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Discussion Starter #1
I bought the car Monday for real cheap. 2000 3.8L manual. I'm in the middle of home renovations, so I haven't spent much time on it.

The PO said it had a dead battery and bad fuel sender. He said it had been sitting for 6 months and hadn't started in 3 months. Judging by how rusted and locked up the brakes were/are, I'd say it's been longer.
At his house, it behaved similarly to my previous Miata with a bad ground, which was fixed with new terminal clamps. Some lights and clicks when the key is put in, and not much changes when the key is turned to ACC or ON. When it was turned to START, everything died. (This was tested just with my good battery. His is bad.)

I had a good battery and I put a cable end repair kit on the negative side.
I got more normal behavior from the chimes and lights. The odometer finally displayed actual numbers. I think I heard the fuel pump running when I turned the key to ON. I didn't try the windows or top. When I turned the key to START, I heard a pop (probably relay), everything died, and the lights/chimes went back to the previous condition until I disconnected the battery. No crank, no start. Again, similar to what a previous car did that had a ground problem, so I'm leaning that direction for now.

I quit at that since I had other things to do. I should probably try jumping the starter to see if that's the, or a, problem. I don't have an owner's manual or wiring diagram yet, so I don't know what fuses/relays do what or where the major ground points are. I also need to buy new electrical tools this weekend.
 

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You will need to make electrical measurements

Your claim of a bad ground cannot be made by just clicks, and lights

High resistence in any circuit can make loads do funny things

We will need a wiring diagram after you measure voltage drop at the starter during crank
 

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Discussion Starter #3
Yes. I need to take electrical measurements and reference a wiring diagram when I have the ability to do so. I haven't spotted an EVTM or wiring diagram online anywhere yet. Barring someone knowing where I can find one, I'll buy a haggard one off eBay and wait for it to arrive. I agree that measuring the starter is a good place to... start.

I apologize if my wording sounded like I had absolutely diagnosed the problem based on some noises which sound like an unwell R2D2 unit. I tried to imply uncertainty by using the words "similar" and "leaning," as well as making a post asking for advice after a few searches turned up nothing relevant.
 

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try bbb industries for a diagram

once you have a meter

measure for voltage drop during crank on both the signal, pos and neg sides of the starter
 

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Discussion Starter #5
There is an owner's manual and a wiring diagram on the way. The owner's manual comes with some other stuff, some of which is wiring related for the PATS. Might help, might not.
I picked up a cheap meter last weekend, so my goal this week is to make a friend so I can read the meter while they turn the key... and help with some renovations at the house.

Other than that, I got the rear windows to go up and down. The driver side mirror works, passenger is dead. The driver power seat works, passenger is manual. Map lights work.
The front windows cause a huge power draw and wouldn't budge. I'm assuming the car has to be running to drop the top.

I noticed the car has two radios. Looks like the original was a split unit and the CD portion is a slave. Apparently the 2001-2004 got a double din trim panel with some buttons below.

That's about it until I can get a helper.

EDIT:
I decided to yank out the radio and factory CD player. None of the original harness was hacked up, which was good to see. There was a harness plugged into the back of the shift bezel. I'll have to figure out what that is.
I had to hook the battery back up to get the exact mileage to get the title transferred, so I decided to check a few more things. The driver window didn't work, but the passenger front window did, slowly. The lights and high beams all came on. I tried to start it, of course, and as soon as the key turned to start, I heard a loud click and everything was dead. I expected that. No crank, same as before.
 

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Discussion Starter #6
I was going to wait until I could get help taking readings, but conditions have changed. All on their own. The car is self healing. It must be a transformer.

Anyways, we've upgraded from no crank no start to crank no start.

Last night I hooked the battery up for some reason and decided to try starting it. It started to crank, barely, and then the starter made a bunch of rapid clicks. I looked up the possibilities and found: bad starter, low battery, and other inadequate electrical connections.

I checked the battery tonight, it was drained some, so I charged it. Then I made an attempt to start it... it cranked a few times, then rapid clicks. I tried twice more with the same results, but less cranking each time. I couldn't find my jumper box to try and help it out a little. (I'm between houses right now, so it might be at the other one.)

So it's cranking now instead of shutting right off. I don't know that I can get it to start given the PO said the fuel sender is bad. Of course, there's always starter fluid. The tank is probably full of manky fuel anyway.
I'll update if there are changes, measurements or progress.
 

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the battery is not the problem

neither is a jumpstart
 

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Discussion Starter #8
I charged the battery up. I grabbed a jumper battery with an air compressor yesterday at Harbor Freight since I can't find my good jump box.

I hooked them both up and the car cranked harder than Jason Statham in that bad action comedy flick.

I can't explain why the car seemed to improve on its own. Maybe the shop cat found a wire to play with and wiggled it just right.

I am going to assume that the problem is fixed, for now, and move on to fuel. The PO said it had a bad fuel sender. I haven't heard the pump run recently, so I'll probably drop the tank this week and see how that looks, then order parts if needed.
 

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i have never seen a mech/elec problem go away on its own

i have seen misdiagnosing claiming a false positive from faulty testing

if you think its just fixed itself, or the cat did, that is fine
 

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Discussion Starter #10
I am beginning to remember why I stopped visiting Mustang forums back with my first car...

Anyway, a friend stopped by on his way home from work to operate the starter fluid can. We got the car to run. I'll be going through the electrical on the fuel system as I find time this week. If that leads me to dropping the tank, so be it. I'll post the results of that, in case this comes up in someone's search.

At least is starts now. I still have no idea why the relay would shut the car off on start, or why it stopped. If the problem returns, I'll post my findings.
 

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you remember?

were you given advice that was helpful, but required work and knowledge, and you didn't want to put the effort in?

to be consistent, more help from me,,,,,,,,try to stay away from starting fluid

it can self ignite easily, masking a possible not spark

if you think you have a no fuel, can you hear or measure amp draw from the pump?

have you thought of actually measuring the voltage to loads?

as I advised in the first reply? you have the meter, and diagram, no?
 

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Discussion Starter #12
As stated previously: Yes, I have a meter. No, the diagram has not arrived yet.

Also previously stated: I thought I heard the fuel pump run the first time I turned the key at home, but have not heard it since.

I have tested what I have been able to test by myself. When I finally got help, some of the problems that I needed to test were no longer manifesting. I cannot test something that is not currently (pun intended, because you've missed my previous jokes and sarcasm) going wrong. Yes, I have considered testing things, and have done what I could. I have looked up (elsewhere) more fuel specific things to test and said I would be doing that when I have time this week.


Yes, you gave advice that I already said I needed to try when I had the tools/help. Aside from parroting me, you've mostly said that I made claims that I never made and low key called me stupid, lazy and incompetent.
 

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I am going to disregard all your comments, pertaining to your whining


when you get the diagram, post that you have it, then i will show you how to diagnose

i am not going to hold your hand

you want to work on your own car, there are many competent shops out there, you have to learn how it works
 

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Discussion Starter #14
My whining? Dude, you're a trip.

I tested for voltage at the fuel pump fuse, and also at the connector leading to the fuel sender, multiple times. There was 2V at most on two of the pins once. The other times I checked it was less than half a volt, and same story at the fuse. I'll have to sit down and see what each wire goes to and figure out what the readings should be. I can hear the starer relay click when the key is turned to on. (I hear three separate clicks, the other two for other relays I assume.) The wiring diagram arrived, still waiting on the owner's manual. According to the wiring diagram, the fuel pump relay is part of a larger control module and it's under the passenger side fender.

Some of the odd behavior it originally displayed returned for a moment after leaving the key in the on position while I took measurements. No surprise there. I'm going to try and find time to get the battery tested this week, just to make sure it's still good. That will be a good time to dispose of the bad one that was in the car when I bought it.
 

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You got 2 volts at the pump in crank?, run?, what?
 

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Discussion Starter #16
ON position. (Accessory > Off > On > Start) My wing span and number of appendages don't allow me to hold the key in start and simultaneously test a connector behind the gas tank.

I went through all the pages relevant to the fuel pump last night, away from the car. The specific connector (C420) doesn't have diagrams of its own, and the system in general doesn't have testing data in the manual like other circuits have. I'll have to make notes on the wire colors and positions tonight, and find the other relevant connector (C451, I think) to do the same. I keep forgetting the main relay module acronym (CCRM maybe) that's under the fender, but I'll see what wires are bundled in that loom and identify them as well.

Owner's manual came in yesterday, but that's redundant at this point, for this problem.
Life is going to be super hectic through the end of the month with mandatory volunteer work, as if that wasn't killing my time already. Hopefully I can get someone to help after that.
 

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ON position. (Accessory > Off > On > Start) My wing span and number of appendages don't allow me to hold the key in start and simultaneously test a connector behind the gas


that ain’t an excuse

rig up jumper leads that extend to your meter sitting in view

they make wire
 

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Discussion Starter #18
Or I can wait until someone lends me a hand. It's a far more efficient use of my time, and at least one of the pins should be getting 12V with the key in the ON position, so it looks like I have a problem upstream of that connector anyway.
 

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Or I can wait until someone lends me a hand. It's a far more efficient use of my time, and at least one of the pins should be getting 12V with the key in the ON position, so it looks like I have a problem upstream of that connector anyway.
In crank, pump power only happens with the proper rpm signal to the eec

In run, same thing

You can get tricked
 

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Discussion Starter #20
Alright, for connector 420 (C420), I'll come up with an arbitrary number assignment for the pins:
4321
8765

1 YE/WH - Instrument cluster 19 fuel gauge from thermistor
2 RD/BK - pump motor, Fuel Pump Driver Module 3
3 BN/PK - pump motor, Fuel Pump Driver Module 10
4 BK/OG - from thermistor to ground
5 RD/PK - PCM 62 Fuel Tank Pressure Transducer,
6 GY/RD - to PCM 91 signal return
7 BN/WH - from PCM 90 reference voltage VREF
8 empty/unused

I got partial voltage readings from 1 & 5. The low fuel CEL came on after I unplugged connector 420, so that circuit seems to be working.

1 & 4 run through a thermistor. These are probably the least relevant. 1 had some voltage and if 4 is just going to ground, then it makes sense that it had no reading.

2 & 3 run through the pump, shield is grounded at G400. The diagram conflicts itself for the Fuel Pump Driver Module. The convertible page has it located same as the coupe, "underside of luggage compartment." The coupe page references a convertible page and location that call out the Inertia Fuel Shutoff Switch.

6 & 7 go through a potentiometer, and 5 is also connected. All these are directly to/from the PCM.



I might be able to get the battery tested tomorrow. We'll see how the day goes.
 
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