XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

V12 Vac system 15 minute timer

Old Jun 4, 2021 | 01:29 AM
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Default V12 Vac system 15 minute timer

Salutations

the link to the u tube video in this post is a how to to remove the 15 minute timer on a V12 Jag HE ...

i disconnected the wiring on the 15 minute timer a while back now, but have always had an excessively rich idle when cold ..... warmed up its OK......despite attending to a lot of other thinks like earthing, coolant sensors, new ecu etc etc ... so i intend to go down the path of what "Cos Graham" has done in his video. I did think that by disconnecting the wiring that it stopped the timer set up.....?

anyway i will be working through this over the weekend and will report in when compete .... any and all comments are welcome before and after ......

all good ... Darren
84 HE V12 .... the Mistress
 
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Old Jun 5, 2021 | 05:51 PM
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I noticed in the video that the presenter says that he does not take his car over 4000 rpm. I certainly take my car higher than that. I'm not sure what his modification accomplishes beyond what is accomplished by running vacuum directly from the top of the throttle body to the distributor. I suspect his setup gives additional vacuum advance at idle when the throttle is closed, or near closed. I suspect this could lead to some detonation if driven with a heavier foot. No, I have not tried his modification at this time.
 
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Old Jun 6, 2021 | 03:56 AM
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Salutations

removed the 15 minute timer set up as per the "Cos Graham" utube video, started the mistress up, fired as normal with a significantly different idle .... not the rich fuel smell from the exhaust and a steady consistent idle through the warm up ... ambient temp here this afternoon is about 17degree C. This is a step in the right direction. DLeit53's comments are valid as i do not really understand the reason for the loop via the dump vale ?.... but hey give it a try....!.... easy enough to remove this from the system if need be.

Getting late in the afternoon here .... but its a public holiday tomorrow so it will be a good opportunity to take her out for a spirited run and see what difference this change has made.

all good

Darren
 
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Old Jun 9, 2021 | 09:31 PM
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well the spirited drive did not happen

started ok on the Sunday .... reversed her out of the garage and was hosing off the dust while she was idling .... had not had her out for a few weeks. Car would have been idling for 5 + minutes then stopped......! ..... it started gain with the initial prime, idled happily then stopped again .... did this a few times and it would start then stop again .... looking at the fuel pump or blocked filter ..... happy this happened in the driveway.. just have not had the time to check things out properly.

the below ebay link is to an aftermarket fuel pump which looks to be reasonably priced at Au $45.00, has anyone used one of these .....?...... i may just change the pump regardless of the actual fault for peace of mind as i do not know how old the existing pump is ... going by the rest pf the car i think its the original fuel pump.

https://www.ebay.com.au/itm/173343413604

all good and thanks ... any and all comments welcome....

Darren
 
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Old Jun 12, 2021 | 04:03 PM
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it appear your fuel pump is at least running when the key is first turned on, priming the system. I would do some testing, as I would be a bit surprised if the pump is your actual problem. I don't have any experience with the pump on ebay, but the price is right.
 
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Old Jun 12, 2021 | 07:17 PM
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Thanks Doug ..... i am running what appears to be the original fuel pump so will go down the path of ordering a new one ..... may just change it anyway or it will be on the shelf when i need it ... !

correct ,.. have pretty much ruled out a fuel problem as i am getting pressure and flow to the fuel rail ..... and the failure stop mode was a cut out .... no stumble or run down just a dead stop.... ps will not start now at all ..... checking out the amplifier today and the shielded wire and work my way through the other electricals today if i get time ...

please ... any and all comments are welcome

pss .... how do you check the crank position sensor on these beasts

All good

Darren
 
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Old Jun 13, 2021 | 12:19 AM
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Darren
I would start by carefuly checking the connectors that attach to the coil. The copper can fracture insude the connector boot, and what seems like a decent item is actually faulty. Then check every other connector in the igntion.
Y our 1984 model does not have a crank position sensor only Marelli cars have them.
 
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Old Jun 13, 2021 | 02:04 AM
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Greetings .....

thanks Greg .... new coil not that long ago and re- dit all of the connections then ... mistress now has the single coil set up .... but thanks for the advice as "electrickery" is not my gig and will take all of the advice and help offered in this "Lucas Dark Art" business. And also thanks for the heads up on the crank position sensor .... will save a long and fruitless search.

referencing the Grant Francis "No Start doc" as i did last time this happened, it then being the condenser in the amplifier which was the culprit and was turfed.

Went back into the amplifier and tested the black GM Module, the "bad boy gremlin" in this instance, which ended up failing the Step 2 test as per the attached.

Also tested the shielded wire which had continuity.

So will track down new GM module next week .... still Sunday here in the land of Oz ... plug it all back together and try for that spirited drive next weekend.

https://www.ebay.com.au/itm/164878279567 ..... will this one do the trick ...?

all good .... all comments and questions welcome.....!

regards

Darren




 
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Old Jun 13, 2021 | 07:59 AM
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Originally Posted by darrhel

So will track down new GM module next week .... still Sunday here in the land of Oz ... plug it all back together and try for that spirited drive next weekend.

https://www.ebay.com.au/itm/164878279567 ..... will this one do the trick ...?
Outwardly it looks like it would do the trick....and it probably will....but the listing doesn't specifically state that is it intended to replace the GM module. personally, I'd look for something a bit less generic.

Is there any hope of sourcing a genuine GM/Delco part in your neck of the woods? If so, do so. Over the years many have reported fewer problems with the genuine part. The Delco number is D1906.

Cheers
DD
 
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Old Jun 13, 2021 | 08:13 AM
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Ideally you'll find a module that has the unique grounding tab as seen in both your pic and circled in yellow in this pic:



The significance of this tab was been mulled over in the past and I'm not entirely clear how/why it might be important. It isn't essential but is apparently desirable....and was one of the things that the Delco replacements had and the others didn't. I say "was" because, nowadays, even the Delco replacement doesn't have the tab.

This is not something I'd fret over, personally, but I'd consider it a 'plus' if your replacement module had the tab.

Cheers
DD
 
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Old Jun 18, 2021 | 06:33 AM
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Greetings

tracked down an ignition module at Napa / Covs ....Au $60, it comes with instructions to use silicone heat transfer compound ....? .... old one did not have it ....! ... just curious ... i will use the compound when it goes back together over the weekend .... probably late Saturday or Sunday.

just thought i would ask / seek comment from the forum about the use of the silicone compound ....?

all good

Darren

 
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