2G Test 2Gb fuel pump/MFI relay

[Redwan]

Did you ever find the problem? Please let me know, thanks.

 

[JGeezyyy]

Did you ever find the problem? Please let me know, thanks.

Not exactly positive but I’m pretty sure it was either one of my ECU cables coming loose, or a bad ground. So if the testing as shown above passes, I’d check for loose wires and grounds. Good luck my man

 

[Miker1st]

So, long time lurker, first time poster...
I have a 99 Eclipse with a fresh head gasket and lower bearings that I've reassembled and all put back together and I've run into this issue as well.
I'm 90% sure it's a grounding issue since I have zero reliable frame grounds from the battery. The fuel pump was replaced about a thousand miles before it skipped a tooth on the exhaust cam. I got a little carried away resetting timing and ended up with pistons on my bench.
But I digress. Fuel pump doesn't run on crank with all sensors plugged in. I also don't have the test plug on the firewall, just the blue test plug. I don't really want to pull the cruise control box and tear into the loom to try and find it either.

 

[luv2rallye]

99 Eclipse 4g63 or 420A? Makes all the difference.

 

[Miker1st]

Definitely 4g63. It's the Eclipse GST.

 

[luv2rallye]

Ah, same as mine. The firewall blue test plug is not a FP check connector on the 99 (they changed that for 99). I'd first check to see if the FP works by removing the FP relay and shorting it's connector wires. That way you're also testing it's ground. The relay is the bottom relay on the inside of the right center stay (just above console floor right side - passenger left leg could touch the side of the console [https://www.dsmtuners.com/attachments/mfi-fuel-pump-relays-96-99-jpg.90631/]). Remove relay and in the connector short one of the black-white wires to the black-blue. FP should go on when ignition key is then turned on.

Or if happen to have access to the ECU connector (safest to have ECU removed), you can ground its pin 8 (white-red wire) with the relay in place and then turn the key.

If the FP works, then you either have a bad FP relay, bad ECU, or bad wiring to/from ECU controlling the FP function.

 

[Miker1st]

Oh boy! That's got me all motivated again.

For some reason, I had it in my head that the relay set was buried in the center console and I was going to have to pull the dash to get to it, therefore leading to procrastination. It's still pretty tucked up in there behind that piece of frame, but one interior panel vs. a whole mess of panels sounds better. My interior is in really good condition and I've been hesitant to do anything for fear of cracked plastics.

Here's to hoping it's just the relay or simple wiring.

I'll get on it here in about 10 hours and see what I come up with.

 

[luv2rallye]

You'll have to remove the floor console assembly (that has the arm rest, cup holder, shifter, etc) which IS the panel that hides the center stay the relay is mounted on. But first you'll have to pry out (it snaps in) the small center panel that goes around the radio in order to get at 2 forward upper screws that hold the forward part of the floor console. Pry it carefully with a masking taped over flat screwdriver blade to keep from scratching it. There's clips behind this center panel, halfway up on the outer edges right and left sides which is where you MUST pry or you'll crack it - go slow and be careful - if you are going to crack some plastic this will be it! Another 2 clips on bottom left and right but those usually pry out easier. The floor console then has 2 more screws down under the cup holder and 2 more in the rear on the sides. Finally there's a couple wire connectors (cig lighter and cup holder light) you'll have to unplug once you start lifting the floor console. I've done this many times.

 

[Miker1st]

Not to cry, but waaaaaahhh!
That's exactly what I thought I had to do!
So much for it being easy. #dsmproblems
Well, it's only been in the garage on jack stands for over a year...

 

[luv2rallye]

It's not as hard as you think. Plus I just told you everything you need to know (i've done this at least 20 times)! Another option is pull the back seats and apply +12v the FP itself (but there's a number of wires on that connector some which are the same color so you better choose correctly).

 

[Miker1st]

I know. I really appreciate it.
I've done this on three different vehicles in the last two weeks, just not on my absolute treasured possession.
I'll take heart, armed with your wisdom, and apply the knowledge to this undertaking tomorrow morning first thing.
Once again, really appreciate the steps from someone else who has gone on this adventure before!

 

[luv2rallye]

Ok I've been thinking about this. First make sure you have good battery negative cables connection (one battery negative cable to body/frame and a separate battery negative cable to starter mounting bolt on tranny - these are 2 separate cables BOTH FROM battery negative, not one going to the other).

Then I think you should check voltage and ground right at the FP 6 pin connector itself (under rear seat on top of gas tank), before you take the floor console out. This may be the entire problem and so removing floor console would be a waste of time if it's a bad ground at the FP. You said yourself you suspect a bad ground. Does anything else electrical not work like fuel gauge? There is a major ground connection point (for the FP, fuel gauge sender, and other stuff) under the drivers seat carpet (manual shows it as "front floor upper cross member, left side") which may not make good connection if it becomes loose or corrodes. You may have to remove drivers seat to get at it. If that ground is bad/loose, that is a commonly reported cause of FP not working. If that's ok, then see if you have voltage on the larger black-blue wire at the 6 pin FP connector when key is on. If so then check continuity to ground on the largest black wire of that connector (which goes to that "front floor upper cross member, left side" point).

 

[steve]

+1

Since the fuel pumps can draw quite a few amps the quality of that ground is important. All the current going in has to come out, or you'll only get as many as the most resisting point will pass.

 

[Miker1st]

So, I pulled the big plug that goes to the fuel tank harness on top of the pump assembly and found the following:

Black/Blue wire has no voltage with key in the On position.
Black wire has 23 ohms to any number of frame ground points under the back seat (read:seat belt bolts).

One of the centerish pins shows 11.3 volts.
The battery has about 11.9 volts right now.

The fuel guage seems to work and shows I have a quarter tank of (most likely orange) gas.

Fuel pump works great when connected directly to a battery at the connector. Its really loud.
Gas isn't in terrible condition, but I'd still rather have fresh for a first start on a rebuild.

 

[luv2rallye]

I'm sorry, I was looking at the 1999 AWD turbo diagrams. The 1999 FWD turbo diagrams show a 2 pin FP connector (E-36) right at the FP. Use that one. And that 2 pin connector's large black-white goes to ground (at that major ground point under the drivers seat - see attached pic figure #8) and should have near 0 ohms resistance (or you will have problems). The 14 pin connector you show (E-60) also has the larger black-blue coming from the E-36 connector at the pump (and going the other way to the FP relay through 3 more connectors). Don't know where all the other wires on that E-60 connector go so don't test them.

BTW, at the pump you will only see voltage while the engine is spinning (cranking or running) on the black-blue - NOT while the key is just in the ON position and engine not spinning. Of course if you want you could just apply 12V and ground to the E-36 connector to make sure the FP works.

 

[luv2rallye]

Just to let you know I added some stuff to post 42 so re-read it.

And just in case anyone in the future needs to know, here are all the 2g grounding points:

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[Miker1st]

I was wondering about the voltage while on.
I applied voltage at the E60, FP side, and the pump kicked over. As soon as I get a second set of hands to turn the key while I hold the multimeter I'll get the voltage while cranking on the E36.

I rearranged the grounding from the battery terminal to shock tower post to firewall post where all the harness grounds connect.
Then, I figured I'd check the resistance on the ground at E-36, then realized I'm pretty tall, I can probably push the clutch, hold the multimeter contacts and turn the key all at once...
I'm getting 21 Ohms on the ground leg at E-36
And 8.5 Volts while cranking!
So I thought, well heck if I'm at least getting voltage here, then everything is probably working like it should so I reconnected the FP plug, E-36, and lo and behold, the fuel pump runs while cranking!

So next steps are going to be jumper the pump to run out as much of the old gas out of the tank and then refill with non ethanol premium for first start!

Thanks a bunch guys!

No FP test connector for pump out?
No problem!

 

[luv2rallye]

I'm getting 21 Ohms on the ground leg at E-36.
And 8.5 Volts while cranking!

21 ohms from ground leg at E-36 to where?
And 8.5 volts are measured from where to where?

 

[Miker1st]

21 ohm from black and white wire on E-36 to one of the bolts for the seat belts in the back.
8.5 volts at E-36 across the terminals while cranking with a battery voltage of 11.6 volts.
It was cold this morning and that battery is on its last legs. Due for an Optima red top soon!

Either way, that got it running! Went out for a spirited break in drive. I forgot how fast this car was, and now that it has fresh rings/bearings, it feels incredibly tight.

 

[luv2rallye]

21 ohm from black and white wire on E-36 to one of the bolts for the seat belts in the back.

That's the FP wire to ground and is supposed to be near 0 ohms (<0.5 ohm max)! You have a poor FP connection to ground, probably at that fig 8 location of the picture in post 42 which is where it goes (it's a common poor works loose ground connection area). Your FP may work now (probably barely and at severely reduced capacity) but you are going to have major problems in future if you don't fix this.

8.5 volts at E-36 across the terminals while cranking with a battery voltage of 11.6 volts.

Even though your battery is low, that voltage at the FP is way too low to operate properly and is almost certainly because voltage is dropping across your poor (high resistance) ground connection when FP current flows (remember V = I x R). The FP voltage should never be less than 1 volt of the voltage at the battery whether engine is cranking or running (and would be if there wasn't a poor connection). Even with a new battery you are still going to drop 3 volts across the poor connection - a new battery won't change this.

 

[Miker1st]

Tracking. I'll chase the ground down here when it warms up a smidge.

Duh, ohms law. I should have run the math first, you're right.

I'll get after extra grounding from the battery as well. At this point, I have a laundry list of things that need fixed now that it is running, but at least it's running!

 

[luv2rallye]

The grounding problem is at the FP. You should still check that fig 8 grounding location (for corrosion/rust/looseness/frayed/broken) since it's used for other things too, but if needed you can always add another wire from that black and white wire on E-36 to a good ground (to at least make sure the FP has a solid ground). Just splice into it so it then goes to both ground places.