How to: Starting my 00M12 Installation

[heddykevy]

Thanks for the responses

Since I've never tackled any sort of auto repair on my own at this point, I brought the car in to a mechanic. Of course, the weather warmed up around here recently, won't be cold until next week, so he couldn't reproduce the problem.

He did a whole lot of tests, and said that everything looks fine, no vacuum leak (while it is warm), and says that he thinks that it is the IAC motor that is the problem, wants to charge me $250.

Does this sound right? Would temperature effect the results of this vacuum test? I'm tempted to just get in there and replace the gaskets/clean the IAC valve and mannifold myself, but again, I have NO experience with this, and while I feel confident that I can follow instructions, the last thing I want to do is mess this up further.

Thank you for your help.

 

[heddykevy]

And to clarify, I specifically asked the mechanic if the cold weather would affect the outcome of the vacuum test, to which he confidently said, "no." He says that he is "fairly confident" that the IAC motor needs to be replaced, but he would "hate to just take a gamble on that."

 

[2000StreetRod]

replacing IAC valve

I don't know what year your vehicle is but the IAC valve for my 2000 is $114.06 from Tasca. After market ones are cheaper. It should only take you about 10 minutes to replace the valve. That might be a good starter project that eliminates one potential source of your problem. I assume that your problem is high idle at cold engine start.

 

[thorney_5]

Replace tensioners?

Sorry for the old(ish) bump.

Dale, is it wise to install this kit (tensioner, intake gaskets are obvious) as preventitive maintenance? I consider myself blessed with nearly 153,000 miles of completely rattle free operation. I would like to keep it that way for as long as possible, because currently my bank account is not terribly friendly with the number "5.0". If my research is of any use, I believe there is another tensioner just aft of the number 3 spark plug hole, in addition to the jack shaft chain tensioner. Part numbers are no issue thanks to your part numbers thread, but wow are they expensive.

Common sense would say to replace all of them, but along the same line of thinking that 200,000 mile ATF should be left alone, I am in doubt. This is why I am here, asking you. Your expertise on the 4.0 SOHC is second to none.

As for the rest of the kit (gaskets), I hate to even imagine all that carbon sitting in my intake. Cleaning of the intake(s) will take place regardless of whether or not the tensioners will be replaced.


Thanks in advance.

 

[2000StreetRod]

replacing hydraulic tensioners

I used to recommend that the left (front) and right (rear) hydraulic tensioners be replaced every 75K miles because the spring weakens with age. The spring tensions the jackshaft to camshaft chain by pushing the cassette guide against the chain. It is needed when there is no or low oil pressure (engine start) and the hydraulic piston is not effective. However, members who have purchased the tensioners in the last year have noted that the spring pressure of the new one is often weaker than the old one. Therefore, I suggest that you not replace the tensioners as long as there is no cold start rattle. My 2000 Sport had leaking upper and lower intake gaskets at 150K miles and a significant cold start "flare". If your gaskets are original they are probably dried out and leaking. That means unfiltered as well as unmetered air is being pulled into the intake manifold. When the PCM is in closed loop it can compensate (up to fuel trim limits) for the unmetered air but the air/fuel mixture will be lean when the PCM is in open loop (engine start and moderate to full throttle). I suggest replacing the upper and lower intake gaskets (inexpensive) and cleaning out some of the deposits from the EGR (time consuming but also inexpensive).

 

[thorney_5]

Thank you, that's just what I was looking for. I have noticed a cold start flare after this winter, and I'll probably take a look at the fuel trims this afternoon.

 

[BMiller]

$17 in gaskets and 3 hours of my time (taking my time) and my CEL and rough AM starting problems are gone. It runs and pulls better too. Thank you for the write up!