After reviewing some threads about boost pressure loss, I got to wondering why mine is still doing well. There were debates about connectorization, clamping and piping. One of the key things that I have noted was the issue of the clearance of the tmap sensor from the A/C piping.

Not sure if some have been following the "where can I get my kit installed" threads, but the dealer service dept that I used was favored by many in our group here at chevyhhr.net.

I know that they use the proper tooling for the crimping (the proper crimping tool & torch from the J-38125 terminal repair kit). Because the kit is around $6k, some dealers may just use a generic crimper or even pliers and not hermetically seal the splices as required (maybe they don't know any better). Solder and shrink will work, but it is not weathproof unless something like 3M ScotchKote is applied. Moisture will eventually penetrate untreated shrink tubing and eventually corrode the conductor. But this would probably take a few years to develop and owners will likely part with their vehicles by then.

What I never checked in regard to my particular installation by my seemingly "golden" service department was how they addressed the lower tmap clearance. I was wondering if I was sitting on a timebomb in regard to this issue.

Well, I put the HHR up on a floorjack this morning (on the passenger side) and put my head under the thing, and there between the starter and the A/C compressor was what I had hoped to see. These guys had the foresight to slightly reroute the A/C piping upward and away from the connection as well as to actually tie off the conductors so as not to contact it in the event of torque roll. I have included photos of the incorrect method, courtesy of a "before repair" photo by jmacallister as well as the proper install on my HHR (sorry about the poor quality; it's a blackberry camera).

I would urge anyone who goes for the kit to be observe the fundamentals; If your service department crimps the "airbag" connectors, be sure that they have the proper kit (J-38125). Ask them. If they don't and they need to solder & shrink the connections, be sure that the tubing is hermetically sealed. If they don't have the product to do so, then do it yourself (you can brush it on after the install).

Use this (professional electrical supply product):
http://www.paigewire.com/pdf/3Mscotchkote.pdf
If you can't find 3M, a decent substitute is this (homeowner product):
http://cableorganizer.com/gardner-be...ectrical-tape/

Incorrect method (photo courtesy of jmacallister)



Correct method (sorry for the poor resolution, but you can see the wiring clearance and 180degree routing)
Also, note that the socket (toward the left) was properly "trimmed" to allow a firm, even connection to the pipe.

 

I think you mean the kit is around $600 not $6k. GM has said to watch for the map boss not letting the lower map seat and to slightly bent the AC line to get some clearance. So the facts are out there.

As for the connections, I solder, shrink and then add two layers of a high temp quality electrical tape, tie wrap the ends, cover with high temp loom and cover that in quality tape. I have never had a problem with connections even if it was low on the car and subject to water. I would think the supplied splices work fine when used correctly but it sounds like even the dealers aren't necessarily doing them right. Like the aftermarket loom, standard electrical tape just isn't up for the job. At a minimum the adhesives can't handle the water and heat and let go even if the vinyl itself hangs in there.

I'll be installing my Stage 1 kit next week and I am sure I will see just how hard that lower map is especially around changing the connector but I have stared at it multiple times and other than doing quality water-tight splices, it still don't see why it's so hard to get right. Trim the boss, make sure it's seated, do good crimps, check the AC line clearance and move it and it should be good for the life of the car.

Some dealers are good and others are, well, not good. And the fact the engine moves like 10 feet on it's torque mounts doesn't help anything.

 

For a dealer to get outfitted with the entire kit, around 6 grand. Maybe the individual tools can be purchased for less, ala carte...
https://gmspecialservicetools.spx.co...s/GM08-195.PDF

We use similar products on HVAC and electrical power path systems for mission critical facilities ("5-nines" availability). Can't take any chances. Perhaps cars are more forgiving.

 

Oh, I thought you meant the Stage 1 kit! Yeah, all J tools are a bazillion dollar! The crimp and seals can be done with standard tools but if I was doing it as warranty work I would certainly use the 38125 kit. I have the metri and weather pak tools and while expensive they are nice.

The lower intake map harness is short and hard to get good access to it without just removing the intake pipe. I still haven't found a good two hand path to it from the top.

 

Don't forget , no two cars are exactly alike, one car may have alot of clearance while the next one in line because of slight parts movement during assembly( or bolt tightening) will place it closer so there isn't any clearance..this car wasn't designed for this sensor, its a Bosch and the GM version is slightly different giving greater clearance. Another factor for the same reasons is the motor mounts, some mounts allow more movement then others, like mine, and that contributes to wire contact.

 

One thing that no one has mentioned is the possibility of getting better motor mounts (ie filled or solid), reducing the engine's rotation and therefore reducing or eliminating the chances of this happening, even on an "inferior" install where the wires aren't covered in loom, soldered, etc. I know no one makes them for the HHR SS like they do for the Cobalt SS, but that might help with those folks that are experiencing boost loss problems. The trick is some aftermarket company making them or someone who's creative enough to fill the stock MM with a quality durometer urethane(?) filling.

Later
Allex

 

87, glad you could put my photo to good use. There's another picture in one of the other boost problem threads that shows how another technician didn't follow the directions when changing the lower sensor; didn't make the required cut. I'm guessing that over half of the boost problems reported here are due to bad installation procedures and not failed parts. Thanks for the post.

 

I noticed some of the Solstice/Sky people are buying the raw connectors and pins and wiring directly to the factory harness and dumping the pigtail. You obviously have to crimp the pins correctly but it might be the better move.

I am luck to have the 38125 crimper from the kit but not the torch although the docs say you can use any heat source at about 175F to shrink the connectors. I would add another layer of water proofing to that. I have never run into an issue with crimp/splice or soldering connections as long as the wires don't bend at those points.

I am just waiting to get a couple of quotes from the dealers before i decide if I want to do it myself or not. In some ways I would like the installation to show up in the vehicle history if there is an issue but I admit I am not convinced they will do the installation any better than me.

 

My question is - how in the heck did you get that picture of the lower TMAP? I'm trying to figure out how to get down there to check my install.

 

I had to use one of these. Once it's jacked up and bolstered by jackstands (or other), it's pretty easy to slide under the passenger side front on a creeper in order to get a bird's eye view. I was happy to see that I have at least 1/4" or more of clearance, and the wiring was neatly harnessed in a 180d fashion preventing contact with the A/C tubing. Remember, torque roll will come into play during hard acceleration, so be sure to have comfortable (not marginal) clearance.