Ok, for the past few days the car has been sitting because it will not crank. I have been to busy to fool with it till this afternoon. I had just changed the fuel pump because it was running very bad and when I went to crank it, nothing. Checked the hoses and no fuel so i started checking relays, all seemed ok. I jumped the fuel pump plug on the passenger fender and the pump still didnt run. Then I pulled the pump and put it straight to battery power and it worked. So then I was stumped and had no more time to work on it till today.I just stuck a screwdriver in the afm to hold the door open and the pump works. What does that mean? Is the afm gone or is there a relay that tells the pump when the afm is open? Thanks for any help. I need to get this car fixed asap, im using my father in laws truck and it loves gas...lol.
Jeremy

 

On page 50-34 of the wiring diagram it shows the AFM controlling the circuit opening relay for the fuel pump... but the pump should work when it is jumpered with the key turned to ON.

 

The pump is supposed to run when the AFM door is open, but will not run with the door closed. That tells you that the circuit opening relay inside the AFM is working.

The other factor in all of this is the fuel pump resistor relay. Have you checked it yet? It's worth a look; there was just someone that posted on here that fixed his fuel delivery problem by replacing the resistor/relay.

 

When you jumpered the fuel pump check connector the pump should have run. All it does is put a gnd on the circuit opening relay. The vane in the afm being pushed aft does exactly the same thing. So it's hard to comprehend why the pump did not run with the jumper in the fuel pump check connector.

There's a second coil in the circuit opening relay that makes the pump run IF the key is HELD to START.

 

Yea Hailers, thats what I thought. I dont understand why it runs with afm open but wont with it jumped. Any ideas? Where exactly is the fuel pump resistor relay...im having problems finding it. I checked the relay under the dash and the volts were off but the ohms were correct...whats that mean....bad relay? Thanks again guys.

 

The fuel pump resistor relay looks like the one in the attached jpg that I stole off this forum.

Did you jumper the wrong plug? It's yellow and has two sockets and is near the boost/pressure sensor area

It's circled in the second jpg I attached, also stolen off this forum.

I don't think it's the fuel pump resistor relay assy since the pump runs when the vane in the afm is pushed aft. In fact there is nothing really wrong with your fuel pump/circuit if the pump ran when the vane was pushed aft and or the pump ran when the key was HELD to START.

Try this. Get on the gnd on near the left front wheel. Reach under there and feel for the small connector on the starter. Pull it off. Now put the ignition switch to START and HOLD it there. Listen for the fuel pump. You should hear it running. If you do, then there is nothing really wrong with the fuel pump/circuit imho.

The fuel pump resistor relay is only on the Turbo cars if you have a series four car. Series five have it on both turbo and non turbo cars

Two actions make the fuel pump work NORMALLY. Key HELD to START makes it run. Engine running and pulling the afm vane aft makes it work.

Key to just ON does NOT make it work.

Is this a stock series four turbo car? or a hybrid car? or what? Harness changed lately?

Fuel pump resistor relay package is just in front of the airfilter and bolted to the bulkhead the right headlight is attached to. Not a problem if you read what I said above.

 

Ok, I did use the correct two prong plug Hailers. Its a na 88 SE and I was thinking the resistor relay was only for the s4 TIIs and the s5s but I wasnt sure. Lets see, the harness was changed I believe with another s4 because the old one was shot. I bought the car running good. The car has been fine until about a month ago and it started bucking and backfiring and I changed the fuel filter and it wouldnt start back up. Ran the day before and the next...nada. There was all sorts of rust in the tank and there was no dam sock on the pump... But if I open the afm vane and hold the key to start the pump runs....should the pump run just by opening the afm vane with the key on without holding it to start? And if I did pull the starter wire and the pump runs then what else could the problem be? Thanks for all the help so far Hailers man.

 

You go to Start. The pump turns on and pressurizes the rail. The engine starts and you let the key return to ON. NOW the air coming thru the afm pulls the vane aft and makes the fuel switch in the afm so the pump keeps running.

In other words, having the key to On and pushing the vane aft just a touch should make the fuel pump work. Usually you only have to push the vane aft about a eighth inch to get the pump to run. Anything further aft and it should stay running.

The jumper not working could be caused by someone messing with the ECU ground wires, either AT the ECU or on top of the engine where the gnds teminate.

Lack of ECU grounds equals no spark or fuel injection.

 

It could be a blown engine with the backfiring etc. Pull the lower sparkplugs. Put a finger over one plug at a time while cranking the engine over. Feel to see if there is a very noticable difference b/t the front and aft sparkplug. When turning the engine over the pressure in the chamber should be trying to blow your finger off as each chamber of that rotor reaches TDC.

I'd do that first. It takes but thirty minutes or so. Remove the EGI fuses prior to turning then engine over so you have no spark.

It could be something totally different, but at least you can get this out of the way right now.

 

Ill do that, but I dont think its blown. The car would backfire and run like crap like I said, but it would only do that after the car warmed up a bit. Until then it was basically fine. Anyway, im gonna go pull the starter wire and see if the pump runs, if it does, then what does that mean. Thanks for all the help so far dude.

 

It only means the fuel pump is working as it should. Nothing more, nothing less.

When you hold the key to ON, the fuel pump starts working. When the engine finally starts, the micro switch in the AFM makes the fuel pump work. In other words you have no fuel pump problem and your prolem is *another thing*.

 

LOL...ok then. Thanks Hailers.

 

I fouled that up. It should read "when you hold the key to START, the fuel pump runs. Once the engine starts, the vane in the afm moves aft and causes the micro switch in the afm to make the fuel pump run.

When you put the key to just ON......the fuel pump does NOT come on. Only holding the key to START will do that or the vane moving aft.

The fuel pump check connector being disabled should have no effect on the pump working or not. Something to fix another day, though.

 

Yea, I knew what ya meant. BTW, if I left that starter plug disconnected, would I then be able to start the car and drive it until I figured out the true nature of the problem?

 

No. Wouldn't start.

 

Ok. Thanks again.