420A Will not idle intermittently. Bad fuel pump?

[Josh96]

I drive a 95 Eclipse RS 420a N/T Manual

For a few months I've been having an issue where it will not idle intermittently unless I keep my foot on the throttle. It will also do it where it won't quite stall but it will get really low RPMs and shutter and then kinda kick back up and do that for a while.

2 Weeks ago it wouldn't start for me after having this issue so I had it towed. Shop re-did wiring to fuel pump and replaced the connector and also put in a new relay. Seemed to be working fine. (Shitty shop IMO....)

Now it's been doing the same thing again. The only similarity I've seen is it seems to happen when my tank reads below or around 1/4 full. To test this out tonight it was happening again so I topped it off with 9.5 gallons and drove it home. By the time I got back (around a mile) it seemed to be doing better. I'm going to go for a quick test drive again in a little bit.

I also have new spark plugs within 5k miles.

At this point I am thinking fuel pump since I always hear it trying to start, it just never catches. It is also rough to start cold, I usually have to hit the throttle or it kinda shutters before getting up to a normal idle.

Any other thoughts for I drop cash on a pump.....?

Update on that drive.....

I drove about 15 miles just around the area. Got it up to 70mph and started pushing it a little hard at a couple points shifting around 6K RPM then my normal shifts around 3K. No troubles with that pulled in and no issues. Seems to me to back up the theory with the low tank.

 

[Travis Grant]

It sounds like fuel pump to me. Anyway you can check the pressure at the fuel rail to see if there is a drop off? My 96 esi had these same problems before I replaced the fuel pump and that was the problem. Ran fine afterwards. Just some other things to try before replacing the pump. Are the plugs gapped correctly? Is the fuel filter clogged? Is the throttle body butterfly gunked up? Is all the maintenance up to date involving fuel and air ?

 

[Josh96]

How would I go about checking the pressure there? Sounds like a tool or something I don't have .

Plugs are gapped to .030. Haven't really taken a look at the throttle body but I can. For maintenance the air filter is fine, idk about the fuel filter, fresh fuel it doesn't sit long. Not sure if anything else would need to be done? Never done anything with the injectors besides some seafoam.

How do I check the fuel filter for clogs? I don't know what state it's in, original from when I bought the car, and from what I understand it is a horrible experience to change it out...

 

[Nicholas Andrus]

I would change the fuel filter and fuel pump to start.

Have you changed the injectors? What fuel pump do you have in the car?

 

[Travis Grant]

There is a tool ! Kind of looks like a compression tester but with different fittings and drain hose. They are not fun to change but since our cars are getting older there could be a build up of sediment in there. I'm pretty sure it is your fuel pump but I would definitely recommend the fuel filter with it if you don't know how old it is. The thing could be original also get some throttle body cleaner and spray that butterfly valve down you'll probably be able to feel a ridge of gunk that's close to the valve that might be causing the car to be having a hard time idling. After all that she should be running smoothly.

 

[Josh96]

Yea I don't have one of those tools.

I've never done anything to the pump or injectors but I've only owned this car since April. When I took it to the shop they said somebody had already been at the fuel pump so I'm assuming it isn't stock. This car hasn't received the absolute best care so idk but if necessary I can pull up the back seat to check on the pump myself.

I'll replace the fuel filter on it this week when I have a chance and try running it down on fuel for a while.

For cleaning the throttle body, any recommendations on what product? And is it necessary to remove the whole throttle body to clean it or can it stay mostly in the car? Never cleaned one before.

 

[Travis Grant]

http://www.amazon.com/CRC-05078-Throttle-Air-Intake-Cleaner/dp/B000M8PYO2

I like the crc stuff but I'm sure all of its the same. Try to stick with throttle body cleaner I'm not sure if carb cleaner is the same or if it's hard on the rubber seals in our throttle bodies but it's safer to stay with the throttle body cleaner. You'll find it at any parts store. I think you'll get a better clean if you remove it but than you'll have to worry about the gasket. Just depends on how thorough you want to be. I work at GM and we usually leave them on when we do a "tuneup" and spray and wipe with a microfibre cloth. Let me know how it goes !

 

[Josh96]

Is the fuel filter as much of a horror story as I've heard?

 

[luv2rallye]

To measure fuel pressure many get this and mount it on top of the fuel filter (replaces banjo bolt): http://www.amazon.com/46054-Fuel-Pressure-Gauge-Set/dp/B000CIKCG2

 

[Travis Grant]

It's not terrible it's not fun either. I take the battery and battery tray out and the windshield washer reservoirs to gain access and some room. Depending on how rusty they might be it could put up a fight. Just take your time. Some penetrating fluid helps. DONT use a torch There's a write up on here I believe. What luv2rallye showed is a good idea too since you'll be in that area anyway and it could verify your concern with your fuel pump.

 

[luv2rallye]

Here's how to change the fuel filter. Just make sure on each end, you use a wrench holding the filter's fixed nut in place while using another wrench to unscrew the fuel line nut going into the fixed nut (or banjo bolt for top one). If you don't do this you will bend the solid fuel line going into the bottom. If can't get at the fixed nut (or there isn't one), then hold filter on other end with a wrench. It also helps to first spray the connections with PB Blast, tap it and leave sit awhile before wrenching. http://www.plymouthlaser.com/fuel.htm

 

[Nicholas Andrus]

Thanks luv2rallye you inadvertently taught me something today!

 

[Josh96]

To measure fuel pressure many get this and mount it on top of the fuel filter (replaces banjo bolt): http://www.amazon.com/46054-Fuel-Pressure-Gauge-Set/dp/B000CIKCG2

That product page doesn't really tell me much.... Is that thing just supposed to be quickly slapped on top and the gauge just sits in the engine bay and I take it out once I got my reading? Or is it like a kit to set up another gauge for the instrument panel?

I'll do the filter probably by Friday and keep you guys posted. Thanks for the help!


EDIT:

And any recommendations on the brand/part of fuel filter? I checked the the Fram G6553 doesn't seem to be compatible with the RS trim from what I can tell. Wanna make sure it's right one of course.

Amazon tells me compatible parts (I was already on the site >_>) are the G8164 and the G7768. Not sure what the difference is except the 7768 is about twice as heavy...

 

[Josh96]

Ok from what I can tell.... The G7768 is marked as OE for a N/A 2G and the G8164 is marked as univsersal for (from what I can tell on their website) 1G and 2G? Idk if I'm looking right.....

G7768: http://www.fram.com/search-parts/Part-Detail/?PN=G7768&AT=Passenger Car/Light Duty Trucks&VT=All&YR=1995&MK=Mitsubishi&MD=Eclipse&EN=L4 2.0&CP=&PT=Oil Filter,Air Filter,Cabin Air Filter,other&OF=&MF=&OT=

G8164: http://www.fram.com/search-parts/Part-Detail/?PN=G8164&AT=Passenger Car/Light Duty Trucks&VT=All&YR=1995&MK=Mitsubishi&MD=Eclipse&EN=L4 2.0&CP=&PT=Oil Filter,Air Filter,Cabin Air Filter,other&OF=&MF=&OT=

 

[luv2rallye]

Look at the outlet (the bottom in the pic - filter is shown upside down) to see if it matches yours - that is crucial. Also the outside diameter is different for the two (to fit in your bracket - measure your old one). The G8164 matches my 99 turbo so the other is probably your N/A one.

 

[luv2rallye]

That product page doesn't really tell me much.... Is that thing just supposed to be quickly slapped on top and the gauge just sits in the engine bay and I take it out once I got my reading? Or is it like a kit to set up another gauge for the instrument panel?

I've never had one but it looks like you mount it on top in place of the filter's banjo bolt. Then take the reading and either leave it there or remove it and return the banjo bolt to normal. Sounds like it has a fitting to go into the filter to place it in-line. So I suspect also when you're done you could just leave the fitting on, remove the gauge, and cap off where the gauge attached (for next time) if you don't want to leave the gauge there (I wouldn't leave it - if gauge leaks you've got a fire).

 

[Josh96]

Look at the outlet (the bottom in the pic - filter is shown upside down) to see if it matches yours - that is crucial. Also the outside diameter is different for the two (to fit in your bracket - measure your old one). The G8164 matches my 99 turbo so the other is probably your N/A one.

Yea I ended up going to the autozone in town and for whatever reason they couldn't order the other one and yours was marked as universal. They had a duralast that was marked direct OE fit so I just had them order that one. It should be here tomorrow.

 

[Josh96]

After an ABUSRD amount of time trying to find new crush washers, the filter has been replaced but from what I can tell right now there may still be an issue.

The old one I'm assuming was at least a little clogged because when I undid the bottom almost nothing came out and there was still fuel sitting in the chamber at the top. I'll continue monitoring and keep you guys posted.

 

[Lester B]

This may seem stupid. But did you check your air filter?

 

[Josh96]

Yea it doesn't look great but according to the manufacturer it is fine if I can still see the mesh crap on it which I can

 

[Lester B]

The easiest check for the fuel is the unplug the hose from the rail to the filter. Turn on ignition and should have fuel spilling out.
If not then pump isn't up to par.

Almost sounds like a boost leak. Or vacuum leak. I just found a huge one that was making driving horrible.

Do a boost leak test to ensure its not a leak. Just my two cents man.

 

[Josh96]

It's a non turbo.

And it is flowing I just haven't check pressure

 

[Lester B]

Turbo or not you need to know if you have un-accounted air entering your motor.
That will cause your car to run as you describe.

And truthfully that is a fundamental of cars, often overlooked, that will screw you up endlessly.
Must make sure you have no vacuum/boost leaks. I truthfully think it's your problem.
But we don't know till you verify this fundament.

 

[Josh96]

I don't understand how I can have a boost leak without a turbo? And a vacuum leak by definition would cause it to run rich not lean. I'm no expert so please correct me if my understanding is wrong...

 

[Lester B]

Even though your air inlet isn't as long as a turbo you could have a loose fitting sucking in air that hasn't been metered. Since it hasn't been accounted for the engine is getting more air than it thinks.

So the ecu will squirt enough fuel to make the correct afr..

Since there's too much air the condition would be lean.

But the car will run like crap with air leaks. It can't hurt to double and triple check your connections.