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I'd like to start a conversation about the carburettor on a 4.2 petrol. I've had my '90 GQ since 2001. Doesn't get a whole lot of use, mainly 'cause of it's thirsty habit.
I bought it primarily to tow a boat but I love it and am determineed to keep it. It tows well and it's very capable off road especially in sand.
I know little about it's history prior to me but it had 99k on it when I bought it and on the way home from buying it the odo clicked over to 100k and stopped. Since then it works intermittently. It still only reads about 150k but it's done probably twice that since I've had it. Short answer - I have no idea of it's mileage! It runs well, generally, and I've spent some serious money on brakes the auto etc in the time I've had it. It's a great toy!
A few years ago it started playing up a bit and when I investigated the carburettor I found hoses cut and blocked and a vacuum thingy disconnected etc. Someone has had a good go at disabling 'things' on it. The Nissan service manager at that time checked it out and said, words to the effect of "I have no f…… idea what's been done here, my advice is to leave it alone while it's running and forget about it."
Well that's what I've been doing but lately the little hesitations and the odd backfire, rough idle and sometimes fast idle are getting me down.
When I look at the carb, it freaks me out with it's complexity - I'm used to SU's.
I want to hear from those who have overhauled their carby or changed their carby for something more straight forward.
Sorry for the long post, I hope you were able to put up with my ramblings.
I switched my nikki carb for the Holley 330 carb due to simplifying the carby and it's given it a bit more power and a slightly better fuel economy but not much maybe an extra 30km a tank.
You can fit the injection stuff if you wanted to for better economy and power but mine is like yours not a daily driver and not a touring wagon. It comes out now for 4wdriving and some quick trips around town.
If you have a big of knowledge you can fit and muck around with the Holley because they are a basic carby and easier to fix. I had the nikki apart twice re jetting and rebuilding it but it didn't fix the problem with high idles and backfiring that's why I switched to the holley
What I would suggest if you haven't already is download the manual from here and it will tell you where all the vac hoses would go. Also get a carby specialist to have a good look at your vehicle. I was lucky to find a bloke in my town that
1. Is a carby specialist
2. Cut his teeth on the early GQ and used to work for the nissan work shops in Perth I. The late 80's and early 90's
Well, I had another go at the carby today, took off the air cleaner and checked the mounting of the carby. Couldn't find anything amiss with that but I did find the two longer vac hoses that go to the front of the engine in very bad shape and one - the vac advance, I think was not connected and where it should have been connected was blocked with a short hose with a screw in the end. ????
Anyway, I replaced all 4 vac hoses - the 2 short ones up to the air cleaner and the two longer ones to the piping at the front of the engine.
Seemed to run ok after that but I now have an issue which is running concurrently with this and it appears that has something to do with the alternator as the battery has now gone flat.
Last edited by GQsweep; 14th August 2014 at 11:15 PM.
Reason: God, auto correct pisses me off!
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Originally Posted by GQ TANK
