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RRC Guru's Call To Arms: Non-Starting 93 RRC 4.2 LWB

5K views 27 replies 6 participants last post by  Tom109  
#1 · (Edited)
USA version 1993 Land Rover Range Rover 4.2 County LWB Problem: Does not start 12.12.19
Before you dive deep here - thinking it may be the fuel inertia switch
If so, then where is that located???
Here is how she has degraded over 2 months:

a. Running good
b. Starting bad/flooding
c. Engine cutting out while driving
d. Very difficult restarting after engine ceased during drive
e. Won't start in morning
Symptoms:
1. Has spark
3. Fuel pump not engaging when ignition is on, no current at pump, no pressure at engine
4. Fuel pump works when hot wired (75 pounds) - but engine won't start
5. Engine "catches" when injecting starting fluid in plenum
6. The new starter is turning the engine over good but she's not catching on & starting - You can smell the starting fluid from the exhaust pipes?
Replaced:
1) Idle control switch
2) Fuel pump & Fuel Filter
3) Fuel pump fuse & pump relay
4) Injector fuse & Injector Relay
5) Spark plugs
6) Spark plug wires
7) Starter
8) Installed Ashcroft LT230 T-case. (Park Neutral Switch Stops the Starter From Working, Not The Fuel Pump)
9) MAF Replaced
10) Ignition Coil
Other events - Events possibly contributing:
a. Removed dash a few months ago, could ignition wiring have been damaged & caused this?
b. Cleaned relay contacts with electrical contact cleaner (after problem started)
c. Timing set in June 2019
Finally, would someone kindly share some insights as to what I should test next?
Cheers ~ Dave Oz
 
#2 ·
Please see below: Let’s start with the basics….

Symptoms:


1. Has spark – How much spark? A good bright pop? Or, weak sounding and blue? (sorry, objective way to measure) Thinking the ignition amplifier is bad.

3. Fuel pump not engaging when ignition is on, no current at pump, no pressure at engine
4. Fuel pump works when hot wired (75 pounds) - but engine won't start – Are you measuring pressure at the fuel rail? If so, what is the pressure?
5. Engine "catches" when injecting starting fluid in plenum
6. The new starter is turning the engine over good but she's not catching on & starting - You can smell the starting fluid from the exhaust pipes?



Replaced:

1) Idle control switch
2) Fuel pump & Fuel Filter
3) Fuel pump fuse & pump relay – Do you have switched power at the relay connection?
4) Injector fuse & Injector Relay
5) Spark plugs
6) Spark plug wires
7) Starter
8) Installed Ashcroft LT230 T-case. (Park Neutral Switch Stops the Starter From Working, Not The Fuel Pump)
9) MAF Replaced
10) Ignition Coil – Is the coil functioning/wired properly?
Other events - Events possibly contributing:
a. Removed dash a few months ago, could ignition wiring have been damaged & caused this?
b. Cleaned relay contacts with electrical contact cleaner (after problem started)
c. Timing set in June 2019

Have you checked the cylinder compression?

There are so many variables here….. I would stop buying parts. : )


Best of luck!

Chris


 
#4 ·
Thanks Chris - Here's what I know:
1. Spark - She pops, did off grounding the ignition coil 1/2 inch from the body
2. Fuel 75lbs at the rail
3. I have no clue what to check at the relay but replaced them both so I'm thinking the next thing I should check is:
4. Fuel Pump Inertia Switch - I cannot find this - Looked at firewall, Looked under passenger seat
5. Do you know where Inertia Switch is located? They keep moving it - but does anyone have certain information?
6. Ignition coil 'new' but good point - I'll double check this but it did run well after replacing. Also, terminal are well marked.
7. Compression was checked the other year "purchased in May 2018 - was good then but it's not getting fuel - possible Inertia Switch as the 93 theft system doesn't shut off fuel pump, seems to maybe the weak link.
Cap and Rotor - new but regardless, it's not getting fuel
2.
 
#6 ·
Hi Mikieman~~~I've no control no clear understanding of where the Idle Control Switch is located.
OK - I'm not as "All-Seeing" as my wife but I don't see the Idle Control unit on the firewall, or under the passenger seat.

Good point - test relays - I've no clue how/where to test.
The expert guidance of you & the RRC team would be so much appreciated. Cheers ~ Do
 
#7 ·
Idle air control valve is on the back side of the intake on the left side close to the fuel pressure regulator...there is a vacuum hose the connects from the idle control to the regulator....
The throttle position sensor is right next to air intake hose that connects to the intake....
There is also or should be a built in code reader under the passenger seat
Facing the passenger door...
Hope this helps at least...some..
Mine has the 3.9
But they should be similar
 
#11 ·
This is obscure but needs checking.

On the fuel pump mounting plate in top of tank, the wires to to pump pass through a nylon? Plug going through the metal plate.

The wires inside that plug are soldered to the pump terminals coming out from the tank, and they can corrode. The corrosion is because that whole assembly sits in a well that can just hold water from use in wet conditions, the copper wire turns green, resistance rises, connection eventually fails. Interim is it's unreliable and may just start, but with mine like that you could start it and drive a short journey then it wouldn't go again.

Mine had a problem with the relay too (you've changed that but verify if it's non- original kit) and with this it have very confusing faults.

I ended up cutting the nylon away, then resoldering they terminals, then re encasing with epoxy resin to waterproof.
 
#14 ·
I at one time I had fuel pump problems...
It was the ground wire and or the plug...
I located the ground on the frame above the rear drivers wheel well but I had also unplugged the fuel pump and
Then plugged in back in and then it just ran ....
Another thing I’ve done is to run power
Straight to the pump and fired it up just to get it running to make sure it was
Not the problem
I removed the pump to make sure I knew How to power it....
Another shade tree mechanic trick
Is to have someone turn the motor
While someone slowly turns the distributor
When I have trouble I will turn the distributor it tiny increments to get it to fire.......now in not saying your timeing is off...I’m on a roll and just throwing out ideas....
I will post a picture later when I go to the garage of the inertia switch location in the 91
Good luck with your rover
Mike
 
#15 ·
Reading through again to see what's been done, and that check you've got on fuel pump pressure, is it really 75psi?

Installed in system it should only be about 38psi as the fuel regulator shouod on to return line on its way back to tank.

If it is that high when checking the installed / complete system it will make it significantly rich and probably prevent it running as it'll just wet the plugs.

To get a rough check of the above, you can pull the fuel pump fuse to make it inoperable then take off air intake to plenum and see if it'll run longer just by spraying eazstart direct into there.

If it does run longer it's definitely suspect for fuel pressure.

As Mikieman, if we keep throwing out our thoughts you can use what you need to hopefully get further into a diagnosis.
 
#16 ·
What about the ignition amp? This may have over heated. They are cheap and easy to install but the dizzy needs to come out so retiming is required. If you can source a known good one it might be worth trying.
 
#17 ·
If I am following this thread accurately:

Currently, you have far too much fuel pressure at the rail – should be 38psi. You do not have switched power to the fuel pump – not certain about power to the pump relay, and you have good spark.

Next questions:

Are the injectors firing – they receive the signal from the coil (which is why I inquired about the coil wiring)?

Are the relays you replaced know to be functioning – new means nothing in the Lucas world!

Are the spark plugs wet with fuel? This would indicate the injectors are firing – if wet, they are possibly overfiring.

Have you recently done are work around the fuel rail?

Is there anything odd with the function of the ignition switch itself?
 
#19 ·
2 more items have been removed from the triage list yesterday.
1. Did a manual check of the timing / TDC, it is good
2. Thank you Mikieman - I found the Inertia switch under the drivers seat & the button was not popped out
Next - Lockettc - your idea of checking the injectors is what we'll tackle as soon as my Rover buddy can come over w/his tool to test for a signal at the injector.
3. Leads me to the ECU possibly after that - Would anyone have a clear diagram of the wiring between the ECU, Injectors & Fuel Pump please?
 
#21 ·
You should by able to download wiring diagram from "rave manual" contained in the sticky section at top of classic topics.

The injectors are batch fired, non sequential with left and right fired as each set. If you put oscilloscope function meter on them you should see base pulse length and changes to increase with rpm. You may not be able to check the increase without it running, possibly.

Fuel pump, as a temporary test you can pull the relay and leave it out. Then make a small jumper from cigarette lighter feed side to pump feed side in fuse box, that'll bypass all logic and inertia switch to give an assured supply for testing, it'll just go live as soon as you switch ignition key.
 
#23 ·
Apologies, if you go one step back from how you view this thread when displayed to the index of most recent threads, then the first six or so of the list are labelled INFO and contain various sources of perpetual information that always stay at the top of the listings. The last one I think is rave manual which you should be able to download a copy to locally read while working offline from forum.
 
#27 ·
It’s most likely because the rovers are all basically the same...and one of the best things about them...
Parts are interchangeable for years...
And the electric is basically the same with a few tweets as time goes on
The 94 and 95 are soft dash and the interior is more like a discovery
I would start with the 92 and if I couldn’t find what I was looking for I’d then look at the 95.....
It’s all a puzzle you have to put together...just be open minded and creative
 
#28 ·
Check the harness from the coil to the ECU. There is a wire that triggers the ECU to fire the injectors, on my 1995 it’s black/white. If this is broken/intermittent the injectors will not fire, easily confused with the fuel-pump/relay/filter. Also check the fuel injector fuse.