Stopped by Steve's house last night to grab some parts, and the car had been off for 10-15 minutes.

Got in the car to leave, cranked it and it ran EXTREMELY rough, idle varying between 400-600 RPM... coughing, sputtering, nearly stalling. Even worse once you put it in gear.

I was able to limp the car up to the garage door. We immediately checked the obvious things... vacuum leaks, unplugged battery for ten minutes, etc. Same issue. It would start, run rough as hell (almost as if a cylinder wasn't firing).

We swapped the camshaft position sensor with a replacement unit. Interestingly enough, once we got everything buttoned back up, it wouldn't even fire. It would crank and crank and crank, but never once fired off.

So.......

We're stumped. Next test tonight is to reinstall the OEM CPS, and if it starts but idles rough then we know the replacement unit is junk. If it doesn't start at all with the OEM unit in place, we have bigger issues.

Another thought was the coil packs... but if one coil pack was bad, it wouldn't cause the whole engine not to start.

Engine is getting plenty of fuel, I have a Walbro unit and the intercooler pump is a new Johnson CM30 as well.

Any pointers? Any hints as to why the engine would run (roughly) prior to replacing Camshaft Position Sensor, then wouldn't run at all?

Cheers,

 

If you havnt checked the rubber gasket inbetween the throttle body and supercharger, i think, check that. We had one torque its spacer apart racing and had a similar issue

 

It sounds like the CPS to me..... mine did a similar thing at the track, but only for a very short period... replacing the CPS fixed it... I did get a P0335 code too....

The crankshaft sensor and the camshaft sensor are used together, 8 pulses of one has to occur between 2 pulses of the other(crank to cam I think) or it wont start....

 

James purchased a cheap CamSPS and it was dead out of the box.

"Buy Bosch or walk home" is my motto.

I'm sure the Chinese army buys it's spare parts from the West, while our armies buy their spare parts from China. LOL

 

Check that the IAT sensor on top of the Y-pipe is still inserted.

 

Re-solder the RCM! Clean the contacts on the relays there while your at it.

 

Worth noting that I got absolutely no CELs on the dash, even when the car refused to start.

We haven't checked the RCM yet, but certainly haven't ruled it out. Checked all hoses and nothing was loose/unplugged.

The Cam CPS we used was an ebay part, had the metal probe versus the full plastic OEM BorgWarner unit in my car.

 

After you check this stuff get a fuel pressure gauge and make sure your Walbro didn't puke.

 

The IAT sensor didn't cause a CEL on my car when I blew it out, but the car was idling very high from the unmetered air. Probably not the cause of your issues, but it's easy enough to check.

 

Not sure if it means anything, but when I switch the key to "run" you hear the pump running stout as ever. I even waited a moment after the pump had been running, in case it was the valve that leaks fuel pressure out of the rail... didn't affect it at all...

Anthony -- My car isn't idling high... it's stumbling as if it's not getting enough fuel/spark. Of course, now it won't run at all.

 

I'm sure if you go through this list of things to check you will find your problem. Chin up!

 

Hope you get it up and running, you have not had that beast long enough to have it dead in a garage!

 

It's definitely just a minor electrical nuissance... the thing was running like a beast in the last week...

 

Good luck. I am battling a somewhat similar issue. After getting the SC bearing fixed the car drove fine. Next morning the car would barely run and you could smell unburnt fuel. Disconnect the battery and the car runs fine all day. Let it sit overnight and it does idles like *** again. Getting a P0105 on OBDII reader but I believe the SDS is showing something an undetermined fault.

Still waiting to see if a map sensor has really gone bad or if it is something else.

 

John does the fuel pump keep running or stop after it pressurizes the system. Mine only runs a few seconds until the pressure builds up , (when i turn key on) also go get another CPS and you will probably be good.

 

Alright gentlemen, here's where we're at:

Swapped the rear CPS (crank) tonight with a brand new Bosch unit. No difference.

New CPS (Camshaft) is installed as well. Still no start.

Inspected the RCM, it looks perfect. All fuses intact and unburnt. Did the old school trick of removing a spark plug and (with it connected to plug wire) laid it on top of the valve cover. Cranked car, and it's definitely getting spark. Noteworthy that when we had the spark plug removed, you could smell the unburnt fuel very strongly. So, she's getting fuel AND spark.

Fuel pump runs until pressure builds up, then stops. So there's nothing preventing the system from pressurizing.

At this point, we're stumped. Replaced every sensor related to timing. All hoses are connected. No fuses are blown. Engine gets fuel, air, and spark.

Still, the end result is "crank crank crank crank crank BURP crank crank crank".

No warning lights, CELs, smoke signals, etc.

Something is telling the car not to start, seeing as it has every key ingredient needed for combustion.

 

Since you know it is getting spark and fuel, try this:

Before you turn key on, hold throttle to floor and then crank. If it won't start in 10 seconds of cranking, stop and turn key off, but do not let your foot off throttle. Wait 15-30 seconds and try again. Do this cycle about 5 times to see if anything happens.

By having your foot to the floor before key on and while cranking, you are in 'clear-flood' mode and it will stop dumping fuel into cylinders.

James

The 14 years I had my Saturn, it flooded on me 3 different times. I have started many FI engines this way in the fleet I maintained. It usually will happen more in cold weather. Just a fluke in the ECM I guess.

 

Definitely worth trying... hadn't thought of that, thanks for the suggestion.

 

After all that, it now sounds security/skreem/key related.

Did you try your second key?

 

Didn't have it with me, but Steve said that was the very thing that happened to member DaytonaJae.

Problem is, Steve also said he got a warning message where the odometer counter is, saying "start error"...

I got none of that.

Nonetheless, I'm going to try my spare one tomorrow. And James' trick