Hello,
I have been having an unusual engine stuttering problem (mostly at higher speeds 50-70mph) when I apply any extra electrical component on such as the radio, heater, or lights. This happens even when only 1 of them is on, not just all 3. When I turn them off the engine returns to nice and smooth. I must be electrical of course. Any ideas? Alternater?
Thanks in advance
joe myers
Faulty ignition switch is my best guess, possibly engine to chassis earth. Measure the voltage on the ignition live wire when stopped, then see if it drops when one of the extras turns on. It would help if you said what sort of Landrover and petrol or diesel. JD
It's PROBABLY not a 3.9 diesel, JD.
Peter R.
The truck is a 1992 LSE V8 3.9 running on gas not deisel.
My guess is that it's not speed related but is RPM related, happens at between 2800 and 3000 RPM ?
If so then I have been chasing the same problem for about a year ! I get a misfire in this specific rev range unless I turn the lights and heater off. Above or below these revs it runs fine.
So far I have ruled the ECU out by substitution and have tried a shed load of different things to try and narrow it down. I am about to move the engine into another vehicle so I'll find out then if it's a vehicle wiring problem ! I've yet to determine whether it's an ignition or injection problem but if I get the same problem in the new vehicle I'll be replacing the distributor and amplifier to try and narrow it down.
By the nature of the problem, I've decided it must be a voltage drop at either the ECU or the ignition amplifier. This could either be caused by a high resistance connection in the positive feed or (more likely) an earth connection problem that is raising the effective earth potential whenever one of these circuits is in use. Why either of these would only effect it in a specific rev range is a mystery to me though.
If you do find solution - let me know...
cheers
Dave W.
my tuppence....
with symptoms you describe, this sounds like either an alternator or rectifier problem as you thought.
I really would want to connect a voltmeter across the alternator and ground, when the car is idling, and expect 12.volts, then give it a good rev ... even if the voltage checks out... i.e a healthy 13.5 - 14 volt, this does not put the alternator and / or rectifier in the clear... but you really would expect to at least 13.5 + volts with the engine running at 2000rpm.
Test the alternator first if it's ok post again... it may be 'kicking in', but may no longer be able to supply the required current..
BTW do the same test at the abttery terminals .... this will test your earth strap.
later
tom
thanks Tom,
I will borrow a voltmeter and give the testing a shot. BTW another symptom that makes me suspect the alternator is the battery light in the binnacle glows a bit and dissapears when revved. I have heard that this happens with a weak Alt? So far though, the tach is still working well which can die with a bad alt. I could easily take the alt. off and down to the local auto store for a quick test, assuming they'll be able to read any faults with it, since I don't have a voltmeter. I will give it all a whirl. thanks all for the help.
joe myers
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