The floppy cup holder

One would think that the people of 90’s were on the verge of dehydration for the number of drink holders in these trucks. The one in the dash, that pulls out under the heater vent, just looks like a sticky soda disaster waiting to happen. For the amount of residue in the heater vent and on the carpet, I know the previous owner used this one.Over the years, it would seem that they get looser and looser only compounding the “launch” that occurs when you hit a bump.

I had the dash apart for another reason so I decided to tend to this floppy drink holder. The pull out tray rides in a track on each side. Since mine had lots of horizontal and vertical play, I knew that tightening the track up would help the situation.

Start by popping the vent out or by removing the dash bezel. If you’ve never done this, it is held in by simple spring clips. Start at the top and pull out slightly until the first two give, then work your way around. Tilt the steering wheel all the way down and rotate the top of the dash recess out. Next remove the (4) screws under the lower dash cover (by your legs) using a bit driver. Again, pop the spring clips out until you can lower it out of the way.

Next, remove the two screws in the black bracket under the drink tray (see picture). Pull the drink tray all the way out (until the side drink holder pops out) and look underneath. There is the black plastic stop that has to be turned (like a dashboard light bulb base) and pulled out before the whole tray slides out. In the picture, the tray has been removed for clarity to see what the stop looks like. Now you have access to one remaining screw in the rear of the bracket.

Once the bracket is out, check how much horizontal slack you have between it and the drink tray. Using a vice, squeeze the outer end (towards the passengers) of the bracket track until tight. Reinstall everything and enjoy your new (un)floppy drink holder.

Troubleshooting: Low or no boost [P0236, P1656]

Trouble shooting: Low or no boost
Error codes: P0236 and P1656 only under certain circumstances
Potential problems: turbo, clogged catalytic convertor, leaking vacuum lines, bad wastegate solenoid, bad vacuum pump

In April, I attempted my first tow with the Suburban. It had been faithful to me thus far but I was still a bit apprehensive about my first tow being @ 270,000 miles. I had already installed an EGT gauge and used Torque Pro (Android App) to watch water and transmission temperatures. I had to tow about 4,000 lbs from New York to Maine.

At first, it seemed easy with no concerns over power. My bigger concern was braking fast since that is an area of my truck that needs some attention. The first series of hills changed my mind. I was having a hard time keeping up speed and EGT’s would climb too high. So I spent most of the trip controlling EGT’s with the throttle. Which meant going 45mph instead of 65mph on inclines. This was the first time error code P0236 was flagged. I had never held the throttle down so long.

The generic OBDII definition is simply “Turbo/Super charger boost sensor “A” circuit range”. When you read deeper and specifically to the 6.5, it means that if you are over 2000 rpm and target boost cannot be achieved for so many seconds, the coVDO 153002 Pressure Gaugede is thrown.

Given the trouble the stock vacuum pump system gives, one would assume the worst and think the pump is toast. Eventually though, P1656 was thrown, again with the generic definition not helping at all. For the 6.5, it is a code for the wastegate solenoid. I lived with it for a while, eventually installing a cheap boost gauge to determine what was going on. Surprisingly the truck never gave me any indication that power was missing, except when towing up hill.

After installing the boost gauge I could see that I would get a 3-6psi spike for about 2 seconds and then boost would drop to 0. This isn’t a turbo failed type of response. It seemed too binary to be a leaking vacuum hose. To troubleshoot, I hooked a hose straight from the pump to the wastegate.

WARNING: Your boost is now not controlled, you have to control it with your foot, do not blow your truck up

ACDelco 214-1073 Turbo Boost SolenoidIf I still had no boost, then it was the turbo or the vacuum pump (I have a Diamond Eye 4″ exhaust so it wasn’t a clogged convertor). I had plenty of boost and noticed turbo whistle immediately even at a slow speed. So now I knew it was either the solenoid or the vacuum lines. At $25 for the solenoid, I took a chance.
The solenoid is mounted with a single 10mm bolt at the driver’s side valve cover. It has one 2-pin electrical connection and one 2-barbed vacuum connection. Swapping it out is a simple 2 min job. No question, my solenoid was clogged or wore out. I don’t know how long I had little boost, but I do know I am enjoying a working system now.

Welcome to the Diesel Suburban

Welcome to the site! Here I’ll chronicle modification, tips, tricks, and maintenance of my 1996 6.5 Turbo Diesel Suburban 4×4. Much of the information here will be common to any C/K series GMC vehicles, the Hummer engine, and sometimes the older 6.2 as well.

I hope you find something here that helps you with your own vehicle or helps you decide whether a 6.5 Turbo Diesel is right for you.