Turbo Dodge Forums banner

1985 Shelby Charger problem

9567 Views 18 Replies 5 Participants Last post by  BobD
I just bought a 1985 Shelby Charger. I've owned a 1987 for 5 years, so I am familar with the cars.

Problem: The car wont start. I don't hear the fuel pump primeing (like i can in my other shelby charger). I looked under the hood and it looks like i have a couple of exposed wires coming from the firewall. I dunno if its an electrical problem or the pump is bad. I did replace my fuelpump on my other (1987) Shelby charger. I hope I don't have to do that again ($300 or so bucks!).

What can I do to check if the fuel pump is bad, or the electrical connection to the pump?

Where can I get a wiring diagram for the 1985 Shelby Charger?

Can anyone help?
1 - 19 of 19 Posts
First you have to be sure there are no problems with the ASD Relay(part of the PM on 85-87) or the HEP. When the key is first turned on the controller actuates the ASD for 1 second to turn the pump on and pressurize the fuel rail. After that the controller will not actuate the ASD until it sees a crank signal from the HEP.
The ASD relay provides power to the fuel pump, injectors and + coil.
To actuate the ASD to check for power locate the underhood diagnostic connector and with the key on/engine off ground the DB/YL wire, this will actuate the ASD so you can check for power at the pump, injectors and + coil,if power is not present repair the ASD circuit(s), if all checks well disconnect your ground and while cranking the engine check for power at the + coil, if not present check/repair the HEP circuit.
Also be sure the distributor is turning(broken timing belt)
If all you are missing is fuel and power is present at the pump (spark is present and power is present at the DG/BK wire at the injector harness while cranking) check the ground for the pump, it is external, if power and ground are ok replace the pump.
See less See more
$300 for a fuel pump?!?! :eek: They can be had for less than half that!
Thanks! I'm going to do what you suggested this weekend. I'll let you know how it goes on monday.
I forgot to post the fault codes that I had.

11 No ignition reference signal detected during cranking (bad Hall effect) OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor. See note #8 below.
Note #8
Can cause the engine to stop working entirely with no limp-home mode. Note: An anonymous poster wrote, “Code 11 will only be set upon clearing the codes, most commonly by disconnecting the battery. It says in the factory diagnostic manuals that code 11 means no ignition reference signal has been seen since battery disconnect. As soon as the vehicle's engine is cranked, and a reference signal is seen, code 11 will go away immediately on it's own. It also won't be set upon failure of a part such as a hall-effect pick-up plate, or loss of the timing belt. If no reference signal is seen during cranking after a battery disconnect, code 11 will remain. This is a helpful indicator in a no-start condition.” (Chrysler did sometimes change codes depending on the year, so it may be that some of these apply to differentyears.)

12 Battery or computer recently disconnected (will occur on most cars most of the time, it indicates a low / missing battery happened in the last 50 key starts. Don't worry about it. — Tom Wand)

36 (turbo) Wastegate control circuit open or shorted
36 (3.9/5.2 RWD) solenoid coil circuit (air switching)
36 (Turbo IV) #3 Vent Solenoid open/short
42 Automatic shutdown relay circuit open or shorted
42 Fuel pump relay control circuit
42 Fuel level unit - no change over miles
42 Z1 voltage missing when autoshutdown circuit energized (SEE NOTE #6)
NOTE #6.
The Z1 voltage is the voltage of the circuits fed by the autoshutdown relay. This typically includes fuel pump and switched-battery feed to the ignition coil(s). In my Le Baron, the Z1 circuit leaves the power module and splits into two paths: the fuel pump and the positive side of the ignition coil. Internal to the power module is the auto shutdown relay (in my case, it's a sealed box about 1" by 1"). The output voltage is monitored to determine whether the relay responds correctly. I suspect that the ASD relay (and, therefore, the Z1 circuit) also feeds the fuel injector(s) driver(s) and current sensing circuit, but can't prove this.
I've used the Z1 voltage to test for good power connections to the power module. I connected my OTC 500 multimeter from the battery's positive post to the ignition coil's switched battery terminal and measured the voltage drop using the bar graph to monitor peak voltages. Voltage spikes of around 200 mV to 300 mV are ok -- anything more means tv tuner cleaner time (or replacing the power module). Another thing to check is the maximum voltage drop during the priming pulse. With the old power module, I was losing about 2 volts across the circuit; the replacement is losing about 1/4 volt. (Thanks, Bohdan Bodnar)
Unconfirmed correction: The Z1 Circuit is used to feed the engine computer; if it is lost, the delayed turnoff will not occur, and restarting will not go well. I forget but think it is the engine flair (speed flair up upon starting) that is lost. It also feeds the injectors and solenoids and other relays. (Thanks, Tom Wand)
55 End of codes
See less See more
"ASD Relay(part of the PM on 85-87) or the HEP" what is the "PM"? and the "HEP"? Where can I find them?

Where is the underhood diagnostic connector?
The PM is the Power Module.It is 1/2 of your computer system and it is located under the hood by the battery.
The other 1/2 is the LM, Logic Module and that is located inside the car behind the R/S kick panel.
This setup was used 84-87.
88 everything was moved to 1 controller under the hood(SMEC) Single Module Engine Controller. The PM and LM were combinded into 1 housing with 2 connectors and the ASD relay was moved from the PM to a relay on the left fender.
90 they did away with 2 circuit boards and everything was put on 1 board with 1 connector(SBEC) Single Board Engine Controller.
All of the systems operate the same, just wiring changes.
The HEP(Hall Effect Pickup) is located in the distributor just under the cap.
On MPFI (Multi Port Fuel Injection) vehicles(2.2/2.5L turbo) there are 2 connectors, 1 sends a crank signal to the controller(your code 11) and the other is a fuel sync signal so the controller knows where #1 cylinder is(that would set a code 54)
As I said earlier the controller will not actuate the ASD relay until it sees a crank signal from the HEP so there will be no fuel or spark.
HEP failure is a very common problem on our vehicles but also as I posted be sure the distributor is turning.
Follow the instuctions I posted which will allow you to test the ASD circuit and HEP to determine which circuit is causing the problem.
Let me know what you find and I will help guide you thru diagnostics.
Here is a pic of the diagnostic connector. the same connector is used on all domestic Chrysler fuel injected vehicles from 84-95.

See less See more
The connector is located in the wiring harness near the PM, just follow the wiring back from the controller and you will find it sticking out.
I did everything I was told. The ASD, Coil, and injectors. All okay.

My car is in my garage, with the passanger side close to the wall. So I couldnt find the ground for the fuel pump. Where is it? I have power to 2 of the 3 wires, (the grey wire).

How do I check to see if its a Hall Effect Problem?

yeah 300$ is way out there you can get a walbro for like a 1/3 of that
can you do the key off on off on off on trick to get codes on those cars?
If you have a HEP problem there will not be any power at the + coil while cranking the engine. You also will have no power to the fuel pump or injectors.
The fuel pump and sending unit share the same ground. The wires are seperate then are spliced together and run to a common ground which is somewhere near the left quarter panel.
Yes you can use the key on/off method to retrieve fault codes, just remember that you may have set some codes during diagnostics, so check the codes, clear the codes(be sure they are cleared) and then crank the engine for 10 seconds and recheck.
I have power at the coill.

where is the ground for the fuel pump? Is it the grey wire?
Yes it is the GY wire and it is located in the L/R quarter panel.
Did you clear all the codes and recheck? Wondering why you had a crank signal and ASD code?
whats a " L/R quarter panel"? Passenger Rear or what?

No I havn't cleared the codes and rechecked.
Left side of the vehicle is the drivers side, everything pertaining to left and right on a car is from the drivers perspective sitting in the drivers seat.
Fenders are in the front, Quarter Panels are in the rear.
I just can't understand why you would use left and right. Its all relative. Driver side/passenger side and Front/Rear is understood universally.

btw. i know what quarter panels and fenders are and which are which.
Left and right are used universally in the automotive industry, read any service manual or parts catalog, anything pertaining to one side or the other is listed as left and right.
Just wondering if you ever got the fuel situation figured out.
Does that car have 2 fuel pumps? If so, under the carpet above the location of the fuel pump/pumps if you have 2 pumps, there's a splice in the wires for the two pumps. I've personally had a bad connection there and didn't get enough voltage to the pump to make the car run and I believe to even hear the pump. This was for the external pump. I was told by another L-body guy about this problem. He had fixed his brothers car with the same problem years earlier. I was getting voltage at the pump. Just not enough. The splice is a soldered joint and if it had gotten wet, it could deteriorate. That was my problem. You just need to pull up a corner of the carpet to find the splice. I hooked a hot wire to the splice and heard the pump go.
If you have one pump or have fixed the problem, nevermind.:D
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.