interesting thing going on with my 86

[Spartanzz]

ok so today car ran fine and started fine as i left work got home shut it off and went back to leave and started very sluggish chugged and died. Did this many times. First happened when i went to make sure my timing stayed where i set it so i thought it was because of me shorting the ALDL connector or something so unplugged it and tried to start it and same thing chugged dropped rpm and died. Checked the pressure and shorted the connectors on the relay (as per dons suggestions) and pump runs has a good bit of pressure. Pump runs when relay is fine. BUT, when this happens the fuel pump get louder. The engine almost sounds like it isnt getting fuel when its doing this so yeah...whos got any ideas?

P.S. i had trouble a while back with my AC trying to hold my engine back alot and when i switched relays with the fuel pump relay the pump didn't kick on with the AC relay. Anyone have a FP relay i could use to see if that causing my AC clutch to not engage?

Thanks ahead of time guys!

[Donster]

Is it throwing a code?
If not, disconnect the battery for about 20 seconds and then try again.
 
\D

[jwrape]

Put a fuel pressure gauge on the rail and run the car or try to start and see if you pressure stays constant or close to it. I think it runs right at 40psi, if I remember correctly.

I never trust the fuel pump circuit. Yours might be going out.
Does your Oil Pressure gauge work? You have the secondary circuit that runs through the oil pressure sensor. If the primary fails the secondary will work. Mine runs off the secondary only because the primary burnt up on the ECM board. I also have a switch hot wired into the OBD connector and use it when/if the fuel pump stops. It's done it a couple times. It's like a fail safe for me.
Don't know exactly why they fry but it does sometimes.

Here is what my primary circuit looked like


Here's your Fuel System circuit

[Spartanzz]

no my pressure guage no longer works it did but now just pegs on start up.

[jwrape]

Might be part of the problem. Mine was working part of the time and then stopped, shortly after the gauge stopped I started having issues with the car hesitiating and then stopping and then I could restart it and it would be fine for another 10-15 miles and do it again. It eventually left me stranded at Home Depot (Charlie remembers me calling him for advice that time) and I eventually got it home and found I had no Fuel pressure unless I Hot wired the pump via the OBD plug.
I traced the circuits and found all my relays work and the pump works and the only thing that was bad was my oil pressure sensor and then I smelt a bad smell inside and used my nose to find the circuit burnt in the ECM.
I have another ECM without the circuit burnt but it acts the same now. It initially worked for a day and stopped too. Replace the oil sensor with a new one and the secondary circuit will work again most likely.


I still keep my switch that connects the hot wire on the OBD plug

[Spartanzz]

Ok ill call the advance and see if they have one. Where is that sensor located?

[jwrape]

Ok ill call the advance and see if they have one. Where is that sensor located?

Is your car a GT? or a 4cyl.?

On the GT it's here on the front of the engine


Looks like this

The 4 cylinder version is a Oil Switch

[Fierofool]

The oil pressure sender circuit is a backup for the fuel pump relay.  In the event it should fail, the car will still start and run as long as it has sufficient oil pressure.  You can even unplug the oil pressure sender and the car will still run if the fuel pump relay is still good.  This is a good test for the fuel pump relay.  If you unplug the oil pressure sender and the engine dies, you know the relay is bad. 

I WOULD NOT buy an oil pressure sender from Advance or Autozone or O'Rielley's.  They all sell the BWD brand which are made in Mexico or China.  I have encountered 2 and 3 at a time that were incorrect.  Come over and get my mechanical gauge and install it to find out what your true oil pressure is.  We discussed that Saturday.

Then go to AC Delco or NAPA and get yourself a decent American Made sender, install it and compare the hot idle oil pressures.  You may want to take a photo of the hot idle pressure with the mechanical gauge and the new electronic sender in the event you might get one that's faulty. 

The oil pressure sender stands right under the front of the EGR solenoid where you have the missing hose. I'll give you a call today.  I'll take the mechanical gauge with me to the Gwinnett Mall area and we can get together this afternoon on your way home from work.   

[Robs Fieros]

ok so today car ran fine and started fine as i left work got home shut it off and went back to leave and started very sluggish chugged and died. Did this many times. First happened when i went to make sure my timing stayed where i set it so i thought it was because of me shorting the ALDL connector or something so unplugged it and tried to start it and same thing chugged dropped rpm and died. Checked the pressure and shorted the connectors on the relay (as per dons suggestions) and pump runs has a good bit of pressure. Pump runs when relay is fine. BUT, when this happens the fuel pump get louder. The engine almost sounds like it isnt getting fuel when its doing this so yeah...whos got any ideas?

P.S. i had trouble a while back with my AC trying to hold my engine back alot and when i switched relays with the fuel pump relay the pump didn't kick on with the AC relay. Anyone have a FP relay i could use to see if that causing my AC clutch to not engage?

Thanks ahead of time guys!

Sounds like the vent tube for the fuel pump is stoped up. Take a blower and put it on a compressed air hose and blow the vent tube out. Not into the tank but to the outside. If it can't breathe it will build up a vacuum and decrease the pressure.

[Fierofool]

While I was searching for a picture of the sender, Jason gave you some fine examples.  See the INTROL on the side of the sender?  Those are marketed as BWD, Niehoff, and sometimes even AC Delco, so you need to look at the unit before accepting it.  On the underside, it says Made In Taiwan.

[TopNotch]

The sender used on 88 Fieros is superior to previous years, and you may want to consider using one. You have to replace the electrical connector to do it. I haven't heard of any of the 88 senders being bad, like some of the 84-87 senders are.

[Spartanzz]

Ok cool guys Thanks for all the info! Charlies just give me a call when you can and that would be great if u can lend me that. It started up and ran prefect this morning just felt like it was missing a little more than usual at idle

[Donster]

........... I never trust the fuel pump circuit. Yours might be going out.....
............Mine runs off the secondary only because the primary burnt up on the ECM board.
Don't know exactly why they fry but it does sometimes.

Here is what my primary circuit looked like

It is so funny you mention that.
After the St Patty's Day Cruise, the very next day I wanted to charge the A/C on the Phoenix. Long story short - the exact same components on the ECM fried while I was trying to charge the system. A/C compressor kicked in and the car died. Turns out the PROM was for an automatic non A/C and obviously they don't play well together. Thanks to Charlie who had a spare ECM for a V6 4 speed A/C & cruise, all is well again.
Jason's picture above could actually be a picture of our ECM, they look like they burnt absolutely identical, same circuit, same component!

\D

[Spartanzz]

ok so i got the stuff Charlie dropped off today and didnt get time to swap any out or put the gauge on. So tomorrow ill put the gauge on and see what my oil pressure looks like. And Charlie i know i asked this before but i forgot lol but where does the connector for the mechanical gauge go again? Just found out we are going to have to find a place to live VERY soon and starting to stress out over it so it just slipped my mind with all the crazyness going on.

[Fierofool]

In this picture that Jason posted


Disconnect the harness from the top of the sender.  Use your adjustable wrench to hold the square base where the sender screws in.  At the same time, use an open end wrench to loosen and remove the sender unit.  Once you've removed the sender, screw the brass fitting on the end of the tubing of the mechanical gauge into the square base where the sender was located.  You may want to remove the small fitting from the 1/4 NPT fitting first so that the tubing doesn't twist as you install it.