Fuel Problems
 

Hey guys, I'm trying to revert from a Walbro back to a stock pump, but I'm having some problems. I figured the trailing plugs kept flooding because there's too much fuel from the aftermarket pump. So I got a used stock pump, installed it, and tried to turn on the car. It started, but ran really rough, and when I tried to gas it a little, the car just died.

Now, fuel doesn't even make it to the motor, as in, I crank but neither plugs are wet when I check them. But disconnecting the fuel lines from the fuel tank leaks fuel as if the pump was working. Does anyone have any suggestions? Also, my coolant light keeps buzzing/going off, and I've never had this problem before, so I was wondering if this had anything to do with it?

Checked for leaks between the tank and the injectors?
Checked to see if the fuel filter is clogged?
Checked fuel pressure?
Can you hear the pump running?

No leaks between the tank and injectors. Also, the fuel filter was recently replaced; it has less than a couple hundred miles. The fuel pressure was fine before, so I assumed it would be ok, since when I swapped for the Walbro originally, I didn't have to mess with it, but I guess I should check it. And that's the weird thing: no, I can't hear the pump running, but when I checked the lines after I tried to crank it, there was fuel in the lines.

I should also mention that when the car first ran rough with the stock pump, the trailing plugs came out wet again.

Oh, and when I disconnected the fuel lines after the car suddenly died, there was fuel in the lines. So I tried cranking again later, and at that time, the plugs were dry, but when I disconnected the lines again, there was still fuel in the lines again.

I tried cranking again and nothing, but I'm going to check the lines again to see if there's fuel. Also, I don't think I plugged the send/return lines incorrectly: the send line is the high pressure line with a mark, and the return line is a normal fuel line, correct?

Another update, this time, only the trailing plug from the front housing was wet. The plug wasn't drenched, though. I disconnected the fuel lines, and they still had fuel in them. Also, is the bottom of the pump supposed to have a hole where the outer groove is? I never noticed until I just pulled it out, because it was leaking other than where the strainer goes.

I just realized that maybe the pump is working, but the injectors aren't spraying? Could there be an electrical problem that would cause that? I'm going to check the grounds, all the fuses are ok but maybe I should replace them anyways.

I checked the grounds and they seem fine. I tried cranking it again with a trailing plug out and on metal, and it's not firing (I've tested this method before and the plugs have fired before). The coils are not bad, since I checked after according to the FSM and the resistance is below 1 ohm. I'm going to try the lead too, but I'm guessing the leads are fine since the car started roughly and the plugs were never wet before.

I also checked the fuses and they were fine as well. The tach does not jump at all when I'm trying to start the car, like before.

Oh, and last but not least, sometimes when I disconnect the battery and reconnect it, when I try to start the car, the power dies and I have to disconnect and reconnect the battery again. Not sure if this problem is related.

It seems that your trailing coils aren't working. Not only for the fact that they're not sparking, but the tachometer is related to the trailing coils.

Is there ANYTHING electric or fuel related that you may have messed with and forgot to mention?

Update...the leading plug that I checked sparks once, but then does not spark as the engine continues to crank.

I checked the coils, though, and they're both well under 1 ohm as specified in the FSM. Is it the ignitor? Would that be related to all of my problems?

Also, there's still a fuel problem. When I try to start the car, the fuel doesn't make it to the motor. It's in the lines when I disconnect them from the tank, but the plugs are dry (except for T1, which has a tiny bit of fuel on it). I just replaced the EGI INJ fuse, but that didn't help any.

The 15 amp Engine fuse powers the fuel pump.

I replaced it, but I still don't hear the pump running. Could it be a bad pump? Do I have the lines to the tank flipped?



Well, I checked the CAS with a multimeter, and it's within specs. If anyone could help describe how to check the trailing ignitor, it'd be greatly appreciated.

I think there's a short somewhere, so I'm starting to go through everything (electrical/wiring).

The key has to be on "and" the fuel check connector jumpered for the pump to run. W/the jumper in place and key to on the Blue wire in the Circuit Opening Relay will have power. This wire powers the fuel pump. Relay is Yellow and Black and found just under the dash and to the right of the steering wheel column. Plug has five wires in all.

I'm not familiar with the fuel check connector (jumper). Is it found in the tank area or in the relay area?

It's part of the Emission harness found near the passenger strut tower. The plug is Yellow and it's shrouded in a Black rubber boot. Plug has two wires. One is Black while the other is Brown. The very same thing can be done by jumpering the bottom two wires at the Circuit Opening Relay. The wires are the same color, Black and a Brown. Since you want to check the voltage of the Blue wire that powers the pump it then makes sense to do the jumper at the relay.

Ok, I saw the blue wire. I'm not electronically inclined, so what do you mean when you say "jumper/jumpered"? I'm about to look for the fuel check connector now. I appreciate your (and everyone else's help) so far.

It means to bridge two wires together. So a short lengthed wire, bare at both ends, and basically in a "U" shaped position are used to connect two separate wires together which in this case is done by shoving one jumper wire end into plug where one wire resides and the other end of the jumper wire into the plug of the second wire. Just focus on the relay for now.

Ok, so I should basically find the black and brown wires at the relay and jump/bridge them with a separate wire. What's the best way to check the voltage of the blue wire using a multimeter? I'm guessing the positive goes to the blue wire, but what about the negative? And I'm looking for 12V, correct?

And the other meter lead goes to a ground. The Black wire in the five wire relay is a ground so you could use that. The two wires you are to jumper are in the bottom row of a plug that only has two wires in the bottom row ( a Black wire and a Brown wire).

And the reading should be 12 volts or close to it.

Alright, I'm going to check it tomorrow, since it's kind of dark and there are way too many mosquitos out right now, hehe. I really appreciate your help again, and will update as soon as I check.

Oh, and just to be sure, if the meter reads 12V, that means that the pump is getting power and that something must be wrong with the pump, right?

If the Blue wire has power that means the relay is sending voltage to the fuel pump relay and resistor which is found on turbos. From there the voltage then runs to the pump. There is a plug at the rear of the car that connects to the fuel pump. If the Blue wire in the Rear side of the connector has 12 volts then the pump is receiving voltage.

Ok, so I tried to put the Walbro back in and start it, and there was still no fuel.

I finally tried your advice, and when I turned the car on, I hear whirring coming from the fuel pump area. I'm not exactly sure what I'm supposed to do next, or what this all means, because when I unbridge the connector, it doesn't whir when I turn the car on. Do I try to start the car this way?

Yes, you can.

I just wanted to give you a heads up...I didn't want to try that yet since I know that there isn't any spark right now.

I was looking at some of your other posts to try to figure out this tach/injector/trailing coil problem, so I found a post where you said to try jumpering the main relay, I believe B/G to B/Y and W/L to B/W. After bridging those and trying to start, there was still nothing. I'm trying to read the rest of your posts and look at the wiring diagram to figure out what's going on, but I can assume that the relay is not bad, correct?

The coils are powered via the Black/Yellow wire and have 12 volts w/key to on. Does the leading coil have this voltage? There's a Green check connector near the leading coil w/four wires. One of these wires is Black/White. W/key to on it should have 12 volts. This wire powers the ECU.

I know this is a really stupid question, but where do I ground? The positive to the wire i'm checking, and the negative to just bare metal on the block?

The negative terminal to the battery or the alternator housing are good ground candidates. And the Brown wire at the TPS should have 5 volts w/key to on as this will reflect that the ECU is powered up properly by the Black/White wire. So if the Brown wire has proper voltage then you know the B/W wire must have proper voltage as well.

Ok, I checked the two wires referred to in the post before the one I quoted, the ones near the leading coils, and they are good, like 12.2V.

The brown wire on the TPS, though, was like, in the mV. 303.4 to be exact. So power is getting to the leading coils, but not to the TPS/ECU, correct?

And the Brown TPS wire was measured w/key to on? You can check the same color wire at the Boost Sensor as it should read 5 volts w/key to on.

Yes, only a few over 200mV at the Boost Sensor.

This could be a total shot in the dark, since I have no idea what I'm really doing while looking at the wiring diagrams, but could it be the fuel pump relay/resistor? I'm not sure which wire to check, though I'm guessing it's probably the black and white one...

Disconnect the AFM and check the Brown wire w/key to on at either the TPS or Boost Sensor. If the ECU is powered properly, but the Brown wire has practically no voltage, then chances are the AFM is shorting out the ECU. You can also check pin 3I (Black/White wire) of the ECU as this is where the B/W wire from the Main Relay ends up. Should have 12 volts w/key to on. If 3I has battery voltage then the AFM is the likely cause. If 3I does not have battery voltage w/key to on then this would be the problem you need to solve.

I tried both the AFM and the fuel pump relay/resistor...I got no voltage when I unplugged the AFM, but 5V when I plugged it back in and unplugged the fuel pump relay/resistor.

Is there any way to bypass it and get the car to start? Or repair it? Or do I have to wait to get it swapped out?

Maybe I could jumper the fuel pump check connector like before, but I'm so paranoid about screwing things up further that I don't want to try it, lol.

If the Fuel pump Relay and Resistor being unplugged causes the voltage to be restored to 5 volts on the Brown wire w/the AFM plugged in then unplug the fuel relay and jumper one of the Blue/Red wires in the plug to one of the Blue wires in the same plug. Doing this will bypass the relay. Just unplugging it would kill the fuel pump.

Satch, thank you so much for all of you help. I really couldn't have done it without you, and you got me out of a tough spot, I wish I could repay you somehow. I'm going to try to get a relay while I'm off at school and change it out when I get back from out of town.

Last question, does the relay that I bypassed have anything to do with the water temp sensor/gauge? If not, I guess I have another thing to replace, lol.

You could probably go w/o the relay for a while as there are those that run w/o it all together. And this fuel relay is not directly related to the water temp sensor/gauge, although I'm not sure what you mean by that.

Ahhh, I see. Cool, that's good news for now. Again, thanks so much for your help.