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Discussion Starter #1
I've been having joy with a misfire on a 1990 Classic Lucas Hotwire..

it was running fine on one day, then the next day it was used was misfiring. i've trouble shot as much as i can and now stumped as it's gone from misfire to no start and clutching at straws now and thinking Fuel pressure regulator

here's a recap..

day 1 started and ran fine, no issues whatsoever.
left it 48 hours in the driveway then:
day 2 drove to petrol station, on starting and the drive there it was misfiring at 2,500 rpm

replaced HT leads, plugs, rotor arm, distributor cap and fuel filter.

still misfiring at 2-300 RPM

Spent the day with a friend going over all we could, with the result of a suspect MAF problem due to sooted plugs on both banks from rich running.. timing done (6deg +/-1deg) and set. Ordered a new pattern MAF, ran like crap, put the original MAF and a spare MAF on, it ran again, but not above 2500 RPM.

Swapped out the Fuel ECU (PRC 7081) for a spare (PRC 9061) no change still not running above 2,500 RPM,

Swapped the Fuel ECU's back (PRC7081 back in), wouldn't fire, swapped them back again (PCR9061 back in), wouldn't fire and battery now depleted.

While on recharge, temp sensors changed (3) and both O2 sensors changed, swapped the ECU again (PRC9061 back in) left it to charge.

Tried again this morning now charged. Still not firing.



 

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787 Posts
I was haveing a back fire problem
I changed the coil
And the spark modulator
That solved my problem
It was bad spark
 

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1995-2002 Range Rover Classic
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1,413 Posts
try looking at your spark under load with and oscilloscope, more than likely your pick up is failing, keep in mind even the lowest mileage and newest classic is 22 years old. needless to say electronics will fail sooner or later.

btw check your static fuel pressure.
 

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i thought i had a good spark also....
i also replace everything you posted too....
plus the distributor....just sayin....
i do hope you solve this ...it can be agravating
best of luck...
 

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Presumably when you changed HT leads you also changed coil/king lead? I had one of those go bad which I just couldn't explain as you could see a spark when you cranked it, it just wouldn't go though. Have you got an alternative for that one to try?

Is it showing advance and retard with a strobe when it runs?
 

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Discussion Starter #8
Hi RR London,

yes to both. new coil to dizzy lead changed with the old HT leads (not that old)

yes it is showing on the strobe when runs (not above 2500 RPM though :) )
 

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1970-1995 Range Rover Classic
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1,458 Posts
As 95classilwb posted, what's the fuel pressure? Will it fire up with ether?


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