Driving my 86 F40/Fiero today, when it missed, there was a bang, and then the engine quit. ( 86 2.8 V6) initially had ignition lights, then that went off, and no power to the car anywhere now. I thought I blew the engine, but after towing the car home, jacking it up, and wrenching the crank pulley, the engine turns freely with no abnormal noises. Where do I start?
Links can die from "old age" as water can get at a link for several reasons but have check everything runs off the link before just replace it/them. "Cheap" small DC Amp clamp or "Short Detector" kit makes this a lot faster. get both @ amacon and many others.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I vote fusible link...never had anything like that happen to me in a Fiero but that exact same thing happened to me in my 1984 modified Z-28.....poor engineering on my part allowed a bit of harness to bounce around and it hit my header and the link blew. The car was fine, driving down the road and then a loud pop sound and then car was 100% dead.
Start with the simple things. Only three things are required to start a motor...air, spark, and fuel. I would start with the spark. Do you have power to anything?
...no power to the car anywhere now. Where do I start?
Steve... I would say start with the battery (duh! ), and work your way from there. See if there's power at the battery junction terminal below the C500 connector.
Thanks everyone! In answer to one question: no power anywhere. I have a heavy work schedule, but will repost as I have time to explore this. Thx for the picture, Patrick, not sure where that is exactly, but will look for it. Steve
Ok, a preliminary examination turned up a couple of things. 1) battery and connections fine 2) no visible damage to any of the fusible links ( no burning of the insulation covers anyway) 3) by fiddling around, I got power to the ignition, power windows, but my two auxiliary cooling fans that come on with ignition, didn’t. The fans are powered by a wire that runs into one of the two relays on the driver’s side of the firewall. The three pin connector for this relay is melted. Don’t know what this relay controls, but direct power from the battery runs the fans. 4) with the ignition on, when I try to engage the starter, there is a click, and all power shuts off again. This seems to reset itself after 10 to 15 seconds, and I have ignition again. That is all I had time for today. Comments?
...my two auxiliary cooling fans that come on with ignition, didn’t. The fans are powered by a wire that runs into one of the two relays on the driver’s side of the firewall. The three pin connector for this relay is melted. Don’t know what this relay controls, but direct power from the battery runs the fans.
As an afterthought- I think this relay where the three port connecter plugs into the relay is burnt, is the fuel pump relay. My two engine cooling fans are powered by a wire that connects to one of the three female ports on the connecter. If they don’t come on when the ignition is turned on, it would be reasonable to assume the fuel pump is not being activated by the relay either. Could it be this simple why the engine quit? If this were so, the only confusion would be why it all unpowers, when I try to engage the starter.
Diagnosing electrical issues isn't my strength... but if it was my Fiero, I'd be wanting to know why that relay got so hot that part of it melted. Keep in mind, I hear these cars catch fire!
Thanks, Ogre, now that makes a lot of sense! I did not set this up; it came that way when I bought it. I will look into another power source for the fans. Assuming I acquire a new connector, I will still have to determine if the starter will engage , or that is another problem somewhere else. I will continue to update this as I progress…
I think the Fiero had fantastic wiring from the factory... but I'm starting to wonder if it wouldn't be better for all of us to simply start replacing the harnesses with something newer. Does anyone offer a complete replacement kit for the Fiero's harness? Like through Painless? Specifically... the engine compartment harness, not really concerned about the inside stuff.
Originally posted by 82-T/A [At Work]: Does anyone offer a complete replacement kit for the Fiero's harness?
Isn't simply to make a kit to replace engine section IE 500 Zone alone.
Ignore 84 that's only 84... At minimum you have: 85-86 Duke w/ Auto trans 85-86 Duke w/ manual trans 87-88 Duke w/ Auto trans 87-88 Duke w/ manual trans 85-88 V6 w/ Auto trans 85-88 V6 w/ manual trans
That's with "extra" wiring for AC and other things that car may not have. like owner will "upgrade/downgrade" OP Sender, SI or CS alt, or have extra plugs crossing 87-88 "wall"
Other "odd things" like Think 85 Deck Lid Switch is on 400 zone w/ taillights but later is in 500 zone w/ plug on right side hinge.
Plus many Plugs you can't find from any source.
Not much sense to make many versions for a car that has very limited sales to start and fewer cars now after 30+ years and many don't want or can't afford to buy new 500 Harness. Whatever "Shop" might make a one off harness but you are going to pay Top $ for it.
&*€£#+ I am attempting to install a new connector to replace the burnt one on the fuel pump relay. I have a spare 2.8 complete motor and wiring harnesses. The replacement connector off that motor, has four color coded wires; 3 on the top of the connector to mate up with three in a line pins on the relay- blue, green and purple. The fourth wire is black with white stripe, which I presume is ground , and mates up with the 4th separate pin on the relay. Now here is my dilemma:whichever idiot did a wiring job on the motor in the car eliminated the color coded wires from the factory, and has all manner of red and black wires, that are impossible to identify. I can’t find anywhere that tells me which pins on the relay hook up to which of the three wires on the new connector. From what I can assume, on the connector with the three ports at the top, the left one is power, the middle one is the wire to the fuel pump. For some strange reason, the middle port on my car has two wires; one is the fuel Pump power? And the other one hooks up to the third right port along with a wire there, that was the power wire for the fans that were running off the relay. The presumeably ground wire hooked up on the car to a dead terminal ( also burnt) that was not connected to anything, so I am mystified how ground was established. I HATE normal wiring let alone the mess I am trying to sort out here. Anywhere to establish what ports on the connector hook up to what ? I would think you have to have power, ground, and a power wire to the fuel pump. That leaves one terminal to do what?
Here we go again! I found a wiring diagram with color coding for the relay. The burnt relay is NOT for the fuel pump! My car, and the extra motor, have two relays side by side. One for the fuel pump ( five wire connector) which appears to be in good shape, and the other one with 4 wire connector which is burnt. That is the one I need to figure out. What is this relay for? I do not have an air conditioned car.
Yes, I understand that you only have two relays on the firewall... but I found a couple of posts that state the left side relay (not labeled in the diagram) is for the cooling fan(s).
Just to confuse the issue further...
The difference in locations mentioned for the cooling fan relays might be dependent on the year of the Fiero.
[This message has been edited by Patrick (edited 02-13-2023).]
Thanks, now I have found a diagram identifying the colors of wires coming out of the connector off my spare motor ( it was an air conditioned car) That one was for the A/C compressor. The burnt one on my car has no factory color coded original wires, but appears to have been set up to power the two cooling fans in the engine compartment. They were not working after my problem happened; tracing the power wires from the fans led to this relay. So now, unless that relay is responsible for something else as well, I am back to what the real problem with the car is again!
Originally posted by theogre: Isn't simply to make a kit to replace engine section IE 500 Zone alone.
That's with "extra" wiring for AC and other things that car may not have. like owner will "upgrade/downgrade" OP Sender, SI or CS alt, or have extra plugs crossing 87-88 "wall"
Other "odd things" like Think 85 Deck Lid Switch is on 400 zone w/ taillights but later is in 500 zone w/ plug on right side hinge.
Plus many Plugs you can't find from any source.
Not much sense to make many versions for a car that has very limited sales to start and fewer cars now after 30+ years and many don't want or can't afford to buy new 500 Harness. Whatever "Shop" might make a one off harness but you are going to pay Top $ for it.
I know Ogre... I just really, really want something solid. I've not "hacked" my Fiero wiring, but I know that among other things, the wiring is one of those things which just deteriorates over time... like rubber hoses and bushings.
I've got my Fiero, which I've owned since 1996, and while I've never had any wiring issues, I know that I've been tinkering with the car for years... and I suspect the engine compartment wiring (being that I'm in Florida) is probably barely adequate at this point.
I could build my own, but I just know it wouldn't be the quality that I would come to expect. I rewired my 1973 VW Bus years ago, but that's a 73 VW Bus... like... everything is mechanical, hahah... it was so simple.
[This message has been edited by 82-T/A [At Work] (edited 02-15-2023).]
Dumb question, have you tried and alternate battery? I had this happen on my jeep once, where the battery would be fine until real load was placed on it, then it would shut off.
They sell cartridges for label makers that have heat shrink tubing that you can print on. This is great for labelling a harness with. My Microsquirt I am installing in my 3900 swap has wires that are all labelled with their functions printed on them. I would like to do the same with the factory wiring I retain to make it super easy to locate things without having to trace wires to the C500, C300, or ECU connectors. Especially once they pass through the bullkead it becomes very hard to make sure you are tracing the correct wire.
I don't think it would be hard to produce a generic harness where pins that are unneeded can be depopulated, but the limiting factor here is the various connectors used, sourcing new C203 and C500 connectors, as well as different ECU connectors for the 2.5 vs 2.8.
I have found that failures that I have had in the harness are generally at splices, or at the pins themselves. For example, my C203 pins that powered the ECU were pretty corroded, and those are inside the cabin. Also I had a failure with the 2 wire harness that goes between the ignition control module and the ignition coil in the 2.8, that was easy to rebuild as you can buy both connectors with wire leads from Rockauto and crimp or solder them together. Fierostore sells them too.
I think in general it is worthwhile at some point to pull all the tape and tubing off the harness, inspect the splices and maybe re-do them, as well as check all the pins in the connectors for corrosion and replace them if necessary, I made a new post in tech recently outlining the engine harness connectors and the pins used in them at all the spots, along with wire color and wire gauge. Pins can be ordered for Mouser for less than a buck each, wire can be ordered from "The Wire Barn", go for GXL wire, and you can de-pin and reuse your stock connectors. I have these Wirefy Crimpers plus the open barrel crimp jaws that work with the GM crimps
All in all very low cost, and maybe a weekend worth of work and you can build a brand new harness with very little effort. Can be done in your living room while watching TV. You will want some depinning tools or a selection of picks to release the original pins for the connectors.
[This message has been edited by zkhennings (edited 02-15-2023).]
I have identified the replacement connector as one for the AC. I will test tomorrow what burnt wires from the old connector do ( ground, power, signal, etc) and then splice in the new connector. I will try to fire the car with that hooked up, but suspect that connector and relay has no effect on running the car; just to power the two cooling fans in the engine compartment. If nothing changes except the fans run again, when I turn on the ignition ( as they used to before the connector burned, ) I will have to look elsewhere for my problem. I replaced the ICM a month or so ago, and went through a bad new one before getting one that worked ( Autozone crap, my only option here in Mexico)
I am going to keep asking for input as I describe symptoms as I progress… today I wired in the new connector to the A/C relay, that used to power my two engine compartment cooling fans. With a tester, I have no power on any of the wires going into that, from the harnesses in the car. With no AC in the car anyway, I am assuming all this circuit used to do is run the cooling fans, and that circuit is now redundant. I can rewire the fans from some other source. I am assuming this has nothing to do with my problem starting the car. When I turn the ignition on, I have power to almost everything; windows front cooling fan, lights etc. when I try to engage the starter, there is a click, and then ALL power goes off for the car. Let it sit for a minute or two, and I have power again.. The battery reads 12.6 volts. I got under the car and tested the main power to the starter- good. When I ran a screw driver across to the solenoid terminal, I got a spark, a minimal result out of the starter, and then nothing. AND all power is off again for the whole car. Would I be wrong assuming there is a short in the starter solenoid? This may not be why the engine quit, while driving, but I am going through the steps here, and can’t see if the engine will fire until I get a working starter. Not sure why, after each time I try to engage the starter , I lose all power, and then after a couple of minutes, it comes back on by itself. What is that about? Thankyou for all your suggestions, Steve
Patrick, I will have to try that another day; been at this most of today and am beat. Where would I put the two probes from the multimeter to check this? I did pull out the starter and bench test it. It functions perfectly. Steve
Thanks, Patrick, work is gonna be demanding for the next couple of days. Looking at the junction, it looks like it hasn’t been cleaned since the car was built, along with some of my other connections. I am going to try to clean everything along the path before I do any power checks. First, I have to reinstall the starter; I remember that not being fun trying to line up the holes for the bolts with the shim. I will update this after getting that done.
Patrick, I cleaned both the terminal posts on the connection you have indicated, and their corresponding connection wires. Before trying to engage the starter, with power through the ignition ( all dash lights on) the voltage at the terminal is 11.34 volts. After trying to engage the starter ( which immediately cuts all power off) the reading is still 11.34 volts. I don’t know what that is telling me, except there is still power to that terminal even though the power appears to be off everywhere else ( no dash lights, power windows don’t work, etc. ) The fact that power cuts off immediately after the starter is tried, would indicate a short somewhere in the starter circuit? I have not gone after all the ground straps yet in the engine compartment. Steve
Patrick, I cleaned both the terminal posts on the connection you have indicated, and their corresponding connection wires. Before trying to engage the starter, with power through the ignition ( all dash lights on) the voltage at the terminal is 11.34 volts. After trying to engage the starter ( which immediately cuts all power off) the reading is still 11.34 volts. I don’t know what that is telling me, except there is still power to that terminal even though the power appears to be off everywhere else ( no dash lights, power windows don’t work, etc. ) The fact that power cuts off immediately after the starter is tried, would indicate a short somewhere in the starter circuit? I have not gone after all the ground straps yet in the engine compartment. Steve
Probably less a short, and more a really shitty connection on the battery terminal, or branching from it
If you get 12.6 to ~ 13v at the battery... then get ~ 11.3v at other places...
then yes, likely have crap Grounds and likely power connections/wires too.
You have to start a 1 spot like the battery and engine and clean/fix all grounds, + box under C500, etc. Then do same for other Grounds listed in my Cave, Wire Service
Before try to clean/fix problems w/ I-switch and more delivering power.
⚠️ Careful: Even after clean/fixed all of that, hi amp draw things like HL Bulbs other have ~ 0.5v less when On because have so many switches and other issues causing V-dropping covered in Electric Motors even when was a New Car.
So ~ 11.3 or even less is a problem... you likely never see exact volts at the battery and alt output at other places. Even ECM Data Stream Volts reported by Scanners are different then "battery volts" because has switches, long wire path, etc. to get power to use and read volts.
4 ref: Just the Starter Solenoid draws ~ 30 amps normally before Starter Motors draws 120+ amps on Full Charge Battery. Car w/ iffy Wiring cause Low Volts then Solenoid or both tries to pull more amps and can't get that and just make noise or do nothing. Starter Motor has Big cables to the Battery but the 30 amps to run the Soleniod has a long path thru the I-switch on the S-column.
[This message has been edited by theogre (edited 02-20-2023).]
Thankyou much! Wired, but just fiddling around with all the wires at c500, got the car started. I have no idea why, and don’t trust it until I do more thorough cleaning and checking. A couple of years ago I installed a racing type interrupter battery switch, to cut battery power when not using the car. There was a small battery drain going on before that. I will post final results after going after the ground cables. Thanks to all for the responses! Steve
Originally posted by stevep914: A couple of years ago I installed a racing type interrupter battery switch, to cut battery power when not using the car.
Patrick, I cleaned both the terminal posts on the connection you have indicated, and their corresponding connection wires. Before trying to engage the starter, with power through the ignition ( all dash lights on) the voltage at the terminal is 11.34 volts. After trying to engage the starter ( which immediately cuts all power off) the reading is still 11.34 volts.
I've suspected all along that there's a poor battery or ground connection somewhere (probably on the battery itself), which is why I wanted to know what the reading was off the battery junction terminal... as all power to the car (except for the starter) goes through there. As others have addressed, 11.34 volts is not what it should be.
I understand you've now gotten the car to start (yeah!)... but out of curiosity (and to rule out a "weak" battery), what is the voltage reading directly off the battery terminals?
[This message has been edited by Patrick (edited 02-20-2023).]
Patrick, , I have 12.6 volts at the battery, and 14.5 at the battery when the engine is running. I am going to attack all the ground strap connections before I trust driving the car anywhere. Will continue to update…
Well as I hope, a final on the engine starting and running issue, I went over the ground straps I could find, and because this is a replica, and somebody eliminated some of the factory ground straps, the only one I could find was a big one from the negative battery terminal to a stud on the front of the engine head near the front exhaust manifold. It looked corroded enough I was hesitant to try undoing the nut. Instead, I purchased a new ground cable ( nobody here carries the braided flat ones) and ran it from battery negative, to a threaded empty socket on the block above the water pump. Cleaned everything before the install, and got 12 volts from the block to the connector pins on the terminal below the C500. The engine starts fine , but I have not run the car yet on the road. I figure while I got it up on jackstands, I may as well do a oil and filter change. Is still have to repower my two engine bay cooling fans that used to run from the old air compressor relay. I would still love to have them powered from there, but have no idea which of the three non negative wires on the relay do what. There is a 4 th wire that is obviously ground. Any suggestions here? . The original wire harness that was connected to this is dead from what my testing indicates. I can’t thank you all enough for all the input. The car looks and drives so nice , one tends to forget it is a 38 year old car! Steve
Thanks Patrick, got at this on my day off, and wired the fans into a circuit without the relay. I could not find anything going on with the relay when I tried to put power to it. I fused the line at 20 amps, and there is no heating of the wires. ( they are not large fans) Maybe the relay is why the cooling fans quit in the first place. Took the car out for its usual spin, and everything is working perfectly! Despite all the old car grief, it is worth it for the way this car behaves on the twisty road I take it on. I had a stock Fiero which I drove for awhile, and then stripped it for parts. Night and day between how the two cars behave. My Fiero/Ferrari is 1 and 1/2 feet wider, and runs on 245 tires up front, and 275’s on the back, and drives like it is on rails. Thanks to you, and all who helped me on this. Maybe at some point I will become knowledgeable enough to be able to assist others. Steve
As an afterthought- I think this relay where the three port connecter plugs into the relay is burnt, is the fuel pump relay. My two engine cooling fans are powered by a wire that connects to one of the three female ports on the connecter. If they don’t come on when the ignition is turned on, it would be reasonable to assume the fuel pump is not being activated by the relay either. Could it be this simple why the engine quit? If this were so, the only confusion would be why it all unpowers, when I try to engage the starter.
Am I reading that right, that you (or a previous owner) had the 2 cooling fans connected to the same relay that energizes the fuel pump?
(It all 'unpowered' because you had poor connections that showed to have 12.5 VOLTS but the high resistance connections wouldn't allow enough CURRENT to flow. You can connect 9 AA batteries in series to produce approx 13.5 VOLTS but that doesn't mean they will turn a starter.
The fuel pump relay is fed by a 'hot at all times' orange wire from fuse block (10amp fuse) that transitions to an orange/blk wire at one of the connectors (c-203?) . A good OEM fuel pump probably won't pull but about 6 amps, but those fans have to be included in total current running to and/or thru the relay. They (fans)need to be on their own protected circuit even if you may have gotten by using the power input side of the relay as supply voltage for the fans.
The other thing to remember is that IF the engine is running and IF your oil pressure switch is good, the fuel pump can/will be powered thru the OP switch even if the fuel pump relay fails. But, a major bad connection at battery or at a fusible kink or at the battery junction can prevent the fp from recieving any power.
[This message has been edited by maryjane (edited 02-25-2023).]
), and work your way from there. See if there's power at the battery junction terminal below the C500 connector.
