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Distributor "grounding"?

4K views 14 replies 9 participants last post by  redfury 
#1 ·
I have a '97, 4.3 and have an engine that won't start. Not a fuel issue. I have spark coming out of the coil wire and going in to the dizzy cap, but not coming out the cap. I was told that the spark was grounding to the block somehow. How can this be? There are no wires in the cap or rotor, and the pickup wires are in a plug on the outside? Any ideas where I might look. BTW new cap, rotor, pickup, spark plug wires, coil, camshaft sensor.
 
#2 ·
1 - Who told you it was grounding to the block? What made them think that?

2 - Disassemble and reassemble the cap and rotor. Clean the inside of things while you're there but simply think of it as a "reboot".

3 - Unplug all but one sparkplug wire from the distributor cap. See if you get spark from that one wire.

4 - If you've been spinning it, does it LOOK like the tip of the rotor and the contact points on the inside of the cap are making contact? Wear marks?

Lump
 
#3 ·
Thanks for responding Lumpy.
Answers: 1. Backyard mechanic. Claims spark is taking the path of least resistance, rather than having to jump the spark plug gap. How it can go to the block I can't imagine. 2. Did as you suggested. 3. I forgot to try this. 4. No wear marks on either rotor or cap.
I thought maybe the distributor may not be timed right, with the coil firing in between the posts, and that none made it out to the plugs. So I brought the motor up to No. 1 cyl. TDC, and the rotor was pointed right at no. 4 cyl on the cap, so that's okay. I really believe the ecm may have gone out, but don't know how to check it. Any ideas?
 
#5 ·
Lumpy said:
Amnesia Wes said:
... I brought the motor up to No. 1 cyl. TDC, and the rotor was pointed right at no. 4 cyl on the cap, so that's okay...
... :confused:

Lump
Hate to reply to a question WITH a question but curious; did you have the distributor out for any reason while you were working on the ignition system?
 
#7 ·
Amnesia Wes said:
I really believe the ecm may have gone out, but don't know how to check it. Any ideas?
I would rule the ECM out since you're getting spark from the coil.

Amnesia Wes said:
So I brought the motor up to No. 1 cyl. TDC, and the rotor was pointed right at no. 4 cyl on the cap, so that's okay.
This doesn't sound right. :confusion-scratchheadyellow: Does the engine do ANYTHING while you're cranking it (like backfire, spit or sputter) or sound like it is cranking fast then suddenly slow?
 
#8 ·
Even if the distributor is pointing to the wrong spark plug wire when at cyl #1 TDC, you should be able to see a spark from a spark plug wire to ground. Stick a screwdriver into the end of spark plug wire and hold it close to grounded metal. The arc should be able to jump at least as far as a spark plug gap. You can also use a spark plug instead of screw driver. You do need to connect the spark plug body to ground. The spark my be hard to see in brightly lighted room or in direct sunlight, but should be easy to see in dim lighting. Depending on how good your ears are, and how much noise your engine makes when it is cranking, you should also be able to hear the snap of the spark. Find out if you really do not have a spark. If you have spark, then look to whether the distributor rotor is pointed to the right cylinder at the right time. If you had the distributor shaft gear unmeshed from the cam shaft gear at any time, then you must be sure that you get the gears meshed properly so the spark occurs at the right time and the rotor points to the right cylinder.
 
#9 ·
I am not getting spark at the plugs.
With the harmonic dampener at TDC, the distributor should be pointing at either the no. 1 cyl. or the no. 4, and it is. If I were to turn it one more revolution, it would have been pointing to no. 1. Sorry to confuse things. Bottom line, dizzy is not off one or two teeth, but sitting properly. And no, it does not backfire or spit. Cranks at normal speed. Battery is fully charged. (So far I've changed within the last year, the camshaft sensor, crankshaft sensor, distributor/cap/rotor/pickup, ignition coil, spark plug wires, spark plugs, coolant temp. sensor, thermostat, air mass sensor, timing chain, water pump and fuel filter.) I'm just about ready to buy 5 gal. of gas and a match!!!!!
 
#12 ·
Are you sure you have spark from coil before it connects to distributor? And you do not have spark at spark plug wires? You said new distributor cap and rotor, right? Are you sure the rotor is the right one for the distributor cap you are using? Maybe no connection from coil wire (center of distributor) to rotor? Failure of spark plug wires? I doubt they could be that bad. Rotor pointing between two cylinders on distributor cap when coil generating spark? I think you'd still get something at the spark plug. Keep at it, you'll get it.
 
#13 ·
just one thought: brand new parts does not always mean good parts I am sure I am not the only person on this site that has bought brand new yet faulty parts. Go back to the old parts one at a time such as try the old rotor button then the cap then the coil & so on. I bought a brand new MSD coil and it shot sparks everywhere But the wire in the past just an example.
 
#14 ·
Thanks for responding guys.
N6: Yes, I'm getting spark from the coil wire, not just the coil itself (the whole spark plug set is new). I tried different caps and rotors.
markmitch: I agree. I've had "new' parts fail on me too, that's why I tried several different combinations to isolate the problem.
I'm starting to think that the ecm went out, because every time I pulled a code within the last year, I have changed the part: crankshaft sensor, camshaft sensor, distributor pickup, distributor, cap, rotor, spark plugs, spark plug wires, coil, coolant temp sensor, air mass sensor. Also changed water pump, timing chain, radiator, fuel filter and other minor stuff. I don't know if it means anything, but whenever I use the turn signals, the fuel gauge hand would "twitch" in time with the signal! I sure wish there was a way to test the ECM. Everyone I asked around here says: no.
I would hate to spend another $200 on a rebuilt ECM, if it doesn't help. Over the last year I have spent a ton of money, but don't have the heart to give up on her. Hope you guys understand my reluctance to keep throwing money at her. At some point, you gotta either fish or cut bait. I getting really close to cutting my losses and parting her out if I can't fix this problem.
 
#15 ·
Sounds like you need a factory service manual so you can go through testing components one by one.

I would suggest at this point, to invest in a test light ( or build one if you have a spare 12v bulb and some wire and a fuse ) and start looking for a reference signal to your coil. If you are getting a pulsing light at the coil, and you are getting spark, then your spark timing is off. You didn't mention which codes you had gotten. Sometimes you will have problems getting a van to start if the crank sensor has been replaced and you need to do a CASE relearn procedure ( requires a bidirectional scan tool like an OTC Genysis or Snap on ) The other thing that you might be having problems with is the new crank sensor might have to be shimmed. Pull it out and look for wear marks from the crank on it. Lots of new crank sensors will go wonky on you because they don't have the proper air gap.
 
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