The View from hStreet

On Saturday, September 14th we had another hStreet Cars and Coffee.  What made this one special was the view from the top floor of the Capital View parking garage!

It was a morning of great conversation and great rides with all cars making their first hStreet appearance.

Throttled Up

The throttle linkage assembly on my 280z had always been somewhat of an eyesore in my engine compartment.  Recently I decided to do something about it.

Removing the linkage was pretty straightforward and entailed a few bolts, a nut, e-clips and a cotter pin.

Using mostly wire brushes on a drill as well as a Dremel, I removed 40 years of gunk from the pieces and prepped them for painting.  To simulate the look of the cadmium-nickel plating, I use a Rustoleum product called Metalizer in the color of Champagne Mist.  While it's not a perfect match to the plating, the color is pretty darned close.  The below picture shows an area of the linkage that was not painted since it slides into the pivot assembly.  Since this area was behind a rubber boot it was fairly protected and retained much of it's original plated finish.  You can see below where the painted area meets the plated area.

Once the paint had cured the parts were greased where appropriate and returned to their home.  Another small item off my punch list.

Solid Distribution

At some point (likely during the engine swap by a previous owner) the distributor in my 280z was swapped for a later unit; this was a common modification.  One thing that I didn't appreciate was the way in which the trigger wires were spliced using acorn-style crimp connectors.

Not only is this style of connection susceptible to loosening over time but the way this particular splice was performed left the connection open to the elements and corrosion.  I removed the radiator for maintenance so I decided to clean up this splice while the area was open.

To properly splice these connections I first cut the connectors out and removed a good bit of the brittle sleeve over the wires.  I then slid larger heat-shrink tubing over the old sleeve to act as the outer layer of protection.  I then slid individual heat-shrink tubes over the individual wires to cover the joints once soldered.  The next step was to strip and solder the individual wires.

I slid the individual heat-shrink tubes over the wires and used a heat gun to set them.  Note the glue on the edges; I just discovered this type of heat shrink tubing and it is now my preferred protection for wires.

Finally, I moved the outer tubes into position and set them.  This gave me a splice that is not only protected from the elements but also requires a close look to determine that it is not as delivered from the factory.

The Smoking Chamber

The next find from my DIY smoke machine was a leak around the throttle valve shaft.

One of the common issues with the L28E engines that could contribute to idling issues is the BCDD (boost controlled deceleration device) mounted to the bottom of the throttle body.  This leak is a great reason to not only clean and rebuild the throttle body, but also check out the BCDD as well.

Removal was quite simple since I already had the air flow meter removed.  Four bolts and the assembly came right off.  In this picture I had already removed the dashpot and bracket.

Removal of the throttle valve itself involved removing the throttle return spring and linkage from the side of the body as well as the throttle position sensor.

Then the two screws holding the throttle valve plate to the shaft could be removed and the shaft slid out the side.

At this point I used throttle body cleaner to thoroughly clean the body, valve and shaft.  Upon inspection of the shaft, I found no apparent wear and the shaft fit fairly snugly into the body.  Not wanting  to reassemble without addressing the leak around the shaft, I addressed the leak from two directions.

First, I used silicone grease to lubricate the shaft bushings.  This likely would have addressed the leak for some time, but I wanted to take it a step further.  I then decided that a perfectly spaced o-ring that barely touched the throttle body when it was closed would prevent a leak at idle (where the leak would make the biggest difference).  To do this I mounted an o-ring on the throttle valve shaft and used a thin piece of aluminum (from the bottom of a Coke can) to space the o-ring.

The spacing is critical because no lateral pressure can be applied to the shaft otherwise the throttle valve will bind; it was meant to have some free play from side-to-side and the closing of the valve would center the shaft.  In my case the o-ring ever-so-gently came to rest against the body when the valve was closed.  Some silicone grease on the o-ring will hopefully prevent it from shrinking for some time.

I then moved-on to the BCDD.  I once attempted to adjust the BCDD to see what impact it would have on my idle issues, but the set screw against the adjuster was frozen.  With the throttle body off the car I should be able to loosen this set screw easily.  Well...

So much for that idea; the set screw sheared.  The good thing is that with the unit removed, I can drill out the screw easily.  the other good thing is that the BCDD has two set screw locations, so I don't need to tap the hole that I drill and thus I won't have to disassemble the unit.

I reassembled the throttle body and reattached the throttle position switch.  I adjusted the switch such that the idle position was triggered at the very end of the travel.  I also verified that the "full throttle" position was triggered at about 30 degrees rotation per the FSM.

The throttle was then returned to it's home on the intake manifold using new stainless bolt and a fresh gasket.  

Since my original throttle duct had a crack in it (that I fixed with Shoe Goo) I purchased a new unit from Z Car Depot.  It turns out that Nissan still makes these!  Based on the casting flaws matching on my original and new duct, the same mold is still used to make these.

With everything reassembled I ran another smoke test.  The o-ring seal and greased shaft was holding pressure, along with the other fixes documented in previous posts also being effective.

Smoking in the Can

The next vacuum leak revealed by my DIY smoke machine was at the valve of the fuel vapor canister.

A closer inspection revealed a crack in the valve cap (see below photo just at the base of the nipple).

Since the crack in the nipple was only in the top of the valve, I was able to use my plastic welder with a fiber-flex rod to seal the leak.

Once the weld cooled I used my Dremel to smooth out the weld and make it look good.

Since this air line was in-line with the vacuum advance solenoid, I not only sealed up some unmetered air but I also let the ignition advance get the vacuum it needs to work properly!

It's All Smoke and Meters

After building a smoke machine to detect vacuum leaks, I hooked up the machine to my 280z.  After just one pump I noticed some smoke coming from the air flow meter.

In this case the smoke was coming from the bottom of the cover over the resistor board.  Since I had never run any tests on the AFM, I decided this was the perfect opportunity to remove and test the unit before sealing it up.  Additionally my fuel pump would run when the engine was not running.  This is a safety feature controlled by the AFM so this would give me an opportunity to correct this issue as well.

After removing the AFM I gently scraped the existing glue and silicone from the cover (it looked like it had been opened before).  Removing the cover revealed some internals that looked almost new.

Fixing the fuel pump shut-off was simply a matter of slightly bending the small spring that counteracts the main spring at the very beginning of the movement (seen opposite the weight in the picture above).  This bend allowed the door to completely close and thus the fuel pump switch to open when no air was moving through the intake.

I then ran through the tests outlined in the factory service manual, measuring resistance between pins.  All tests passed with flying colors.

I used some Ultra-Black RTV silicone to reattach the cover and seal the unit.  A subsequent smoke test proved that resealing the cover corrected the leak.  I also confirmed that the fuel pump did not run until air was flowing through the meter.

Building a Car Vaping Machine

I've been chasing an issue with my 280z where the car idles very low when cold but runs perfectly when warm.  To start ruling out potential causes, I decided to look for vacuum leaks.  Now certainly one could check for vacuum leaks using some DIY methods like spraying carburetor cleaner all over an idling engine until a difference in RPM is heard.  Those carb cleaner and propane methods of detecting leaks seemed imprecise to me.  Recently I had watched some videos on YouTube on how to make a smoke machine for the purpose of detecting vacuum leaks in engines.  This video is the one that I followed most closely to construct my smoke machine: Best Automotive Smoke Machine You Can Build.  The video details the steps to build the unit, which requires a pickle jar, soldering iron, bicycle pump, epoxy, a Bic pen, vinyl tubing, a sock and baby oil.  It feels rather McGyver-ish, but the end result is VERY effective.

In addition to building the smoke machine, I also picked up a device that can inject smoke into the manifold while also sealing the end: AUTOOL Easy Intake Adapter.

This device made it extremely easy to test the intake manifold for leaks.  

I will detail the detection of each leak and it's correction in subsequent posts.

Harnessing the Power

Recently when examining one of the spark plugs on the Pulsar NX, I found that the ignition wiring harness was in poor shape with every coil connector broken and held in place by friction only.  I found replacement connectors on eBay for $2 each.  

To get the harness out of the car, the intake must be removed as well as the cover over the ignition coils.

The harness can then be removed by removing the coil connectors as well as two connectors near the airbox and a ground wire.  You can see in this pic how degraded the coil connectors had become.  Once removed I stripped the sheathing from the harness so that I could access each wire.

Working one connector at a time and one wire at a time, I cut the old connector off and soldered in the replacement.  Heat-shrink tubing was used over each splice and electrical tape was used to wrap the entire harness once complete.

Before replacing the harness I took the time to clean and inspect each coil pack.  I removed dirt and carbon from the bit that contacts the spark plug and applied a light coating of dielectric grease to help prevent arcing.

Once the coil packs were back in place the harness was ready for re-installation.

Once the cover and intake tube were back in place a quick test drive was taken to ensure all was in working order.

 

Wheely Shiny Wheels

Amy was pretty insistent about wanting the wheels on the Pulsar NX painted silver.  I had already experimented with Plasti Dip and had coated two of the wheels in black.  I did not proceed with coating the other two wheels since I knew that I had to have new tires mounted; an operation which would destroy the Plasti Dip finish around the rims.  In researching possibilities to paint the wheels silver, I read reviews on Plasti Dip Bright Aluminum Metalizer.  Many people were using this to color their wheels with great success.  A quick search on Amazon made me realize that this was a very popular color and the price per can was in the $25 range.  I decided that this was the route I wanted to take and I was able to locate three cans of the Bright Aluminum color at Pep Boys for $8 per can!

The Plasti Dip Metalizer coatings require a base coat of another basic color.  Black Plasti Dip is cheap enough and works perfectly as a Metalizer base coat.  After thoroughly cleaning the wheels, I began by masking the tires then applying three coats of black Plasti Dip to the front and back.

After the black basecoats three coats of the Metalizer were applied.

I must say that the coating exceeded my expectations.  The wheels look as if they were made of cast aluminum.  Amy was quite thrilled to see them on the Pulsar!