angelyno55

Hello...
i purchsed a '01 996 with no engine in it, and than i got an engine for it supposably with 61k on it. Now it's already on the car, but when i started up, threw me a few codes. 0300 multiple missfire, 0306, 0304, 0305, 0117 engine coolant temp circuit low imput, P1397. I don't know anything about the engine history. The guy who i bought it from said that the engine was running well.
Any advise woul'd be apreciated.
Thanks in advance

Macster

Misfires with a coolant temp circuit code suggest to me the coolant temp sensor may be bad (or the circuit/wiring) and the coolant temp supplied to the DME is wrong and the DME doesn't supply enough fuel and misfires (lean ones or the CEL would flash) are the result.

P0117 - engine coolant temperature - malfunction. An excessively low voltage signal from the sensor is sent to the ECM (DME).

Just in case you want to get all kwazy with a volt/ohm meter... from my references: Caution do not use ECM ground terminals when measuring input/output voltages or signal! Doing so may result in damage to the ECM or otehr components. Use a ground other than the ECM terminals such as the battery ground.

Anyhow, a fault is recorded after approx. 0.4 seconds if the measured engine temperature is lower than the calculated engine temperature minus approx. 68F.

There's more believe it or not 5 tests. Too much to type in. If you PM me I will make a PDF copy and send you the PDF file.

Or... with the engine dead cold -- or at whatever temperature the engine was at before when the symptoms have appeared -- use an OBD2 code reader/data logger to view the intake air temp and coolant temp at engine start and after. If either differ too much from each other or ambient the sensor with the reading that differs most from ambient and the other sensor is the suspected bad one.

But I suspect it is the coolant temp sensor. Throw money at the sensor or throw time at using the OBD2 test tool to try to nail this down. (I know what I would do: I do not go anywhere without an OBD2 code reader/data viewer in my Boxster.)

Oh about that P1397 error code...my references are it is a camshaft position sensor 2 signal implausible.

Briefly this is recorded when the engine is running and it is a loose contact or a bad camshaft position sensor. Since the car is new to you and the engine was added afterwards you have to suspect a loose contact. Someone just didn't this connector connected right. Or the harness was damage during install or the position sensor is bad.

If both sensors are bad the engine can take longer (10 seconds?) to start and the timing can be retarded. This is another reason for the OBD2 code reader/data viewer...you can look at ignition timing.

Could the misfires be related to the sensor error?

Well, all the misfires were on bank #2 and note the camshaft position sensor is the #2 sensor.

Stranger things have happened.

Or there could just be two problems: a bad coolant temp sensor and a bad camshaft position sensor connection or sensor.

Anyhow, checking out this sensor is a bit more work and unless you're a pretty good shade tree mechanic I'd advise you to have this looked into by someone with a Porsche test computer and the know how to use it.

Sincerely,

Macster.

ChristopherG

As Macster mentioned cam shaft position sensor and all misfires on that bank make sense. If the misfires were coolant temp related I would expect them to be on both banks.

Coolant temp sensor is probably also bad.

angelyno55

i see. thanks for your answers. decided to replace the IMS bearing, and along with it, one of the blocks (it's cracked, welded with some kind of welding glue). i have the original engine which is apart, so i have parts for this one. now, oi have rebuilt a few engines, mostly vw and audi. i heard that porsche is i little complicated. special tools and all that. have you guys rebuilt one of these engines? any advise what should i do and what shouldn't? and also, how can i check the cam sensors with a volt/ohm meter? actually i'd like to check all the sensors, knock, cam .... woul'd be a big help if someone could give me some directions....
thanks again!!!

ChristopherG

I hate wiring and usually take the lazy way out. If the computer throws a code for a sensor I just change it out and only if the code returns start digging through things with a volt meter.

Macster

If I read your post correctly you cannibalized half an engine (one of the "blocks") to and combined it with another half a block from another engine make a whole engine, well a complete engine block consisting of the two cylinder block/banks?

I'm not sure that's allowed. I would not expect the block halves from one engine to be interchangeable with another engine.

It is like the main bearing caps on a (for instance) V8 engine in which the block is machined with the main bearing caps in place. They are not IIRC -- it has been a few years since I rebuild my last (not a Porsche) engine -- interchangeable between engines.

Generally any time you have two pieces that bolt together and are machined as one unit these pieces belong together from then on.

If one side has to be replaced the unit needs to be remachined. In the case of say having to replace main bearing caps the new caps would be picked to have a smaller main bearing diameter then the block carefully positioned on the boring mill table and the boring bar cutting tool adjusted to just graze the original main bearing bore diameters of the block and of the original main bearing caps removing material only from the new ones.

This preserves the original dimensions of the engine, which one assumes were within factory acceptable limits.

(Yet another technique would be to take a cut off the surfaces of the block to which the main caps bolt to which then results in a smaller (and no longer round) main bearing bore at each main bearing, then again properly positioning the engine block on the machine table boring out all the main bearing bores keeping the same centerline and of course to the proper diameter for the bearing shells to be used.)

If you want to check all the sensors you are going to need access to a factory manual that lays out the steps based on one or more error codes that point to the sensor of interest.

You might be better off just seeing what (if any) error codes appear and then going after that particular sensor.

If you suspect one or more sensors are bad you might be better of just replacing them outright vs. testing them as ChristopherG mentioned in one of his replies.

Sincerely,

Macster.