Mirage Fuel Issue - Replaced Pump - Won't turn over

[akamiller]

So my 89 Mirage was running fine, parked it for a couple of months, and now it won't turn over. I had a 255 Walbro fuel pump in the car and typically hear the whining noise, but didn't so I replaced the fuel pump. Still the same issue and no whining noise. My next thought was MPI relay, but I was doing some researching and found a thread stating that the car wouldn't even attempt to turn over if I had a bad MPI relay. Just trying to make sure I'm going down the right path here. Maybe missing a fuse somewhere? Haven't seen anything on any of the diagrams for fuses though.

I have pulled the MPI relay, but having a hard time finding a replacement as the dealer told me Mitsubishi does not make it anymore. Can anyone point me toward a new or used/working MPI relay for an 89 Mirage? Part Number E8T06771. I think the related part number is MD127351.

 

[GRAVEDIGGER]

So you're saying that it currently won't even engage the starter to turn the engine over, correct?
Okay... back to the basics first. Are you sure the battery is fully charged? Do the all the dash lights/warning lights etc come on when you first go to "key on" position?

I have a hard time believing that a relay went bad while the car sat, but of course anything is possible.

 

[steve]

The MPI relay has nothing to do with the starter circuit working, can you point us to the bad information?

 

[akamiller]

Sorry guys, wasn't getting the email notifications that you replied.

Car will start when I use starting fluid but obviously will die shortly after. In other words, battery is fine, starter is fine, spark seems to be fine. Just seems like it is not getting gas. After I attempt to start, the FPR is showing only 23. It used to be on 43 I believe. My initial thought was fuel pump. I dropped the tank and replaced the fuel pump (255 Walbro). Now that I have the new fuel pump in and I'm positive it is in correctly, I still do not hear the fuel pump whining like you normally would with a Walbro. So, fuel pump is replaced, next thought was a relay. That is where I am now. It took a bit to find the MPI relay as it was tucked away not in it's normal bolted position behind the radio. Am I going down the wrong path to think its the relay?

 

[steve]

Have you measured the voltage at the pump and at the battery?
You can test the MPI relay, there isn't much to it. Make sure that there is continuity across the relay coils, that you get battery voltage to the connector to feed the switching contacts and the coils, and that the other side of the coils are getting grounded to activate the relay. I don't have a manual for the mirage so I can't tell you which pins.

Be careful probing the connectors during testing, The ECU side needs the coils resistance to avoid too much current passing through the transistor switch in the ECU and blowing it. ie: don't let battery voltage get directly connected to the ECU signal lines.

The relays are pretty robust, it's usually

 

[akamiller]

Thanks Steve. I have not measured the voltage. I will try to find some time to do that this week and update.

 

[Dsmkauai]

check fuses and for power at pump.

 

[GRAVEDIGGER]

Sorry guys, wasn't getting the email notifications that you replied.

the FPR is showing only 23. It used to be on 43 I believe. My initial thought was fuel pump. I dropped the tank and replaced the fuel pump (255 Walbro). Now that I have the new fuel pump in and I'm positive it is in correctly, I still do not hear the fuel pump whining like you normally would with a Walbro. So, fuel pump is replaced, next thought was a relay.

So you have 23psi showing on the fuel pressure. That tells me that the pump and everything is working electrically, but you aren't getting enough pressure. Have you replaced the fuel filter? That would be where I would be looking next.

 

[akamiller]

So you have 23psi showing on the fuel pressure. That tells me that the pump and everything is working electrically, but you aren't getting enough pressure. Have you replaced the fuel filter? That would be where I would be looking next.

Yes, I replaced the fuel pump and the filter that goes on the end of it at the same time. Unless there is a filter somewhere else I'm missing?

 

[akamiller]

check fuses and for power at pump.

I haven't been successful at finding any fuses related to the fuel pump. As Gravedigger suggested, I am showing 20-23 psi on the fuel pressure regulator so the pump does seem to be working, but not adequately. I did replace the filter on the end of the fuel pump. I also confirmed that my MPI relay is working just to rule it out.

If either of you guys can provide me some detailed instructions on how to check the power at the pump, I will do that this evening. I dropped the tank again over the weekend so I would have access to everything. The pump is not on while the key is correct? The engine actually needs to be cranking over for the fuel pump to work. I read something about a test connection that allows you to bypass all of that and send power directly to the pump. Should I do this? Where is it located on the 89 mirage?

Thanks for all your help!

 

[akamiller]

Also, once the car has been off for a bit, the fuel pressure drops back down to basically 0. Not sure if that helps at all or if it should constantly stay at 43 (or 23 for me at the moment).

 

[thomcasey]

There is a Fuel Filter in the engine bay. Follow the left side of the fuel rail. The line there goes to the fuel filter. It is a black canister.

 

[GRAVEDIGGER]

The fuel filter I am talking about is not the "sock" on the fuel pump but an actual filter. On my 1g dsm it is on the firewall in the engine compartment and after looking one up for a Mirage real quick it looks like the same fuel filter as my car, so I am assuming that it is similar on your car, although I'm not positive as I have never worked on a Mirage.

As for the fuel pressure dropping down to zero... It is normal for the pressure to drop to zero after some time, but it shouldn't do it really quickly by any means. It should slowly bleed off pressure and be almost unnoticeable while watching the gauge.

 

[Dsmkauai]

Make sure the top seal and little plastic piece are in right. If the are ripped or not seated right you can get the psi problem and drop.

 

[akamiller]

The fuel filter I am talking about is not the "sock" on the fuel pump but an actual filter. On my 1g dsm it is on the firewall in the engine compartment and after looking one up for a Mirage real quick it looks like the same fuel filter as my car, so I am assuming that it is similar on your car, although I'm not positive as I have never worked on a Mirage.

Fuel filter is off and part ordered. I will have it tomorrow after work. Being that I have to put the tank back in to test the fuel filter, I would like to go ahead and test the power at the pump since some have suggested that. I'm just wondering how I go about testing it. If anyone could give specific instructions for my 89 Mirage, that would be awesome!

 

[akamiller]

Have you measured the voltage at the pump and at the battery?

Steve - could you provide instructions on how to check the voltage at the pump? I have a voltmeter. Just need to know what to check.

 

[GRAVEDIGGER]

If it's like a dsm which it probably is... Look for a large/thicker black/white wire... That is usually the fuel pump power. Make sure you are getting battery voltage. (This is most likely only when engine is cranking)
Next is there is a large/thicker solid black wire. That is usually the ground wire. Make sure it is a good ground.

 

[steve]

Steve - could you provide instructions on how to check the voltage at the pump? I have a voltmeter. Just need to know what to check.

Based on http://www.lilevo.com/mirage/89 Colt Summit Mirage Turbo Factory Manual .PDF/14 - Fuel System.pdf you measure the voltage between the large Black w/White strip wire and and the Black wire (ground) at the Fuel Pump. You want to do so while the engine is running so the alternator is active.

 

[akamiller]

Based on http://www.lilevo.com/mirage/89 Colt Summit Mirage Turbo Factory Manual .PDF/14 - Fuel System.pdf you measure the voltage between the large Black w/White strip wire and and the Black wire (ground) at the Fuel Pump. You want to do so while the engine is running so the alternator is active.

Can this be done with the tank removed and fuel lines disconnected? Does the pump need to be in the tank? If the voltage is low, what are next steps to troubleshoot? Would I just need to do the rewire that I have seen a lot of posts about?

 

[steve]

Just under normal operation. You want the pump to be under load. When developing the rewire mod the voltage testing was done while driving the car and monitoring the voltage.

Before going to the effort, please restart the current problem. When you tested the fuel pressure was it with the vacuum line to the regulator disconnected and plugged? 23 psi wouldn't be too far out of wack for idling with the FPR vacuum line connected. What's the base fuel pressure specified to be per the Mirage FSM? Is it like a 1G Turbo DSM where the base pressure is like 36 psi with the line disconnected and about 9 psi lower with the line connected at idle?

 

[akamiller]

Just under normal operation. You want the pump to be under load. When developing the rewire mod the voltage testing was done while driving the car and monitoring the voltage.

Before going to the effort, please restart the current problem. When you tested the fuel pressure was it with the vacuum line to the regulator disconnected and plugged? 23 psi wouldn't be too far out of wack for idling with the FPR vacuum line connected. What's the base fuel pressure specified to be per the Mirage FSM? Is it like a 1G Turbo DSM where the base pressure is like 36 psi with the line disconnected and about 9 psi lower with the line connected at idle?

The car won't start so I can't test it under normal operation. I didn't test the fuel pressure. I purchased this car as is with 4g63 swap already in place. I just looked at the fuel pressure gauge under the hood and it used to show much higher than 23. I did not disconnect any lines. It is a huge pain to drop the tank to get to the fuel pump and I have to disconnect all the fuel lines to do so. So I'm not sure how I can test the voltage at the pump under normal operation. Its still just so weird that the car ran perfectly fine and after parking it for about 2 months or so, I now have this issue of not starting. It sounds like it wants to start, but just not getting the gas. I guess I will put the fuel pump in and put the tank back in to see if that was the problem. I am getting pretty quick with dropping the tank by myself with a floor jack and my feet .

 

[steve]

That manual I referenced showed an access plate for the fuel pump in the trunk.

When did you last charge the battery?

Are you sure that the connection between the walbro and the hardline isn't leaking? An a DSM the coupling uses a plastic cap and o-ring on the pump outlet that doesn't swap over to a walbro very well and often leaks causing poor on no fuel pressure.

If the engine isn't running there won't be any manifold vacuum dropping the base pressure so assuming an unmodfied 1G ECU you should set the pressure to 36.3 psi. If you don't have a Adjustable FPR then you need to figure out which of the OEM FPR's is installed since the NA, Turbo Automatic, and Turbo Manual versions each have a different value.

The newer walbro pumps have a foam sock on the pump to sound deaden them. Did yours?

Lastly, the fuel pump only runs during cranking and once the CAS is rotating. How are you testing/running the pump?

 

[akamiller]

That manual I referenced showed an access plate for the fuel pump in the trunk.

I believe LIL EVO's mirage was a sedan. Mine is a hatchback and does not have an access plate that I can find. I have even removed the rear seats.

When did you last charge the battery?

The battery is brand new Red Optima. After it sat for a bit, my battery died and I got a new optima for free due to warranty.

Are you sure that the connection between the walbro and the hardline isn't leaking? An a DSM the coupling uses a plastic cap and o-ring on the pump outlet that doesn't swap over to a walbro very well and often leaks causing poor on no fuel pressure.

I don't believe anything is leaking. I was having this same problem before I replaced the pump. The car already had aWalbro 255 in it. When I started having my problem of the car not starting I was told to try to start it with starting fluid. I got it to start but it quickly died. I was then told to replace the fuel pump. So I did and still the exact same problem. So I'm trying the fuel filter now and I wanted to check the voltage at the pump before putting the tank back in.

If the engine isn't running there won't be any manifold vacuum dropping the base pressure so assuming an unmodfied 1G ECU you should set the pressure to 36.3 psi. If you don't have a Adjustable FPR then you need to figure out which of the OEM FPR's is installed since the NA, Turbo Automatic, and Turbo Manual versions each have a different value.

I have a 1G ECU and I have an adjustable FPR with a Big 16g and 550cc injectors.

The newer walbro pumps have a foam sock on the pump to sound deaden them. Did yours?

Both the old and the new had the foam sock.

Lastly, the fuel pump only runs during cranking and once the CAS is rotating. How are you testing/running the pump?

Yes, I know the fuel pump only runs when cranking and when the car is running. The car is not going to run so can I test the voltage while someone else is trying to crank the car over?

 

[steve]

If your wiring harness has the fuel pressure test connector in the engine bay you can apply battery voltage to it or you can ground the coil for the fuel pump at the MPI relay like the ECU does to activate the pump.

When you replaced the pump what shape was the pump hanger in? The ground connector on a 1G runs to the cover. then there is a stud on the inside that the pump ground connects to. That makes the external connection key to getting a good ground.

Have you tried turning the pressure up at the AFPR?