Fuel Filter & Idle Questions

[mentis]

Hey everybody . Been gone for a long while. I was doing a bunch of traveling, and ended up moving again. Now I'm in Wilmington, NC. Anybody else living here with their subies? Well, I'd be glad to know if you are.

 

Now to the matter at hand. When I was gone, my trusty old '87 GL-10 Turbo Wagon didn't see much use. It stood around mostly for about six months. Needless to say it wasn't very happy when I came back. I've been having little issues with it since then.

 

So far I've replaced the battery, some leaky hose, head gasket, oil and filter, etc. Now I've been wanting to replace the fuel filter, and tried getting it to run dry by taking out the fuse for the fuel pump. Unfortunately, that didn't seem to work. It just kept going.

 

1. So I'm trying to figure out how I can shut of the fuel pump so I don't get doused in gas when i disconnet the line going to the filter (unlike the first time I ever did that!!).

 

2. My other question is this. My idle has been doing stupid things now. It used to, very rarely, jump up and down between 1k and 3k rpm while stopped (at a light for instance). But now it has started doing this quite a lot. Even after the car is warmed up, the idle will stay at 2k or 3k, and then drop to 1k and go back up. I'm guessing this has something to do with the idle controller. I know nothing about what and where that actually is though .

 

Any help would be greatly appreciated, so thank you in advance!

[I)arkZrobe]

Cant Help With the RPM thing but when I change out the fuel filter I just clamp the lines

[mentis]

Oh. . Ha ha, well that's probably a lot easier than messing with the fuel pump. Anything in particular that you use to clamp? Cause there's pressure in those hoses, right?

[daeron]

Get under the car, unplug the fuel pump, and start the car. Thats what I had to do.

 

Just loosen a line and watch your eyes... I've never been able to fully depressurize a fuel system, but doing this much gets rid of alot of it.

[misledxcracker]

use visegrips on the hoses for the fuel filter, or c-clamps even

[mentis]

That's good tips, thank you guys. Now I just need to locate where the fule pump is, and where the electric plug on it is as well.

 

I have a haynes manual, but that this is not always very helpful.

[daeron]

fuel pump is on a shelf, on the passenger side of the car, just in front of the tank. Its pretty much right next to the rear passenger jacking point.

 

the plug is obvious :- )

[I)arkZrobe]

I should have used some regular clamps... But I had some medical clamps I used. (Someone tell me why I have medical clamps in the back of my car?)

[mentis]

I'm not sure I want to know , ha ha .

[heartless]

i have found that trying to clamp a line with just the vise grips doesnt really work all that well - you still get some fuel flow, but - a pair of quarters - or a couple of large flat washers for you broke guys - on either side of the hose (between hose and visegrip jaw) will cut off ALL fuel flow - spreads out the clamping force equally across the width of the hose.

[mentis]

Thanks, heartless. That's good to know. So now I just need to see if anyone's got an idea as to what the heck's going on with my idle (from first post above).

[daeron]

i have found that trying to clamp a line with just the vise grips doesnt really work all that well - you still get some fuel flow, but - a pair of quarters - or a couple of large flat washers for you broke guys - on either side of the hose (between hose and visegrip jaw) will cut off ALL fuel flow - spreads out the clamping force equally across the width of the hose.

 

I used a couple wooden shims last time I needed to do it. I always seem to forget this part, though, and do it the wrong way first. Face full of fuel, not fun. *play Price is Right Loser music*

[mentis]

I appreciate all the hose clamping tips guys, but I think we've got that one figured out. And thank you for that.

 

Still, a bigger issue now is the problem with the idle. So I just thought I would reiterate my issue here, since we're on the second page now...

My idle has been doing stupid things now. It used to, very rarely, jump up and down between 1k and 3k rpm while stopped (at a light for instance). But now it has started doing this quite a lot. Even after the car is warmed up, the idle will stay at 2k or 3k, and then drop to 1k and go back up. I'm guessing this has something to do with the idle controller. I know nothing about what and where that actually is though

.

Thanks in advance for your replies!

[Skip]

the idle problem could be related to corrosion on the

FI CTS connector.

(Fuel Injection Coolant Thermosensor)

 

It is possible the ECU does not know the

temp of the engine.

 

The IAC (Idle Air Control) is mounted

on the goose neck (upper rad hose connection).

 

It therefore gets a signal from the ECU and is warmed by the coolant.

 

If the ECU is not feeding it the proper signal due to the

corroded contacts on the CTS.

The two could be working

as adversaries rather than in compliment.

 

The CTS is buried back on the lower run of the intake manifold, pass side.

Shown here with the corrosion in evidence.

Hope this helps.

[mentis]

That's good info, Skip. Thank you. So is the FI CTS also the sensor which shows the temp of the coolant on your dash?

 

I'm assuming it's not though, but I thought I'd ask. I previously had the IAC confused for the temp gauge sensor. Which is actually why I had replaced it at one point. So that's probably good . Now I'll have to go take a look at the FI CTS.

 

Is it difficult to replace the FI CTS? It looks fairly accessible, but that doesn't mean anything in terms of removal. It also appears to be located underneath the turbo "cooler" (ha ha, as if ).

[Skip]

Sir Mentis, you are most welcome

and are correct but also not so correct.

 

The dash gauge "thermometer" is not the same as the

thermosensor.

The thermometer is located up front has a single spade connection.

 

As for CTS access, sorry that is a bare manifold I used

so one could see it.

 

It is very hard to reach and one must becareful of the

ceramic knock sensor located close by.

 

At least you don't have my problem reaching it - I hope

My EA82T

[mentis]

Ah yes, I do remember seeing that picture before . That's quite the crazy setup you've got yourself.

 

Well, if I don't have time to get under all that stuff to the FI CTS, then I might ask a mechanic to replace it for me. However, is it visible enough to allow me to inspect it for corrosion? Because that might be enough right there.

 

On a slightly different note, since you've got an IC in there, I noticed that the stock "cooler" has a small hose coming in underneath it (in mine). When I will be installing my IC, where should this hose be connected to? Before the intake of the IC, or after the output?

[Skip]

The hose you question is connected after the IC

in my set up.

As I retain the factory intake plenum.

Which is what I believe you call a "cooler".

 

Cleaning the connections is always a "first place to start".

 

Garygoss has soldered the wires on his to the tangs.

 

Good luck, it is not an easy 5 min. job as it is burried.

 

If the factory boot is torn it will allow the watter to sit in the

well and well you know the result.

 

If the factory connector is still clipped on, I use two pieces

of wire to hold the spring clip so the connector can be removed.

 

Shown here on the AAV - (Aux Air Valve) that is also in question here.

[mentis]

I'm not sure that I entirely understand the purpose of soldering the wires to the tang. Doesn't that bypass the sensor? I'm sure I have no idea what I'm talking about though .

[daeron]

I'm not sure that I entirely understand the purpose of soldering the wires to the tang. Doesn't that bypass the sensor? I'm sure I have no idea what I'm talking about though .

 

He means clipping off the plug, and soldering the wires of the harness directly to the terminals on the CTS, so that in the future there is no sliding terminal connection to be made poor by corrosion.... This CTS issue is arguably one of the most common problems with the EA82T, (its a very common problem with fuel injected vehicles in general) and soldering is a more "permanent" fix to the problem than cleaning terminals that WILL corrode again.

[mentis]

Thank very much, that makes a lot more sense now . I guess the picture confused me, because it looked like the wires were attached to the outside of the sensor.

 

Now, I've seen some anti corrosion compound on battery terminals before, would something like that help if I decided not to solder?

[daeron]

Thank very much, that makes a lot more sense now . I guess the picture confused me, because it looked like the wires were attached to the outside of the sensor.

 

Now, I've seen some anti corrosion compound on battery terminals before, would something like that help if I decided not to solder?

 

I think it would help, but consensus seems to be that soldering is the best way to go.

 

IIRC (my car is non turbo so its a different sensor) the CTS should basically just be a plug that screws into the manifold and sits in the water flow.. so I would consider taking it out of the manifold to make soldering easier.. but its your choice. Cleaning the terminals (wire side and sensor side) should clear your problem up.. You might consider replacing the spade terminals on the wire harness, but a crimp connection is only going to fail eventually.. However, as I said, it seems to me from reading that solid soldering seems to be the only way to eliminate the problem permanently.

[Gloyale]

To get back to the idle issue, I think you're AAV may be malfunctioning. The AAV(Auxillary Air Valve) supplies extra air to the intake for fast idle during warm up. It is not a sensor, or a solenoid, and the ECU can't "control" it so to speak. It mearly gets 12v from the fuel pump relay circuit. It has a small heating element that warms up after a certain amount of time. Very much like the old auto chokes. Heating up closes the valve and lowers the amount of air entering intake below throttle. It is mounted on top of the T-stat housing so that if the heating element fails the heat from the engine will close it.

 

But if the bi-metal spring that closes the valve has broken or slipped, the AAV will stay open and let too much air into the throttle chamber at idle. The ECU would try to compensate and match the amount of air coming in, raising the idle. Inspect the AAV. Also try plugging it altoghether. If you then get no Idle issues then that is your culprit.

[mentis]

Is the AAV visible in any of the previous photos? I'm not in close proximity to my car at the moment, so I can't go look at it.

 

But those two items are certainly good places for me to check. I'll try to inspect both of them this weekend maybe...

[Gloyale]

 

Shown here on the AAV - (Aux Air Valve) that is also in question here.

 

That is a photo of the AAV. It is mounted atop the thermostat housing. Follow the upper rad hose to engine to find it. The tube you spoke about, questioning whether to connect it before or after the IC, feeds air to the AAV. the other tube coming out of AAV goes to the throttle body, just below the actual throttle valve itself. When AAV is open(cold) air goes from that tube coming out of bottom of the "cooler" you called it? then goes below the throttle into intake to keep the engine supplied with enough air to prevent it from running overrich and bogging during warmup.