Fitting a HEI Module in Transistor Ignition Unit 1977 280Z

[Captain Obvious]

30 minutes ago, HusseinHolland said:

So the issue with the ballast was that without the center post, there is no continuity.

Haha! Well THERE'S your problem! 

So about the video of the hunting issue...  You're holding you foot steady and it's doing that rocking back and forth between 2500 and 3K all by itself?

[Zed Head]

Watched the video.  The problem seems ready made for a timing light for a plug wire and a noid light for an injector.  I don't think that "hunt"
 is the right word for the problem.  Sounds like you're losing either ignition (which will also kill injection), or just injection.  You're losing all six cylinders at the same time, not even a sputter.  Seems electrical for sure.

A noid light in parallel with an injector and a timing light on any plug wire, pointing at your face while you sit in the driver's seat, while you do that test should tell you something.

[HusseinHolland]

37 minutes ago, Captain Obvious said:

Haha! Well THERE'S your problem! 

So about the video of the hunting issue...  You're holding you foot steady and it's doing that rocking back and forth between 2500 and 3K all by itself?

That is correct. Since it's not due to the HEI module conversion, the only other obvious thing I had worked on was replacing the fuel lines at the rail. It seems plausible that there is debris in the line(s) that chokes the flow under higher demand. Regulated fuel pressure is good, but that doesn't mean the volume is there. Can't think of anything else I have done that could cause the issue at this point.

[HusseinHolland]

38 minutes ago, Zed Head said:

Watched the video.  The problem seems ready made for a timing light for a plug wire and a noid light for an injector.  I don't think that "hunt"
 is the right word for the problem.  Sounds like you're losing either ignition (which will also kill injection), or just injection.  You're losing all six cylinders at the same time, not even a sputter.  Seems electrical for sure.

A noid light in parallel with an injector and a timing light on any plug wire, pointing at your face while you sit in the driver's seat, while you do that test should tell you something.

When I tested it with a timing light & held the rpm steady at 2500-3K, the timing would surge slightly in time with  rpm drop, but that would seem pretty normal, no?  If there is a flow restriction in the feed side of the rail, that would also do it. I've seen cases where a 'flap' of debris moves & chokes flow under high demand. I'm only thinking of this now because when I pulled the feed hose, there were particles(old hose breaking down, perhaps) in the inlet to the metal feed tube. 

I'll put a noid light on it, to see if the EMS is dropping out , does also seem plausible. Trying to go over systems I have specifically altered in some way that could be the cause.

Edited October 5, 2023 by HusseinHolland

[Zed Head]

Another thought - a dead spot on the AFM wiper.  You might be able to test that by manipulating the throttle by hand until you hit the zone, then moving the vane to see if it goes away.

[EuroDat]

On 10/3/2023 at 2:56 AM, HusseinHolland said:

I ran the motor & used the timing light, leaned over & revved the motor. Timing advances as expected when revved, and sits at approx 8º BTDC at idle.

The motor goes completely flat when revved & held at around 2500-3K. Fuel pressure does not falter, I have a line gauge after the filter. 

I tried reversing the wires from the reluctor, and that had very bad results. It cranked normally for a few revolutions, then turned over very slowly, then not at all. After that, it was completely dead. I thought the battery was drained - I found that cranking like that blew the 125 Amp fuse breaker on the starter cable from the battery. I replaced that, put the wires back & it started again normally. 

I don't understand why the ignition system is creating such an extreme current draw when the reluctor wires are switched.  No one has previously mentioned any issues with reversing the reluctor wires.

I tried another coil, in case that was an issue.

I'm going to put the stock module and coil  back in & confirm whether the issue is with the HEI conversion or not.

re-wired to plug into the modded harness

It's hard to believe a 125amp fuse blows by swapping the reluctor wires, but there must be some relation if that is the only change you made before the fuse blow.

I had similar problems with not revving past 2500rpm. Mine would rev cleanly to 2500rpm and then sputter around 2500rpm. It wasn't a hunt, more erratic running. I'm doing this from memory, since it is some years back.

Like you noticed, I accidently swapped the green and red wires on the HEI terminals when I quickly fittrd it for testing. When I changed them back, the promlem was gone.

 

FUEL:

I don't think you have problems with fuel flow. If that was the case, you would loose fuel pressure. Pressure and fuel are very much related. You can have pressure with a restricted line, but when the injectors open for more fuel, the supply (flow) can't keep up and the pressure will drop. If your pressure is stable, then your fuel delivery is good.

These old ECU's don't read fuel pressure. Bosch (and Hitachi) solved this by creating a constant pressure differential over the injector tip and using a Fuel Pressure Regulator with vacuum assist. Remember fuel pressure will follow the to vacuum in the manifold so I think it will vary a little with this problem. If you add a vacuum gauge next to the fuel gauge, they should work in unison.

IGNITION:

If you are using a 12volt coil then the ballast is not helping. It will reduce the voltage to the coil and cranking voltage is already reduce due to the high current draw from the starter. That was the whole reason for the lower voltage coils. During starting they would bypass the resistor and the coil would get battery voltage to help starting.

Do you know the history of the Volvo coil? Could it be failing? Do you have another coil to test and see if that reacts differently?

I'm still trying to get my head around your 125amp fuse blowing. It can't be going through the HEI. Nothing in the HEI can handle such high current draw. It must be a high labouring starter drawing so much current, but what could be creating such a resistance/load on the starter? Pre-ignition or timing firing way to early. You would think it would cause backfire. The motor is turning?

I hope I'm helping and not adding to your problems.

Chas

[HusseinHolland]

On 10/5/2023 at 3:50 AM, EuroDat said:

It's hard to believe a 125amp fuse blows by swapping the reluctor wires, but there must be some relation if that is the only change you made before the fuse blow.

I had similar problems with not revving past 2500rpm. Mine would rev cleanly to 2500rpm and then sputter around 2500rpm. It wasn't a hunt, more erratic running. I'm doing this from memory, since it is some years back.

Like you noticed, I accidently swapped the green and red wires on the HEI terminals when I quickly fittrd it for testing. When I changed them back, the promlem was gone.

 

FUEL:

I don't think you have problems with fuel flow. If that was the case, you would loose fuel pressure. Pressure and fuel are very much related. You can have pressure with a restricted line, but when the injectors open for more fuel, the supply (flow) can't keep up and the pressure will drop. If your pressure is stable, then your fuel delivery is good.

These old ECU's don't read fuel pressure. Bosch (and Hitachi) solved this by creating a constant pressure differential over the injector tip and using a Fuel Pressure Regulator with vacuum assist. Remember fuel pressure will follow the to vacuum in the manifold so I think it will vary a little with this problem. If you add a vacuum gauge next to the fuel gauge, they should work in unison.

IGNITION:

If you are using a 12volt coil then the ballast is not helping. It will reduce the voltage to the coil and cranking voltage is already reduce due to the high current draw from the starter. That was the whole reason for the lower voltage coils. During starting they would bypass the resistor and the coil would get battery voltage to help starting.

Do you know the history of the Volvo coil? Could it be failing? Do you have another coil to test and see if that reacts differently?

I'm still trying to get my head around your 125amp fuse blowing. It can't be going through the HEI. Nothing in the HEI can handle such high current draw. It must be a high labouring starter drawing so much current, but what could be creating such a resistance/load on the starter? Pre-ignition or timing firing way to early. You would think it would cause backfire. The motor is turning?

I hope I'm helping and not adding to your problems.

Chas

 

Apologies first of all for cluttering your thread with my problems!

I'm still going to remove the rail & flush it. I have had situations where regulated pressure indicated was in range, but volume under demand was not. I'll have to see if I can record line pressure somehow on this system.

Sorry for the confusion with the coils & ballast. I am NOT using the ballast with the HEI setup, that was when I switched back to the stock setup to test.

The coil is relatively new (old stock), however I did try a couple others I have, no change

The 125A breaker is on the starter feed, so the current draw with dwell/timing out must be very high. I can switch it out for a higher rating, but that won't resolve the cause.

I've left this alone for now so I can get the interior /dash reassembled. I've also installed the WBO2 for the AEM controller, so I can see what the AFR's are doing when the symptom manifests.

[Captain Obvious]

Well that 2500-3000 oscillation is really wacky. So you said that you had a timing light on it when that was happening and the light did not drop out, right? The actual timing advance number changed some as the RPM's changed, but other than that, no issues?

And the hunting issue occurs with both the original stock module and the GM HEI?

A test light on the injectors is a good idea. Not sure it'll show anything, but who knows.

What about your changes to the BCDD and the blockoff there. Did it run correctly after you put on blockoff revision 2? Wonder if maybe something in there is flapping around.

And you have that fancy idle controller thing, right? Are you sure it's not screwing something up?

Just tossing out ideas.   

[HusseinHolland]

1 hour ago, Captain Obvious said:

Well that 2500-3000 oscillation is really wacky. So you said that you had a timing light on it when that was happening and the light did not drop out, right? The actual timing advance number changed some as the RPM's changed, but other than that, no issues?

And the hunting issue occurs with both the original stock module and the GM HEI?

A test light on the injectors is a good idea. Not sure it'll show anything, but who knows.

What about your changes to the BCDD and the blockoff there. Did it run correctly after you put on blockoff revision 2? Wonder if maybe something in there is flapping around.

And you have that fancy idle controller thing, right? Are you sure it's not screwing something up?

Just tossing out ideas.   

Thanks for the input, CO.

Yes, timing only fluctuated in conjunction with rpm. 

Yes, either ignition module/setup

I don't see it being related to the BCDD block off, that only caused a high base idle condition, there's nothing in there that could be flapping around.

The CIS system is fully operational - the easy test is to crimp off the feed hose from the low vacuum external side of the tb, and that will negate the IACV, dropping the idle to whatever base value is set at the butterfly & idle compensation (bleed) screw. As soon as the hose is released, if the system is functional, the IACV will surge the idle to around 1200, then settle at the controlled value of approx 850. Turning on the AC raises the idle about 100 rpm, so I'd have to say it's fully operational.

I did all the mods without the dash in place (so no wiring to EMS, etc), so I did not run the engine after each set of mods as I would normally do to function test the work. So, fuel rail hoses, HEI mod, CIS additions, were all done without post-testing each individually. Basically, Murphy's Law has struck me for not following my usual protocol 🤪

I've almost got the dash/console back together, so once that's complete (mostly need to wire the WBO2 controller, so I don't contaminate the LSU9 WBO2 sensor) I will run it again & see what's up. The reason I'm leaning to a restriction is in part due to the fact there were hose particles evident when I removed the lines, and currently the system pressure does not drop off within the usual time frame (typically within a hour), it holds pressure for HOURS. I'm just going over the things I fiddled with to double check my work.

 

 

[EuroDat]

8 hours ago, HusseinHolland said:

Thanks for the input, CO.

Yes, timing only fluctuated in conjunction with rpm. 

Yes, either ignition module/setup

I don't see it being related to the BCDD block off, that only caused a high base idle condition, there's nothing in there that could be flapping around.

The CIS system is fully operational - the easy test is to crimp off the feed hose from the low vacuum external side of the tb, and that will negate the IACV, dropping the idle to whatever base value is set at the butterfly & idle compensation (bleed) screw. As soon as the hose is released, if the system is functional, the IACV will surge the idle to around 1200, then settle at the controlled value of approx 850. Turning on the AC raises the idle about 100 rpm, so I'd have to say it's fully operational.

I did all the mods without the dash in place (so no wiring to EMS, etc), so I did not run the engine after each set of mods as I would normally do to function test the work. So, fuel rail hoses, HEI mod, CIS additions, were all done without post-testing each individually. Basically, Murphy's Law has struck me for not following my usual protocol 🤪

I've almost got the dash/console back together, so once that's complete (mostly need to wire the WBO2 controller, so I don't contaminate the LSU9 WBO2 sensor) I will run it again & see what's up. The reason I'm leaning to a restriction is in part due to the fact there were hose particles evident when I removed the lines, and currently the system pressure does not drop off within the usual time frame (typically within a hour), it holds pressure for HOURS. I'm just going over the things I fiddled with to double check my work.

 

 

When you change multiple things and something goes wrong it will always be a challenge with fault finding.

If this problem wasn't there when I started, I would be changing things back one at a time to try and locate the cause of the problem. The question is: Can you change back or are you past the point of return?

You already swapped the TIU and tried other coils with no improvement so the problem doesn't seem to be related to those units.

I'm interested in the Volvo IACV thingy. I probably should read through the other thread, but I'm feeling a little lazy so I'll just ask. How does the Volvo system know where the idle is? The timing light seems to indicate no issue with spark, but could it be interfering with the ECU and fuel management?

I don't think your problem is fuel delivery. You can have a blockage in the injectors and that will cause fuel starvation. If it's a blockage in the fuel system, then it will be after the fuel guage.

Edited October 7, 2023 by EuroDat
Added fuel delivery

[HusseinHolland]

56 minutes ago, EuroDat said:

When you change multiple things and something goes wrong it will always be a challenge with fault finding.

If this problem wasn't there when I started, I would be changing things back one at a time to try and locate the cause of the problem. The question is: Can you change back or are you past the point of return?

You already swapped the TIU and tried other coils with no improvement so the problem doesn't seem to be related to those units.

I'm interested in the Volvo IACV thingy. I probably should read through the other thread, but I'm feeling a little lazy so I'll just ask. How does the Volvo system know where the idle is? The timing light seems to indicate no issue with spark, but could it be interfering with the ECU and fuel management?

I don't think your problem is fuel delivery. You can have a blockage in the injectors and that will cause fuel starvation. If it's a blockage in the fuel system, then it will be after the fuel guage.

There is an ongoing issue with the HEI setup - I have the stock system in it now, as the last time I switched it back to HEI, I had the no start/slow crank condition return. I assumed the battery was low/ drained from all the start attempts, so I trickled charged it over a day to rejuvenate it, but that wasn't the cause. In any event, I ordered a genuine AC Delco HEI module, so eventually I will swap that out & see what happens. Since it starts/ runs as one would expect with the stock module, I'm leaving ti until the load condition is resolved.

The only system aspect left to revisit is the fuel delivery at the rail, to check the FPR and tubes for any debris. The Volvo system takes the TPS idle signal for base line. The CIS Module uses an ignition pulse taken from the negative side of the coil to know what the engine speed is. If it were somehow interfering with the stock EMS, I would expect it would be across the board, however I can disconnect that wire from the coil to confirm that.

I have the WBO2 controller ready to be connected to the car, just have to wire the power/ground -  that is the main thing delaying the restart / testing at this point, don't want to foul the new WBO2 sensor. Hopefully the rain will stop by Sunday, and I can get back to it.

 

[Captain Obvious]

Well at this point, the next thing I would do is disable the idle controller system. Pull the low side vacuum hose off and plug both resulting holes. And if that doesn't have any effect, I would disconnect the wire from the coil as well and see if that does anything.

I'm not contesting that the system works fine at idle. I'm concerned that it's not working properly ABOVE idle. Breaking out into some sort of oscillation, or switching between it's different modes when it should not be. Something like that.

Again, just tossing out ideas in the hope that you get to the root of the problem.