Need Help 03 cranks by no start, sometimes.

Fred'S'nake

Also a hobbyist and scholar.
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Nov 5, 2010
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Lafayette, La
OK, rundown: 03 cobra, 60000+ miles. Ran fine up until some months back. Clutch and half shaft replaced. Next, cooling mod and head pipe/hoses replaced. Got car back, don't like the way the clutch is. Brought back had it readjusted, also had Steeda quadrant, new cable, new SS throw-out bearing all installed with new clutch. Followed by rear wheel bearings replaced. Oh, also had inner and outer tie-rods, MT rear tires and rear Bilsteins replaced early last year. Now back to the story, Car back, still don't like clutch, was readjusted again closer to my old burned clutch. Forward to a few weeks ago, had all hoses left, changed for silicone, new thermostat, etc. Car derivable, getting use to the clutch, Spec 2. Went back and had all pulleys (idlers and tensioners) replaced along with new belts. Which brings us to this week. Almost ran out of gas, finally put half a tank, rode 5 miles and car spit and died. Got it cranked after a couple tries, parked, went in a store, came out, cranked up drove home, 5 miles. Next day drove to work 8 miles, no problems. Left for lunch, car running kind of rough, got to 50 engine died on highway had to pull over. Tried starting, spits and coughs. That lasted a few times. 35 mins later it cranks up like nothing wrong I drive back to work. Leaving work on Friday, car would not start. Finally, popped a few times and started. Let it run, where now it would run for 2-5 mins then just die like turning the key off. Checked fuel pressure at rail, 43 lbs. No start. pulled MAF plug, checked MAF, reinstalled, left unplugged, tried to start. Plugged back in, no start. Pulled a coil pack, used a spark ground on car metal, no spark while cranking. Oh, yeah, ran a scan tool from a dealership, because I work there, guess what,.... no codes. Check rail again on sat. no fuel but a little dribble, thinking fuel pumps. Get back Monday, put coil pack back on plug, button everything up. Hook up scan tool, check codes, nothing. Check fuel rail, back at 40+ psi. Now I'm thinking crankshaft position sensor, so using the scan tool I go to engine data, check everything, I guess. Look at RPM is 0, so I spin the engine over to get a reading on RPM to see if crankshaft sensor is working. Guess what... the car starts. I sit there wondering what I missed. Engine sounds like before this started, readout on scan tool shows RPM working. Car dies after about 5 mins. Tried starting, nothing. There is a strange buzzing sound coming from around the front right fender when I turn the key on. Again RPM was showing like 1024 to 1330. I am lost at this point. It has spark then it seems not to. It has fuel then seems not to. Hell I don't even know if it is getting real air now. Can anyone make sense out of this circus. Its my daily driver,.. well it was before this, being I am stuck with no wheels. Anyone out there have a check list I can follow....lost..
 

Roots-type

+displacement
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Possibly the crankshaft position sensor. When they start to fail they're intermittent with misfiring and dying suddenly without warning. The strange buzzing by the front right fender is probably coming from the intercooler pump that's been wired to the ignition instead of being controlled by the computer.
 

Fred'S'nake

Also a hobbyist and scholar.
Established Member
Joined
Nov 5, 2010
Messages
109
Location
Lafayette, La
OK, for everyone out there, this is what I found. There is a thing called a "Power Distribution Module." There was a code associated with it. I will try to get that information and post it. It had to do with a comm. error with a BUS. There was also a buzzing sound and no mileage, just dashes on the odometer when I would turn the key on. I had a mechanic that works on my car for big stuff, like this. It took him less than 30 mins to find the problem. It had to do with this module voltage integrity. The voltage would be low and oscillate up and down and was still below what it should be. I think the voltage was below 11 volts and would drop, even with a jump box on the car. The module was $65 and change. I hope this helps. Took me six days basically to decide I couldn't find the issue, took the mechanic less than 30 mins. Of course I don't do this for a living, I understand why now.
 

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