Revs great at idle but....

[Ean Austral]

Gday All,

Today the RRC 3.9 would rev no problems at idle , no miss , nice and smooth , but take it for a drive and rev it out a bit thru the gears and it would start coughing and spitting , at a couple points I actually thought it would conk out.

At a guess I assume its electrical but not having had anything to do with these engines before I am a bit of a loss.

Any suggestions on where to start and things to check.

Thanks and Cheers Ean

[grey_ghost]

It could be any number of things, but when this happened to me it was the fuel pump (about 230k)

[rangieman]

Breaking down under load is normally plug leads ,
Id start with 1 st check plugs then maybe replace the leads ,and if no change rotor button , Dissy cap[bighmmm]
Could also be ign amplifier maybe a Bee Utey mod here [wink11]

[theelms66]

With the engine running throw the bonnet (in the dark of night) and you may see the spark arc from one lead to another . My young blokes nissan patrol was like a disco club in the dark with dud leads

[Patrick M]

With the engine running throw the bonnet (in the dark of night) and you may see the spark arc from one lead to another . My young blokes nissan patrol was like a disco club in the dark with dud leads
[bighmmm]I have had a similar problem on a few occasions, once it was the high tension leads, another time the amplifier on the side of the dizzy, then the coil, and on another it was a lack of current to the coil which was due to the immobiliser malfunctioning.
But the one that gave me the SH@#$ the most was the fuel pump.
I have replaced many of them in RRC's and Disco's over the last 27 years but the last one was a beauty, this was in a Disco and was suffering from similar symptoms to what you have described.
The previous owner had replaced it before I purchased it so I ruled that out and turned my attention to electrical and replaced coil, h/t leads the lot but it was still the same.
I even pulled the heads off and checked it all out but the problem still remained.
Eventually I went back to the fuel pump, bit the bullet and replaced it and the whole rig ran fine after that.
The new after market commodore pump was faulty.
I have not used any more of these pumps as they break down with monotonous regularity (once while out in the Gibson Desert).
I am now using the "WALBRO" brand units which was supplied to me by Steve Newing of EFI Hardware, he was a very easy bloke to talk to and after I explained the problems I was having with the other pumps he recommended the Walbro so I bought two so that I have one spare just in case, but so far so good.

Hope that this helps mate.
Regards:-
Patrick M.

[Pedro_The_Swift]

dig out your 12V meter and test each lead for resistance, 10min well spent..