I fixed all my vaccuum leaks on my 10th AE, but the car will still only run for a few seconds and shut off. Once you restart it, it does the same thing, but starting is still easy and quick. Im thinking it could be a problem with my AFM. Is there anyway to test the AFM? Should I try unpluging it and starting it to see if it does the same thing? The car has fuel, and everything. I also noticed that the Air Bypass Solenoid is not plugged in. The vaccum lines are hooked up, but the plug is not connected. Could this be causing my problem also? Where do you plug in the Air Bypass Solenoid? I looked, but cant find an open plug. Thanks for your help.

RoninRX7

 

If your Turbo Inlet Duct (TID) is cracked where it clamps to the turbo, enough air could be going in through the crack rather the AFM, it wouldn't open it enough to keep the fuel pump running. To test this, jumper the connector right near the AFM, this keeps the pump running.

Vince

 

Ok ill try that. What about the Air Bypass Solenoid next to the intercooler not being plugged in? Where does that thing plug in, and what would it do if it wasn't hooked up? Thanks

RoninRX7

 

It will not cause your car to not run.(having it unhooked) the abs solenoid

 

I just got my jspec in, and its doing the same thing. When it starts i cant rev it to keep it alive if the AFM is plugged up. But if i unplug the AFM the car lets me keep it alive.

I think the motor had a minor street port done to it, and a SAFC was installed, i can see the spliced wires. If i remember correctly when i installed my SAFC i cut the AFM wire so thats probably why the ecu isnt adding fuel to the air.

 

Where is the plug for the Air Bypass Solenoid go to? I've been looking for it, but cant seem to find a free plug.

 

Ok, today I tested the AFM, as per the specs in the S4 FSM, and it checks out just fine. I also checked out that Air Bypass solenoid, and it is working properly, and also i think i found the correct plug for it too. Its tied together with another plug at the back side of the UIM. Does anyone know the specific wire colors that the other connector should have? Im not sure if i hooked it up right, but its plugged in.
I also had a boost leak tester that i made from my talon that i hooked up and pressurized the whole intake tract. I found out there is a substantial leak some where under the intercooler. Im thinking its at the TB, but the elbow is on as tight as I can get it. I think this could be part of the issue, because it wont hold more than 4 PSI and it will all leak out in a few seconds.
What else could it be if the AFM is working propperly, and the plug wires are correct, and so is the rest of the ignition. It has to be something with the fuel. I know the fuel pump is running, but im not sure if it stays running. Is there anyway to hot wire it so that it stays constantly running? If so, where do i hook up the wires and where is the fuel pump relay on this thing? Thanks guys for all your help.

RoninRX7

 

bump, any clues? Hey just out of curiosity, where is the fuel pump relay located at? Does anyone have a good pic of its location?

 

It is located underneath the stock air box right behind the passenger side headlight.

 

The resistor relay under the airbox has nothing to do with the AFM.

The circuit opening relay under the dash beside the steering column is switched on and off by the airflow switch in the AFM. A loose connection in the AFM might cause intermittant fuel pump power problems. Connecting a DMM to the fuel pump plug and watching it while driving would show you if this was the case.

See page 50-34 of the FSM wiring diagrams.

 

Do you think that could possibly be it? I know the pump is switching on from the ECU at startup, but im thinking that after it switches from cranking to run, it shuts off and starves of fuel? Am i on the right track at all?

 

The wiring diagram shows you how it's all related. The the circuit opening relay is closed by either a start signal form the key or an aiflow signal from the AFM. Without either of the these the fuel pump is switched off. Check the circuit opening relay to make sure it's working properly. It's mounted near the steering coloum and has a black body, yellow base and white plug.

 

Its probably not your AFM:

Adjust your TPS. I think you can get it close if you remove the thermowax between the throttle bodies and the firefall.

Keep checkin for AIR LEAKS!!

 

No, it does not have anything to do with the AFM, but if it is not working the fuel injectors will not supply any fuel to the motor.
During the start up of your car there are 3 points(relays) that the signal must go through. The relay that NZ Convertible mentioned that is located on the right side of the steering column under the dash. The main curcuit relay which is located on the drivers side fender well between the trailing coil and the clutch master cylinder. Then there is the AFM. all three must be in working order for your car to fire up.

If your ground wire for the fuel injection system is not good then your injector relay that I spoke about in my earlier post will not fire the injectors. I went through this experience with my car before. The ground wire is located underneath the tmic bracket. If I recall correctly it is bolted to the intermediate iron. I would start there if you have had no luck with the AFM.

Grounding is known to be an issue with our cars. There are several write ups about it in this section. If you search you can find the threads quite easily.

Nolan

 

I would think if it is a bad ground, it wouldn't even start. At least, that was the symptom with my car. It was backfeeding power through the grounds at the ecu.

 

My problem was intermitant with my car. It would work sometimes and others it would not. You would have to have a huge vacuum leak for it to behave in the manor it is.

 

YOU said there was a substantial leak under the intake manifold. Fix it. Probably fuel injector gormmets.

The fuel pump check connector is yellow in color with a piece of black shrink tubing around it. Located near the boost sensor. It has two sockets. Jumper them. With the key to ON, the fuel pump will run constantly in this configuration.

The leak could also be another thing. Find out what.

 

YOU said there was a substantial leak under the intake manifold. Fix it. Probably fuel injector gormmets.

The fuel pump check connector is yellow in color with a piece of black shrink tubing around it. Located near the boost sensor. It has two sockets. Jumper them. With the key to ON, the fuel pump will run constantly in this configuration.

Air Bypass Solenoid only works for 17 seconds upon a COLD engine start. Engine temp b/t 55F and 95 F or figures close to that.

Thats the airsupply valve on the back of the throttle body with the harness wires to it and the Air Bypass Valve intertwined. See the online wiring diagram for wire colors. One wire is black/white and the other is in the FSM.

IN my humble opiinion the engine runs for only a few seconds because upon starting the fuel mixture is rich and a few moments later goes leaner. The leaner mixture combined with the air leak is causing the engine to terminate.
The leak could also be another thing. Find out what.

 

This is what the plate behind the passenger side headlight has on it.



So which one is the fuel pump relay? Thanks. I think i found the fuel pump checker, is it this thing i circled?

 

Untrue. That relay doesn't switch the pump on and off, it simply switches the resistor in and out of parallel, and it's wired to be fail-safe. If it fails the fuel pump will get full voltage all the time rather than reduced voltage at low load.

The relay (on the left) controls the resistor (on the right). They control the voltage sent to the pump and hence it's speed. as I described above. This will not be causing your problem. The circuit opening relay under the dash is what turns the pump on and off. Like I said, see page 50-34 of the FSM wiring diagrams.

Corrrect.

 

I think that im gonna try to jumper the fuel pump check thing to see if it stays running. I know that it has a Walbro 255 pump in the tank, so Im not sure what ill have to do to make it work properly with all the other OEM stuff. Do you think that it could be and ECU problem? Im thinking that when the shop the guy took it to did the fuel pump wiring they screwed it up. The vacumm leak i still cant find, so im gonna put the boost leak tester directly on the TB, and plug that thing that routes air from the UIM back into the air tract before the IC, and see if it holds pressure. If not, then its after the TB. If its at the TB then its a problem with how well the 90 degree elbow seals on the TB, even though i tightened it down as much as i could. Maybe some sylicone should be used.

RoninRX7

 

Oh, and its also running an upgraded turbo. Its made by a company called Turbo Engineering Corportation, and its a Sport 350 turbo. The thing has almost a 3 inch inlet, its freaking huge.

 

Should of done that ages ago...

It's a direct swap, so no changes need to be made other than maybe some tuning to compensate for the richer low-load mixtures.

Very unlikely. ECU problem's are relatively rare. Bad sensors and bad electrical connections are not...

It's only two wires, so all they could do wrong is connect them the wrong way around (unlikely since it works okay some of the time) or leave a loose electrical connection. This would show up if you tested the fuel pump voltage while driving like I said.

 

I cant drive the car though since it wont stay running for more than 10 seconds. When i got it, even the spark plug wires were mixed up, so if they could do that i can only imagine what other dumb things they messed up. I know the top injectors (secondaries) are red, and since i cant really see the bottom ones, im assuming they are the same. Is it possible that its running rich because injectors are mixed around? I thought that all the injectors should be red, and i believe they are, maybe i should check...
Im just trying to think of any possible things that could be wrong. No idea could be to outlandish, for as weird as some of the other things were, i cant really assume anything. Thanks for the help, at least i have a few more things to check. Is there anything else i should check? I know they moved the electronic distributor thing around too, but i cant really check timing on the thing until i can get it to run for a while longer. Could really bad timing make it run like this?

Oh and one more thing, how do i test the module under the dash next to the steering colomn?

RoninRX7

 

So measure the fuel pump voltage durung that 10 seconds. You'll quickly see whether or not all this fuel pump discussion has been a waste of time.

They should all be the same.

It's just a relay, and the FSM has instrucitons for testing it. Of course the fuel pump voltage test is quicker and should be done first.