Hi Austin,

I don’t need any repair -  yet. My question is when.  I have a 1995 Nissan Altima with a metal timing chain on the 2.4L 4-cyl engine.  That engine is great but the upper chain guides get misaligned and cause noise. Nissan eliminated the upper guides in later models, so the usual solution is to remove the upper guides.  That’s a real labor expense, so my question is, what if I just live with the noise?  I’m retired, drive 3k miles a year and the car has 50k miles on it. How much longer can I live dangerously?

Sincerely,

Larry

Larry,

if you are certain that the noise is coming from the timing chain guides….I would replace them. Worst thing that can happen is the chain jumps and causes internal engine damage.   I have not seen of these cars do that but I know they had a serious oil leak from the timing chain seals years ago and it was a big job to replace them. Overhauling this engine because of a timing chain failure would be more money than the car is worth.

This is a sound engine otherwise and will last for years if properly maintained so if you want to keep the vehicle I would recommend the repair now.

Austin Davis

Hello Mr Davis,

I am impressed with your business style. It is refreshing to see in today’s times. Now for my question;

2006 Nissan Altima 2.5 4cyl automatic, bought new in December 2006, it has 52,000 miles on it, has received scheduled care from the dealer it was bought from, Monday of this week the wife went to go to work.

It would spin the motor but would not start, as I was 60 miles away at work and it was still under warranty we had it towed to the dealer, spoke to them later, they said it started but with black smoke, he explained they have seen this in the fuel injected cars when the weather turns cold.

Their explanation, you move the car, you have it running for a few minutes and turn it off, it is running rich because it is cold, it floods, the official Nissan procedure is to hold the throttle 2/3 to all the way and crank for 20 sec at a time until it catches.

I was at work and otherwise distracted and did not think about it until later, but on the plus side they did not charge me, though about it later and did not agree with their assessment, did some internet research and found one reference to a problem with the intake cam valve timing,

have researched this problem and found the flooding is a result and not a cause of the no start condition! The real failure has more to do with variable valve timing.

What really happens:

1 During a cold start in cold weather the oil is very thick.

2 The E.C.M. (engine control module) tests all the components – this happens every start cycle, but this problem only occurs intermittently during cold weather cold starts.

3 The I.V.T. (intake valve timing control solenoid) receives its test pulse, but due to the thick cold oil can drive the intake cam to an over advanced condition.

4 With the intake cam advanced for operation beyond 2,000 RPM and the starter motor cranking the engine below 500 RPM the near static compression is nil compared to the dynamic compression of a high revving motor with an advanced cam.

5 Cold cranking an engine with low compression while injecting fuel results in a flooded engine.

6 Holding the gas pedal down while starting from this failed condition causes more fuel to be injected, more air to flow through the engine and the throttle position sensor to tell the E.C.M. that the throttle is wide open.

The E.C.M. senses the RPM of the engine is at cranking speed (too low for an advanced cam), The PHASE (camshaft position sensor) signals the E.C.M. that the cam is advanced and the E.C.M. commands the I.V.T. to retard the cam, however since the oil is still cold and thick this takes several cycles to work – resulting in more flooding until the engine finally starts.

This was posted on carsurvey.org by the owner of a 2002 Altima

I like his explanation better. I was wondering if you had any experience with this or any knowledge of the problem.

Thanks and keep up the splendid work

Robert
Hey Robert

I am sorry for my delay. I had to attend a funeral in the back country of Utah and did not have access to my computer.

These types of “no starts” are hard to diagnose unless you can catch it in the act and have some test equipment hooked up to the engine. At the time of the no start, the engine either lost compression (you would hear the engine spin over faster and with less effort since there is no or less compression than normal), the engine lost spark at the spark plugs, or there was not enough fuel pressure at the engine…due to a dirty fuel filter or a problem with the fuel pump or a sensor problem.

If you were at my shop we would”

1. Read the onboard computer codes and see if any information was stored there

2. Check the basics – spark plugs, fuel pressure etc. etc. etc.

3. Check for any loose under the hood…vacuum hoses, electrical wires and connections. Things do come loose and corrosion does get into wire connections that can cause haphazard starting

If there were my car, I would replace the spark plugs and fuel filter and make sure I was using the recommended weight of engine oil…most likely 5w-30 just as maintenance and a little insurance.

Blessings,
Austin Davis