Hi guys..I Haven't been on here for a while.
I'm having some kind of issue with the electrical in my 88 TC.
About a month ago I drove car to work..when I cut car off I noticed fuel pump was still on..this blowed my mind considering that the key to car was out of switch and in my hand.
So I put key back in switch turned switch on and then back off and fuel pump shut off.
That's the only way to get the pump to shut off.
I've also noticed my gauges also acting crazy and car isn't running quite right.
I can have car running(not driving it) and I can run the rpms up to 2000+rpms and the speedo is running around 20-30mph and I'm sitting still.
I've been driving around B4 and watch my temp,oil,and fuel gauge jump up to Max and then come back down within a few minutes.
The speedo also sometimes jumps up when I roll my windows up and down.. pretty much about anything I do inside the car will make the speedo jump up.
I've read that this is a common problem with these cars.
As far as running goes..when I 1st crank car it dies..I might have to crank it twice B4 it starts up and runs without stalling.
It will start but it bucks fusses and complains for alittle bit and then it will smooth out.
That has recently started to..I'm wondering if the electrical problem is causing that too.
Then yesterday I drove car it was doing it's normal thing..then when I pulled into my driveway the car was barely idling at 400-500rpm.
Ive had ignition module issues which I've replaced about 6 of them since I've own car.
I changed the ignition switch..using an on switch..that didn't change anything.
I just don't know what to do anymore.
Any suggestions would be helpful
Thanks
Please explain what you mean by "using an on switch" .
Did you replace this switch?
Yes..that's the switch I replaced
has anyone ever.............
1- fiddled with the fuel pump relay in the trunk to force the pump to run?
2- did a 3g alt upgrade
3- had the instrument cluster out
comment- there is a large resistor on the back of your instrument cluster.
-remove the cluster
-go to lowes and buy a stick of "soap stone". this is what welders use to mark metal. its about 3/16'' thick, about 7/16'' wide and about 5'' long.
-cut soap stone to length of the instrument cluster resistor (big white skinny doo dad bolted to the back).
-inspect the instrument cluster flex print for burn marks or any runs that are busted then repair if needed.
-use a round chainsaw file longways along the soap stone to transfer in a groove that matches somewhat the profile of the skinny resistor.
- loosen up or remove the resistor
-slip the soap stone under the resistor
-tighten down the resistor.
Now all heat generated from the resistor will not make it to our fragile plastic flex print.
this mod cured my son's 5.0L 88 bird erratic gauge issues
in all likelihood, it sounds to me like you may have two separate isolated problems....
Thanks jcassity
No on has messed with the fuel pump relay and if I recall the fuel runs off that black box that looks like a computers mounted to the right side strut tower.
I had had the instrument cluster out.
It had been taken out B4.
The last time I had it out..was about a year or so ago.
I did notice when I had cluster out that there was a black wire coming out of harness that wasn't hooked to anything and I couldn't find a black wire anywhere to reattach
You are right, your fuel pump relay is in the IRCM module on the strut tower. The EEC power relay is also in the IRCM.
There two ways the fuel pump relay should de-energize:
1. The EEC recognizes the engine is not running and removes the ground from the fuel pump relay coil.
2. The EEC power relay de-energizes and removes the power to the fuel pump relay coil.
The EEC power relay should de-energize when you turn the key off.
If fuel pump problem happens all the time, or frequently enough to trouble shoot, try this:
1. Turn the key to RUN but don't start the engine:
2. Does the pump run for 2 seconds then shut off?
3. Probe one of the red wires that go to all the fuel injectors. Should have battery voltage.
4. Turn the key off. After a 5 second delay you should lose the power on the injectors.
If the problem is intermittent, try this sequence several times to see if you can catch the power not shutting off to the injectors.
This would indicate that the EEC power relay is not de-energizing when you turn the key off.
Ok thanks.
When I turn my switch on..the fuel pump runs then shuts off like normal.
There has been a couple of times the fuel pump did turn off when I turned off switch but most of the time it stays on.
Could the ignition module cause some of them issue.
Just wondering because I just recently had to change module..then this happened the same day I changed it
The TFI ignition module does generate the PIP pulse to the EEC to indicate that the engine is running. I guess when electronic things go crazy anything is possible.
Still would like to know if the EEC power relay is dropping power to the injectors when the key is off.
I'll have to check EEC relay this weekend. I'm bout tempted to go get a motorcraft or an accel module and try that just to see what happens. Like I said earlier..I've been through a lot of modules on my car
I would do some trouble shooting before buying parts.
If key off cuts power to the EEC power relay, that should also cut power to the fuel pump relay. No matter what the TFI ignition module is doing.
Voltage from the ignition switch at "home plate Y" to module pin 13 picks the EEC power relay.
EEC power relay contacts closing puts voltage on the fuel pump relay coil and puts voltage on the RED wire on module pin 24. (the same RED wire that's on the injectors)
The EEC puts ground on module pin18 and picks the fuel pump relay.
Fuel pump relay contacts closing puts voltage on module pin 5 and the pink/black wire to the fuel pump.
IRCM module diagram:
Thanks..I wish it was simpler lol.
I did get another module cause I'm tired of this cheaper ones that I've been going through every few months.
I got an accel module.
I do think I've got another issues with the electrical but I'm not the world's smartest at trying to figure out an electric problem.
I've had a problem with some of the electrical anyway.
Like someone has wired something into the fuse panel and burn up one of the fuses in the panel..it's burnt to the point to where it is fused together and I can't get a fuse in it.
I'll try to diagnose the EEC this weekend I hope
Thanks for help
do you have a multimeter and a test light for trouble shooting electrical problems?
Which fuse position is screwed up?
I do have a multimeter..it's digital.
The #17 fuse is the one that's burnt and it had to get hot enough to fuse it together because everything that fuse works does work
I suggest you pick up a test light. They are cheap and have a sharp point probe that you can back probe a connector or push through the wire insulation to check for voltage.
$3.80 at NAPA:
Thanks
I'll check into getting one
So what are you seeing with your new test light?
Well I haven't quite got to that point yet. I've been getting the car to run right..well somewhat right. I bought a new accel module and my car didn't like it. I don't understand unless it was a bad module so I got a replacement in and the car still didn't start right and then it wouldn't start at all. So I put my old module on the car and it fired right up and run as always. I did try something tonight to see what happens. I started the car and let it run for a few minutes and then turned if off and instead of turning switch on and then off to shut off fuel pump..I let fuel pump run until it shut itself off, it took about 30 seconds and fuel pump turn off on its own. So I did the sequence again and after shutting off car the fuel pump ran for about 30seconds again and then shut off. I have done any electrical testing on car yet because of weather but I do plan to. It just puzzles me why the pump runs for 30sec. then turns off.
It's making me wonder if I do have a EEC problem and if I do where would I find one
Do you remember at any point smelling a burning smell around the time the problems started? If a capacitor or something burned out in the ECU you might be able to smell it, like an electrical fire smell. You could also just pull the ECU out and see if any visible damage or shorting has occured, if so that would tell you for sure what the problem is... When mine burned up it left a nasty black streak across it where the cap burned out
Is the IRCM module bolted to the strut tower? I am pretty sure they have to be grounded.
The voltage on the RED/Light Green Stripe wire on the IRCM connector pin 13 should drop to ZERO when you turn the ignition switch off, and the fuel pump should stop.
If the voltage is dropping to ZERO and the pump keeps running, the IRCM is broke. That is if you are in a stock wiring environment.
Is the fuse 17 socket still getting hot?
If the fuse 17 socket was shorted out with something because it was blowing fuses and it got hot enough to melt the fuse socket.
Then the wire from fuse 17 to whatever was causing the overload would have gotten hot enough to melt the wire insulation.
And it could have melted the insulation on adjacent wires in the same cable harness. So you could have some circuits shorted together.
.
I never had any electrical burning smell in car. I did get a reman ECU this year and has to send back because my car wouldn't run at all. The IRCM is mounted on fender well or strut tower. As far as I know the car was all stock, but obviously the guy I bought the car from had alot of issues with it. I don't know if something got hot in the wiring and burnt the fuse panel or if the guy had something wired into it and overloaded it. Ive often wondered about the wiring. I'm constantly going through inginiton modules, my fog lights will cut off and my headlights will turn off if I drive it for 5_10 miles..as long as I don't run the fog lights the lights are fine. My gauge cluster acts funny from time to time. I did do a dash swap in int a couple of years ago and I never noticed any burnt wires when I swapped the dash.
The headlight switch has a built-in circuit breaker. It opens when it gets too hot and closes when it cools off.
The fog lights put additional load on the headlight switch.
Are the headlights and fog lights stock?
If you look at the connector on the HL switch it will probably look like it has been overheating.
A new switch and cable harness plug would be the fix.
Or take the heavy electrical load off the HL switch by installing relays to carry the load.
Thanks. Car has original fog lights and I have sylvania ultra bulbs in it
Not familiar with those bulbs. Don't know if they draw a higher current than stock.
This is a good idea no matter what, it will make the headlights brighter to by eliminating the "bottleneck" of the stock headlight switch, and is also a good fire prevention measure...
Article on installing relays for the headlights and fog lamps:
http://turbotbird.com/techinfo/installing_headlight_relays.htm
Thanks for all yalls help.
I haven't got around to doing much to the car.
Check the wiring going to your dimmer switch. My '84 had issues there and did what your lights are doing. The insulation was breaking down allowing wires to touch and short out.