n00blar

Well, after replacing that heater valve now my sensor light comes on (on my '81 ZX this the the top left light on the cluster gauge).
Good old Haynes says that this is the Exhaust gas sensor warning lamp, now my question is; does this mean that the exhaust gas sensor is bad or could it be something else?
Coincidently, I've been hearing sort of a humming/buzzing noise under my car and I can't really pinpoint where that buzzing noise is coming from. The noise is on all times from idle to when I'm driving. I've set the ignition key all the way to ON (before getting the engine to crank) and the buzzing noise doesn't come up there, so I don't know what that noise is all about.

naviathan

When putting it all back together you probably hooked up a green and yellow wire under the passengers side of the dash. This is the 30,000 mile checkup light and is disconnected by the dealership after said mileage. Just disconnect it again as it's unneccessary now.

n00blar

Hmm...I will check on that. Thanks

n00blar

Yup, that did it. Thank you!

n00blar

I have come up with two other things that have been going on with my ZX.

1. I've been hearing sort of a humming/buzzing noise under my car and I can't really pinpoint where that buzzing noise is coming from. The noise is on at all times from idle to when I'm driving. I've set the ignition key all the way to ON (before getting the engine to crank) and the buzzing noise doesn't come up there, so I don't know what that noise is all about.

2. I turn the car on and let it idle for about 15 minutes. After 15 minutes it begins to sputter and shake...it goes back to its normal rhythm. A couple of minutes later it sputters and shakes again - goes back to normal rhytm. Eventually it sputters and skakes and it turns off.

Any suggestions on what may be going on?

RodMoyes

Sounds like the fuel pump to me...

Rod.

jfairladyz

yeah, sounds like the pump is taking a dump. The sputter may be from fuel starvation as the pump is quiting.

n00blar

Do you guys recommend buying a brand new fuel pump? I ask this because I do have a 'parts' '82 ZX in my backyard.

duowing

I'd say if you've got a parts 280zx, take the pump off that and throw it on your running ZX. You've got nothing to lose and switching the pump isn't a huge deal or so I hear. I'd say it's worth it to give it a try. Might save you money, might not.

SHADY280

easy to switch, just needs some ramps or jackstands and its forward of the tank pass. side

n00blar

Yeah, that's it...I actually put my ear to it and that's where the noise's coming from.

Gonna read Haynes on some 'safety' and 'tips' on how to get this baddy out.

I will try the one from my spare ZX as Advance Auto has it for $96.00 and that's the cheap one!

Thanks guys

n00blar

Ok, the fuel pump from my spare ZX is out.

One quick question though, I noticed that there's some sort of ceramic/hard glue covering the + and - connectors - does that ceramic/hard glue have to come out in order for me to remove the + and - cables?

Since I'm doing this on my spare ZX, I pulled all the wires from the back of the car; obviously I'm not going to do that on my drivable ZX.

n00blar

Ok, the spare from the 'parts' ZX is louder than the one I had on my ZX. So, I guess I must buy a new one.

jfairladyz

The noise isn't a problem. The pumps are noisy. The problem was with your car cutting out. Dont replace it based on how loud it is. How is the car running now with the swapped pump?

n00blar

Same problem; after 10-15 minutes of turning the car on and let it idle...it sputtered and shut off. One thing I found though, this fuel pump got increasingly loud..very loud.

jfairladyz

have you checked fuel pressure yet? Hook up a fuel pressure guage and check the pressure. Keep an eye on it so you can watch the pressure as the car dies.

n00blar

Ok, now I'm totally confused and clueless.

I got a brand new fuel pump; however, it's lauder than the stock ones! Here's what I mean by loud. I used my camera to record small videos so you guys could hear how loud this new pump is, so I'm thinking there's gotta be something else that's wrong with my car.
Could it be that I was given a defective pump? The car did take a long time to crank with the brand new pump, but I was thinking maybe because there was no fuel in the pump. This goes over my limited knowledge and I don't know where to even begin.

jfairladyz

The system will have to prime after you change the pump so that's probably why the long cranking to start. So did the new pump fix the problem with it cutting out?

Dont be concerned with the noise as part of the problem. You can try to further insulate the pump so it's not so noisy in the cabin if it's too much.

n00blar

No, still cuts off after being idle for about 10 minutes.
Also, is it normal for water to drip from the gas exhaust pipe?

jfairladyz

yes. thats normal. It means the combustion process is producing H2O. No big deal. Of course, this shouldn't be happening with the car off

How is it idling? Does it idle fine within those first 10 minutes or so? Does it just idle, or can you rev it during this time? If the car is running fine before hand then you might want to suspect the cylinder head temp. sensor.

n00blar

The car idles just fine for the first 10 min or so, towards the 10-12 min mark the car begins to shake and sputter a bit. It goes back to normal for another minute or so, then it shakes again and and begins to lose its normal engine rythm. It shakes again and eventually loses power and it dies.
Now, during the times that it shakes and it appears to lose power; I can step on the gas and the car regains power and continues to idle fine for another minute. Stepping on the gas and revving the car does seem to stop the car from shaking and stalling, but if I don't step on the gas, the engine shakes and eventually loses power and dies.
However, when I drive the car I don't see that problem as much (maybe because I don't let the engine idle for such a long time), so I only see this problem when the engine idles for a while.

jfairladyz

and what happens if you try to start it again right after it dies? Does it start back up or do you have to wait a while like it needs to cool down? Check for proper EGR valve operation. And check the vacuum hose to the Thermal Vacuum Valve (follow line from EGR). The TVV or EGR may be creating a vacuum leak as the engine warms up. The TVV prevent vacuum from signaling the EGR while the vehicle is cold. But once that TVV opens as the car warms it could be allowing for the vacuum leak. A vacuum leak usually wont affect the vehicle if you have the acclerator depressed but it can kill a car at idle. it could also be recirculating too much E.G. at idle which is causing the motor to die.

If the vehicle wont start right back up then try starting it back up with your foot on the gas and see if that helps.

n00blar

Yes, the car starts back up again after it dies. I do have to give it some gas to start it back up though, but it does come back up.

jfairladyz

Once it's back up will it keep running or will it go through this routine again? If it's still cutting out after you start it back up, does it happen right away? Or is it another 10-15min before it starts acting up?

n00blar

It cuts again after I start it back up. Yes, it happens right away if I don't press the gas pedal.

Here's something that happened today. I finally drove it all the way to my office...which is a good 38-40 miles from my house to my office. As I was exiting the highway and I stopped at the first red light, the car began to shake and engine began to stumble. Engine cut off, but I was able to get it to run again.

On my way back home from the office, to pick up a new gas pump, I get to the auto parts just fine. I had it parked for about 5-8 minutes while I was getting the new pump. I head back home and engine stalls as I slow down to the a stop sign. Engine stalls twice and this time I have to put the car in Park and crank it that way.

I install the 'new' fuel pump. Engine won't stay idle for a minute, it dies if I don't step on the gas. And once again, this fuel pump is louder than the original...way way too loud, at times louder than the engine itself! .
I'm thinking the problem is not with the fuel pump, but something else.

I don't really know what to do now and it's frustrating the hell out of me. I just hate it when I don't know how to fix something.