Buckin Bronco Episode iV

[aviator22]

Reference prior listings about bucking. Now it won't even start.

Well all. I fixed the plug wires to the proper firing order on the plugs and coil. Now the son of a gun will not even flat out turn over at all. It smelled real rich, so I pulled all the plugs again for re-inspection. I have never seen so much unburnt fuel and residue on a spark plug before in my life. I have to believe maybe cylinder number one if any of the cylinders was getting any spark. Not sure what to imagine it could be now. I think I'm ready to pull this thing apart and take a closer look. I may test the o2 sensor for kicks, but this engine is really making me believe it needs a serious rebuild. I might be able to borrow a boroscope from work which would be nice, cause I sure want to see what the cylinders and pistons look like at this point.

 

[luigisho]

Just to be sure the wires are routed correctly.

Engine cylinders: 1-2-3 rear bank
4-5-6 front bank

Coil pack: 5 1
6 2
4 3

 

[aviator22]

thier correct. Checked em several times to be sure. It seems odd that all cylinders were fouled. ALthough with out the engine turning over I guess it makes sense. I still suspect that coil. Can A bad CPS really make it impossible or nearly impossible to start a SHO?
Anybody? I feel like I am chasing my own tail here. Too many possible problems!!!

 

[sdpatt]

The crankshaft position sensor is the event trigger that signals the DIS to make a spark from one of the three coils in the coil pack. The EEC adjusts this spark timing according to the engine's other sensed operating parameters. Without the signal from the CPS, the EEC and DIS are not aware that the engine is even rotating. Therefore, there is no spark generated. Anywhere. Anytime.

But the CPS doesn't cause the engine to run badly like you have described before. It just doesn't have any spark and won't run at all.

When you say the engine won't turn over, you confuse things. I assume the starter is spinning the engine, but saying it won't "turn over" indicates that this isn't happening. You mean that the engine will crank, or turn over, but not fire or run. Is that correct?

 

[aviator22]

Thanks for correcting me. That wasa poor description. It wont fire. It cranks but won't fire. hence the excess fuel leftin the cylinders.

 

[HopefulSHO]

.......Camshaft sensor..altho you said it wasn't throwing any codes, though?

<small>[ August 07, 2002, 11:14 AM: Message edited by: HopefulSHO ]</small>

 

[91SHO]

you may want to check to see if the ground strap is connected to the back side of your intake. It will cause your car to run like crap, not sure if it won't allow it to start. It is connected to the left rear intake support bracket. If it is not connected your DIS, on the intake, will not be grounded. Just a thought that popped into my head.

 

[aviator22]

I will try EO (engine off) code scan again today. Ground strap is secure. I will also be testing the coil pack today since I am obviously not getting any spark anymore.

Here's a thought all. Whomever owned the car before me had hooked up the wires and coil pack wrong. The car may have been running on only a few cylinders for a long time. It never was the speed demon I expected it to be. Maybe when I was getting it to start before it was because there was just enough spark in the few cylinders that were hooked up incorrectly to get her going, but not enough to make her run smooth. After driving it this way long enough greater damage was incurred, and when i hooked it up right, then there was no longer enough spark to the right numbered cylinders to even get her to fire because most of the ignition system is no longer in real great shape. I'm thinkin hard here and hopin I make a breakthrough soon.

 

[CharlieSHO95]

I'm with HopefulSHO, it could be the cam sensor. When my '89 had that problem, it acted up on the highway when hot one summer, then started behaving and lasted until the next summer! When it started acting up again the following summer, it had the highway problem again a couple of times (loss of power, like the key turned off for a second), then wouldn't start after getting home from work and sitting in the driveway. If I checked codes when the engine had cooled off and the sensor worked again, it would not show a code, except in the stored codes (previous occurences). After replacing the cam sensor, I had to crank it with the throttle wide open for 15-20 seconds before the gasoline cleared out.

I also have a '95 that lost the cam sensor. It stuttered only a couple of times in a two week period, then shot craps after a hot soak at the car wash. It had to cool off for thirty minutes before it would start.

Your problem sounds like what I experienced with my '89. The failure was gradual.

 

[luigisho]

Do you live near any TX SHO owners? Just in case you end up checking the more expensive parts. You could swap coil packs, DIS modules and PCM's if the ignition problem goes beyond cam and crank sensor. Just saves throwing money at new parts. Also, I saw someone parting out a SHO on e-bay with cheap replacement items. Maybe pick up a used coil pack and dis module for cheap.

 

[brianl]

Is your fan on when you turn the key on?

My SHO died on the way home from work awhile ago. Apprently a connector at the rear of the motor had dropped onto the exhaust manifold. Cured a stuttering/bucking problem I had for quite some time...

 

[bobdub]

brianl:
Is your fan on when you turn the key on?

My SHO died on the way home from work awhile ago. Apprently a connector at the rear of the motor had dropped onto the exhaust manifold. Cured a stuttering/bucking problem I had for quite some time...

What connector are you talking about? I'm trying all leads that I can think of to get rid of my bucking problem.

 

[brianl]

Unfortuntely, I did not do this one myself. Didn't feel like going on a Gremlin hunt, so I took it to my mechanic. One wire had melted through and some connector near the rear exahust manifold. I'll try and take a look today.

Is your fuel pump priming like it should? Does everything else seem normal (ie, idiot lights, tach while cranking, fans, etc.)?