn’t start after that. Had it towed home for the 4th time in the last 4 weeks. I’m done driving this thing until I can for sure figure it out.

It HAS to be a bad wiring issue at this point right? I tested the old coil pack & plugs when it was having problems starting. No spark on either original coil pack or the new one. The likely hood of a bad ICM on both is… unlikely.

Has to be a bad wire somewhere… it just doesn’t add up. It’ll randomly fit itself sometimes after sitting for a day or seven.

[fdryer]

With changing symptoms, this may be more difficult to narrow down. To review the ignition system; the pcm sends ignition signals to the ignition control module (ICM), the ICM sends power signals to the coil pack, the coil pack generates high voltage for spark. You're now describing intermittent spark failure if spark is lost then found at random. This would suggest either intermittent wiring between pcm and icm or intermittent icm. Other considerations may be high mileage.

With high mileage, 300k kms/186k miles might suggest lower compression. Acceptable compression from service manuals, 185 psi yet many swear their engines with 125 psi compression are fine and acceptable for old reliable transportation. A dry then wet compression test may help determine engine state of health with a compression gauge borrowed from Autozone. Dry test with a cold engine, wet test after pouring a tablespoon of motor oil into each cylinder. Oil is distributed around piston rings to help seal against worn rings lowering compression for a temporary boost. Compare dry with wet tests.

[barriosl]

I didn't figure 186k miles would be too high. Especially with a good maintenance history, right? Maybe I'm too optimistic there.

I definitely think it is something between the PCM & the ICM. I'm going to try & add a couple more grounds (found some diagrams on these posts).

If the compression is low, wouldn't the car run poorly when it does run? The thing runs so smoothly when it idles, you can't even feel the motor through the steering wheel.

[barriosl]

Turns out it was something super simple. The CPS wiring harness was barely holding on for dear life. Hardly making a connection.

When I replaced the CPS, I noticed the connector didn’t have the little clip to retain the connector securely. I didn't think much of it - turns out the whole wiring harness for the CPS was bad.

That was an EXPENSIVE ordeal for a 30 dollar wiring harness lol