Hi all,
Been doing some work on "Gracie" tonight, a 1991 HDJ80R GXL Landcruiser with the 4.2 1HD-T turbo diesel "powerplant". I'm looking at putting in some sensors as a part of my long-term plans to make her a little more modernised, and easier to manage when on (or off) the road with the camper trailer.
Essentially, my plan is to mount various senders, or read off the OME ones, and send the data to a PICAXE microcontroller (with blame going to Robin Miller for introducing me to them :-D - thanks mate!) which will be initially displayed on a custom LCD screen, and then eventually on a laptop or PDA by serial connection.
Currently thinking about cylinder head temp, boost, and EGT. There are others for down the track, but I'm still experimenting with these ones for now!
I have read several articles and forums from Google, LCOOL, IH8MUD, and this wonderful resource about gauges/sensors, however was hoping for a little more focused help. These gauges seem to often require drilling holes into manifolds, and tapping them out, which I will do if necessary, probably on spares obtained from a wrecker first.
Figure 1 - For orientation, here is a picture of my engine bay - the observant will note I have a CAV style fuel filter and and a diff breather air filter, and that the air intake from the filter to turbo has been removed and covered:
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First boost - others seem to drill a hole in their air intake pipe and mount a pressure sensor downstream of their turbo. The service manual says that turbo pressure (?boost) should be measured by placing a pressure gauge (sphygmomanometer) off the air pressure hose running from the side of the intake pipe via a T-
junction to the bell on the top of the injector pump, and revving the engine to 4,400 rpm (direct from Toyota Service Manual). I was wondering whether anyone has done a setup where they splice in a T-
junction in this rubber hose, and run that to a boost gauge? Can anyone see a problem with this setup? Refer to picture below:
Figure 2: Air pressure hose from air intake pipe with possible location of air pressure sender. The mechanic may have placed the T-
junction on this hose the wrong way - Toyota's manual says that the base of the T should be connected to the air pipe. Easy to fix...
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Cylinder head temperature should be easy enough, unless this particular threaded hole has another function I'm not aware of. See Figure Three below for where I plan on bolting a temperature probe, and please tell me if there is a reason you can think of why this could be a bad idea!
Figure 3: Possible location of cylinder head temperature sensor (green), and the mystery allen keyed bolt (blue) on cylinder block and turbo, respectively:
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Also on Figure 3 above, I was wondering what the threaded hole in the front of the turbo unit is for? It seems to accept a 5mm allen key, however I did not budge it... I can see this in two books I have on the 1HD-T, but neither time is it labelled.
Same goes for Figure 4... Not looking to put something here, but I was wondering what two components are for. There is a threaded hole just over Cylinder 5, with a sensor unit looking as though it's fairly close underneath. I was wondering a) what is this threaded hole (magenta) and b) what is this sensor (cyan) for?
Figure 4: Last two items to identify:
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Many thanks for answering these questions, guys! I really appreciate your help and collection of experience. The posts of several members in archived threads (especially Graham H and Robin Miller) have been extremely helpful for providing guidance and inspiration, now it's time to make sure I can apply these points to my engine - the 1HD-T (as opposed to 1HD-FTE or Patrols, or even Mitsubishi Lancers as I have read about on other forums - boy racers in street cars love boost gauges apparently!)
I look forward to your input.
Kind regards,
Charles