sandsk8erz400

iTrader: (1)

So, I've searched on here and have been trying to diagnosis it myself, but I'm having some trouble. The problem only happens once every 10 starts or so, and I'm at a loss of what to try now.

Problem: Car cranks but will not start, no CEL or security light, cranks as normal just does not fire.

Tests: I've changed the fuel filter and initially thought my fuel pump was the issue after searching the forum. Fuel pressure test - Pressure held steady at 55 psi or so w/ ignition on and running. Holds pressure fine after turning the vehicle off as well, so it's not "leaking" back into the system via a bad regulator or pump. Is it still possible for the pump to be the problem after performing these tests? I was even able to have the car crank without starting and the pressure held constant at 55 psi while cranking.

It is not the VATS system, have simulated this condition by unplugging the vats connector and got the security light flashing while trying to crank, but it did not crank at all. So I'm positive it's not the VATS.

I've swapped the relays under the hood (Ignition and Fuel Pump w/ AC and fan) and it will still have the problem once in a while.

The Ignition Switch has also been verified to be good. (Have a remote start on the car which bypasses the ignition switch, problem has happened under remote start condition, verified good voltage past the remote start connection is good.)

Should I check for spark during the no start condition, and if so, what would that point to if there was no spark? Could the crank sensor be the problem even if the car cranks? Coil Packs? Where would you all suggest I go from here?

bayer-z28

iTrader: (14)

^ Crank sensor is a good guess. If the PCM doesn't see the engine turning, then it won't fire the coils. It's also the cause mor intermittent stalling or a car that dies out of the blue. Do you know anyone with a TechII Scanner? Or some way to look at the syn wave of the sensor while cranking..... Or if you just feel like throwing parts at it.. It's up to you.

sandsk8erz400

iTrader: (1)

The car has never stalled or died out of the blue, just has the intermittent starting issue. I'll ask around and see if anyone I know has a TechII scanner, I know a few friends with scanners, just can't remember what kinds they have. I guess the first thing to verify would be no spark though, I'll do that this weekend when I get some time and let you guys know what I find out.

Athlon2k2

iTrader: (2)

It sounds like you tested all the basics like you should have. I don't believe it is fuel related. Probably no spark is the problem. The question is why. I would look for obvious things like shorts or unplugged wires. Has anything happened to the car that coincides with the start of the problem?

LS6427

iTrader: (2)

Yup.....a very good guess.

.

bayer-z28

iTrader: (14)

A TechII Scanner is pricey, so you'd probably know if someone has one.... It's like knowing if one of your friends has a time machine... just one of those things that would stick in your mind. It's an advanced technician scanner.

And it's probably not a fuel issue. But the PCM uses that crank sensor for fuel AND spark. So if it goes, your injectors are probably not being controlled either. Not to mention no spark.

sandsk8erz400

iTrader: (1)

Confirmed no spark during the no start condition. Nothing has happened to the car that coincides with the start of the problem. The only other thing is the ABS in-op light comes on once in a while, initially thought it was low fluid, but tank is full so now I'm thinking a wheel sensor.

Browsed over most wires and connections, nothing jumped out at me. I haven't been able to find a scanner that can check the crank sensor, might just take it down to the dealer to have them diagnosis it.

Don't know if it's just a coincidence or not, but figured I'd mention it. While messing around with the car, I tried cranking the car a total of 6 times or so this morning. On 2 or 3 of them, I noticed the "Service Engine Soon" light was not illuminated while just having the ignition on, but all the other lights were on as normal. It only did this for those couple attempts, then the light came back on as normal. Under either condition "Service engine soon light on or off prior to cranking" the car still cranked without starting.

I just wish the problem wasn't so intermittent, and runs like a top when it runs. Might just throw a new crank sensor in to see if that solves it, if it doesn't I'll just take it to the dealer and let them deal with it, kind of at the dgaf anymore point.

bayer-z28

iTrader: (14)

^ true..... I don't see anything else that the computer would reference for a start other than that.

Does your fuel pump come on every time? I know you said you had fuel, but was wondering.... Might be a ground somewhere too. checked your PCM relay/fuse too?

But if you take it to the dealer, just post back as we're all curious to what it is.

LS6427

iTrader: (2)

The dealership.....are you serious...?

It takes 10 min to change the CPS.....try that first. A bad or failing CPS causes intermittent no-starts.

.

bayer-z28

iTrader: (14)

It can be easy to over-think these things too. Sometimes a sensor is just a sensor..

Come to think of it.

sandsk8erz400

iTrader: (1)

Well, you guys are going to get a kick out of this. Threw in the Crank Position Sensor, seemed to be fine for a while (since the problem's so intermittent.) Finally didn't start the other night and I was just infuriated by this persistent problem.

So I started metering EVERYTHING (again) from under the dash to out under the hood. Traced the problem back to the relay box, but since I just replaced the relays I jumped to the conclusion that the connections on the bottom of the relay block must be bad. As I started to remove the block, my father suggested I might have received a bad relay. I tried testing the relay and it seemed to function properly, but since the problem starting the other night, the car consistently wouldn't start now.

So, I run up to the dealer and grab some OEM relays (which were cheaper than the f*cking autozone relays I first picked up) and threw those in. Car's started fine ever since. Granted the problem used to be intermittent, starting fine most of the time. I guess I can't say that this was the issue with 100% confidence, but I'm pretty sure that it was and I'll update this thread if I have any more problems (fingers crossed I don't.)

Moral of the story, with all the headaches I've had with this due to a faulty autozone relay, they've lost my business for good.

Thanks for all the help guys, I really do appreciate the wealth of knowledge I've gained from here over the years and the resources I have at my fingertips from searching the forum. Happy Holidays to everyone.

Nathan C

Glad it seems to be an easy fix.

99Silver6.0

iTrader: (2)

I know Im digging back up an old one. But, I had almost the exact same issue. I wasnt really cognizant of it before I had my car retuned. But, the shop I took it to called me when he was tuning it and asked if it was a problem I had been dealing with for a while. Car would sometimes take exactly 2 key switch hits to get it to start. I could walk out to it at times and the first turn and hold of the ignition would yield nothing but a long crank until I let it go. Hit it once more and it would barely crank over then boom, starts right up. I farted around and checked everything I could. Checked CKP and CMP in EFI Live, etc. Tripped across this thread when I was searching and decided I would replace the fuel pump, starter and ignition relays with ACD parts and see what happens. Well, Ive been going to the car and starting it at random times for the last 2 days and the problem has not reoccurred since.

ETA: I spoke to soon. Still does it.