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Need some help on figuring this out...
72 cutlass, Sniper EFI system, running Hyperspark Dizzy...Been running 100% normal, I cleaned up some headlight wiring and now this...so I obv did something incorrect but tracing my steps I can’t figure it out...
I have brand new ignition switch (just replaced it this AM)
I have had an internally regulated Alt for over a year now, this includes the jumper harness at the solenoid
when i place key into “run” i can see all 12v switch sources turn hot *if* i do not cycle the engine, and just turn key to “off” or “lock” - all 12V switch power goes cold.
when i start the car, once i cycle key to “off” - car stays running, all 12v switched sources shut off as expected (i.e no radio)
I have used a test light while engine still running (when key is “off” and fully removed) and i can see on the alternator that both White and blue wires are hot white is hot 100% of the time - Blue is hot after engine starts and then key is turned to off and removed - stays hot.
I am able to get the motor to stop running by pulling the alternator clip from the housing
If it stops running when you unplug the alternator, the alternator is keeping the EFI powered.
Did you mean to post a link ?
and yes when I unplug this engine will cut off...
White wire is hot 100% of time, when the engine is cranked on and running blue is then hot...after ignition switch turned to “off” this blue wire stays hot
I think yes a bad diode. A diode is a gate that should only allow electricity to flow one way, in this case it would be allowing flow in both directions. Let's see if anyone else chimes in. Alternators aren't complicated if you can get a manual and a volt/ohmmeter.
I think yes a bad diode. A diode is a gate that should only allow electricity to flow one way, in this case it would be allowing flow in both directions. Let's see if anyone else chimes in. Alternators aren't complicated if you can get a manual and a volt/ohmmeter.
Good luck!!!
got ya... as I was mentioning above, if i just cycle the key from off —> run —> off, i can see the blue wire side go cold/hot/cold in that order BUT once i crank the engine, that blue wire stays hot no matter what
Ignition switch replaced before or after the no shut-off situation?
Although I don't think it is a ground problem, are all grounds e.g., headlight, batt to fender, firewall to cylinder head and batt to cylinder head clean and tight?
Ignition switch replaced before or after the no shut-off situation?
Although I don't think it is a ground problem, are all grounds e.g., headlight, batt to fender, firewall to cylinder head and batt to cylinder head clean and tight?
switch replaced AFTER this started
yes i went thru all my grounds, 6 hours worth of time today...
FWIW, after reviewing several forums involving Sniper EFI & engine running after IGN turned off, they all recommend installation of an additional diode on the wire between the alternator & the IGN SW (as suggested above by SugarBear - alternator is feeding the IGN circuit). Apparently, the alternator diode is not sufficient to suppress electricity flowing in one direction along this wire; albeit, the additional diode between the alternator & the IGN SW. I have no idea why/how your issue would all of a sudden manifest itself by simply noodling with the headlight circuit.
Here is one URL link discussing the issue, but there are several other forums involving your issue which are addressed via the additional diode in the ALT>IGN wire. Good Luck.
As Sugar Bear has already made mention, a diode operates as a gate and allows electricity to flow in only one direction. However, a diode must be rated at a value sufficient to suppress electricity from flowing. Additionally, you can add diodes in series to curtail electrical flow.
I wasn’t suggesting there is anything wrong/broken with your alternator or the diode in the alternator; however, it appears from several forums there is additional value added with an additional diode in the ALT>IGN SW circuitry employing the Sniper EFI especially when coupled with the Hyperspark/Solenoid jumper. All-in-all I tend to agree something is feeding the IGN SW circuit off the ALT. I think it might be beneficial for you to follow-up on Sniper ALT wiring scenarios?
The GEN light is blown (evidently) which may be only part & partial of the real issue - the fact the engine doesn’t shut off in the off position. It will be interesting (I guess) to see what happens with a new GEN bulb installed. I believe (if it’s like my 1971 CS) the GEN lamp illuminates when key IGN SW is turned to ON. The GEN light stops illuminating when the engine starts after the ALT is engaged. I wonder if a new GEN bulb will blow (1) when you turn IGN SW to ON, (2) if GEN lamp blows immediately after the engine starts (not simply doesn’t illuminate but actually is blown), or (3) after you turn the IGN SW to OFF & engine continues to run.
Post 17 you said GEN bulb blown since Sniper installed Post 17 you said GEN bulb good? With no GEN bulb engine turns off. More confused. What happens to the GEN bulb if you test the GEN bulb against the scenarios I mentioned (1,2 & 3) Post 16?
EDIT: IOW, does the GEN bulb EVER illuminate and when does it blow?
To clarify what I meant was that bulb was apparently no good since the start of my sniper install and and my sniper was working fine. over the weekend I had the dash apart for other reasons and I replaced the bulb with a new 194 bulb ... the issue of not turning off showed up post install of a fresh 194 bulb
The testing results and the same with a good bulb it never shuts off with a blown bulb it’s the same thing as no bulb and always shuts off.
and yes it will illuminate in the run position with a good bulb and bulb turns off while engine is running... but again the engine will never turn off with the presence of a good bulb or the bulb itself
So further testing ...I have a LED 194 bulb (polarity matters in this one ) and if I use that ...ignition will shut off AND the bulb functions as expected ...
The answer is the LED bulb is a diode: LED = Light Emitting Diode, so current flows only in one direction, whereas an incandescent bulb is a resistor so current can flow in both directions. So your LED bulb is acting the same as installing a diode in series with an incandescent bulb, which is what the info in Matt's link showed.
So, you’re saying a non-LED (diode) bulb in the GEN lamp socket caused the engine to continue running when the IGN SW placed into OFF position. With no bulb in the GEN socket the engine turns off when IGN SW placed into OFF position. Using a LED (diode) bulb allows the GEN bulb to illuminate properly & the engine turns off with IGN SW placed in OFF position.
Baffling, IMO.
All LED lamps operate based upon the correct polarity - in one direction only. Diodes do not operate with reverse polarity although they can be ‘protected’ with integrated reverse polarity (such as your Sniper). It almost begs the question if you actually do have a bad ground, ground fault scenario somewhere in your electrical circuitry. Weirdness. You been changing out other non-LED bulbs with LED bulbs anywhere else? Something seems a muck.
Well, Kenneth beat me to the post and I understand Kenneth is suggesting the LED diode scenario, but IMO I have to call foul play here. The GEN lamp occurs AFTER the IGN SW if I’m not mistaking. Additionally, do we really think a Sniper system is designed to only operate with an LED GEN bulb? I’m not buying it.
I believe the GEN lamp would illuminate properly with a standard 194 bulb and the engine would shut off with the IGN SW in the OFF position if the diode were UPSTREAM between the alternator and the IGN SW. What do you guys think?
So, Holley could save a lot of owner aggravation for GM built cars (as per Matt’s link) if instead of following Sniper’s recommendation the owner simply replaces a non-LED GEN bulb with an LED GEN bulb - effectively installing an additional diode in series by replacing the GEN bulb with LED.
While this is for a MSD box, I would assume the same thing could happen with an EFI system where the timing is controlled.
In the troubleshooting section:
ENGINE RUN-ON
If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is6turned off.
Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag. By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from entering the MSD. Figure 6 shows the proper installation for early Ford and GM vehicles.
Note: Diodes are used to allow voltage to flow only one way. Make sure the Diode is installed facing the proper direction (as shown in Figure 6).
Ford: Install the Diode in-line to the wire going to the “1” terminal.
GM: Install the Diode in-line to the wire going to terminal #4.
GM: 1973 - 1983 with Delcotron Alternators.
GM: Delcotron Alternators use an internal voltage regulator. Install the Diode in-line on the smallest wire exiting the alternator (Figure 7). It is usually a Brown wire.
So, Holley could save a lot of owner aggravation for GM built cars (as per Matt’s link) if instead of following Sniper’s recommendation the owner simply replaces a non-LED GEN bulb with an LED GEN bulb - effectively installing an additional diode in series by replacing the GEN bulb with LED.
bingo ! I’m gonna call Sniper/Holley support on Monday as I’ve called there in the past for other things they seem rather helpful I’m going to make sure they jot this down and run it by the engineers to make sure they approve but they really should get this in their owners manual.
it’s like a similar note if you run a power master mini starter and the potential for needing the in-line diode as well ...it’s in the fine print but at least it’s in there
I don't have anything to offer other than "this has been a fascinating and enlightening thread!" The things to be learned while troubleshooting are myriad!
bingo ! I’m gonna call Sniper/Holley support on Monday as I’ve called there in the past for other things they seem rather helpful I’m going to make sure they jot this down and run it by the engineers to make sure they approve but they really should get this in their owners manual.
it’s like a similar note if you run a power master mini starter and the potential for needing the in-line diode as well ...it’s in the fine print but at least it’s in there
I guess it's too late now, but I would've tried putting the car in run and cranking with a crank trigger jumper, then seen if it would shut off. My reasoning is he replaced the ign switch. But, I guess he fixed it.
