This may be long, but I want to provide as much info to help as possible - car is a 2000 corvette:

Saturday night: Bought some gas, came home and cleaned engine compartment with some orange cleaner and spray water from hose. Dried everything with towel, put away for the night.

Sunday: Drove normally about 20 miles running errands

Monday: Did not drive car

Tuesday AM: Took car to dealer to fix cruise control. Was going to have them look at code P1637 (generator l-terminal) and P1111 (IAT voltage intermit. high). Decided to just have them fix cruise due to cost.

Tuesday PM: Left dealer, drove home with working cruise control. Got check engine light, traction control warming up, and new codes: P1637 again, P0113 (IAT voltage high) and P0327 (front knock sensor)

Wednesday: Followed diagnostic steps in service manual, isolated problem for code P0113 to a broken connector wire. Repaired that with a new pigtail. Found that was also related to traction control warm up from past posts. WHILE AT IT, CHECKED VARIOUS GROUNDS FOR CORROSION, TOOK BATTERY OUT OF CAR TO CHECK FOR LEAKS FROM BATTERY. Found none, put battery back in and hooked back up.

P0327 (front knock sensor) code still current, but check engine light is off.

Drove around all day - check engine light is still off, but after clearing P0327, it came back again. Tried this twice - cleared code, it comes back.

The prospect of taking off the intake manifold isn't something I look forward to - it would be the most involved project yet for me.

I assume I must have screwed up the knock sensor when I washed the engine bay. I have not bought more gas yet - could it be the gas was bad? Again, the check engine light is NOT on - was on before we took battery out, but off when we put the battery back in and hasn't come on since, despite this code. I thought P0327 would make the check engine light come on.

Please advise. If we do end up going the route of replacing the knock sensors, what else is there I should go ahead and replace since I will have gone to the effort of taking the manifold off? wiring? oil pressure sender?

Again, I know this was long, but I wanted to provide info that might be relevant. Please advise if you think there is anything I should do before jumping to the stage of taking off the intake. Thanks!

I am teaching myself all of this, and still nervous about it all.

 

There is a good chance washing the engine did precipitate the code. There is a TSB about the knock sensors, and putting a bead of RTV around the covers to keep water out. Unfortunately, you'll have to pull the manifold to access them.

 

The more I read the more I think you're right about the water being the problem, unfortunately.

Looks like the check engine light was on due to code P0113 (IAT sensor voltage high). Now that it is fixed, that would explain the check engine light being off, right?

Anyone else have thoughts on this? Shuld I replace anything else once I take the manifold off, or just replace both knock sensors for good measure?

-David

 

While this refers to the rear sensor, you can use it as a reference for the RTV.

 

When reinstalling the intake manifold, it appears there is NOT a gasket that needs to be replaced.

Am I understanding this correctly? Reinstalling the manifold does NOT require a new gasket?

-David

 

By the letter of the law(service manual), they call for replacement. When I pulled my intake manifold, I inspected the gaskets, and found them in perfect condition, so I reused them. Many others have done the same with no ill effects. Let the condition of the gaskets be your guide.

 

They aren't really gaskets in the traditional sense, rather more like formed o-rings which aren't round in any way. Unless your's are messed up, you can probably get away with not replacing them as lucky said. Taking the intake off and putting it on agtain, is easy. The rear two bolts on the opposite sides are the only problem and if you use a piece of tape to hold them up just right, life will be good for you. Consider extending slightly the vacuum tube for the HVAC since you'll be disconnecting it. Doing so will also make that real easy.

 

When I did my knock sensors, I did both and the well bottoms they sit in since one had some oil in it, I also replaced the small harness that connects them since the ends were very brittle when I removed them. I also used all new gaskets-almost wish I would have relocated the Oil sensor at the time.

 

I have ordered the new knock sensor wire harness and two new knock sensors. I think I will assume that the gasket can be reused, and if needed, I can replace it with a Fel-Pro set I can get locally for $20.

Should have the items some time next week.

 

it's a pretty easy job

 

David,
I would also replace the Bank 2 A.I.R. Check Valve when you have the manifold off. Mine failed (P1416 code) at about 30k miles.

Follow lucky's advice about sealing the knock sensor cavities with RTV also. It was definitely water intrusion that caused your PO327 code.

The Fel-Pro gasket set is what I also used.

 

I had to do this on the 6.0 engine in my truck. The rear sensor was corroded. I replaced both of them with aftermarket units, reinstalled doing the RTV seal like on the TSB, code comes back! One of the new sensor is out of specs! I didn't check it before installing it... I really didnt feel like taking the intake apart a second time, so I plugged the rear sensor signal to the PCM onto the front one. Been working that way for over a year with no troubles. I wished I had done that before replacing the sensors! Got a bunch of pics if that can help you out.

 

Good idea replacing the harness as well.. did the sensors in my buddies 02 and the clips get brittle and shattered when removing them. Be carefull not to pinch the harness between the intakes when reinstalling, heard it to be a common problem causing knock sensor codes after reinstall.

 

What an ordeal this has turned into! Got both sensors replaced, and replaced the wire harness at the same time. The front sensor was clearly bad - heavily corroded and covered in a white jelly-like material. Cleaned out the mounting location real good and set about reassembling things.

That damn 1/16" vacuum hose at the rear of the manifold is a huge problem! We're reassembled everything 3 times now, and each time that damn hose pops out and you hear the vacuum hissing when the engine starts! Good news I guess is that the car does start.

When we disassemble again, we're going to work on extending that hose first, since it is clear that we are not going to be able to get it reattached as is. Any tips on reattaching that hose or what to use for an extension?

Also, when we restarted the engine, we had not ever disconnected the battery. The engine sounded as though there was a tick or knock at idle. I am assuming that is because we need to disconnect the battery and then re-train the PCM for the correct idle, as outlined on page 6-1057 of the factory service manual?

 

I extended the vacuum line by adding a 4" length of 1/4" vacuum hose, and a 1/4"x1/4" barbed hose connector.

Attach one end of the 1/4" vacuum hose to the manifold vacuum tree, and push the barbed hose connector into the other end of the new 1/4" hose.

Then you can connect the 1/4" side, of the existing 1/4"x1/8" molded rubber adapter, to the other end of the 1/4" barbed hose connector.