98 GU Patrol rough running
Submitted: Wednesday, Dec 07, 2005 at 23:07
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28693
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GU-Troll
I have a 4500 patrol that is having a bit of rough running problems, wondering if anyone else has experienced this. I have just changed the plugs, oil, oil filter and fuel filter and since then have noticed rougher idling and surging/hesitation under light/medium acceleration, it was ok before. The plugs were
well worn and
the gap was significantly bigger than the new plugs ( old plugs and new plugs were identical NGK). I checked under the distributor cap and noticed fouling on the points and rotor, I have since cleaned this off but that didnt fix it one bit.
Im guessing it could be one of 3 things, either dodgy fuel pump, perhaps old leads or a vacuum leak? Anyone have any suggestions before I go
fork out the money I had set aside for the missus' christmas present chasing pixies under the bonnet?
While Im on the topic, can anyone tell me what sort of fuel economy they get? I filled up both tanks and drive roughly 550-600ks city driving, is that normal?
Cheers in advance
Ashley
Reply By: Rick (S.A.) - Wednesday, Dec 07, 2005 at 23:12
Wednesday, Dec 07, 2005 at 23:12
yep, normal city running..........bugger it.
Sorry, can't help with the rough running prob.
Cheers
AnswerID:
142909
Reply By: Billowaggi - Wednesday, Dec 07, 2005 at 23:37
Wednesday, Dec 07, 2005 at 23:37
How many k's has it done all up, over 100,000 may be due for plug leads, especially after pushing and pulling on them to change the plugs.
Regards Ken.
AnswerID:
142914
Follow Up By: GU-Troll - Wednesday, Dec 07, 2005 at 23:41
Wednesday, Dec 07, 2005 at 23:41
Hi Ken,
Bout 200k's and judging by the condition of the plugs, I would say the leads havent been changed for a long while. They were really tight and required some "gentle coaxing" to get them off.
FollowupID:
396416
Follow Up By: Boc1971 - Thursday, Dec 08, 2005 at 21:18
Thursday, Dec 08, 2005 at 21:18
I does sound like leads , they can be very fusy things -- had the same prob in my 4runner .... after a plug change ... put new leads on and ran like a puppy ! ( and $200 + for leads ?? WTF is that about toyota ??? )
Frank
FollowupID:
396531
Reply By: Voxson (Adelaide) - Thursday, Dec 08, 2005 at 07:39
Thursday, Dec 08, 2005 at 07:39
Sounds like a plug
gap problem...Open
the gap up...
AnswerID:
142931
Follow Up By: GU-Troll - Friday, Dec 09, 2005 at 12:11
Friday, Dec 09, 2005 at 12:11
They are brand new spark plugs, I would expect
the gap should be set perfect out of the factory??
FollowupID:
396589
Reply By: Member - JD - Thursday, Dec 08, 2005 at 15:24
Thursday, Dec 08, 2005 at 15:24
Hi GU-Troll,
Look for the simple things first...the plug leads could be the culprit..if you check your manual it should tell you how much resistence a good lead will have..than check with a multimetre...lift the hood at night and run the engine, some times you can see the elect discharge around the leads you have to look closely be carefull not to get draged in by spining parts under the hood..reset the timing as cleaning the contacts slightly changes things...but start from the simple things first...the last thing you touched before it played up.Hope this helps.
JD
AnswerID:
142984
Follow Up By: GU-Troll - Friday, Dec 09, 2005 at 12:13
Friday, Dec 09, 2005 at 12:13
Yeah I need to
check the timing, I bought a timing light but made the fatal mistake of being a tight bastard and bought a neon tube instead of a xenon tube, cant see a thing, will have to take it back and change it. I dont have the nissan manual with me, does anyone know what the setting for the timing is?
FollowupID:
396591
Reply By: Exploder - Thursday, Dec 08, 2005 at 19:00
Thursday, Dec 08, 2005 at 19:00
200,000k’s yep the leads would be shagged if original, like said above run the engine at night and look for the lightning show under the bonnet. Also look closely around where the leads sit close together for burn (Arcing) marks on the insulation.
Probably would not hurt to run a bottle of Injector cleaner thro it as
well on a tank of premium.
As you say Vacuum leaks would be another possibility.
Get the fuel pressure checked at the rail also, if this is OK it will cancel out the fuel pump.
AnswerID:
143008
Follow Up By: gqpat - Friday, Dec 09, 2005 at 11:13
Friday, Dec 09, 2005 at 11:13
would suggest plugs and leads as
well .take a look at the airgap on the rotor button to dizzy cap as
well on all gq's we used to mig up the rotor button as they had a huge
gap this helped heaps .If the k's are also high the tappet settings will also need adjusting most people overlook this as a tight tappet will give a miss at low revs almost the same as bad spark..
FollowupID:
396582
Follow Up By: GU-Troll - Friday, Dec 09, 2005 at 12:10
Friday, Dec 09, 2005 at 12:10
Changed the leads, it has made some improvement, but I can still feel some grumbling from the motor when under light acceleration. I thought about the bottle of injector cleaner, but in the passed when I have used it, I have never once noticed any difference, is there a good brand that does the job?
FollowupID:
396588