Short inside fuel tank!?! Am I gonna burn up alive? 0_0

TurboSquirrel · 03-18-2010, 08:17 PM

Hopefully someone has seen this before (and survived).

After having the RX-7 sitting on the carport since November I recently found out it wouldn't start. It turns over fine but never builds any fuel pressure (as in zero fuel pressure). Checked both fuel relays and they seem fine. Could not hear pump come on, even when jumpering F/P and GND in diagnostic box.

Well.... I was going through the service manual, testing continuity back at the fuel pump. Could not get continuity on the external pins for the connector that leads into the fuel tank. With the lid off and the pump out of the car I tested the pump and it had continuity across where the two pigtails connect after the come down from the "lid" where that connector with the pins is located. (sorry I don't have a clue what to call these)

Well I decided to unplug the pig tails from the connector on the inside of the lid and here is what I found (see pics):
DSC04845.jpg DSC04846.jpg DSC04848.jpg

I've also attached an image from the service manual showing what the photo's are of.
burned_connector.jpg

I need to replace the lid / connector for sure, but I'd *really* like to know what would cause something like this. I'm running a Supra fuel pump and have done the fuel pump rewire mod (fuse removed from inside block and new 20A fuse inserted into the block near the shock tower under hood). It's been that way (happily) for over 2 years. Only other wiring I had done was to add grounds as recommended in the fuel pump mod (Chuck Westbrook instructions).

Thanks for any ideas you might have!

afgmoto1978 · 03-19-2010, 10:00 AM

Don't know the cause of that, but I'm looking into upgrading the plug with a high gauge wire setup. Unfortunately the one's I found are $100+. Been trying to find a Denso unit that's reasonably priced, but can't seem to find anything.

http://www.pegasusautoracing.com/gro...FUELCELLWIRING

mazdadude7 · 03-19-2010, 04:45 PM

Idk if your cars going to catch fire but if your going to dgrr can you not park next to me? LOL

TurboSquirrel · 03-19-2010, 08:34 PM

Quote:

Originally Posted by mazdadude7

Idk if your cars going to catch fire but if your going to dgrr can you not park next to me? LOL

Lulz, sure thing. Man after seeing that burned / melted connector I'm thinking it would be more of a dramatic fireball explosion myself.

And thanks for that link afgmoto1978, that connector looks pretty similar to the stock one. Would be nice to upgrade the wiring and know it's "fuel safe".

My plan atm is to just get a new "lid thing" with new connector and hope this was a freak occurrence. I just wish I knew how this could have happened to begin with (or when it happened exactly).

Seriously though, no one has seen this before?

My5ABaby · 03-19-2010, 09:24 PM

Gasoline in that situation wouldn't explode. Hope that helps.

TurboSquirrel · 03-20-2010, 12:19 AM

Quote:

Originally Posted by My5ABaby

Gasoline in that situation wouldn't explode. Hope that helps.

Whoa! I used to work with a fireman who would always smoke while he filled up with gas. He said if you could breath it wouldn't ignite.... Not sure I ever wanna test that.

But thanks though for the support! Hehe.

***TitaniumTT*** · 03-20-2010, 01:01 PM

First off, that connector will NOT fit an FC.... trust me, I have it, I hate it, I spend ~$250/ connector for some Mil-Spec hermtically sealed connectors. They have 8 pins I believe? Each contact is rated @ 13A so i'm going to be running two wires per terminal for the pump, and two for the sender.

Also, 20A is too high a fuse rating for that wire. If that's 16ga wire, which I believe it is, it's rated for something like 15 or 17.5A depending on the shielding. Eitherway, I'd drop it down to 15A NOT 20.

TurboSquirrel · 03-20-2010, 08:12 PM

Quote:

Originally Posted by TitaniumTT

Also, 20A is too high a fuse rating for that wire. If that's 16ga wire, which I believe it is, it's rated for something like 15 or 17.5A depending on the shielding. Eitherway, I'd drop it down to 15A NOT 20.

Thanks TitaniumTT.

I thought the stock fuse for the fuel pump (fuse block in driver side footwell) was a 20A. It's hard for me to gauge (no pun intended) the size of that wire just by eyeballing it, but I agree, it's pretty thin looking. I was just following Chuck Westbrook's guide with the choice of fuse.

Regardless, I'm gonna try starting it up tomorrow. Just finished installing a new lid w/ connector I got from David Jerome (that man has saved the day for me many times) and was able to see fuel pressure up to normal.

No explosions so I'm hoping all is well.

***TitaniumTT*** · 03-20-2010, 09:53 PM

What fuel pump are you running?
There needs to be about 2" of clearance between the top of the lid and the bottom of the access panel to use that fuel safe connector.
You should run an amp test at low voltage and high psi if you can to see what the pump is pulling for A and make a decision from there which fuse to use..... for some reason I thought this was an FC. FWIW my Supra pump is pulling like 12A @ 11V and 45-50psi.
For that connector to melt like that, it seems that is the symptom, not the problem, and you need to find the problem. Check the gnds, and don't ask how I know that.

linnadawg · 07-06-2010, 01:41 PM

I see burnt up plugs like that constantly. Its caused by a loose connection as in one of the pins is pulled a little too far back in the connector and not making good contact. The electricity then arcs across like a spark plug gap and starts melting the plug.

bryant · 07-27-2010, 12:58 PM

when i upgraded my fuel system my wires were the same as yours. burnt.
scary.

03-18-2010, 08:17 PM	#1
TurboSquirrel The Newbie Join Date: Feb 2008 Location: Knoxville, TN iTrader: (0) Posts: 19 Rep Power: 0	Short inside fuel tank!?! Am I gonna burn up alive? 0_0 Hopefully someone has seen this before (and survived). After having the RX-7 sitting on the carport since November I recently found out it wouldn't start. It turns over fine but never builds any fuel pressure (as in zero fuel pressure). Checked both fuel relays and they seem fine. Could not hear pump come on, even when jumpering F/P and GND in diagnostic box. Well.... I was going through the service manual, testing continuity back at the fuel pump. Could not get continuity on the external pins for the connector that leads into the fuel tank. With the lid off and the pump out of the car I tested the pump and it had continuity across where the two pigtails connect after the come down from the "lid" where that connector with the pins is located. (sorry I don't have a clue what to call these) Well I decided to unplug the pig tails from the connector on the inside of the lid and here is what I found (see pics): DSC04845.jpg DSC04846.jpg DSC04848.jpg I've also attached an image from the service manual showing what the photo's are of. burned_connector.jpg I need to replace the lid / connector for sure, but I'd really like to know what would cause something like this. I'm running a Supra fuel pump and have done the fuel pump rewire mod (fuse removed from inside block and new 20A fuse inserted into the block near the shock tower under hood). It's been that way (happily) for over 2 years. Only other wiring I had done was to add grounds as recommended in the fuel pump mod (Chuck Westbrook instructions). Thanks for any ideas you might have!

03-19-2010, 09:24 PM	#5
My5ABaby Sigh..... Join Date: Feb 2008 Location: Murfreesboro, TN iTrader: (6) Posts: 2,377 Rep Power: 19	Gasoline in that situation wouldn't explode. Hope that helps. __________________ 1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles Community Service Manual RotorWiki "Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."

03-20-2010, 01:01 PM	#7
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son iTrader: (4) Posts: 4,581 Rep Power: 10	First off, that connector will NOT fit an FC.... trust me, I have it, I hate it, I spend ~$250/ connector for some Mil-Spec hermtically sealed connectors. They have 8 pins I believe? Each contact is rated @ 13A so i'm going to be running two wires per terminal for the pump, and two for the sender. Also, 20A is too high a fuse rating for that wire. If that's 16ga wire, which I believe it is, it's rated for something like 15 or 17.5A depending on the shielding. Eitherway, I'd drop it down to 15A NOT 20. __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

03-20-2010, 09:53 PM	#9
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son iTrader: (4) Posts: 4,581 Rep Power: 10	What fuel pump are you running? There needs to be about 2" of clearance between the top of the lid and the bottom of the access panel to use that fuel safe connector. You should run an amp test at low voltage and high psi if you can to see what the pump is pulling for A and make a decision from there which fuse to use..... for some reason I thought this was an FC. FWIW my Supra pump is pulling like 12A @ 11V and 45-50psi. For that connector to melt like that, it seems that is the symptom, not the problem, and you need to find the problem. Check the gnds, and don't ask how I know that. __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

07-27-2010, 12:58 PM	#11
bryant Rotary Fan in Training Join Date: Feb 2008 Location: Montgomery, Al iTrader: (0) Posts: 31 Rep Power: 0	when i upgraded my fuel system my wires were the same as yours. burnt. scary. __________________ 94T-78 (Want 500WHP)

03-19-2010, 10:00 AM	#2
afgmoto1978 Rotary Fanatic Join Date: Mar 2008 Location: Portland, Oregon iTrader: (2) Posts: 381 Rep Power: 17	Don't know the cause of that, but I'm looking into upgrading the plug with a high gauge wire setup. Unfortunately the one's I found are $100+. Been trying to find a Denso unit that's reasonably priced, but can't seem to find anything. http://www.pegasusautoracing.com/gro...FUELCELLWIRING

03-19-2010, 04:45 PM	#3
mazdadude7 Rotary Fanatic Join Date: Feb 2008 Location: Franklin, NC iTrader: (5) Posts: 410 Rep Power: 17	Idk if your cars going to catch fire but if your going to dgrr can you not park next to me? LOL

07-06-2010, 01:41 PM	#10
linnadawg The Newbie Join Date: Jun 2009 iTrader: (0) Posts: 3 Rep Power: 0	I see burnt up plugs like that constantly. Its caused by a loose connection as in one of the pins is pulled a little too far back in the connector and not making good contact. The electricity then arcs across like a spark plug gap and starts melting the plug.

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