Pennock's Fiero Forum
  Technical Discussion & Questions - Archive
  Fuel pump won't turn off/red hot manifolds

T H I S   I S   A N   A R C H I V E D   T O P I C
  

Email This Page to Someone! | Printable Version


Fuel pump won't turn off/red hot manifolds by TylerB11
Started on: 01-15-2004 08:47 PM
Replies: 7
Last post by: JazzMan on 01-15-2004 09:47 PM
TylerB11
Member
Posts: 163
From: Birdsboro, PA USA
Registered: Jul 2001


Feedback score: N/A
Leave feedback

Rate this member

Report this Post01-15-2004 08:47 PM Click Here to See the Profile for TylerB11Send a Private Message to TylerB11Direct Link to This Post
Hey guys,

Just tried to start my 85GT in the bitter cold and went and got gas and came home - the fuel pump kept running after i turned it off, and the exhaust manifolds were glowing red.

There doesn't appear to be a blockage in the exhaust - it is flowing pretty well.

I thought maybe it was red from running rich at startup, so I let it heat up, no difference.

any ideas?

------------------

85GT
Coming Soon:
FASTBACK
3800SC

IP: Logged
PFF
System Bot
PURPLE REIGN
Member
Posts: 4080
From: Minnesnowta ------------------ Land of White Gold
Registered: Sep 2002


Feedback score: N/A
Leave feedback





Total ratings: 303
Rate this member

Report this Post01-15-2004 08:57 PM Click Here to See the Profile for PURPLE REIGNSend a Private Message to PURPLE REIGNDirect Link to This Post
It has a bad oil pressure sender. The sender controls signal to the fuel pump & when bad will keep the fuel pump running, & possibly leaking fuel into the cylinders flooding it making the manifolds glow. Pull the fuel pump fuse to get it quit temporarily. Get a new oil pressure sender in it. Sits on the engine adjacent to the battery.

------------------

IP: Logged
TylerB11
Member
Posts: 163
From: Birdsboro, PA USA
Registered: Jul 2001


Feedback score: N/A
Leave feedback

Rate this member

Report this Post01-15-2004 08:59 PM Click Here to See the Profile for TylerB11Send a Private Message to TylerB11Direct Link to This Post
I was thinking that, but wouldn't the regulator send the excess gas back to the tank?
IP: Logged
PURPLE REIGN
Member
Posts: 4080
From: Minnesnowta ------------------ Land of White Gold
Registered: Sep 2002


Feedback score: N/A
Leave feedback





Total ratings: 303
Rate this member

Report this Post01-15-2004 09:13 PM Click Here to See the Profile for PURPLE REIGNSend a Private Message to PURPLE REIGNDirect Link to This Post
Correct..............but it sounds like fuel is leaking either from an injector or the regulator. Unless it has a timing issue when running, but then it would run real bad.
IP: Logged
TylerB11
Member
Posts: 163
From: Birdsboro, PA USA
Registered: Jul 2001


Feedback score: N/A
Leave feedback

Rate this member

Report this Post01-15-2004 09:30 PM Click Here to See the Profile for TylerB11Send a Private Message to TylerB11Direct Link to This Post
where is it located? i heard its down by the AC compressor..
IP: Logged
PURPLE REIGN
Member
Posts: 4080
From: Minnesnowta ------------------ Land of White Gold
Registered: Sep 2002


Feedback score: N/A
Leave feedback





Total ratings: 303
Rate this member

Report this Post01-15-2004 09:36 PM Click Here to See the Profile for PURPLE REIGNSend a Private Message to PURPLE REIGNDirect Link to This Post
Above the A/C compressor, like I was saying, right across from the battery. Take the right grill off and look for a large bell shaped plastic sensor sitting atop a line with a 3 pin connector on top.
IP: Logged
Dropzone
Member
Posts: 185
From: Fayetteville, NC
Registered: Oct 2003


Feedback score: N/A
Leave feedback

Rate this member

Report this Post01-15-2004 09:38 PM Click Here to See the Profile for DropzoneSend a Private Message to DropzoneDirect Link to This Post
On 2.8, it is next to the EGR solenoid, if I'm not mistaken. Sitting vertically, the body looks to have a hex design to put a cresent wrench onto it. Its a big, beafy looking thing.... Should have 3 wires coming from the top (anyone confirm?) When you go to remove it, but another open-end wrench or cresent onto the fitting that the sender is threaded into. You'll need to keep that oil line from twisting as you try to twist it off....

------------------
-jason
'87SE
'90GTZ

IP: Logged
JazzMan
Member
Posts: 18612
From:
Registered: Mar 2003


Feedback score:    (7)
Leave feedback





Total ratings: 653
User Banned

Report this Post01-15-2004 09:47 PM Click Here to See the Profile for JazzManSend a Private Message to JazzManDirect Link to This Post
On V6 cars with A/C the sender is here:

On non-A/C cars the sensor is screwed directly into the block, just above the filter:

Note, this is the '88 sender, it looks slightly different than the previous years but is still in the same location. Do not use a big socket to engage the hex at the top of the sender, that will destroy it. Use the proper size wrench on the fitting next to where it screws into the adapter. Use an adjustable wrench to grip the block that the sender screws into, otherwise you will crack the tube.

To test if the sender is indeed defective, at least as far as the fuel pump circuit goes, just unplug it. If the pump stops, then the sender is bad. The cause of this type of failure is actually a failed fuel pump relay, oddly enough. When the relay fails the parallel circuit in the oil pressure sender will provide power to the fuel pump after a few moments of cranking to get the oil pressure up to trigger level. Since the sender isn't designed to do this duty full time the contacts eventually fail, usually by welding themselves closed.

JazzMan

[This message has been edited by JazzMan (edited 01-15-2004).]

IP: Logged



All times are ET (US)

T H I S   I S   A N   A R C H I V E D   T O P I C
  

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock