1996 Cobra-- Cranks but won't start

squeak93

10 Year Member
Jun 2, 2005
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Joplin, Missouri
As stated: 1996 Cobra, cranks, fired one time and sounded terrible for 1/2 a second. Then nothing. Just cranks.

I just bought the car, the PO thought the engine was blew (said a compression check said #5 had low compression) but even with that, the engine should still run, so there is another issue. From what I understand 3-4 years ago when it broke he was a bit tipsy and was doing donuts in a field when it died. He had replaced the fuel filter and that's about all the I know. We went in today and put new plugs in it and hooked everything back up as well as a new belt and battery.

From what I can tell nothing has come unplugged, the fuel safety switch in the trk (what ever that thing is called) is not tripped. It has 35-45lbs of fp when cranking at the rail. So we have fuel.

It has air unless the maf is dead... not as likely as the below.

My only guess is a bad coil pack or multiple bad wires. Any thoughts?

I have not hooked a obdII scanner up to it yet but I would think since the battery was left dead for so long that any prior codes would no longer be there.
 
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wmburns

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Aug 14, 2009
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Does is make normal "chug chug" sounds while cranking?

What happens if the MAF is electrically disconnected? Does it start?

What happens if the throttle is held half way open during cranking? Does it start?

Can your ODB2 scanner monitor opperational data? If so, monitor RPM's while cranking. Do they change? If not, suspect a CKP sensor problem.

Have you tested for spark? Have you double checked the spark plug wire routing? Remember if installed incorrectly, the wires will spark but at the wrong time.
 

squeak93

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Jun 2, 2005
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It does make the "normal" cranking sounds. I've not had much time to work with it. Next weekend we'll put a scan tool on it to see if any immediate codes are thrown as well as check for spark. The wires are correct according to the diagrams I've found. If anyone has a "reliable" diagram that would make me feel better. One time We tore a pi motor about 1/2 way down because the plug diagram we found on autozones web side was 100% incorrect. (live and learn)
 

2vNotch

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Dec 6, 2011
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sounds like it could be either mechanical or electrical at this point....as long as u have fuel, fire, and backpressure it oughtta start...is it catted? if so they could be clogged ???
 

squeak93

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Jun 2, 2005
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UPDATE:

The car started but runs rough. It ONLY starts when u put the throttle to the floor. Then you have to help it idle until it warms up. It will settle down and idle, does better w/o the maf plugged in. I had a scan tool on it and the maf registered voltage, o2's read, tps read, iac read, all of it appeared to be normal. We also swapped in a known working set of coil packs to eliminate that. The only item left to try is a set of new plug wires. I ordered a set that will be here tomorrow (seems no parts stores stock wires for a cobra in the area).


There is VERY old fuel in it, I've ran a bottle of heet into it but fear I may have to pull the tank to drain it (can't get a siphon hose down it to do it the lazy way). If the wires don't fix it, I'll have to drop the tank. Not sure I'll have the energy to do that any time before xmas.


Anyone else with any suggestions?
 

squeak93

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Jun 2, 2005
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Update:

I rid the car of the old gas, put new 91 in and same issues. So, I pulled the plugs again and here is what I found. Left bank (d/s), ALL 4 plugs were perfectly clean like they never fired one time. Right bank (p/s) all 4 plugs were covered in carbon.

So, since I know that when I had a scan tool on it, I the computer read the rpm's, I'm assuming the crank sensor is ok and I am leaning towards the CAM sensor as to being my issue.

Anyone have any other ideas.

as a reminder, the plugs, wires and coil packs are all new (coil packs are used but taken off of a running car).
 

courtneb

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Jan 6, 2012
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Update:

I rid the car of the old gas, put new 91 in and same issues. So, I pulled the plugs again and here is what I found. Left bank (d/s), ALL 4 plugs were perfectly clean like they never fired one time. Right bank (p/s) all 4 plugs were covered in carbon.

So, since I know that when I had a scan tool on it, I the computer read the rpm's, I'm assuming the crank sensor is ok and I am leaning towards the CAM sensor as to being my issue.

Anyone have any other ideas.

as a reminder, the plugs, wires and coil packs are all new (coil packs are used but taken off of a running car).

Dude, check your knock sensor at the bottom front of the engine; if it gets damaged or comes unplugged, the car will turn over but it wont start. Also check the inertia switch (fuel shut off) in the trunk make sure the button didn't pop on you. Good luck!
 

2 Foxes

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Sep 8, 2009
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Did you get a code for cylinders 5-8 misfiring?
have you pulled the cam cover to verify no broken chains ?
 

squeak93

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I guess I should update this. I ended up pulling the engine cause nothing was making sense... I also made the mistake of taking the po's word for the compression test. Let me explain lol. I pulled the d/s cam cover to find all 8 follower randomly laying around... No broken/ loose chains. So I tore it all the way down to find all 8 intake valves on the ds head were smashed into the casting and jammed open. So I'm picking up a junk yard aviator motor (c headed) this weekend and will start that swap here soon.
 
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NightryderBSG

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I guess I should update this. I ended up pulling the engine cause nothing was making sense... I also made the mistake of taking the po's word for the compression test. Let me explain lol. I pulled the d/s cam cover to find all 8 follower randomly laying around... No broken/ loose chains. So I tore it all the way down to find all 8 intake valves on the ds head were smashed into the casting and jammed open. So I'm picking up a junk yard aviator motor (c headed) this weekend and will start that swap here soon.
How did this end? I am having the exact same problem. Replaced the spark plugs because they were fouled, all 8. Replaced IAC. Car started perfectly. Let it run a minute and switched it back off. Tried to start it again and I was back to the same issue, continually cranking but not starting unless I floored the gas.