Only getting spark to half of the engine. PLease help.

[Rich]

Repeating from post #4 - and you will need to go in this order....for example, you cannot check the ignition timing using #1 cylinder if there's no spark in the #1 wire due to a problem in any of the first 3 steps here:

Check that you did not install an even-fire distr. cap* (assuming that's even possible).
Check that the distributor is installed correctly per M:01:02 in Workshop Manual based off of TDC for #1. That is critical - assume nothing.
Check that #1 plug wire is on #1 TDC plug tower.
Check that the ign. timing is really set to #1 cylinder (rt front).

We know the distributor was replaced (but the replacement indexing accuracy is unknown so far) and we know there is no spark in the right bank. Spark may be generated for that bank but due to the odd-fire setup the spark could go nowhere if the rotor-cap sync is incorrect (off by one phase either way).

Especially note that when the distributor goes back in the spiral gear can affect the final rotor position/indexing.

[Johnny-T]

I have an update I wanted to share. I am sure that there is no fault with the cap, rotor, wires, or plugs. I just tried installing a new ignition system that had some effect but there is now a different issue that is just as confusing to me. I will try to explain everything in order in the hopes it points to a new clue.

So with the stock set up we found out we had good spark on 4, 5, and 6. No spark at all on 1, and 2. And a very weak spark on 3. But the car fires up and idles.

As mentioned before, we swapped out the ECU, resistor, and coil. We also tried different plugs, wires, and distributors components. All changes had the same results. Still only one bank with spark.

We then plugged in the new ignition system. It basically replaces the ECU, coil, and plugs and bypasses everything else. Once installed we tested the sparks and we finally got all 6 perfect and strong sparks. We don't know what it is that fixed the sparking problem because we had already tried swapping out all the separate components with no effect. In any case, the new system seemed to do the trick so we put everything back in order and tried to start the car again.

This time the car just cranked and cranked and then it would backfire/misfire with a loud popping metallic pinging sound and would cut off. It was acting as if the timing was off so we carefully checked and rechecked that the timing was correct. It was. We tried to start it again and still just got the misfire.

Finally we decided to switch back to the stock set up to see if it would still start again that way. We plugged back in the original ECU and everything except for the new plugs. Turned the key and the car fired right up but it was back to only the 3 cylinders firing again.

So we now either have only half of the sparks working with stock, and the car starts, or all of the sparks working with the new set up but then the timing seems off even tho we know it's good.

The only part of the original system we didn't swap out was the actual small harness that the new system replaces. (Jump harness?)

We now also know that the cap and wires are good because we were able to get good spark with them all. We just don't know what's causing the new misfiring problem when we are using the new set up.

I have videos I will try to add soon. But in the mean time, any other ideas or thoughts with this new information?

[kings1527]

I have an update I wanted to share. I am sure that there is no fault with the cap, rotor, wires, or plugs. I just tried installing a new ignition system that had some effect but there is now a different issue that is just as confusing to me. I will try to explain everything in order in the hopes it points to a new clue.

So with the stock set up we found out we had good spark on 4, 5, and 6. No spark at all on 1, and 2. And a very weak spark on 3. But the car fires up and idles.

As mentioned before, we swapped out the ECU, resistor, and coil. We also tried different plugs, wires, and distributors components. All changes had the same results. Still only one bank with spark.

We then plugged in the new ignition system. It basically replaces the ECU, coil, and plugs and bypasses everything else. Once installed we tested the sparks and we finally got all 6 perfect and strong sparks. We don't know what it is that fixed the sparking problem because we had already tried swapping out all the separate components with no effect. In any case, the new system seemed to do the trick so we put everything back in order and tried to start the car again.

This time the car just cranked and cranked and then it would backfire/misfire with a loud popping metallic pinging sound and would cut off. It was acting as if the timing was off so we carefully checked and rechecked that the timing was correct. It was. We tried to start it again and still just got the misfire.

Finally we decided to switch back to the stock set up to see if it would still start again that way. We plugged back in the original ECU and everything except for the new plugs. Turned the key and the car fired right up but it was back to only the 3 cylinders firing again.

So we now either have only half of the sparks working with stock, and the car starts, or all of the sparks working with the new set up but then the timing seems off even tho we know it's good.

The only part of the original system we didn't swap out was the actual small harness that the new system replaces. (Jump harness?)

We now also know that the cap and wires are good because we were able to get good spark with them all. We just don't know what's causing the new misfiring problem when we are using the new set up.

I have videos I will try to add soon. But in the mean time, any other ideas or thoughts with this new information?

Cranking, cranking, cranking, cranking, cranking, and then......BOOM.....misfire.....rinse and repeat, is symptomatic of the distributor cap being installed upside down. Very easy to make a mistake with that when you're not thinking about it. I'd go back and flip it around 180 degrees and try again. Very much a pain to do with the intake manifold installed again, I know.

[Ron]

Does the "new ignition system" consist of all OEM/Stock style parts?
Either way:
Does it include a distributor?
Please give us a step-by-step of the method you used to find TDC before dropping the distributor in.

I'm with Alex given all of that popping etc (180° off). You don't have to pull the manifold to tell, either.
(We can get in to that...depends on your answers to the above...)

[Johnny-T]

Cranking, cranking, cranking, cranking, cranking, and then......BOOM.....misfire.....rinse and repeat, is symptomatic of the distributor cap being installed upside down. Very easy to make a mistake with that when you're not thinking about it. I'd go back and flip it around 180 degrees and try again. Very much a pain to do with the intake manifold installed again, I know.

Is it possible for the car to fire up and run sparks on only 3 cylinders when the cap is upside down tho? Because if not then it can not be the cap. The cap is never touched when switching between the stock set up and the new system. And again, the car will start and idle when the original components are used, but it's still only on one bank.

The new system gets plugged into where the original ECM is. Then that has its own wires that runs to its own coil. That is attached to the distributor with the normal wire. So everything from the ECM to the wire going into the distributor is either replaced or bypassed.

Now it is possible that the new system calls for a different timing that we are unaware of. That's actually the next thing we are going to try. But we know for sure everything from the distributor to the plugs is correct and working. If they weren't we wouldn't be getting 6 good sparks with the new system.

The sparking problem was definitely caused by something between the ECM and distributor. We just don't know what since we had already tried changing everything with no effect.

It's only when the new system is installed that we finally get all of the plugs to spark but then the car acts like the timing is off. And again, the distributor remains exactly the same with either set up.

[Bitsyncmaster]

Maybe your new ECU has the pickup wires swapped. I found that problem with the FORD unit Bill sent me to test.

[kings1527]

Is it possible for the car to fire up and run sparks on only 3 cylinders when the cap is upside down tho? Because if not then it can not be the cap. The cap is never touched when switching between the stock set up and the new system. And again, the car will start and idle when the original components are used, but it's still only on one bank.

The new system gets plugged into where the original ECM is. Then that has its own wires that runs to its own coil. That is attached to the distributor with the normal wire. So everything from the ECM to the wire going into the distributor is either replaced or bypassed.

Now it is possible that the new system calls for a different timing that we are unaware of. That's actually the next thing we are going to try. But we know for sure everything from the distributor to the plugs is correct and working. If they weren't we wouldn't be getting 6 good sparks with the new system.

The sparking problem was definitely caused by something between the ECM and distributor. We just don't know what since we had already tried changing everything with no effect.

It's only when the new system is installed that we finally get all of the plugs to spark but then the car acts like the timing is off. And again, the distributor remains exactly the same with either set up.

I'm not sure what's exactly firing with an upside down distributor cap since I've never tested it but I also have no idea if you'd even get consistent results with it since it's out of the norm. Is it possible for it to run on 3 sparks with an upside down cap? Haven't a clue but it's much easier to ensure the cap is on correctly rather than try to hypothesize as to why or why not it would operate. SO MANY weird ignition/operation problems have been solved here simply by people going back to OEM plugs and wires without people actually figuring out why the car was running the way it was with the aftermarket stuff installed prior.

I think what's probable is you have two different issues going on.

1) your original ignition is not good (and therefor you're only getting spark on one bank). When you swap in the new ignition, it fixes that problem.
2) now that you get spark on all 6 cylinders with the new, good ignition, you have now most likely an upside down distributor cap that the system is contending with. That's when the misfire happens. Like I said in the previous post, putting that cap on upside down when you're not paying close attention to it is VERY EASY to do. Ask me later how I know that.

I have no idea with the history here on the forum of people having to adjust the timing due to a new ignition system being installed but I do know the topic of adjusting the timing is very rare.

Changing multiple components within the course of a "day's work" can bring on problems with troubleshooting a problem if one arises due to the fact many things were messed with. I think it'd be in your best interest to ensure without a shadow of a doubt that the cap is on correctly before investing the time and effort into a timing adjustment and then take it from there.

[DMC-Ron]

With no intention to beat a dead horse, but have you rechecked/verified the rotor timing position. Is it possible that the distributor is out of sequence/alignment? At TDC is the distributor rotor actually pointing directly at the #1 spark plug contact. If it were off, it might be close enough to spark some cylinders but not others.

Ron

[David T]

Not only must the rotor be synchronized to #1 cylinder you must point it to the #1 position on the cap. As previously stated, the cylinders are not evenly spaced around the cap so it is vital that you have the rotor aiming at the correct position of the cap and that it is for #1 cylinder. Not only is the cap asymmetrical, so is the reluctor ring in the distributor. The cap should have cylinder #'s marked on it and when cylinder #1 is at TDC at the end of the compression stroke it MUST point at the #1 marked position of the distributor cap. That wire then goes to #1 cylinder and then, following the firing order, each wire goes to the next cylinder to be fired. Just aiming at a cylinder on the cap when #1 cylinder is at TDC and then using that as #1 cylinder won't work on the PRV. Volkswagon Bugs had a similar issue, one cylinder (#3) was slightly different (it was ever so slightly retarded) so it wouldn't overheat. If you didn't install the distributor and cap so the correct cylinder, #3 fired when it should, you eventually burn #3 cylinder up. Maybe that's why you aren't getting spark to one side, you have the firing order out of index.

[Rich]

Not only must the rotor be synchronized to #1 cylinder you must point it to the #1 position on the cap. ..... Maybe that's why you aren't getting spark to one side, you have the firing order out of index.

+1 on what David T says, and also what posts #4 and #11 in this thread say, as well as Workshop Manual M:01:02.

The off-index or out-of-sync firing theory lines up consistently with the reported symptom - also is consistent with the fact that the problem started after the distributor came out.

It's easy to check/fix.