June 26, 2013

At long last...

In December of 2010, I parked the Impulse and began tearing it apart.  Even though it only had a hair over 60,000 original miles, the car needed a complete mechanical refresh.  So the motor came out and in April of 2012 I finished assembling everything.  Then things came to a halt as I worked to sort out a problem with the car not idling.  I worked on it on and off over the following months, taking several months off here and there to concentrate on other projects and to ease some of the frustration I was feeling about the Impulse.

The problem was simple.  The car would turn over and immediate stall out.  At first, I thought the problem was with the timing.  But once I was certain that was not it, I thought the problem was related to fuel pressure. After I figured that was not it, it was obvious that it was an air/fuel mixture issue or some sort of electrical problem.

Fast forward to last weekend.  My good friend Tom was in town and we started working on the problem.  He is much more mechanically experienced than I am, which was a great help. We methodically started plugging every vacuum line from the MAF back in an attempt to isolate the vacuum leak that was causing the issue.  For a while we thought it was a vacuum leak at the throttle body, but ultimately, while squirting carb cleaner into every nook and cranny, Tom heard the engine bog down when he sprayed around the injectors where they mate to the intake manifold.

So basically, a tiny gap around all four injectors was allowing a vacuum leak big enough to cause the car to fail to idle, but run smooth if you could get it to turn over and stay running around 3000 RPMs.

So I dug through my bin of parts, and I don't know if it was blind luck or a subconscious memory, but I pulled out the original box that contained the Beck/Arnley injector o-ring kit and I found a little pack of smaller o-rings still in the box.  Voila!

Now, mind you, the original OEM Isuzu injectors had only one o-ring on them.  This being the larger one.  So when I replaced the OEM injectors with a new set, I only installed the large square-shouldered o-ring from the Beck/Arnley kit, assuming the smaller ones must be for a different vehicle with similar injectors.  Bad decision.  Here is a photo:

So we pulled the fuel rail and stuck the small o-rings over the tips of each injector and reassembled everything. Bam.  She started right up and idled just about perfectly.  A few minor tweaks to the timing and idle, and the car now runs smooth as ice. Unbelievable!  All along, it was just this one small oversight that caused the car not to run right.

Left on the list is a complete front end job (bushings, tie rod ends, ball joints, etc) and new brake pads and rotors.  After that, a complete detailing and a new tint job and she will be as good as new.  So, here are a few quick pics of the car as it sits today, and I will post more after a good detailing.

It feels so good to be driving it again.

Special thanks to Tom B. for his expertise and help with getting it going again! You are da man!

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