started but does questionable things thread
 

I finally got my s4 to run after parking it in October because of low oil pressure and smoke. The problem was the OMP was rigged to think it was at full throttle, the PO was premixing, and the low oil pressure was because the front cover's o-ring was blown out(Also an oil cooler line had a slight leak).

The emissions were removed already and a few of the plugs on the harness were broke but held on to the sensor with wire. Most of them were fine but I broke the water thermosensor plug. The car runs but it won't hold idle. It drives but.. not very well. It seems to want to die under 1k rpm or so. It didn't smoke any and the oil pressure is where it should be.

The car also is making a weird wooshing noise that I need to figure out as well as a loud buzzing. The buzzing isn't from any of the fluid warnings that I know of. Everything is full and plugged in. I'm thinking that maybe it has to do with the brakes because the rear brakes were making noise too. I had to have it towed and they pulled it on to the trailer while the handbrake was up.

I didn't drive it for very long, just a circle around where my house is to see what all needed to be fixed and make sure that nothing was messed up internally from doing the front cover swap with the engine in the car.

TL:DR Questions
1. Is there anyway to tell which wire goes to which prong on the water thermosensor? The plug was shattered so I had no way to check it before re-wiring it.
2. Would a small water pump leak cause the car to run differently? The water pump to housing gasket has a small leak in it. I assume that doesn't matter but rotary.
3. Is there any way that the engine would run this roughly just because the front thrust bearing(that's what drops when doing the front cover in the car right)?

There are two terminals to the water thermosensor and it should not matter which terminal gets which wire as long as one gets the wire from the ECU and the other gets the ground wire. And the car would likely not run or drive well w/o the sensor plugged in and working properly.

hm. I had it plugged in and it was running questionably. I am going to remove them and double check. However, I think I may have already found the issue.
I thought I was just bleeding the air out of the cooling system but it started exploding out of the water pump hole. I am starting to lean towards a coolant seal or even part of the water jacket wall being bad. It sat for 8-9 months almost ready to be pulled because I had an accident and fractured two vertebrae. Maybe the anti-freeze/water/w/e corroded the housing or ??

That would explain why it runs so rough. I'm going to pull the plugs in a few minutes and check to see if there is any liquid on them. I hadn't even though about checking something like that because when I bought it; I drove it around 4 hours home.

If the plug was not mating the wire pins to the terminals properly it would cause driveability issues. The check is rather easy as the G/Y wire at the ECU should read 2 to 3 volts w/key to on and the engine cold and .4 volts when warmed.

Gee, I'd suspect the waterpump before seals in this scenario.
Typically, a pressurized system- or in this case, if the seals were bad, an overpressurized system- would pump out of the recovery tank, not the waterpump.
The pump can hold a lot more pressure than the 13psi allowed by the rad cap.
If the pump is spewing coolant and the rad cap is holding, it's the pump that's failed.

Sht. I meant, the radiator cap on the water pump/thermostat housing. I had the cap off and was filling it up. I am used to s5's where you just bleed it by running it with the heater on and you fill it up as it needs it.

I thought I already posted here that is weird. I got it to idle when warm pretty well so I started checking for vac leaks as it still ran really rough; bucking and not wanting to accelerate. However, you could WOT and it would drive mostly okay. I found a vacuum leak that seemed large where the upper and lower intake manifolds connect. However, whenever I took it apart it was only a small part of the gasket that was missing.
How big of an effect on the car running would a .. 1/4inch to 3/4inch strip of gasket missing from the intake gasket have?
I'm replacing it all tomorrow and hopefully it will run normally but that is doubtful.
I will stop spending money on it and just pull it though if the compression numbers come back bad.

Edit: I thought I'd add this in here but the PO also removed the thermowax. I didn't even notice it until I took the intake off again today but it is missing the thermowax and the first set of butterflies in the throttle body. I know that this on top of all the other emissions being removed will create some issues with the idle/starting. However, I've had full stripped s5's before and you just have to help it idle for a few minutes after it starts. Helped me learn how to heel-toe. I just thought it might help someone else help me figure out what else it could be.

check my last? maybe second to last video in my build thread. for under $10 a vacuum tester can be made and will reveal all.

You could make a diagnostic port LED checker, but I doubt you will be showing a code.

I just brought back a 20 year no start, not saying you couldn't have blown seals, but after what hell on earth came out of my engine and how nicely it runs now, I'd be more patient.

I've got it fixed now. I still have to check the compression and make sure the cooling system is good but there aren't any leaks other than a small oil pan leak which I'm not worried about right now. The oil pressure is fixed I used a crush washer for the front cover o-ring after someone else suggested it.

However, now I don't have any vacuum leaks and my car runs rough at low rpm. It will hold idle now but when you pull off sometimes it will die/hesitate/buck. However, I got it warmed up and did a WOT 1st pull on a dead end street where there weren't any houses and it accelerates fine. After 2,000-2,500 rpm you can't tell there anything wrong with.

Could this just be from where I have to adjust to where the thermowax and the first set of butterflies were removed? Maybe TPS? I'm just brain storm out loud, if anyone has suggestions I'd appreciate help.

(Also, clokker, I love your build thread. I'm sort of in the same place you were in at the start of yours. I am 24 but I fractured two vertebrae and I can't work now so I have all the time in world but none of the money.)

Alright, this will probably be my last post here for a few days. I've concluded that the idle problem is simply a result of the car having all of the emissions, cold-start system, and the first set of butterflies in the throttle body.
Once I adjusted to it it is fine in the lower rpm. It won't idle on its own cold and it won't idle if you stop abruptly. Now I have to figure out how to fix my emergency brake and I'm going to remove the power steering rack and de-power since I have to get down there to replace a wheel bearing and a tie-rod end anyway.

Mods, I'm using this as my build thread if that is alright? Once my settlement finishes up I'll have money for all the bling stuff people like to see.

Alright, I thought I'd give everyone an update. I blocked off the BAC because there was a vacuum leak and since everything else is removed I figured I might as well remove it as well. I removed the dashpot because it wasn't allowing the throttle to close back all the way.

Now it is idling at 1000ish cold and 750 warm. It runs so good, like way better than it should after having everything removed. The oil pressure is still good as well. 20-30psi at idle and it goes up 80-90 around red line. It also doesn't smoke so my theory about the OMP being wired + over premixing causing it was correct. I drove it for around an hour last night and it didn't overheat, lose oil pressure, or catch on fire. So I guess this was a small victory.

Now I have to fix the parking brake and the front driver's wheel bearing.
<iframe width="854" height="510" src="//www.youtube.com/embed/OelDLWfkfaM" frameborder="0" allowfullscreen></iframe>