Need Advice - Real Bad start when cold- 2003 I35

[joshuahelmer]

Hey guys new here.. well to the I35 forum,got rid of the G35 lease and bought an I35 cash. Since I bought the car I already replaced a bad Crank shaft sensor. Now when the car sits over night and I start it in the morning it sounds like the engine is going to jump through the hood. Real bad knocking sound and valve clicking it sputters and misses and runs rough. After 3 minutes of warming car runs perfect and starts fine for the rest of the day. Its only doing this when its cold. I am going to change the plugs, I dont know when the last time they were changed. But I did some searching and found some threads on knock sensors??? also does anyone know how many crank shaft sensors their are? The one I replaced was on the driver side of the engine under the throttle body. I was reading there might be one by the transmission? Any advice is greatly appreciated the problem is getting worse and I fear its not going to start soon.

[Markc]

Won't be the knock sensor causing that problem. I assume that you've checked the oil level? Have you checked the oil filter to see if it is some no name brand that could possibly have a defective anti-drain valve or not one at all? How many miles?

[loystock]

Welcome to NICO.

Better get a free OBD II scan from Autozone and the likes to find out if you have any diagnostic trouble code. The problem may be related to the Coolant Temp Sensor or as you have mentioned, the crankshaft position sensor. You can also check/replace the air filter and clean MAF sensor (CRC MAF Sensor Cleaner) and connector. DO NOT CLEAN THE THROTTLE BODY - you can easily damage electronic throttle control actuator/sensor. Other possibilities are the Absolute Pressure Sensor and Air Inlet Temp Sensor.

And yes, the KS will not give you starting-related problem but a lousy acceleration due to ignition timing retard.

From your description, looks like you replaced the Camshaft Position Sensor and not the Crankshaft Position Sensor (located near oil pan). Check the condition and connectors of the sensors - Crankshaft and Camshaft. Oil contamination can mess up their operation. Refer to the EC (Engine Control) chapter of the FSM, starting on pages EC-310 and EC-317 from the link below

http://www.nicoclub.com/FSM/i35/2003/ec.pdf

[joshuahelmer]

Thanks the advice loystock,
Unfortunately I already cleaned the throttle body because it was the worst Id ever seen.I went through an entire TB can. Maybe I shouldnt have done that, it explains the tad higher idle. Im pretty sure the pros outweighed the cons though.
I replaced the radiator as it had a leak and needed it, I cleaned the MAF sensor and Throttle body. I also bought plugs and noticed I have to remove the intake manifold, so I changed the front 3 and behold these are the original plugs- 140k miles. I dont know how this car ran - thats nissan! The electrodes were past coroded. I put the 3 new ones in and put everything back together. Took me about 5 minutes to finally get it to start, I let the computer sort everything out and gave a test drive. So much smoother, when I got back the car started like it was new, started it this morning and it was the same result..like new. Im not sure what did it but i am still going to replace the 3 in the back and clean the valve cover up. I am going to pick up an intake manifold gasket and valve cover gaskets while I am at it. I see a little oil around the plugs and there is build up around the head in the rear. Figured why not since I will have the manifold removed. Any precautions I need to take in this process. Anything else you can think I should do while I have it apart. I dont think this car has been tuned up since factory. I will be putting a stillen intake on it and looking into a cattman catback. Also changing the belts. What do you think about changing the transmission fluid, not flushing just changing. Should I leave it be or take the risk?

[loystock]

The drive-by-wire throttle control is very sensitive and easily damaged during cleaning. Several members (with VQ35 and Vk45) have encountered Idle Speed problems (P050x) after cleaning. I clean the TBs every 2 years but last year, the 03Q TB has to be replaced, fortunately under warranty. So for now, I'm only cleaning the TBs for the I30s and 97Q. Aside from sensitive actuators and sensors on the throttle valve assembly, there is also an anti-gunk coating on the throttle plate and throttle body, which when removed, can also cause high idling issue. If you ever have to clean the TB again, just remove the 2 mounting bolts on the Throttle Plate and clean them separately. Never spray directly into the assembly, use rag. On installation, make sure the mounting screws are tight as you risk the possibility of them being ingested by the engine.

The OEM plug are rated up to 105K miles. So they are definitely overdue.

Since you are going to remove the intake manifold, you might as well replace the Knock Sensor. At 140 K miles and with the hard starting issue you've had, it may fail soon.

If the transmission has not been flushed in the last 85K miles, then there is no point of doing a flush as it could make the transmission worse/fail (so much gunk accumulated over the years can get free up by the flush chemical and circulate in the system). Most shops will refuse to do a flush anyway, unless you have any previous record, due to liability issue. Instead, just do a multiple drain and refill, about 3x. But make sure the engine is warm and the ATF level is correct before doing the drain. After refilling the ATF with the exact amount drained (@ 4-4.5 quarts), run the engine for @ 100 seconds while shifting gears and then repeat drain and refill. The fluid will appear like new (pinkish red) after the 3rd drain and refill. If you have time , you might as well drop the pan, clean it as well as the magnets and inspect the filter (replace as required). Transmission Service Kit can be bought at discounted price from NICO sponsor, IoS (Infiniti of Scottsdale) - infinitipartsUSA.com.

You need Matic-D but Dexron III or the newer and better Dexron VI will do the job.

[joshuahelmer]

loystock when I remove the manifold to replace the plugs in the back which gaskets do I need to replace? I see there are intake plenum gaskets and manifold gaskets also is there an upper and lower manifold. All i am doing is removing the manifold, most likely I will need to replace the gaskets with this many miles on the car correct?

[loystock]

Refer to the attached link to 03 I35 FSM (Factory Service Manual), pages MA-17 for Spark Plug Replacement and EM-9 for Engine Outer Component Removal/Installation (intake, collectors, gaskets).

http://www.nicoclub.com/FSM/i35/2003/