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Did you buy the correct plugs? Is the ground (earth) strap from the alternator clean and tight? Are all of the coils correctly attached to the plus, no broken wires?
It helps others give the most accurate answers if you will provide the model, year and engine displacement of your Jaguar. If you'll add that info to your signature then it will show up with all of your posts.
As Jim mentioned, using the correct resistor spark plugs is important, and the correct plug for your engine depends on when it was manufactured. Some members who have used plugs other than the original equipment NGKs have reported problems.
Another possibility is the Suppresion Module, which is a radio-frequency noise suppression capacitor that connects across two terminals on the alternator. For a 1997-2003 XJ8 with a V8 engine, it's Part 1 in the diagram below. If the supression module was not connected, or the electrical connector shown in its wiring harness was disturbed, your radio will pick up Electro-Magnetic Interference (EMI) from the alternator:
There are other suppression devices in the car, on the fuel pump and elsewhere, depending on model and year, but since you just replaced the alternator I would suspect its suppression module first, assuming your plugs are not the problem.
Please let us know your car details and we'll be able to offer more specific suggestions.
I have just recently, since i have been listening more and more on the radio, invested a couple of days worth of troubleshoting this super annoying problem. First i tried all the simple things that are easily done like cleaning plugs, coilpacks connectors etc. etc. But without any luck at all.
Thinking back, it did start after replacing sparkplugs and doing so, messing with the coilpacks.
My train of thought went like this: Crackle on the radio that follows Engine rpm --> open air spark somewhere --> most likely orginating from coilpacks --> energy from coilpack skipping lead and jumping across? --> Crackle!
I suspected that the energy either skipped the little spring entirely or maybe one or two turns, here and there.. randomly..
So, i removed all coilpacks, removed the rubber sleeves from them and took a closer look at the little flimsy coiled spring connecting the tip of the coilpack to the top of the sparkplug. They all, after a little closer look, seemed to be more or less covered in dirt and a thin layer of corrosion, the same applied to all of the tips on the coilpacks..
All of the tips got cleaned so they looked nice again, then i got some copper braid, the small type you would use to suck up exessive solder when soldering.. cut pieces of the braid and stuck it inside the little springs and folded it over the ends and then i assembied it all again..
Im happy to tell you that i have not had a single crackle on the radio caused by the mighty Jaguar engine ever since :-)
I dont know if its possible to buy these springs separately, but this little improvement are by all accounts a simple and very cheap thing to try. I suspect that theese copper braids will get brittle/corroded over time but atleast now i know what to do if the promlem occur again.
There are other suppression devices in the car, on the fuel pump and elsewhere, depending on model and year, but since you just replaced the alternator I would suspect its suppression module first, assuming your plugs are not the problem.
Hi Don,
could you explain where are the other suppression devices in the X308 are located? I have a whining noise around 1000 to 1500 rpm. But only if the AC button is pressed. With the AC turned off the whining noise is immediately gone.
could you explain where are the other suppression devices in the X308 are located? I have a whining noise around 1000 to 1500 rpm. But only if the AC button is pressed. With the AC turned off the whining noise is immediately gone.
Hi Ben,
Off the top of my head I can't tell you where all of the suppression devices are located. On the X308, the electronic modules tend to have RFI suppresion built in rather than relying on external suppressors, but you may be able to locate any external ones by reviewing the wiring diagrams. The suppressors usually show up as a capacitor or combination capacitor-diode or capacitor-resistor. Sometimes they exist but are not shown on the schematics. You can download the wiring schematics at the link below:
Is the whining noise coming from the audio system or from the engine bay? If it's from the engine bay, I would suspect the A/C compressor bearings, drive belt, or both.
Is the whining noise coming from the audio system or from the engine bay? If it's from the engine bay, I would suspect the A/C compressor bearings, drive belt, or both.
The noise is hearable from both front seats only while driving and I think it is from somewhere inside the cabin.
It sounds like a ground loop whining noise known from alternators. But it is present only if the AC is activated and only at some certain speeds.
Like when I accelerate from 25 to 40 mph. Or the car is running steady at 40mph. (1000 to 1500 rpm)
I completely removed the auto head unit (I have the standard system without amplifier) but it is still there.
Unfortunately, the thread starter never responded in the thread. I sent him a pm.
I look under my bonnet. I have no Suppression Module mounted. Not even a bracket for it nor any cables at the alternator. It looks like it was never equippt with one. Jaguar says it is mounted from 97 to 03.
But not on all vehicles? It is listed for all X308 but for X300 is only with premium sound. Same for the X100. I have a X308 with standard sound and navigation.
The noise is hearable from both front seats only while driving and I think it is from somewhere inside the cabin.
It sounds like a ground loop whining noise known from alternators. But it is present only if the AC is activated and only at some certain speeds.
Like when I accelerate from 25 to 40 mph. Or the car is running steady at 40mph. (1000 to 1500 rpm)
I completely removed the auto head unit (I have the standard system without amplifier) but it is still there.
Ben,
Do we understand correctly that you have removed the audio head unit and so the sound you are hearing cannot be coming from the audio system?
Does the sound seem to come from the front of the car or the rear?
The noise is hearable from both front seats only while driving and I think it is from somewhere inside the cabin.
In your other thread on the issue, you said that your AC control panel "module makes a strange high whining noise". Now I understand that it is not coming from the AC control module and not from the sound system speakers either.
When you switch the AC "on" on the control panel, the AC compressor is activated. It is more likely that either the compressor, or the AC expansion valve, is making the noise you describe. One of the causes of compressor buzzing/whining is overcharged AC system but it could be for other reasons (like internal wear). You could do the following tests with a mechanic's stethoscope:
1. Listen on the compressor body.
2. Listen along the high pressure line and especially near where this line enters the bulkhead (where the expansion valve is located).
If you identify the sound and if it is loudest on the compressor, then it is generated there. If loudest at the pressure line near the bulkhead, then it could be the expansion valve "singing". Depending on what you find, you may need to fist evacuate the AC system and recharge with the correct amount of gas (650 g). If the sound persists, and if it seems to be coming from the expansion valve, then you may need to replace it.
I first thought it came from the radio followed by the AC control panel because of the missing suppression device. After disconnecting the radio and AC panel the noise was still there. So I thought it could be the A/CCM module. But it was not it is silent.
Then I removed fuse #8 in the engine compartment which is the compressor clutch. The noise is away immediately. It looked further and found a post by motorcarman containing a link to:
TSB 412-10 Whistling Noise From AC: https://www.jaguarforums.com/forum/x...6/#post1522323
I have not seen this TSB before as it is not listed at jagrepair.com This description fits my problem. It describes changing the AC suction pipe to a newer 2-piece version.
But I don't read anywhere someone with the same problem. After I put the fuse back in place I did some stationary testing. I can reproduce the noise in neutral revving the engine to 1500 rpm. Holding the rpm constant and set the AC to 17 degrees celsius with the lowest blower position the noise comes every around 20 to 30 seconds and lasts for around 10 seconds. Bevor the whistle noise I can feel the ac compressor clutch engaging.
Today I had no second person to hear at the AC pipe directly if there is a whistle.
It looked further and found a post by motorcarman containing a link to:
TSB 412-10 Whistling Noise From AC: https://www.jaguarforums.com/forum/x...6/#post1522323
I have not seen this TSB before as it is not listed at jagrepair.com This description fits my problem. It describes changing the AC suction pipe to a newer 2-piece version.
Hi Ben,
If that TSB describes your sound, be sure to thank Bob Gauff (motorcarman) for all of the Jaguar documents he has posted and uploaded over the years. We would all be more lost than we are without his generous investment of time and energy in sharing his wealth of knowledge over the past decades. Bob has been helping me since I bought my first Jaguar in 1993. I notice that even though he posted that TSB in 2016, no one even bothered to Like his post, so I just did. I hope others will do the same.
This description fits my problem. It describes changing the AC suction pipe to a newer 2-piece version.
After the discovery of the TSB, it now seems quite likely that your noise is the one described in the document so you should trace the suction (thicker) pipe to determine whether it is one piece. It is, however, strange that the Parts Cataloge does not show the version with one-piece suction pipe, only the two-piece (Items #3 & #4):
Perhaps only early Parts Catalogues showed the one-piece pipe.
Don, you are absolutely right. Without his TSB submission would maybe never come to this source of the noise.
I did some research and I think the picture of the parts catalog belongs to VINs after F11735 within MY00. My VIN is lower. MNC7310BF is newly introduced with the 2-piece version.
I also attached two pictures of both pipe versions.
I have seen quite a few confusing cases in the parts catalogue. The page I posted earlier shows the old p/n MJA7312CA but the diagram shows the new shorter pipe MJA7312CB which must be used together with MNC7310BF. If you search the Barratt website for the old (long) MJA7312CA, it shows that it has been superseded by MJA7312CB which is incorrect - it has been superseded by MJA7312CB+MNC7310BF (the website does not tell you that).
Another thing in the parts catalogue one has to be careful about is when, for the engine parts, it shows two different p/n, early and later, for the same (function) part with a change-over at VIN 853935. This applies only to NA engines and not to SC engines. In such cases, for SC engines, the change-over point was actually VIN 878717 (change AJ26 to AJ27) but the catalogue does not tell you that. Initially, following the parts catalogue, I bought a few wrong parts for my SC engine.
01-15-2016, 01:31 PM
Crackling Radio With Running Engine
