idiotwitharange Posted November 22, 2020 Share Posted November 22, 2020 (edited) Hey guys, my pops Range Rover has been sitting for almost two years now and I thought it would be a fun project to fix it back up for him. It's in pretty rough shape, but the first step is to get it running! I've syphoned out the bad gas, replaced the fuel pump and fuel filter and tested the fuel pump with a power source separate from the car to make sure it works and it does. I also put new fuel in it. the car does crank and begin to start up with starter fluid but it dies back down when the starter fluid runs out so I know it sparks and the injectors work. I found out the inertia switch is actually missing, so I closed the circuit to the wiring harness with an extra piece of radio wire I had lying around. After that, the car still isn't getting any fuel pressure and the fuel pump won't even turn on. Something is stopping power from getting to the pump and I just can't figure it out. My next step is to look at the relays but I don't know which one goes where or how many amps it should have. Please let me know if y'all have any suggestions! Edit: Its a 4.2 V8 Edited November 22, 2020 by idiotwitharange Quote Link to comment Share on other sites More sharing options...
steve b Posted November 22, 2020 Share Posted November 22, 2020 Welcome to the forum Does it have a remote central locking fob/key ? It sounds like it could be immobilised ? I'm sure someone with more late RRC knowledge ( @Bowie69?) will have more pointers In the meantime some pic's would be nice , the 4.2 LSE RRC is a good looking machine cheers Steve b Quote Link to comment Share on other sites More sharing options...
idiotwitharange Posted November 22, 2020 Author Share Posted November 22, 2020 (edited) 2 hours ago, steve b said: Welcome to the forum Does it have a remote central locking fob/key ? It sounds like it could be immobilised ? I'm sure someone with more late RRC knowledge ( @Bowie69?) will have more pointers In the meantime some pic's would be nice , the 4.2 LSE RRC is a good looking machine cheers Steve b I'm sure it came with a key fob, but that is missing along with the owners manual and the diagram to the fuse box on the dashboard... I'll work on getting some pics after I eat breakfast and get out there again! Thanks for the help. That would also make sense if it was immobilized because if I open the rear cargo hatch and then connect battery power the alarm starts going off! I'll look into that next. Edited November 22, 2020 by idiotwitharange Quote Link to comment Share on other sites More sharing options...
idiotwitharange Posted November 22, 2020 Author Share Posted November 22, 2020 update: all of the relays under the passenger seat are gone, and so is the 70 A fuse. wow Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 22, 2020 Share Posted November 22, 2020 If it fires (sparks) on starter fluid it's likely NOT immobilised. The ECU controls the fuel pump, and for it to decide the engine is cranking it needs to see pulses from the -ve side of the coil (white wire, black trace, possibly also via a relay into white wire with blue trace) and the airflow meter reading some flow - flapper ones the flap actually switched some contacts, I don't know about hotwire. What do you mean relays are gone? If they're missing that would certainly prevent power to the fuel pump Quote Link to comment Share on other sites More sharing options...
idiotwitharange Posted November 22, 2020 Author Share Posted November 22, 2020 7 minutes ago, FridgeFreezer said: If it fires (sparks) on starter fluid it's likely NOT immobilised. The ECU controls the fuel pump, and for it to decide the engine is cranking it needs to see pulses from the -ve side of the coil (white wire, black trace, possibly also via a relay into white wire with blue trace) and the airflow meter reading some flow - flapper ones the flap actually switched some contacts, I don't know about hotwire. What do you mean relays are gone? If they're missing that would certainly prevent power to the fuel pump It wasnt the fuel pump relay, but I assume my brother "borrowed them" for his disco. Theyve been replaced anyhow and all the fuses are back. New inertia switch and fuel pump relay. Basically, the fuel pump does NOT get power, resulting in the car not starting. Im pulling my F******* hair out trying to trace the problem but I keep coming up empty handed, even after replacing old wiring harnesses. I also cant get the passenger seat removed because i stripped an insanely rusted bolt (torx30) and cant get my screw remover in there. this is driving me nuts!!! Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted November 23, 2020 Share Posted November 23, 2020 Classic will spark without any input from the ECU, so you'll get firing on starter fluid even if there's no power to the fuelling side. Which you won't have if all the relays are missing, so finding out replacing them is the first step. I can't remember if my '93 had an immobiliser from the factory (I had an aftermarket one fitted for insurance reasons), but if it has one and you no longer have the fob you'll need to find and bypass it. Again, that won't normally prevent sparking on a classic, only fuelling - though I'd have expected it to prevent starter motor operation too (can anyone confirm whether the factory immobiliser does?). Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 23, 2020 Share Posted November 23, 2020 11 hours ago, FridgeFreezer said: What do you mean relays are gone? If they're missing that would certainly prevent power to the fuel pump Exactly this! You need to fill the available slots with relays, they aren't anything special. I think the immobiliser came in with the softdash, which essentially inherited all the Discovery electrics, from what I can work out! Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 24, 2020 Share Posted November 24, 2020 On 11/23/2020 at 11:01 AM, Bowie69 said: You need to fill the available slots with relays, they aren't anything special. I thought there was ONE that was a 5-terminal that has two 87 terminals rather than the more usual changeover type, but that could be Flapper... hang on... Here we go... According to this, BOTH relays (21 & 22) are dual-make rather than changeover, which are not the usual sort of 5-pin relays to be kicking around. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 24, 2020 Share Posted November 24, 2020 Ah, you're right, good call! Quote Link to comment Share on other sites More sharing options...
Escape Posted November 25, 2020 Share Posted November 25, 2020 The fuel pump is easy enough to jumper, just replace the relay with a pigtail for testing purposes. Even if you get fuel pressure, the ECU still needs to give the signal to the injectors for them to open. You can check with a multimeter. The ECU relies on a signal from the coil to detemine if and how fast the engine is turning. That's a WB wire from the coil negative through a resistor to pin 39 (bottom left in the above diagram). Filip Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 25, 2020 Share Posted November 25, 2020 ^ What Escape said, you can jump 12v across the relay socket with a piece of wire with a couple of 6.3mm spade terminals on the end. Note the ECU fires the injectors by grounding them - they get +12v constantly on the other pin from the main relay per the circuit diagram. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.