'93 ATX -> No Start, No Spark

[seraphiem]

Car has been running decent for the past 500 miles or so since I did both the upper and front 60k.

Today, the car refuses to start. When the car cranks over it sounds ridicously bad. Sounds like very uneven firing, wish I can even begin to describe what it sounds like, but it sounds very bad.

NOTE: This is the first time this has ever happened. I never had any warning signs until this occurance today.

Being rather illogical I first suspected the timing as I remember the new belt had a new more slack then I would like when I installed it. I figured the belt jumped as the way the engine shuttered seemed like it was fighting with itself. Yet upon pulling the upper timing cover, I discover both the cam shafts are in time. No clue how the crankshaft itself lines up as I haven't pulled apart the rest of the front yet.

I believe I do not have spark. No arc. I do have fuel, no clue on actual pressure, but figured the car would at least kick over with low fuel pressure.

The CPS is about 500 miles old, the CID is the stock one with 147k on it. Unplugging the CID and extended cranking sessions does no good.

To aid in the uneven cranking and sounds is the tach. The tach fluctates from 500 to 3k when cranking. Again, the engine sometimes sounds as if it is spining waay too fast and then slows down to a more normal cranking speed. I figured the CPS must be working since the tach does work.

I found rangerj's excellent directions to diagnosing a no-spark condition. All components good from his procedures. Checked the under-hood 10A Fuse, good and even dropped in a spare I had.

My questions,

#1 Does this very strange fast and then slow cranking sound familiar to anyone? Again may tach goes upto 3k when cranking over.

#2 Would the no spark condition cause this irregular cranking?

Thanks In Advance

 

[93nighthawk]

Did you torque down the crank bolt to spec?

Did you remove the Crank timming sprocket? If so, how did the woodruff key look?

Was there brown dust inside the timming cover when you removed it? (If so definitely crank cancer)

With the sparatic RPMs and the no spark condition I am thinking that you might have damaged the CKS sensor if it was not gapped correctly or you bent one of the fins on the Crank Sprocket (It does not take much to break them:cry: ). I would check there first.

 

[projectSHO89]

Verify that you installed the lower two DIS mounting screws (they're the importanat ones), that the crossover pipe is properly tightened to the heads, and that the grounding strap is properly installed from above the #1 cylinder to the firewall.

Sounds like a bad ground in the ignition system.

Steve

 

[seraphiem]

I really think its a bad ground too. But I've spent the past 20 hours of the last two days checking every possible ground.

I should probably describe how the car cranks over. While it sounds quite bad, it really just sounds like the car cranks over for a few revolutions and then the starter kicks off for a moment, and then cranks over again.

This can be seen by the tach jumping, and the CEL pulsing as the car is cranking over. This goes along with the horrible noise of hearing the starter click on and off very fast.

But, it still doesn't explain my major and most basic problem.

No spark.

Suspecting my newly replaced CPS, I tear down the front of the engine today and dropped in my old one. Same results. Timing is still dead-on as it was two weeks ago. I'm unsure if the CID works, but the car should start without it, and most defineatly provide spark.

I'm down to coil-pack, DIS, and the main computer in my eyes. The main computer seems to run fine b/c it goes into diagnostic modes and gives me the '111' code.

Don't know about the DIS.

Which brings me to the coil-pack. When testing the coil-pack in the car, ala from C1, the front connector on the DIS, I get;

12 Volts from Vbat -> Coil Pack Main Power
12 Volts from Coil 1 On DIS Connector -> #1 (Coil 1) Pin on Coil Pack
12 Volts from Coil 2 On DIS Connector -> #2 (Coil 2) Pin on Coil Pack
6.5 Volts from Coil 3 On DIS Connector -> #3 (Coil 3) Pin on Coil Pack

Measuring the Primary Resistance Again from the C1 connector to Coil Pack Produces;

1.2 Ohms from Coil 1 On DIS Connector -> #1 (Coil 1) Pin on Coil Pack
1.2 Ohms from Coil 2 On DIS Connector -> #2 (Coil 2) Pin on Coil Pack
11.24 kOhms from Coil 3 On Dis Connector -> #3 (Coil 1) Pin on Coil Pack

I then ripped the coil out to test in isolation. Each primary measures 0.6 Ohms. I couldn't measure the secondary coils by measuring resistance from the main power input on the coil to the plug output, well, my meter couldn't measure the resistance because it was too high. But measuring resistance between each secondary output I measured roughly 13 kOhms.

Well, from these tests it appears I have bad wiring from the DIS to the coil on Coil #3. But, this shouldn't stop me altogether from getting spark from any of the three coils correct? I myself wouldn't think so. But I don't know.

And Steve, projectSHO89, thanks, your help (along with a few others) has been extremely helpful and well used.

 

[projectSHO89]

Your coil 3 readings indicate you have found a fault. Try making those resistance readings with power off directly at the coil and for the # 3 signal wire.

The reading should be the same as #'s 1 & 2.

Sounds like either a defective coil or a high resistance wire run.

That noise you described of the starter is also worrisome. Possible a bad ground connection from the battery to the block.


Steve

 

[seraphiem]

I pulled the Coil out of the car once I saw Coil #3 was an outlier when compared to Coil #1 & #2. When testing strictly the Coil, impendances of each primary coil are identical. To me that indicates the coil is fine. I do know the coil #3 cable from DIS to Coil has a significant loss. That will be fixed relatively soon.

Yet, from my understanding, that would not cause out-right no spark conditions from any of the other coils. Nor would that cause this bucking or starter pulsing.

Is this logical thinking?

I've checked every applicable ground more times then I can think of. I've spent almost the entire two days with the harness of the car. No luck.

All major ignition items such as the DIS, CPS, and Coil have been verified and appear to be working. The remaining item in my mind is the CID. I'm told this can cause the same very rough start condition that I am currently experiencing. And this follows as the CEL comes on while cranking.

Yet, has anyone experienced a failing CID completely disable spark emission?

 

[projectSHO89]

Just unplug the sensor. You will have a 1 of 3 chance of the computer guessing the correct injector timing. You will have a CEL but no tach. I ran my car for a week last summer like that until I got around to replacing the sensor.

Steve

 

[seraphiem]

Update

After re-doing every single ground, checking the harness, and adding new individual grounds for the dual bottom bolts on the DIS I hoped I had the problem fixed.

Nope. No go. So I checked the DIS and all sensors for the third time. Everything seemed fine, still no spark and the cranking just didn't sound right.

Finally checked my starter. The positive cable going to the main harness just flopped off when I barely touched it. Finally something concrete that could cause this. To account for the engine jumping, the entire starter was moving when cranking. IE, one of the mounting bolts was pretty loose.

So I figure when the starter went to generate torque to kick over my flex plate, the entire starter (and solenoid) would move and the battery cable would loose contact and the starter would kick off. IE, the pulsing of the starter and the entire electrical system that I was trying to describe.

All is well now. Engine sounds great when cranking, and fires right up. I'm also hoping after finding a lossy wire (DIS -> Coil #3) I will gain a slight improvement in mileage.

Thanks All