super4 wrote:
But here is a question for you- if that vacuum lead is broken does it affect the running ? It has been broken for much of the cars life and running problems have only recently happened
No- cruise control has its own vacuum pump and is completely self contained. Won't affect running in the slightest..
Thanks - Ob - reassuring to know .
You're not the first I've heard of with problems with older Magnecore leads. For the price they charge for them you'd think the core was solid gold but it seems they aren't that much better than those at a quarter the price or less. I've always used these http://www.island-4x4.co.uk/ignition-lead-4046-9498-eurospares-hls102-hls102g-p-26970.html and changed them every 3 or 4 years.
Orangebean wrote:
super4 wrote:
But here is a question for you- if that vacuum lead is broken does it affect the running ? It has been broken for much of the cars life and running problems have only recently happened
No- cruise control has its own vacuum pump and is completely self contained. Won't affect running in the slightest..
Got me scratching my head now! I have no P38 here to check on at the moment but I was under the impression cruise control on them was plumbed to manifold vacuum? Sure I've heard and corrected vacuum hissing from broken cruise control vac pipe at the firewall end of passenger side engine bay in the past, correcting cruise control function in some cases, and the other end of that pipe went to the manifold..
Lpgc wrote:
Orangebean wrote:
super4 wrote:
But here is a question for you- if that vacuum lead is broken does it affect the running ? It has been broken for much of the cars life and running problems have only recently happened
No- cruise control has its own vacuum pump and is completely self contained. Won't affect running in the slightest..
Got me scratching my head now! I have no P38 here to check on at the moment but I was under the impression cruise control on them was plumbed to manifold vacuum? Sure I've heard and corrected vacuum hissing from broken cruise control vac pipe at the firewall end of passenger side engine bay in the past, correcting cruise control function in some cases, and the other end of that pipe went to the manifold..
The pipe that runs away behind the manifold, in fact runs off through the bulkhead to the brake pedal switch which incorporates a valve to rapidly dump vacuum. Probably that is what you've heard hissing and would stop hissing when repaired.
As for the vac pump:
When cruise control is active and cruise ECU inputs
are acceptable, the ECU energises the vacuum pump
motor. The vacuum pump creates a vacuum in the
actuator which operates the throttle linkage. When the
required speed has been achieved, the ECU switches
off the vacuum pump. The ECU also controls a dump
valve which allows system vacuum to vent to
atmosphere.
The cruise control vacuum pump on petrol P38's is screwed to the back of the EAS box... On a GEMS it's between the EAS box and charcoal canister. On Thor, it's same place - but behind it is the engine ECU.
but but... why not use manifold vacuum? It's free!
Rover must have had a spare committee or something
Morat wrote:
but but... why not use manifold vacuum? It's free!
Because when the pipes perish and start to leak, it's going to make the car run rough. I suppose the other thing is that manifold vacuum may be free but it isn't constant. Going up hill you'll have virtually none which would make the cruise control stop when you need it most. It would be like the old days of vacuum operated windscreen wipers. Great on the overrun but the wipers would stop when going uphill in the pouring rain.......
Looks like I've opened up a whole new can of worms ! My vacuum pipe from the switch on the accelerator pedal (which has a broken clip - hell of a job to put back - no proper space for it) arrives at a sort of actuator that links to the throttle on the inlet manifold. I have the workshop manual for the 1995/2001 V8 Petrol and mine is up to 99MY Gems. Its hard from the manual to find and name some of the parts and there are endless sensors which must be a potential nightmare. One job I have been putting off is to cut a hole in the floor of the Classic to replace the petrol pump - have no pit here on the track and don't see any easy way of dropping the tank out. Have already done this with the P38 when the connector came loose having had a new pump put in by a garage here !!! Bit like surgery - have to get your cuts in the right place ! Thanks for the advice about the ignition leads to get.
Download the full version of RAVE from here. It'll help you greatly when you need to look up components etc
BTW, the "sort of actuator" on passenger side rear engine compartment that you mention is the cruise control unit.
The switch is on the brake pedal, or at least it should be, and is just a valve to dump the vacuum when you touch the brakes. That hose should go to a Tee piece with the two other sides of the Tee going to the actuator and the vacuum pump that lives underneath it. Vacuum pump produces vacuum which is used to pull against a diaphragm inside the actuator that pulls on the cable to the throttle linkage. When you touch the brakes, the valve opens, the vacuum is dumped and the actuator releases. There's another dump valve at the pump to release the vacuum if you turn off cruise from the steering wheel switch.
super4 wrote:
One job I have been putting off is to cut a hole in the floor of the Classic to replace the petrol pump - have no pit here on the track and don't see any easy way of dropping the tank out.
You shouldn't need to, every Classic I've worked on already had the hole there. Dropping the tank isn't difficult, even with no pit. I did it a few weeks ago on a car sitting on the floor although there was two of us doing it. Most difficult part was getting the filler hose to come off having been stuck to the tank inlet nozzle for the best part of 24 years.
Hi Gilbert, sods law said that my particular year of both P38 (1998) and Classic (1990) did not have the hole - missed out by a year - must have been on a tea break - would you believe it ? yes I have heard pipes and fittings are a job to free but having put my back out kicking the front wheels off the P38 - (had not heard the good advice about loosening and turning steering wheel) I am avoiding crawling under that car. The dust and dirt falls in your eyes and the remains of the rats nests shower down too !!! Only going to attempt it if absolutely desperate - as you can guess can't drive or move the car till pump is fixed.
Just found that it costs more to deliver Ignition leads to Spain than they cost - anyone coming out ?
Ob - I think I have the rave thing on the computer - have used it - but have been given the Workshop manual by a friend who was selling their P38 and it is very handy to just pick up - no index as such so sometimes hard to find which category the part is in !
super4 wrote:
Just found that it costs more to deliver Ignition leads to Spain than they cost - anyone coming out ?
Buy them from a Spanish motor factors instead?
https://www.recambioscoches.es/land-rover/range-rover-ii-lp/4086/10253/cable-de-encendido-piezas-de-conexion
for example.
There seem to be quite a few Spanish equivalents of Eurocarparts etc, but my non existent spanglish isn't good enough to penetrate their websites!
I have now learned that Cables de Encendido are HT leads though. I'm sure that will come in handy if I ever go to Spain :)
super4 wrote:
Hi Gilbert, sods law said that my particular year of both P38 (1998) and Classic (1990) did not have the hole - missed out by a year - must have been on a tea break - would you believe it ?
The P38 never got the hole but the Classic did, although it sounds like not until '91
Just found that it costs more to deliver Ignition leads to Spain than they cost - anyone coming out ?
There's a company based in Germany that my mate in France gets bits from. Decent prices and ship anywhere in Europe. Only problem is, I can't remember what they are called......
Thanks for suggestions on leads - I will order the one's from Island 4x4 - only about £15 and I have a friend with a monthly delivery run to here who can bring them out. Only snag is that he has just arrived for the July run with my lpg filter and won't be back here till end of August but I think I can wait.
LPG and set ups. I think I understand (from the very detailed advice) that before one adjusts or changes any settings on LPG the petrol system must be 100%. Since I have got the LPG working again and made some small LPG pressure changes it takes a moment or two to start (on petrol) and will not idle for a minute or so. Before, it always started instantly and idled perfectly when cold. I noted that one should run it on petrol for a good period so that the Car ECU could read/adjust the settings (in ECU ?) for the changed situation and would provide the correct running setup. I did a little bit of petrol running which seems to have helped when car still warm but not sure if this has helped cold starting/idling. What should I expect ? I accept that I should probably do a recalibration but hoping to put that off for the moment.
If you're running purely on petrol, any changes that you've made to LPG will not affect how the car starts, idles or runs- as long as you don't run it on LPG.
As you don't have the means to reset your adaptives you'll have to wait for the petrol side to sort itself out, including starting and idling, which will take a few stops, starts and miles of mixed running to happen. Of course it'll only sort itself out if everything is now working properly. Even a generic bluetooth OBD reader and something like the paid version of Torque Pro will give you the means to look at trims, airflow and lambdas to see what's happening. You're only guessing that it's running right otherwise.
If you give into temptation to switch to LPG at any time, that'll throw the petrol trims back and you'll be chasing your tail again.
By changing things you've upset the calibration. Now when running on LPG the mixture is out so, as it slaves off the petrol system, the petrol system is adapting to get the mixture correct when on gas. Then when you go to run on petrol, the mixture is wrong and it has to adapt again to get it right. Think of it this way. Lets say that for a given revs and load the petrol injectors need to be open for 7mS and at the same revs and load the LPG injectors need to be open for 10mS. The LPG controller takes the pulses intended for the petrol injectors, adds 3mS and uses those pulses to fire the LPG injectors. If the LPG calibration is out and it's only adding 1mS, the petrol ECU sees a lean mixture so adjusts the petrol pulse length to 9mS. All is then fine on LPG but when you go back to petrol, it's too rich as the pulse length has increased so it has to be run on petrol for a while to adapt down to 7mS again. That's why I said don't change anything, it was running fine on both fuels so it was pretty much correct and now it isn't.
For the moment is it too late to change back to the 1.1 pressure setting and one lambda ? Would it remember and forgive me or have I gone down the slippery slope with no return ?
Actually - I still have to change the drivers side ignition leads - simply changing the first side has made an improvement - remember - very slow life here in Spain..........
"Oh what a tangled web we weave when first we practise to deceive ( fiddle with LPG) "