Stator out of phase... ?????

[sschefer]

O.K. here's a good one.

Engine: 90-91 Carbed V135 2.0L V6. SN 0D009389

Problem: Stator replaced with new CDI direct replacement 16amp. I looked at the pics I took and put the pig tail in exactly the same spot as the old one. The pig tail comes out at about 5:00 with 12:00 being the crank.

Cranked it over on the spark tester and got good spark on all six. Put a timing light on #1 and it's out in left field. Check 2 and its in the ball park. 3 and 5 are whacked but 4 and 6 are good.

I swap switch boxes and get the same exact results. I remove the bias jumper (white/black) and remove the rectifier/regulator but the results are still exactly the same.

Finally, I swap red and blue on the inside switchbox (1,3,5) for red/white and blue/white on the outside switchbox (2,4,6) and low and behold now all 6 cylinders are in the ball park. The ball park is around 4 ATDC. Crank is indexed at .462 and dead on.

I'm thinking the stator that was on it was setup wrong and I now need to figure out where it's supposed to be.

I have a new set of switchboxes comming in tommorrow but I really don't think that's the problem. It's definitly not the trigger or I would have the same results on 2 that I have on 1 since they share the same trigger coil.

Thanks

Steve

 

[Dukedog]

Re: Stator out of phase... ?????

Stator harness should be ALMOST directly above tha starter solinoid. They say it makes a difference but I have never seen it and I've tried all tha different positions (just to see for myself). But that is where tha 16 amp was from tha factory. Switch box with tha red/blue goes to 1,3 5. R/w, B/W goes to 2, 4, 6. If thats tha way you have it. and its not working with tha pointer at .462 after you go thru tha TDC procedure then you have a wireing problem somewhere. May be tha stator? Who knows, its a CDI.........

 

[sschefer]

Re: Stator out of phase... ?????

Yep, that's what I have. If I swap the red blue on 1,3,5 sb with the red/w blue/w on 2,4,6 sb then I see 4 atdc on all 6 like it should be with the pointer indexed on .462 and TDC at 0 on 1.

I should have new switchboxes late tomorrow morning so I'll wire it all back up like it's supposed to be and call CDI if the new sb's don't fix the problem.

 

[Laddies]

Re: Stator out of phase... ?????

The stator can go on the engine in any position as all it does is produce the electricity to run the system. It's the trigger that tells the engine when to fire.

 

[CharlieB]

Re: Stator out of phase... ?????

Ditto Laddies post.

But it IS extremely curious that he found a difference by swapping stator leads. Have you made SURE the modules are grounded and switched the stator wires back to original does the timing return to irregular?

I expect there will be NO CHANGE with the new ignition modules.

Only other common part is the flywheel, check again for even the slightest movement of the magnets.

 

[Dukedog]

Re: Stator out of phase... ?????

Other ?'s. Did tha stator and tha coil wires have tha YELLOW sleeves and/or tape on 'em? Do you still have tha old stator? Did it check out good? Sounds like CDI just screwed up with tha wire colors...........

 

[Faztbullet]

Re: Stator out of phase... ?????

Here is diagram of stator wiring, as you can see the HS and LS are common to each other that is why red/blue wire are paired, that why when ohm tested they are tested to ground. The switch over to high/low speed windings are done in the rectifier circuit in the switchbox. You should be able to read betwen the red/blue wire together to find your correct pairs.

 

[j_martin]

Re: Stator out of phase... ?????

I've put stators on every which-a-way and it doesn't seem to make any difference. Logically, it shouldn't.

Firing is determined by the trigger. Opposite cylinders are fired by the same coil, 1 and 4, for instance. You would expect a trigger problem to manifest on the related cylinders.

The other factor in timing is the bias voltage, generated internally by the switchboxes. Picture the sine wave voltage coming off the stator, a zero voltage line through that pattern, and about half way up the positive curve, a line (bias voltage) parallel with the zero line. That voltage is tied together between the cylinders in a switchbox, and between the switchboxes with a jumper. IT IS ALSO MODIFIED BY ANY ADVANCE MODULE OR IDLE STABILIZER MODULE.

Something weird and unexpected is happening. If it were mine, I'd
1. Trash, at least temporarily, the "advance" or "stabilizer" module.
2. Verify that it has a V6 flywheel on it, not an inline.
3. Detail, including actually testing the connections on each end of each wire, All the grounds and mounting screws.
4. Verify that all connections are on the right screws.

Let us know what you find out. This is a real unique one for sure.

John

 

[sschefer]

Re: Stator out of phase... ?????

The stator can go on the engine in any position as all it does is produce the electricity to run the system. It's the trigger that tells the engine when to fire.

Thanks for chiming in Laddies. That's what has me scratching my head.

When your scratching your head like I've been you think of all sorts of weird things.

 

[Dukedog]

Re: Stator out of phase... ?????

Most of tha 9 and 16 amp CDI stuff I've seen only let ya put it in one place anyway cause of tha wire length unless ya strech tha crap outta 'em. Gotta save cost wherever ya can I guess.........

 

[sschefer]

Re: Stator out of phase... ?????

I've put stators on every which-a-way and it doesn't seem to make any difference. Logically, it shouldn't.

Firing is determined by the trigger. Opposite cylinders are fired by the same coil, 1 and 4, for instance. You would expect a trigger problem to manifest on the related cylinders.

The other factor in timing is the bias voltage, generated internally by the switchboxes. Picture the sine wave voltage coming off the stator, a zero voltage line through that pattern, and about half way up the positive curve, a line (bias voltage) parallel with the zero line. That voltage is tied together between the cylinders in a switchbox, and between the switchboxes with a jumper. IT IS ALSO MODIFIED BY ANY ADVANCE MODULE OR IDLE STABILIZER MODULE.

Something weird and unexpected is happening. If it were mine, I'd
1. Trash, at least temporarily, the "advance" or "stabilizer" module.
2. Verify that it has a V6 flywheel on it, not an inline.
3. Detail, including actually testing the connections on each end of each wire, All the grounds and mounting screws.
4. Verify that all connections are on the right screws.

Let us know what you find out. This is a real unique one for sure.

John

Thanks John, It was driving me nuts so I put it on the scope last night and isolated it. I couldn't sleep so why not wake up the neighbors too!

The stator is showing a good clean sine wave and no spike so no cracks in the magnets. The curves on the trigger voltages are nice and smooth the phase separation looks good. I'd have to mechanically time each cylinder and put a indexing wheel on the crank to measure it perfectly. Indexing on .462 puts #1 dead on at 0 deg and using that as my reference the phase separation on the trigger coils are good. That means the flywheel is correct.

By the way, that's an excellent call for someone that's just reading a post. I didn't even consider it until after I had it on the scope.

The switchboxes are all over the map. That means it just the same old common problem of blown bias circuits. Sure glad I've learned enough to time all the cylinders and not just #1

I reason that swapping the blue/red with the blue/w red/w works because the stator is an alternator and there is that phase shift. Theres just enough lag at 300 rpm cranking speed to make it look like its working right and it might even run at idle RPM but it would be steadily advancing as rpm's increased and 3000 rpm would probably put me in at around 50+ degrees if my mental math is correct.

As a side note, the advance module and the warning module are both at the electronics recycling center. I'm running Livorsi EGT's and independent head temp gauges on each bank while I'm setting it up. After it's all broke in and final tuned I'll pull all but one temp sender. I won't be racing this engine so the extra hardware is just to get it dialed in with real numbers rather than guessing with the back of my hand.

EGT's are about the best we can do with these older carb'd engines. Oxy sensors don't work too well when they're covered in raw fuel and oil. Darn, wouldn't that make life easy!

Thanks so much for chiming in. As usuall, you and Laddies were right on track with problem resolution!

The new switchboxes didn't get out of Seattle until this morning. Bill Kelly, (mastertech marine) just called me and said they'd be here tomorrow. This thing may just splash on Monday after all! Bill if you're reading this post.. Thanks so much for making this a priority, you're the best!

 

[j_martin]

Re: Stator out of phase... ?????

Thanks for the response. My next year's tuneup will include a 6 point timing check.

In this age of digital manipulation, the whole bias circuit idea seams like the hard way to do it. Back in the days of analog time generators and relay logic, it was a pretty good idea. (I feel old just knowing what that is.)

Too bad failure usually grenades a power head. Luckily it isn't real common.

John

 

[Laddies]

Re: Stator out of phase... ?????

sschefer, I hope you continued misspelling of my name is through ignorance not a veiled insult as I was only trying to help. As I am not as baffled by some of the BS as some of the other people that post here. Laddies

 

[sschefer]

Re: Stator out of phase... ?????

sschefer, I hope you continued misspelling of my name is through ignorance not a veiled insult as I was only trying to help. As I am not as baffled by some of the BS as some of the other people that post here. Laddies

Easy there Laddies, it was a typo. I appologize, I'm going to edit it right now.. FYI, I was thanking you.

 

[sschefer]

Re: Stator out of phase... ?????

O.K. I was waiting for paint to dry and made a few more phone calls. I don't think this is a new one but the people I talked to had never heard of it. I even ran the tests again just to see if I was out in never never land yesterday but alas... same wierd results.

I guess I'll just put this one in my book and try not to forget it when it happens again.

I guess if nothing else it does show the value in taking a few seconds to check the timing on all cylinders when your tuning up you engine. The service manual says to do it but I don't remember seeing it in the Seloc manual.

 

[sschefer]

Re: Stator out of phase... ?????

Thanks for the response. My next year's tuneup will include a 6 point timing check.

In this age of digital manipulation, the whole bias circuit idea seams like the hard way to do it. Back in the days of analog time generators and relay logic, it was a pretty good idea. (I feel old just knowing what that is.)

Too bad failure usually grenades a power head. Luckily it isn't real common.

John

I agree, I wonder if Brucato has a replacement solution? I should drop them a note and find out. I go over to S/F and see if Tony will respond.

 

[j_martin]

Re: Stator out of phase... ?????

Both CDI and Sierra have replacement switchboxes.

 

[sschefer]

Re: Stator out of phase... ?????

Both CDI and Sierra have replacement switchboxes.

Ohhh.. I misread I didn't realize you were talking quality. I ordered CDI's and have used Mallory's. They're less expensive and I can usually get them faster than Mercs.

 

[sschefer]

Re: Stator out of phase... ?????

Final analysis ----- The new switchboxes arrived this morning and I wired them up. Cranked it over and the results were the same but I did have a much stronger spark. I'll save you all the gorey details of the day's trouble shooting. It was the trigger and there was nothing wrong with it except the id bands were on the wrong sets of wires.

I finally convinced myself to belive what I was seeing and then went online and looked at the picture on CDI's website. I made a phone call and verified that the bands were in fact on the wrong wires.

On the bright side, one switch box was bad and according to CDI and the Merc service manual, they should always be replaced in pairs.

There was some good that came out of all this. It is confirmed that you can put a stator on in any position you want so long as the wiring does not interfere with the flywheel.

Also, indexing your flywheel can be very helpful in at least identifying the existence of a problem. You just have to belive what your seeing to effectively troubleshoot

Yup, I was just a little grumpy around 4:00 this afternoon.. But by suppertime I had it all ready to hose splash tomorrow. If all goes well it will be in the water Monday.

 

[CharlieB]

Re: Stator out of phase... ?????

Is this one of those "Aha!" moments?

Curious,did the scope reveal that the phase (Polarity) of the trigger pulses where reversed?

And this affected the Bias which advanced the timing?

I haven't the opportunity to get my hands on a scope to look but I often suspected that even vs odd bank triggers are opposite phase, but never suspected a phase swap could provoke such havoc with timing.

Good thing you sorted it all out.

Very valuable lesson.