Context: I just purchased my first Fiero, a non-running 85GT that has been sitting for some time(10-15 years). I am a GM apprentice tech and student at a technical school. My knowledge is limited but I can understand car-speak. Electrical diagnosis isn't super foreign to me, either. That being said, I'd like to hear your thoughts on my current situation. After installing a new battery, my friend and I attempted to crank the engine. It siezed up. We removed the spark plugs and attempted to crank the engine, again. It cranked great. Put the spark plugs back in and it was still cranking, however, not starting. After some digging, we found that fuel was not being delivered to the engine. We got inside the car and listened for the fuel pump. We could not hear it priming. We went through diagnosis steps we found on this thread about fuel pumps. We checked the 10A Fuel Pump fuse and it was good, along with the Fuel Pump relay in the engine compartment. I did find a blown 5A V6 Fuel Injection fuse, though I don't know of it's signifigance. I replaced it. Still, nothing from the fuel pump. The only option left that I found was to try and send 12v directly to the fuel pump via the ALDL. I did so with wiring from the battery, and still nothing. We disconnected the line coming off the fuel filter to see if there was any fuel coming out, and there was nothing. And please don't worry; there is gas in the tank.
I wanted to ask if there's anything else to really check before I rip out the tank and replace the fuel pump. I do have a multimeter and can conduct any tests that you guys suggest. I thought about bench testing the fuel pump, but a tech at my dealership did that once and started a fire. Maybe not the best idea. There was mention in the forum I linked saying that there could be a short to ground in the TAN/WHT wire that powers the fuel pump, but I'm not sure the specs to possibly test that wire with once the fuel pump is out. Any advice would be great. I think as soon as I can get the fuel issue figured out, the car will run. When spraying in some starter fluid, it really does go for a bit!
Context: I just purchased my first Fiero, a non-running 85GT that has been sitting for some time(10-15 years). I am a GM apprentice tech and student at a technical school. My knowledge is limited but I can understand car-speak. Electrical diagnosis isn't super foreign to me, either. That being said, I'd like to hear your thoughts on my current situation. After installing a new battery, my friend and I attempted to crank the engine. It siezed up. We removed the spark plugs and attempted to crank the engine, again. It cranked great. Put the spark plugs back in and it was still cranking, however, not starting. After some digging, we found that fuel was not being delivered to the engine. We got inside the car and listened for the fuel pump. We could not hear it priming. We went through diagnosis steps we found on this thread about fuel pumps. We checked the 10A Fuel Pump fuse and it was good, along with the Fuel Pump relay in the engine compartment. I did find a blown 5A V6 Fuel Injection fuse, though I don't know of it's signifigance. I replaced it. Still, nothing from the fuel pump. The only option left that I found was to try and send 12v directly to the fuel pump via the ALDL. I did so with wiring from the battery, and still nothing. We disconnected the line coming off the fuel filter to see if there was any fuel coming out, and there was nothing. And please don't worry; there is gas in the tank.
I wanted to ask if there's anything else to really check before I rip out the tank and replace the fuel pump. I do have a multimeter and can conduct any tests that you guys suggest. I thought about bench testing the fuel pump, but a tech at my dealership did that once and started a fire. Maybe not the best idea. There was mention in the forum I linked saying that there could be a short to ground in the TAN/WHT wire that powers the fuel pump, but I'm not sure the specs to possibly test that wire with once the fuel pump is out. Any advice would be great. I think as soon as I can get the fuel issue figured out, the car will run. When spraying in some starter fluid, it really does go for a bit!
Thank you!
Best thing I would do is to find the wire going directly to the pump, whether that's The output of the relay or whatever, whatever connector is as close as possible to the pump and put 12v directly into it from there, if you hear it, it can be traced to some other electrical issue, if not, it most likely was a mouse that ate the wire, or the pump is somehow clogged/dead. Test with the multimeter on that wire, to make sure it isn't shorted before applying voltage. Sometimes to make it easier, I use a 2s LiPo from an RC car to do testing on stuff like that, smaller then lugging around and wiring up a lead acid battery, less dangerous to, as it is less powerful, only about 8v, could use a 3s LiPo, that would be right around 12v.
85 the connector to the Sending unit harness is located on the forward engine bay bulkhead just below and to the left of the right side Deck lid hinge / spring box. It is a 3 wire connector. test at the vehicle side, if you have power and ground there, then your going to have to drop the tank.
85 the connector to the Sending unit harness is located on the forward engine bay bulkhead just below and to the left of the right side Deck lid hinge / spring box. It is a 3 wire connector. test at the vehicle side, if you have power and ground there, then your going to have to drop the tank.
I will look into that. Any good threads on dropping the fuel tank that you know of?
I will look into that. Any good threads on dropping the fuel tank that you know of?
I don't know any threads off the top of my head, I'm sure someone will post a good thread, I'll be dropping my tank soon too, it's finicky, but should be fairly easy just a lot of little connectors and hoses to disconnect, then wiggle the tank out.
Greetings, jumpmonkey. '85 is right; dropping the tank is not HORRIBLE, just involved. I've dropped mine with the rear of the car off the ground a little. Seems like 6 or 8 inches is enough for the tank to slide out. Remove the nuts from the t-bolts in the tank straps. One 3-wire connector and three or four hoses to disconnect as they expose themselves as the tank is coming down. Easy peasy! You're gonna have a good time with it! Keep us up to date on your progress.
If have a lot of gas, Drain tank by sucking the return line joint near the tank w/o bothering w/ F-pump. Return line w/ added hose will siphon "easy." Don't need to drain all & may help have a couple gallons as weight to help you drop the tank.
Many time you have to loosen or remove all supports the small pipes for Heater to clear the fuel tank & often find other problems... Example: https://www.fiero.nl/forum/Forum2/HTML/146198.html Hidden Fuel and Coolant Leaks...
------------------ 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)
Originally posted by Patrick: Another tip for dropping the tank... Remove the heat shield that's attached with four(?) screws. It'll make access to the hoses a helluva lot easier.
You have to do that depending on year etc just to remove the hoses before removing any tank hardware.
Can be done by loosening 1 or both top screws & remove both lowers so guard swings away from tank. that makes easier to put screws back w/o aiming the guard too to align the holes.
1985 Fiero GT, jelly2m8, CSM842M4, theogre, and Patrick.
Thank you for all the advice on dropping the tank and diagnosing the fuel pump. I removed the tank yesterday and all I can say is YIKES!
The sending unit and pump are disgusting. I still plan on bench testing the pump today to solidify that it isn't running. Then I'll order a new pump, sending unit, and fuel filter. I also have a fuel additive/cleaner leftover from a service I did at the dealership that I'll use.
Those can be easily replaced but there is something that can't be(at least to my knowledge); the tank. It's bad. Very bad. There isn't just surface rust on the inside. There is enough rust that swinging around the tank makes a sound similar to if it were filled with sand. When I poured out the remaining gas, it was brown like river water.
Is there any way to cut the tank in two and clean it? Possibly line it with a coating? The baffle prevents the tank from being cleaned in a normal way. From what I've seen, getting a new tank isn't possible and finding a clean one is difficult.
1985 Fiero GT, jelly2m8, CSM842M4, theogre, and Patrick.
Thank you for all the advice on dropping the tank and diagnosing the fuel pump. I removed the tank yesterday and all I can say is YIKES!
The sending unit and pump are disgusting. I still plan on bench testing the pump today to solidify that it isn't running. Then I'll order a new pump, sending unit, and fuel filter. I also have a fuel additive/cleaner leftover from a service I did at the dealership that I'll use.
Those can be easily replaced but there is something that can't be(at least to my knowledge); the tank. It's bad. Very bad. There isn't just surface rust on the inside. There is enough rust that swinging around the tank makes a sound similar to if it were filled with sand. When I poured out the remaining gas, it was brown like river water.
Is there any way to cut the tank in two and clean it? Possibly line it with a coating? The baffle prevents the tank from being cleaned in a normal way. From what I've seen, getting a new tank isn't possible and finding a clean one is difficult.
Thanks,
Wow, that is disgusting. Generally I think people who clean their gas tanks use chemical cleaners, fill it up with diesel to get rid of the rust, etc, maybe even some light acids. There are new gas tanks being made every so often, but they are usually in batches with a long wait time, Rodney Dickman does or did make new ones. Other option is to try and find a junkyard Fiero, with a better gas tank. Definitely try chemical cleaners first though.
Other option is to try and find a junkyard Fiero, with a better gas tank.
Maybe there are different rules in different jurisdictions... but out here, the wrecking yards puncture the bottom of every gas tank. I guess it's done to fully drain them. Unfortunately, this procedure certainly cuts down on the number of good used gas tanks for any vehicle around here.
Maybe there are different rules in different jurisdictions... but out here, the wrecking yards puncture the bottom of every gas tank. I guess it's done to fully drain them. Unfortunately, this procedure certainly cuts down on the number of good used gas tanks for any vehicle around here.
Interesting, that's unfortunate, I've never visited an actual junkyard, so maybe that's how it's done everywhere, I guess I meant "junk Fiero" not specifically junkyard Fiero, I know someone an hour away from me with 3 or so junk Fieros I can get parts from, so I've never even needed to go to a junkyard!
I found this thread from JohnWPB's build where he cleaned his tank and lined it with fuel tank sealer. I think that be my best bet. It will take some work to get the inside of the tank clean enough to use the sealer, but it would do the job. The sealer even works on the plastic baffle.
I found this thread from JohnWPB's build where he cleaned his tank and lined it with fuel tank sealer. I think that be my best bet. It will take some work to get the inside of the tank clean enough to use the sealer, but it would do the job. The sealer even works on the plastic baffle.
The best way to remove rust from a fuel tank without damaging it is to use the electrolysis method. Google electrolysis rust removal for You Tube videos and instructions. It’s cheap and effective. You may want to do it a couple of times to get all the rust making sure to reposition the tank each time to get the parts you couldn’t get because of the shape of the tank.
After rust removal and rinsing, pour in a couple of quarts (litres) of methylated spirits (denatured spirits) and slosh it around. It will absorb any water left after the rinse process. Use a shop vacuum in reverse to dry the tank before coating. Don’t wait too long to re-coat or it will flash rust. That’s not a deal breaker but the pedantic ones like me prefer to keep rust to a minimum.
After drying, coat the tank. I use Red Kote tank sealer. It’s pricey Down-under but worth every penny. It’s impervious to most petroleum products and ethanol so using anything up to E85 fuel is possible. I’ve used other sealers but ethanol caused them to lift and the rust returned.
For a Fiero tank, you’ll need at least 1 quart of Red Kote. If the tank is likely to have holes or was really rusty, I recommend putting on two coats. It will seal pinholes up to 3mm (1/8”).
I’ve used this method to save motorcycle tanks several times.
Originally posted by Patrick: Maybe there are different rules in different jurisdictions... but out here, the wrecking yards puncture the bottom of every gas tank. I guess it's done to fully drain them. Unfortunately, this procedure certainly cuts down on the number of good used gas tanks for any vehicle around here.
I've never seen a "law" requiring that but many companies will punch fuel tanks & more to drain most fluids to save labor hr.
Some places may have a law/rule requiring that because of so many "junk yard" fires. Near me yards cannot stack cars like old TV show junk yards because of pollution & fires even before the "Green Agenda" got normalized.
They used to stack a lot then sold as 1 piece then that Scrap Co hauls or a lot of time crush & hauls leaving a lot of oils etc. on the ground.
Maybe not the best idea. There was mention in the forum I linked saying that there could be a short to ground in the TAN/WHT wire that powers the fuel pump, but I'm not sure the specs to possibly test that wire with once the fuel pump is out. Any advice would be great. I think as soon as I can get the fuel issue figured out, the car will run. When spraying in some starter fluid, it really does go for a bit!
