The V8 Owners Forum -

had loads of cold start problems before long story short a new engine loom sorted that

but now i have a problem where it starts and sounds as if only one side of the engine is running if i give it a light seccond or two on the accelerator it will run fine and rev on all 8


its a range rover flapper efi system and if the 9th injector is plugged in it will start and then stall needing a good crank to start up again

so ive been starting without the 9th for now i havnt tryed hot starting with the 9th but this is only on the first cold start of the day so to speak if i last used the car at 2 pm today and now started it at 5 it would be fine and pretty much rev straight away


looking for some ideas before i start pulling bits off again randomly lol

could be the resistor pack, but thats unlikely unless it does is intermitantly thinking about it, the 9th injector should hardly ever cut in unless its really cold. Are you sure its not something like the valve stem oil seals fouling the plugs over night?
Phil

dunno its got the early type and they were on the heads when i bought em

any way of seeing if thats it?

other than whipping the plugs out first thing maybe?

by the way i just put these plugs in there the ngk ones i had the bosche super 4 and there proper pump it wouldnt cold start at all with them but at least it starts on these now

maybe something like the coolant temp sensor or thermo time switch?

if i remember before i swapped the loom i had constant power to the extra air valve on a stone cold engine and if i remember by finding out that power is supplied as the engine warms up to close the valve up

I've got a '89 RRC with the same engine. Mine is also a little bit reluctant when it's cold, however I've always put this down to timing as I run on LPG and thus when I start from cold (on petrol) the timing is a little far advanced really!!!

Sorry I can't really help but I'll be watching closely!! I was under the impression that the early RV8's were a liitl temperemental when cold!!

The injectors are fired in banks of four, so if it is truly running on four, it will be a bank going down. Common points are the ECU and resistor pack, and the wire between the two.

Chris.

landybob_v8 wrote:
but now i have a problem where it starts and sounds as if only one side of the engine is running if i give it a light seccond or two on the accelerator it will run fine and rev on all 8

so ive been starting without the 9th for now i havnt tryed hot starting with the 9th but this is only on the first cold start of the day so to speak if i last used the car at 2 pm today and now started it at 5 it would be fine and pretty much rev straight away

Point 1 - it is probably just running rich to start with and with wet plugs it sounds like it is not firing on all cylinders. blip the throttle and the richness disappears and you get back to normal.

Point 2 - Just because you fitted a "new" loom does not mean it cannot be faulty, lots of problems are caused by wiring and connector faults.

Point 3 - you should be able to start the car without the cold start injector on all but the very coldest of days in UK - just give a couple of bootsfull to richen to mixture and it will fire up.

Then you should be able to run quite normally with the thermotime switch and the cold start injector out of the loop as seems to happen.

If successful then this would point to a problem with either of these two components or the associated wiring/connectors.

More so because something is flooding the system to start with, (Point 1) and this again points to the CS injector system

had a look again

it wont start at all if the 9th injector is in until its finished its 12 ish seccond cycle

landybob_v8 wrote:had a look again

it wont start at all if the 9th injector is in until its finished its 12 ish seccond cycle

The 9th injector is there to help with very cold starting. If the car will not start when it is in circuit then it would seem the Thermotime switch is somehow faulty.

Just to be sure that we understand what is happening, the folllowing is an extract from my manual of how the system works.

The thermotime switch is fitted to time the operation of the cold start injector; it is located in the coolant gallery at the left front of the inlet manifold. It must not be confused with the coolant temperature sensor fitted alongside it, but slightly to the rear.

The thermotime switch contains a pair of contact points, one of which is mounted on a bi-metal strip. A heater coil is fitted around the bi-metal strip.

This cold start system is under the control of the ignition switch - it can only operate when the ignition is in the 'crank' position.

When it can operate, the thermotime switch ensures that:

a. The injector does not operate at all if the coolant temperature is greater than 35°C.

b. The injector operates only up to a maximum of 12 seconds to avoid flooding, and the time depends on coolant temperature. In other words the injector only operates for the maximum 12 second period in temperatures of - 20°C; warmer than this and the operating time gets proportionally less.

In the cold condition the contacts are closed; current is fed from the white/red wire through the injector, and then through the bi-metal strip and contacts of the thermotime switch to earth, thus, the injector will operate. The bi-metal strip is sensitive to ambient temperature, and if the ambient is already above 35°C the contacts will be open and the injector will not operate.

The other connection from the white/red wire passes current through the heater element of the switch; it raises the temperature of the bi-metal strip until after a maximum of 12 seconds it will break the contact and the injector will cease to function.

From your description of the fault it seems the thermotime switch is not shutting off the CS injector at normal temperatures and the engine is being flooded.

but the cold start injector is not plugged in when i start i only plug it in to see if there is a difference

when i start it, it starts fine for maybe a seccond then will drop to a very low lumpy idle which sounds like all the plugs have been pulled from one side


then if i rev it it will lump its way up and maybe bang and pop in the exhaust chucking out a blue cloud when it does though it isnt constant like its just ignited fuel in the exhaust??? then as if by magic it runs on all 8 and idles and revs nice

i can switch off and restart as many times as i like after that with no fault

Check the connections at the resistor pack and cables as far as you can. If you find no obvious problem swap an alternative resistor pack in.

jw

shall do

once ive fixed the uj's on the steering column one went pop last night on a roundabout

that was fun!

yep seems to be all good ish now with a new resistor pack started on 8 with the new one

but still started on 4 twice using the old resistor pack until after about 1 min when the other 4 would cut in when i swapped back

the problem never went away

turns out the trottle sensor was pooped although it still thinks its hotter than it is