Uneven running / misfire on my patrol

majelan · Sun Apr 24, 2011 9:19 pm

:smiley15:

evans97 wrote:Hi,

My "new" 98 patrol 4.5 is running badly - feels like it is running on 4 or 5 cylinders, smells like the mixture is rich, loads of heat coming out through the gear change area. .

Could it be a raptured gear shift boots or is the body getting hot. Is your exhaust stock because stock exhaust has heat sheilds.

Or its a good excuse to go extreme have the head Ported and polished let them face it a couple of mm , headders and exhaust:smiley15:

offie · Sun Apr 24, 2011 11:30 pm

evans97 wrote:Thanks for all the advice folks - just got new plugs and cables plus the air filter, sensors blown out with compressed air. It is better and has a bit of pick up but still not 100%. He did a compression test on all cylinders and reckons they are only on 70 instead of 120+ so this may be bad news. I'll try it out tomorrow again and keep changing the bit smentioned. The tick over is still wobbly but it does generally feel smoother and quiter than before. Two questions:

Is the MAF sensor actually stuck on to the fat air filter tube (small square Hitachi box) with 2 phillips screws?
If this is the beast, can I use carb cleaner spray on it?

Thanks again,
Jeff.

yes that is it, the little box on the pipe that is connected to the big filter,
tintin dixed mine wheen it played up last time
for i had same problem and on friday my car decided to pack up again with foot flat to the floor and now power,
put i only had to clean air filter out and the heap went as good as gold,
hope everything works it way to getting better soon

Tue Apr 26, 2011 8:21 am

I have to see the car to give you a report ..

but, lets talk in general .. there is two selutions ..

1- Fixing your car to be able to run for next 3 years without problems ( will bay more that 3500)

2- Fixing your car to be able to run for next trip .. ( will start making a good relations in Senaaeeyaah)

You have the choise

Osprey · Tue Apr 26, 2011 11:16 am

I am now a little re-assured as the mechanic who has it (a different one as the first one might have been on the make) is testing it carefully with a machine and seemed to know the car inside out. It is possible that the cleaning and polishing process last week including a wash and shampoo of the engine - which will not have helped! I wait to see the financial damage but hope to get it sorted soon, after all the advice I will be going for preventative maintenance like changing fluids etc,... this time arounf. We live and learn. I might also ask Lee about a 2" lift kit - could be a summer job.

Osprey · Tue Apr 26, 2011 1:21 pm

Relatively good news - inshallah. I have an engine with a clapped out MAF sensor, as predicted by our resident experts and someone has messed up the timing and distributor settings. So fingers crossed if they sort all this the engine is actually OK. We'll see then weather it gives me anywhere near as much response as the mighty flying Durango.

PR · Wed May 18, 2011 3:02 pm

Good work, Jeff - hope the MAF sensor makes the difference. Definitely the messed-up timing will have had it running funny, so that'll be another important yet cheap improvement.

I'd say hold on suspension work till the cylinder compression is verified again. If the numbers you gave previously are confirmed, use the money for a rebuild and you will have basically a new engine, which will give you peace of mind and run for another 300,000+ km! It could be the earlier mechanic was fudging the compression numbers to create work for himself, so this new guy might give you good news. The Nissan engines are tough so I think you have a good chance the numbers will show average internal wear if not good compression. I know it's hard, but if possible, always be present when they work on your car.

Gluck mate, and keep us posted!

Osprey · Wed May 18, 2011 9:10 pm

Hi Paolo, thanks - it is much better but still I feel about 90%, seems a bit gutless. The tappets are ticking a fair bit but the initial problem with compression was due to someone, maybe the previous owner having stripped the threads on 3 plugs - they were only half way in to the head so the garage had to re-thread them. It is running well now and I just got a new radiator cap and coolant as it boiled over a few times. I'd like to give it a bit more oomph for a small investment and am thinking of changing the air filter and maybe a chip that Lee mentioned. Shame I can't stretch to a VTEC but we cannot manage 40K instead of 23K at the moment, so it is a good strong plodder but does lack power compared to the old V8's of both the Jeep and flying Durango.

PR · Mon May 23, 2011 11:27 am

More good news - re-threading plug threads is cheap and easy! 8) New air filter is a good idea. Keep chipping at it and you will be rewarded

Osprey · Mon May 23, 2011 3:07 pm

Getting closer to a well running car: new fuel and air filters and the second set of new plugs in 1 month! Friends garage in Sanaya changed them together with cables for me but managed to use the ones for carburettor which were wrong, Mehran now installed the correct type for injection and re-did the timing and it is much better. Will have to give it a try in the sands one day but am starting a new job tomorrow in Ab Dhab. See you soon and thanks for the advice.

burn_e · Thu Jun 09, 2011 9:29 am

Just bumped into this thread.

Had some rough running engine on my Patrol as well and it become a bit better after having done all the service you did.

Since your Patrol is not the youngest any more I suspect that your injectors aren't at their best stage (you didnt mentioned the kilometers it has clocked) . Get them pressure tested (Bosch Service e.g.) and replace if any doubt comes up. You will see your car is like new after that.

Did you confirm this funky pressure readings in the cylinders after the spark threads where fixed?

Uneven running / misfire on my patrol

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