V1 Strange Idle Issue

[finazzoty]

It has been driven none - the extent of how far its gone is about 10 ft in the back yard after I let the clutch out. Curious though, how do you come to the conclusion of leaking head gasket?

 

[Gtstorey]

That has always been what it turned out to be with mysterious overheating for me in the past. Cooling system in good shape, thermostat not stuck, water pump moving water, then it's a blown head gasket.

But I thought you were actually driving the vehicle, not just idling. Did you fans cut on before you had the reservoir burp?

 

[finazzoty]

Well every time I turn it to key-on position, the fans cut on (I assume because its so hot outside in Georgia). The strange thing is that it continues to burp. This has happened probably 4 times now where I have to rush over and cut the car off because hot coolant is spraying all over the top of the fuel pump.

I suppose there is a slight possibility that the head gasket is leaking, but its brand new, and the head was just resurfaced when it got ported. There is also no evidence to suggest that the engine is burning coolant, and there isn't any coolant leaking down the side of the block, so it seems unlikely.

 

[Gtstorey]

Radiator fan should not come on with engine on. And I don't think the heat exchanger fan is supposed to come on with key on for the LSJ but I might be wrong there. And I don't know what you have set up with the turbo swap for the heat exchanger.

I have heard of head porting getting into the cooling passages so hopefully you gave it a good visual inspection.

You might want to pick up a vacuum radiator fill kit. Cooling System Test and Refill Kit (harborfreight.com)

 

[escapepilot]

The heat exchanger fan will come on w/ key on in the LSJ Goblin.

 

[finazzoty]

More updates:
1. Swapped the ZZP turbo inlet tube back in and it runs worse than when I had the short DF supercharged MAF tube on there.
2. Pulled the valve cover breather that I installed yesterday and observed that there is absolutely NO oil at all coming out of that valve cover. So that must mean the source of oil is either an internal turbo oil leak, or its coming from the vacuum line that comes from the intake manifold???
3. Gave the throttle a little bit of a push and noticed that the clattering sound completely goes away and then gradually returns as the engine comes back to idle...Which is good news I think?

Also @Gtstorey I checked and the radiator fan does not come on with key-on, I was mistaken. But it does come on eventually.

 

[finazzoty]

Just had another thought on this:

is it possible that there is a vacuum leak coming from in/around the brake booster?

I didn’t even think of this until now, but the other day right after I shut the car off, I noticed a faint hissing noise from from in/around the brake booster. I pressed the brake pedal, there was a sound of pressure release (for lack of a better way to put it), and the hissing was gone.

If there is indeed a vacuum leak, this could cause the idle issue, correct?

 

[Gtstorey]

Yes, it's possible to have a vacuum leak at the brake booster, both internal and on the piping to it. The booster is just a rubber diaphragm that has vac on one side and atmo on the other. You could disconnect and plug at the intake manifold to see.

You really can't swap back and forth between different maf tube layouts and expect it to run correctly. The maf will need to be tuned if it's using it in that situation. I don't know enough about the LSJ tuning to know when it should be using the maf, and of course yours may not be working as stock anyway.

You are throwing a lot of problems out at once. As far as the idle, has your car ever been tuned?

 

[Ross]

I had a vacuum leak at my brake booster. I needed to keep tightening the hose clamp... until the leak disappeared. Shrinking that big hose down took a lot of pressure at the hose clamp. After I made the smoker tester, I did find 4 vacuum leaks in my vacuum system.

 

[finazzoty]

So as far as I can tell there is no vacuum leak. Even ran a smoke test, and nothing - at least nothing that I could see, and I ran it multiple times.

@Gtstorey yes it has been tuned by ZZP. I’ve been going back and fourth with them for weeks on what the issue could be. Here is the most recent (and it appears final) email I have received from them:

So it appears fuel is not making from the rail to the intake port. I’m going to pull the fuel rail today and see what I can find.

I will say this though - I’ve noticed that right when I turn the key on (not start, just key on), the fuel pressure gauge will jump to 45 which is where it is supposed to be and then will fall immediately (to about 20 or so I believe - will double check when I get home). If I remember correctly, when I did first start back a few months ago, this did not occur - it held at 45psi. Is it possible that this could be caused by a bad fuel pump relay or inserting the fuel pump relay incorrectly?

 

[Rauq]

On key on engine off my fuel pressure regulator jumps to 42psi, and then if I key back off (turning the fuel pump off), it falls to about 30. If your fuel pressure never comes back up, it sounds like the pump is only running for a second and then not running ever again after that. That, to me, would point to an issue with the pump or relay.

If I were to pressurize my fuel system, then unplug the fuel pump, then start it, it might fire for a second, but wouldn't run for more than a few seconds like that. If you can still manage to idle for a minute, then that, to me, would point to an issue with the relay.

Are you using all new parts? If it will idle, can you pull the vacuum line to the regulator and see if that changes anything? I've read about some crazy regulator failures before.

One additional note, on my car, on key on engine off the fuel pump will run for about 5 seconds, and then turn off, and doesn't turn back on until you key off key out for about a minute, or send a crank signal (key to start). The fuel pump will not run continuously upon key on engine off. I idle at about 36-38psi of fuel pressure.

 

[Fozda]

Do you have any pictures of your setup?

 

[finazzoty]

@Rauq yep all new parts. New stock fuel pump, brand new fuel rail and injectors, new regulator. If I pull the vacuum line, the car will start and then pretty much immediately die.

@Fozda files attached

 

[escapepilot]

I doubt its a relay issue but that is easily tested by swapping it with another. Can you log fuel pressure while running to see if it is steady or surging? If you add a little throttle, does the surging quit? If you release that little bit of throttle back to idle, does the surging return? Can you remove the air filter and observe the throttle blade while it's surging? - Grasping for anything here really.

 

[Gtstorey]

Might be interesting to see the log that ZZP used to say that it was a fueling issue. Did ZZP provide the Injectors? Have you confirmed pressure with a manual gauge?

 

[finazzoty]

I doubt its a relay issue but that is easily tested by swapping it with another. Can you log fuel pressure while running to see if it is steady or surging? If you add a little throttle, does the surging quit? If you release that little bit of throttle back to idle, does the surging return? Can you remove the air filter and observe the throttle blade while it's surging? - Grasping for anything here really.

So when I give it throttle, the surging goes away completely. When I release it, the surging returns. Because it’s on a turbo tune, I don’t think it will run at all if I remove the charge pipe to see the throttle body. Watching the fuel pressure gauge, it does fluctuate when the surging happens. When the RPMs increase, the fuel pressure drops.
Here is a video of that happening:

IMG_6292.MOV

drive.google.com

 

[Rauq]

I have a lot of speculations, but before I offer them, what's your wideband O2 reading during all of this? Because some of my guesses are that you're running pig rich, but Al makes it sound like you're not getting enough fuel into the engine, e.g. running lean.

Your video of fuel pressure doesn't suggest to me that there's anything wrong with the fuel pump, relay, or regulator. Something's causing the surging, though, and I believe we can figure this out.

 

[finazzoty]

I have a lot of speculations, but before I offer them, what's your wideband O2 reading during all of this? Because some of my guesses are that you're running pig rich, but Al makes it sound like you're not getting enough fuel into the engine, e.g. running lean.

Your video of fuel pressure doesn't suggest to me that there's anything wrong with the fuel pump, relay, or regulator. Something's causing the surging, though, and I believe we can figure this out.

I actually have not installed the wideband yet. I can make that a project for today potentially though. Do you happen to know if there a good thread on wiring one of these? I have the AEM X-Series UEGO (NOT the OBD II one) that ZZP sells.

 

[Gtstorey]

Wiring Wideband O2 Sensors | DF Kit Car Forum

 

[escapepilot]

Wiring Wideband O2 Sensors | DF Kit Car Forum

Keep it up GT and you're going to be as useful as Ross.