Hey guys,

I had a pretty involved off topic thread going on that Savannah Buzz was able to help me through...My RRC was running pretty crappy, and despite my best efforts it nearly outsmarted me...which is not all that hard to do...

My symptoms were surging idle, code 48 on the scanner under the passenger seat, stalling when coming to a stop with AC on, horrible driveability.

I had tried all the basic stuff:
check/test distributor
plugs
rotor
cap
pulled and cleaned O2 sensors
clean/test/swap IAC
trouble shooting O2 sensors
trouble shooting MAF
test for vacuum leaks
set base idle (about 5 times)
adjust throttle cable
test TPS
swap out coolant temp sensor
install new fuel filter
test fuel pressure
etc. etc..

I tried to avoid indiscriminantly throwing parts at it, but I did in fact install a fair array of new items since the rig has 130K anyway, and I don"t mind building a spares kit for off road back-ups..

the biggest help turned out to be that my MAF body was shorted to chassis ground through an improperly mounted air cleaner (this is a pretty sizable tip/trick!)

Also, pulling out and cleaning the O2 sensors and bench testing per the book made a noticable improvement in the vehicles manners..

So it was running great (finally)

then...it started cutting out when it got hot (I'm in AZ in the summer, so I'm going to guess my underhood temps are upwards of 150deg easily..)

SO next I remoted my Ignition module in a DIY style, it came out really sanitary and it made a world of difference. I fabbed up a huge heat sink, and opened up the air inlets in the sheet metal below the air cleaner to allow better ambient air draw. My heat sink is now sitting where it can actually get airflow generated by the inlet to the air cleaner...

All said and done, this thing is running almost flawlessly, it picked up a ton of power, and no more cutting out or surging or check engine indicator.

I just have one minor concern now, and I hope somebody can help out...regarding the vacuum advance, when the truck is at idle and I pull the the little hose that runs from the diaphagm on the distributor to the small nipple on the top of the intake, I see no RPM drop whatsoever. If I suck on the hose I can pull the revs up about 100rpm. I cannot detect any vacuum signal at that little nipple. I have poked a small bit through it, but it just doesnt seem to have enough of a signal there to do anything. Any comments? something stupid I'm missing? I can imagine that if I am able ot pull in the vacuum advance properly, the motor will feel vastly more responsive off idle, and will generaly pull me around far better when I'm off-road..

Any chance to get a RRC specific forum? the range Rover forum is mostly P38 stuff, and the differences are enough that they dont cross over all that well. The classics are covered well in some forums and other online resources, but IMO, this site is the most comprehensive and would benefit the RRC owners to have a dedicated forum.


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if you looking for vacuum advance at idle it wont have any, it doesn't get vacuum until the motor is under load.

 

The details about how exactly this system is supposed to work is elusive, but I have followed the service manual exactly, and my RRC is currently running superbly...far better than it ever has, and without any mechanic aside from me and careful navigation of my docs and a lot of grain of salt forum reading (and a lot of work).

I almost caved and took it in, but after sticking it out and thinking it through I got it to purr....