speedyxjs
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| posted on 15/12/10 at 02:32 PM |
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Idle quality
My engine has developed a problem with idle which seems to be a common fault with the 3.6 AJ6 engine. I can get it fixed but that means a £200 ECU
mod. I have found a 3.2 AJ16 engine which come with the loom and ECU for £150 (recon i can get it a bit less). Thing is, even after delivery, this
should still work out cheaper than the ECU mod as i can sell alot of the AJ6 parts back on ebay.
This would mean moving on to my 4th engine for this car and its not even IVA'd yet 
This is all assuming that poor idle would be an IVA failure. The car wont even start without a bit of throttle and after some banging and shaking,
stalls at idle. Is this likely to fail IVA?
[Edited on 15-12-10 by speedyxjs]
How long can i resist the temptation to drop a V8 in?
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carpmart
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| posted on 15/12/10 at 02:52 PM |
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I'm not sure if its an IVA fail but it will sure as hell make it a pain in the arse to drive!
You only live once - make the most of it!
Radical Clubsport, Kwaker motor
'94 MX5 MK1, 1.8
F10 M5 - 600bhp Daily Hack 
Range Rover Sport - Wife's Car
Mercedes A class - Son's Car
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MK9R
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| posted on 15/12/10 at 02:52 PM |
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seems a little extreme swapping engines because of a relatively easily fixable lumpy idle!
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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britishtrident
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| posted on 15/12/10 at 04:11 PM |
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First port of call on Jags with idle or starting problems is usually the coolant temperature sensor.
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speedyxjs
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| posted on 15/12/10 at 04:38 PM |
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quote:
Originally posted by MK9R
seems a little extreme swapping engines because of a relatively easily fixable lumpy idle!
If it is the ECU problem, its an easy but expensive fix. I hadn't thought of the coolant temp switch but now that you suggest it, i had read
about it somewhere. Would it not improve as the engine warms up though?
How long can i resist the temptation to drop a V8 in?
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RazMan
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| posted on 15/12/10 at 05:07 PM |
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IVA will want to see it idling when they do an emissions check so I would imagine it needs to be sorted or it won't pass. Can the problem be
sorted out in another way?
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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James
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| posted on 15/12/10 at 06:10 PM |
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You know, when we get people posting on here about doing things 'a bit different' we really ought to mention to them the more you deviate
from the norm, the harder the build is!  
What is the ECU mod? Is it not something you (or one of the electronics gurus on here) could do?
How complex can an old Jag ECU be???
As for IVA... if the car runs crapily then it's just a reason for the tester to think the car needs closer examination for it to be safe!
Impressions are everything with this sort of thing!
Cheers,
James
[Edited on 15/12/10 by James]
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"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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speedyxjs
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| posted on 16/12/10 at 07:30 AM |
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Bugger 
This is where i read about the problem. Apparently they add an idle adjustment screw to it but i
wouldn't know where to start! I will however, borrow the coolant temp sensor off my tintop later and try that in the hope that that will fix
it.
Thanks for all your help guys
How long can i resist the temptation to drop a V8 in?
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speedyxjs
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| posted on 16/12/10 at 07:45 AM |
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quote:
Originally posted by James
You know, when we get people posting on here about doing things 'a bit different' we really ought to mention to them the more you deviate
from the norm, the harder the build is!
Yeah yeah What was originally going to taken me a year to build (ha ha!) has taken 4 years so far lol
How long can i resist the temptation to drop a V8 in?
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RazMan
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| posted on 16/12/10 at 10:34 AM |
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quote:
Originally posted by speedyxjs
I can get it fixed but that means a £200 ECU mod. I have found a 3.2 AJ16 engine which come with the loom and ECU for £150 (recon i can get it a bit
less). Thing is, even after delivery, this should still work out cheaper than the ECU mod as i can sell alot of the AJ6 parts back on ebay.
Another thing to consider is how much your time is worth. If I had the choice of paying for a quick fix or swapping the engine (assuming you know your
existing engine is good) I would get my cheque book out
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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scudderfish
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| posted on 16/12/10 at 12:06 PM |
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quote:
Originally posted by speedyxjs
Bugger
This is where i read about the problem. Apparently they add an idle adjustment screw to it but i
wouldn't know where to start! I will however, borrow the coolant temp sensor off my tintop later and try that in the hope that that will fix
it.
Thanks for all your help guys
Reading that page they first suggest relocating the vacuum tube to elsewhere on the manifold. I'd give that a go first. The thing that they
charge £200 for is a trimmer pot that costs pence. I guess they cut a track coming from the MAP sensor and put the pot in line so you can fudge it.
This would be a fudge against the whole range though, not just idle.
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speedyxjs
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| posted on 16/12/10 at 01:49 PM |
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quote:
Originally posted by RazMan
quote:
Originally posted by speedyxjs
I can get it fixed but that means a £200 ECU mod. I have found a 3.2 AJ16 engine which come with the loom and ECU for £150 (recon i can get it a bit
less). Thing is, even after delivery, this should still work out cheaper than the ECU mod as i can sell alot of the AJ6 parts back on ebay.
Another thing to consider is how much your time is worth. If I had the choice of paying for a quick fix or swapping the engine (assuming you know your
existing engine is good) I would get my cheque book out
Engine was an ebay bargain and the seller didn't know whether it ran. I took the coolant temp sender out today and noticed it was only touching
the tip of the coolant so topped that up a bit but that didn't really help. What will the IVA man class as a good idle speed? If i set the idle
at about 1k, its not too bad and certainly much better than at 800. Im going to speak to an MOT tester friend sometime and see if he can put it on his
emissions kit so fingers crossed i may not have to spend much money getting it to an IVAable state.
Cheers
How long can i resist the temptation to drop a V8 in?
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NS Dev
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| posted on 16/12/10 at 02:17 PM |
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we've worked on and owned LOADS of these old jags and I've NEVER had an issue with an ECU. Coolant temp sensor faults plague them, and the
only way to be sure is a new sensor, but they are only £10 so I would just put a new one in for a start! The AJ16 suffers exactly the same temp sensor
fault as well! We bought a complete manual 3.2 sport the other day for £250 as it would not run/idle. New coolant temp sensor and now its perfect!
The other thing to check/replace would be the airflow meter.
Dont' believe the utter crap that is spouted on the good ol tinternet. Everybody on "the forums" says the fault with idle and light
throttle running on AJ16 engines is the lambda sensors...........again, we've never had an issue, its always the coolant temp, and occasionally
the airflow meter as well.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 16/12/10 at 02:18 PM |
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ooh ps ok there is a common ecu fault on the AJ16, its called it getting full of water, but that's kinda obvious! Wasn't wise to mount it
below the bulkhead grommet I guess!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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