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Hey..1984 c4..Im getting power to distributor through red power wire for an extra 2-3 seconds after key is turned off..This is causing the car to run on for a second or two after i turn car off..Any ideas what is causing the delay??
The only thing I can thinks of off hand with out seeing it is that you have a Capacitor (Radio Noise Filter)or something on an Ignition Hot line and its discharging back to Coil, or the Ignition switch is not turning off completely.
This problem just started a couple weeks ago so its not a filter problem..The strange is this happens mostly when the car is cold..First start up of day..If i start car and immediately shut it down its worse then any other time..Ive changed alternator battery tune up timing tps voltage and replaced every related electrical connector. .Car runs perfectly otherwise. Im at a total loss here..
What u said makes good sense..When cold more fuel is being sent so it would be worse when cold..So now the question would be whats back feeding power to coil..Any suggestions how to figure this out would be very helpful..
How did you determine that the coil is staying Hot, Did you put a volt Meter or Test Light on Red lead and turn off car and you see still see Voltage? As for what to look for was anything added to the car Since Bowling Green. You could start with Pulling Fuse on Radio Just incase a possible Back Feed from Memory Hot Lead Thru Radio due to a Bad Diode it doesn't anything to try.
Just an Extra Thought, Is the Fuel Pump Continuing to run during this delayed shut down. Because I am Wondering if the Fuel Pump Circuit could be Back Feeding some Voltage until Oil presser bleeds off?
Carter i found the problem during my lunch break..My cooling fan was wired direct somehow from the previous owner..Its on all the time.I never worried about it cause the car runs at 187 to 195 in all seasons and im good with that temp.. Any way when i disconnect the plug from fan the problem is gone..Im just gonna install a back feed diode on it..I just gotta find out what specs of diode i need and where to get one..
Thanx for the help..
by any chance do u no about diodes?
There Check Valves for wires after that Nothing. But what you found makes Sense. a Spinning Motor is a Generator. as for just leaving the Fan to run all the time before doing it Put it out there to the Forum it's been a topic I'm sure and there may be a better way Because a full time run can be hard on the fan and the Battery/Charge System.
If you really want manual control of the fan, I'd recommend maybe adding a switch or something to the circuit (use a relay to turn it on/off). Like others have said it is not good for the fan or the electrical system to have it running constantly. At highway speeds it is completely unnecessary.
When you say "run" is it no kidding running at full speed (800 RPM) or is it dieseling?
IF it is the latter it is Carbon buildup in the heads. Higher octane fuel might help.
If it is the former then there has to be a capacitive element somewhere. Do you have an aftermarket radio with an amplifier and cap? IF so and if it was there before this then perhaps there is an internal short between the amplifier on relay and power circuit and it is backfeeding all the way to the ignition.
If not then there is another element with a capacitor that is shorted to IGN. I don't think it is the ignition switch or a short between ign and batt because if that was the case it would not stop. It could theoretically be inside the ECM but I would find that far fetched. IT could also be in the heater or ABS computer. I find that a bit difficult to swallow, but theoretically possible.
Having the fan motor connected to the hot wire for the distributor is a really bad idea! Yes, the "back EMF" from the motor as it coasts to a stop will definitely cause this problem, as the motor acts like a generator at that time! In addition, the large electrical load from the running motor puts that extra current thru the ignition switch and the "A" fusible link, which they were not designed to support! You will be stuck on the side of the road if either one of them decides to fail because of being overloaded.
The original design uses a relay for a very good reason: Relays are designed to control larger currents than you would want to go thru a standard switch. The fan and the relay wiring needs to be returned to its original configuration. If the reason for doing this was to keep the engine at a cooler temperature, a CTS with a lower turn-on temperature is a much better answer. The fan relay and its connector may need to be replaced with a higher current rating for improved reliability.
In the '84, if you want to install a switch on your dash panel to control your fan (which wouldn't be necessary if your fan components are working properly), this can be done without running any wires thru your firewall! The wires are accessible under the dash. This grn/wht wire at C115-7E is the wire that controls the fan relay. Ground that wire and the relay will actuate. You can also use that same wire to illuminate an LED to let you know when the relay has been actuated by the CTS, and the fan is running. My '84 FSM calls this wire grn/blk, but it's grn/wht in my car. For years other than '84, check your FSM!
Thanx for all the input and you are all right. Its 2 degrees here in Jersey so i unplugged the cooling fan this morning for the ride into work..Totally different car..Brighter lights better charging voltage and idle..Never realized running the fan all the time was such a bad thing..Car shuts down perfectly when fan is disconnected. .I was thinking of getting this kit as i do like the car running a bit cooler..190sh..
Again thanx ..You all really helped me out..
Im a CNC machinist of 30years. If i can ever fabricate something for one of you guys please let me know! !
Glad you got it working! Lots of good info up above. Do you have the relay for the fan still? If not I think I might have one I could send your way, I'd have to check (and it would be off an '85 but I don't think there's any difference).
Im a CNC machinist of 30years. If i can ever fabricate something for one of you guys please let me know! !
Hey Bfenty...heres the thing..I bought this 84 about a year ago for 3500$..car was a mess..Guy who had it before me just rigged things as they broke..Im still fixing his mistakes...Ive got the running near perfect..But what he did with the fan im not exactly sure about...the fan has the original connector but somewhere in the wire loom he has it wired in so it turns on soon as u turn key on..The oruginal relay and plug that goes in the relay are not there and the wires were comletely cut away..My idea is to put in an after market fan controller..I do have a 1987 fan relay but at this point i feel the aftermarket would save alot of headaches..What do u think?
I bought this '84 about a year ago for $3500..car was a mess. What do u think?
What do I think? I think $3500 for a messed up '84 is a lot of money! But that's behind us now. I also think you're a talented guy that can figure this out! Another opinion: I think that Summit kit would add to your mess. Sticking that temp probe inside your radiator hose is crude, when there's a perfectly good CTS (coolant temp switch) in your engine. That 30 Amp relay is marginal. The fan motor will load that relay to the max during turn-on. I won't even talk about all that wiring.
It sounds like you do not have a copy of the FSM (Factory Shop Manual). You definitely need these two books! The Electrical Supplement (book #2) is excellent! The CTS for your '84 is located in the RH head, between spark plugs 6 & 8. Installing an ACDelco D1855B CTS would have your fan turning on at about 215, and off at about 200 deg. The fan relay is located on the LH fender panel, below the master cylinder.
I bought this 84 about a year ago for 3500$..car was a mess..Guy who had it before me just rigged things as they broke..Im still fixing his mistakes
I was in a similar situation a few years ago-but it taught me a ton about these cars. I'm still a long way from expert but I've seen a lot of these 'fixes'...lol. It's been a rewarding journey, if sometimes frustrating.
Going back to the issue at hand, I have to agree with Hot Rod Roy. Don't get the aftermarket kit, use the real relay. You can replace the coolant temp sensor as he suggested, and if you want you can easily add a manual on/off switch as addressed earlier (you can leave the computer hooked up to it for automatic AND manual control if you want).
01-30-2019, 08:43 AM
Distributor question
