SOLVED: familiar song...SC sat for years, won't start, running out of ideas

Hey guys....hoping there's someone out there who hasn't lost patience with me on this....

Starting going through the no-start list AGAIN today.

I pulled all the plug wires and checked for spark. Got spark on all.

Then I reconnected the plug wires and checked again with my timing light. Even though I had spark on all wires when disconnected, the timing light isn't getting a signal on wire 1 or wire 3, and on wire 2 it's getting a weird double flash i.e. for every time it should fire on that cylinder it's flashing twice quickly instead of once.
Cylinders 4, 5 and 6 are flashing the timing light normally and consistently.

Does anyone know what that double flash on cylinder 2 means? (and/or why I would get spark on cylinders 1 and 3 with a tester, but then not see any signal with the timing light on those cylinders?)

Thanks

K

p.s. all new Autolite platinum plugs and new wires too.
 
Hey guys....hoping there's someone out there who hasn't lost patience with me on this....

Starting going through the no-start list AGAIN today.

I pulled all the plug wires and checked for spark. Got spark on all.

Then I reconnected the plug wires and checked again with my timing light. Even though I had spark on all wires when disconnected, the timing light isn't getting a signal on wire 1 or wire 3, and on wire 2 it's getting a weird double flash i.e. for every time it should fire on that cylinder it's flashing twice quickly instead of once.
Cylinders 4, 5 and 6 are flashing the timing light normally and consistently.

Does anyone know what that double flash on cylinder 2 means? (and/or why I would get spark on cylinders 1 and 3 with a tester, but then not see any signal with the timing light on those cylinders?)

Thanks

K

p.s. all new Autolite platinum plugs and new wires too.



Update: Changed the coil pack back to the original (after swapping with one from a working XR7). Tested for signal on the wires again and got a steady flash on cylinder 3, nothing on cylinders 1 and 2, and the usual steady flashes on 4, 5 and 6 but at TWICE THE SPEED of cylinder 3.

I thought I read something on another thread about the ECM sending double sparks during the start cycle. Did I imagine that?
 
double flash on cylinder 2 means?.

The SC's distributorless ignition system always fires two cylinders at the same time, known as 'waste spark'. The waste spark fires the opposite direction, going from the shell to the center electrode. The coil is actually 3 coils, two terminals each.

Completely normal, so don't let it confuse you.

nothing on cylinders 1 and 2,

Did you notice the no-start N5 list doesn't say plugs 1 & 2? ...they are on different coils. Strange you'd see that if you're working with the right cylinder/plug numbers.

You've changed coils, plugs, wires and still no joy, so it might be time to move in the no-start check, to N7, I believe, but -not- until you've confirmed N3 & N4, of course.
 
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The SC's distributorless ignition system always fires two cylinders at the same time, known as 'waste spark'. The waste spark fires the opposite direction, going from the shell to the center electrode. The coil is actually 3 coils, two terminals each.

Completely normal, so don't let it confuse you.


Ok thanks, I didn't know that. Seems rather lazy of them to have done it that way.

However, I'm not sure we're talking about the same thing...what I was attempting (poorly) to describe is two pulses on the SAME cylinder/plug wire in quick succession, not two different cylinders firing at the same time. Cylinders 4, 5 and 6 don't do that...they just fire at the same steady rate.

To try and summarize in more detail...this is what I believe is causing my no start problem. It's not fuel, I'm certain.

One bank of cylinders (4, 5, 6) receives a spark normally and as expected (based on my timing light). The other bank gets a spark VERY sporadically, not always on the same cylinder, and when it does it's usually two quick pulses intead of one. The spacing between the double pulses are as expected. Again, inconsistent but re-producable.

It seems to me (and I'm nothing close to an expert) that one half of the coil pack is 'weak' or failing. It's the only coorelation I've found in a LOT of troubleshooting i.e. the pack is divided in two rows the same way that the cylinder banks are. However, I have reproduced these results with two different DIS modules and two different coil packs with at least one of each coming off of a running car. I have a brand new coil pack here, but based on what you've said about how the coils fire, it seems unlikely that it would fire differently from one post than the other.

I'm quite prepared to continue with the detailed tests in the no-start doc, but with inconsistent spark like this it seems pointless....I'm REALLY running out of ideas now.

Question: should I be doing all these tests with the cam sensor disconnected just to rule that out? The ECM has a backup timing table it can use, correct?

K
 
I'm just trying to get you to move on from plugs and wires....you can't diagnose plugs/wires on these cars like you can older models. You can't troubleshoot anything about the SC's ignition system like you can with older models.

You have a new coil, new plugs and new wires, You're done with them. The next steps in that process will help you check the rest of the system. Do that. Don't over think it, don't get hung up.

I'm REALLY running out of ideas now.

That's why we follow factory processes. This isn't about 'ideas'.

Question: should I be doing all these tests with the cam sensor disconnected just to rule that out? The ECM has a backup timing table it can use, correct?
I don't recall that process telling you to do that? You have to stop trying to wrestle with the process, and just do it.

You promised to go thru that process in full, and how you're off on yet another tangent.

Good luck.
 
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I'm just trying to get you to move on from plugs and wires....you can't diagnose plugs/wires on these cars like you can older models. You can't troubleshoot anything about the SC's ignition system like you can with older models.

You have a new coil, new plugs and new wires, You're done with them. The next steps in that process will help you check the rest of the system. Do that. Don't over think it, don't get hung up.



That's why we follow factory processes. This isn't about 'ideas'.


I don't recall that process telling you to do that? You have to stop trying to wrestle with the process, and just do it.

You promised to go thru that process in full, and how you're off on yet another tangent.

Good luck.


Listen, I understand what you are saying, and I agree with you....BUT the no-start list says in STEP TWO to confirm good, CONSISTENT spark on all cylinders and I'm not able to do yet that so I haven't moved on to the next step.

What exactly is it that I'm 'hung up' on besides step two in the checklist? If by 'tangent' you are referring to my question about doing these tests with the cam sensor unplugged, I was simply asking if eliminating the cam sensor and forcing the computer to use it's preset timing was a good idea or not?

I have not installed the new coil, only a used working one. I CAN install the new one if it's the right thing to do but I don't like replacing parts at random just to see if it changes anything.

So if my current methods of validating spark aren't correct, please tell me how to confirm good, properly timed spark and then I'll move on to the rest of the checklist.

K
 
Ok so I've gone through the no-start list and found no issues. Spark on all wires using a spark tester. New plugs. Crank sensor good. Wiring from crank sensor to ecm good. Fuel pressure good. No upshift light while cranking. No codes.

No clue where to go from here. TPS?
 
If you've got spark and fuel pressure, the only thing left is the injectors.

https://www.wikihow.com/Test-Fuel-Injector


I believe it IS the injectors. I had done the starter fluid test before and it made no difference, so I was skeptical about the injectors. But then I realized that when the car isn't running, the valve to the supercharger is OPEN, meaning any starter fluid vapour has to go through the supercharger and intercooler before it reaches the intake. You have to jam the vacuum control for the supercharger open, which closes off the supercharger and sends air straight to the intake. I did this and then the starter fluid test worked.

So five years from now when someone is up against the same problem I am (really old gas clogging the injectors), remember to block open that vacuum control when testing with starter fluid.

Thanks to all who helped!

Kevin
 
Another no start 89SC ..

It's a way too familiar problem lately. My 89SC 5sp ran flawlessly for over ten years and 128,000 miles after the restore. Put on a new crank sensor with the BHJ balancer in 2008 and just drove it.
It sat in a damp driveway under a waterproof cover for two winters ( I did drive it during good weather) and barely started last month so I was just barely able to drive the car up the ramps onto a trailer and get it here to Las Vegas. It acted like it was out of fuel, and at times backfired as if the plug wires were 180 degrees out of phase.... but the exhaust stream was saturated with raw gas. so it does not appear to be a fuel shortage issue.

Cam sensor and DIS are known good units borrowed from another SC, and like you, there appears to be no more inventory of new crank sensors and I've done a diligent search. I am guessing the permanent magnet in the sensor has a detrimental effect on the induction coil in the sensor when left in the magnetic field for a long time. It seems to matter where the shutter wheel stops when you shutdown the engine. If the shutter is blocking the magnetic field from the sensor's coil, then an extended period of engine inactivity does not hurt the life span of the sensor assembly; but if the shutter wheel stop in a position that leaves the coil exposed to the full force of the permanent magnet, then the sensor's coil will slowly lose its ability to generate a clean pulse signal for the ECM and result in this condition. Anyone got another theory we can toss about. I am going to check the sensor output with an oscilloscope to see what the pulse amplitude and width actually looks like and compare it to a running SC system.
dr.dave
BTW// Looking to connect with any SC owners in the Vegas area.

cheers!
 
That's a fascinating point re: leaving it parked with the vane inside the sensor. I'm anxious to see what you find as it sounds like you're experiencing very similar symptoms.

To recap what I've done: After replacing the injectors the car starts, but barely, and will only run if I keep pumping the gas pedal...but if I press the pedal and hold it, the engine will die, as though out of gas.

I've swapped the DIS with the one from my perfectly running '92 but it made no difference.
I've swapped out the crank sensor (twice) and adjusted the gap until it was as close to perfect as I could imagine. Still no change.
I've tried a known good ECU from the same year. No change.
I've tried brand new coil pack. No change.

If this were a carbureted car, I would describe it as: It will only run on gas from the accelerator pump and not from the main jets.

Only other thing worth mentioning is that the tach doesn't work but it DOES receive power when I turn the key (it jumps a little). However, I've done all my testing both with and without the cam sensor connected and it runs the same regardless, so I'm fairly confident that the tach issue is NOT indicating a bad cam sensor because timing from the sensor seems to be the same as the programmed timing in the ECU. The fuel gauge also isn't working so I'm hoping there is a ground issue within the cluster or something. Still....the tach issue is something I was going to pursue for lack of any other ideas.

Really hope there's more people here that have experienced something similar.
 
Only other thing worth mentioning is that the tach doesn't work but it DOES receive power when I turn the key (it jumps a little). However, I've done all my testing both with and without the cam sensor connected and it runs the same regardless, so I'm fairly confident that the tach issue is NOT indicating a bad cam sensor because timing from the sensor seems to be the same as the programmed timing in the ECU.

ACTUALLY ... it sounds more like you've VERIFIED that the cam sensor is bad; because it's the same with and without, which pretty much says it's running without all the time.

RwP
 
ACTUALLY ... it sounds more like you've VERIFIED that the cam sensor is bad; because it's the same with and without, which pretty much says it's running without all the time.

RwP

Thanks Ralph...

I agree with your logic in any other situation, but not with cam sensors on SCs and XR7s. The ECU has a backup timing table in it and it will use that if it's not getting a signal from the cam sensor. The car should run in a reasonable fashion without the cam sensor plugged in. Not at it's best, but it should DEFINITELY idle. Several people have confirmed to me that this is the case with these motors but if I'm missing something, PLEASE set me straight.

K
 
I should add that the only code I am getting now is CID sensor failure (019). However, I have tested with a good DIS and I've changed the crank senor too (no upshift light while cranking either)

If that gives anyone here a clue where I should look next....


p.s. does anyone know of a way to test a crank sensor OFF the car? Is there a resistance test or anything like that?
 
Thanks Ralph...

I agree with your logic in any other situation, but not with cam sensors on SCs and XR7s. The ECU has a backup timing table in it and it will use that if it's not getting a signal from the cam sensor. The car should run in a reasonable fashion without the cam sensor plugged in. Not at it's best, but it should DEFINITELY idle. Several people have confirmed to me that this is the case with these motors but if I'm missing something, PLEASE set me straight.

K


Update: I changed the cam sensor...partly because of the tach thing and partly because Ralph's advice just makes so much sense regardless of whether the car should run without the cam sensor.

The tach works now, so there was DEFINITELY an issue with the old cam sensor. However, the car still won't idle. It starts easier and runs a BIT smoothly, but I still can't hold a steady RPM without it stalling out as though it has no gas. Pumping the pedal keeps it going as long as I want.

So....progress....but still nowhere near right.

Thoughts?
 
Another update:

Reset the ECU and started it again. Still the same...only keeps running if I am constantly pumping the gas....BUT HERE'S SOMETHING I NOTICED THAT MIGHT BE A CLUE.

If I press on the gas, it initially bogs and wants to die, but as soon as I release the pedal it recovers for a second or two and is smooth...but then it sputters and eventually dies if I don't pump it again. So if I keep pumping the pedal quickly in tiny amounts, it will run and run smoothly. I can also rev it as high as I want but it won't stay there no matter how steady my foot is.

The thing that is so surprising to me about this is that when I press down on the pedal it bogs and starts to die but as soon as I lift my foot it recovers briefly and smoothly before sputtering again and stalling. Completely backwards to what you expect.
I also noticed before, when starting it wasn't as easy, that it would often catch and want to run immediately AFTER I released the key. Weird right? But I have reproduced it many times. The split second I would stop cranking, it would catch and try to run.

I keep thinking about vacuum but I've got lots of vacuum on the gauge right up until it dies. It should definitely idle with that much vacuum in my opinion, but by all means tell me I'm wrong!
 
If the vacuum is tight and solid, and absolutely no leaks, I'll bet that the FPR is off, or your injectors are off.

It sounds like there's just not enough fuel coming in. And that the ECU is overcompensating.

Cold, it's not using the O2s, so we can ignore them for right now.

What's your fuel pressure? What shape is the under-body fuel filter in? When's the last time the injectors were pulled and cleaned?

(No, I'm not saying ANY of those are the problem, I'm just armchair troubleshooting at this point.)

RwP
 
If the vacuum is tight and solid, and absolutely no leaks, I'll bet that the FPR is off, or your injectors are off.

It sounds like there's just not enough fuel coming in. And that the ECU is overcompensating.

Cold, it's not using the O2s, so we can ignore them for right now.

What's your fuel pressure? What shape is the under-body fuel filter in? When's the last time the injectors were pulled and cleaned?

(No, I'm not saying ANY of those are the problem, I'm just armchair troubleshooting at this point.)

RwP


Thanks Ralph....

The fuel filter is new, and the injectors are new. It was the injector change that breathed life into it again. Pressure on the rail is 40 pre-start and 35ish while running.

I just did another test and I want to add to my description of having the pump the gas to keep it running....

If the revs are high enough (above 2000) it will rev normally when I press the pedal and very responsive. Anything below 2000 and it bogs before revving.

After that test I started to wonder if there is TOO MUCH fuel and that's why it's bogging and stalling at lower rpm? Is that possible? Does FPR = fuel pressure regulator?

The injectors spray as much as the ECU tells them too, correct? Is there some other system or sensor that could be telling the ECU to spray too much fuel?

It starts on it's own and WANTS to idle now, which is an improvement, but it dies within 5 seconds if I don't pump the gas even though it's trying like hell to hang on. The exhaust smells rich to me BUT I am no expert on that. Lots of moisture on the floor under the mufflers, and both mufflers are equally hot after the test. The cats have already been removed from this one.
 
I just took the fuel regulator off of a donor car that was running a month ago and when I look at the ports on it, it occurs to me that the same gunk in the gas that clogged all the injectors after sitting so long may have messed up the regulator too? Is that plausible? Any way to test a regulator off the car?
 
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