My Bosch +4 Experience--Awful!!!

[mnwolftrack]

I had such a bad experience recently with Bosch +4's I just put in my '99 D2 that I thought I'd share my story. You may have already read some of the posts regarding my original saga starting with an SES (service engine soon) light on steady but with truck ran quite well overall. The SES light OBDII codes were P0300, P0306, and P0305. Thinking I should do the basics, I started with replacing the plugs and wires. I choose Bosch +4s based on some other threads I've read (but overall my impression was people either loved them or hated them). I hate them. Anyway, a few days later I installed Magnecor 8mm wires also per advice from this board. I don't think I found any negative comments on the wires.

Anyway, the SES light did not go off, and there was a slight miss occurring that a mechanic friend of mine noticed. I didn't quite hear it myself, but I figured the plugs and wires didn't fix it yet and there must be another issue. I decided to clean the engine with seafoam via 1/2 can in the crankcase and 1/2 can through the intake via the brake booster port. As expected, the seafoam caused a ton of smoke and really ticked off the SES light to the point of flashing all the time. However, the smoke took a few hours worth of running to go away between driving and idling. It should only take a few minutes. Gradually and rather quickly, the Disco began running worse and worse, plugs were getted saturated in gas, and new P030x codes were showing up. It was causing me a TON of grief, the miss was getting very VERY noticable and the problem(s) just weren't clear. I did find that I had slightly lower compression on one cylinder, but people on here didn't think it was low enough to cause the trouble. A horrible miss/shake developed at 2000RPM at idle or while driving that would cause the SES light to start flashing instantly.

So at this point I figured seafoam must have cleaned something out or somehow did something to escalate the issue. I should clarify I didn't think seafoam caused the problems, rather I just figured it unmasked something lurking. However, the problems just kept getting worse and worse and the engine running poorer and poorer, to the point I couldn't even drive 55mph.

So finally, I decided to start putting the original parts back in (plugs and wires) and see what happens. I started with the original Champion double platinum plugs (same part number as in the D2 owner's manual RC11PYPB4). I pulled the Bosch's out, and geez, two plugs wet again. This time a different one. I put the champions in and it runs like a champ! The power is back. The rotten egg smell is gone (no more unburnt fuel exiting the exhaust from easily fouled +4 plugs). The miss at idle is basically gone again to how it was when I bought the D2 2 weeks ago. The horrible miss/shake at 2000RPM is definately gone and the engine revvs very smoothly. I pulled the champions after running the engine for about 10 minutes and taking another 10 minute test drive. All plugs were dry!

The Bosch's are going back to the parts store first thing tomorrow, and I will never buy them again. Other people on this board mentioned in previous posts that Bosch +4's fouled easily and caused all kinds of codes. Guess what? Yes they do!

Never again! Maybe Seafoam and Bosch +4's don't get along. Maybe +4's don't like being in any vehicle's engine that isn't in tip top shape. I'm not sure how the other people had luck with them, but I will never waste almost $60 on plugs again. I wasted many hours chasing problems that only existed because of these new plugs. Not to mention 3 or 4 long threads and many posts by other people trying to help me diagnose a downward spiraling problem caused by the infamous Bosch +4's.

 

[sven]

You're not the first person to complain about these plugs.. Its great that you figured this out before ripping out the heads

 

[Chris-St Louis]

Told ya! First post even.


(Flame suit on). I cannot tell you how many cars I fixed in the field, and hove many techs I talk to at work about these Goddamn Bosch plugs.

They cause more problems then they fix.

(blurry memory shot----like on TV when going in the past)

Me - Sir, you need to replace these spark plugs. They are causing your misfire.

Customer - BullShit! Your a hack. I just put in new Spark plugs. Got them from the zone. The guy behind the counter told me Bosch Platnuims are the best, and I want the best for my car. Your trying to rob me.

Me - No, I am not. I have a scope pattern to prove it. The plugs are your problem.

Customer - Ok (Eye Rolling) Sure. Go ahead, put some plugs in. Then, when it doesn't fix it I want my money back.

Me - Deal.

Later, after I do the work, The customer gets his car back. Weeks go by. I see the customer while changing his oil.

Customer - I hear you like Miller Beer.

Me - What?

Customer - I was a ass, you were right. The truck runs great. I'm sorry for badmouthing you. I hope this beer will smooth it over.

Me- Um, Sure. (Dumbfounded Look on my face) You Bet. All sins are forgiven.


True story!!!!


If Bosch plugs work for you, great, have at it.


If you have drivability issues, It's smart to swap them out with OE plugs as a foundation for a good diagnosis.

 

[garrett]

Told ya! First post even.


(Flame suit on). I cannot tell you how many cars I fixed in the field, and hove many techs I told to at work about these Goddamn Bosch plugs.

They cause more problems then they fix.

(blurry memory shot----like on TV when going in the past)

Me - Sir, you need to replace these spark plugs. They are causing your misfire.

Customer - BullShit! Your a hack. I just put in new Spark plugs. Got them from the zone. The guy behind the counter told me Bosch Platnuims are the best, and I want the best for my car. Your trying to rob me.

Me - No, I am not. I have a scope pattern to prove it. The plugs are your problem.

Customer - Ok (Eye Rolling) Sure. Go ahead, put some plugs in. Then, when it doesn't I want my money back.

Me - Deal.

Later, after I do the work, The customer gets his car back. Weeks go by. I see the customer while changing his oil.

Customer - I hear you like Miller Beer.

Me - What?

Customer - I was a ass, you were right. The truck runs great. I'm sorry for badmouthing you. I hope this beer will smooth it over.

Me- Um, Sure. (Dumbfounded Look on my face) You Bet. All sins are forgiven.


True story!!!!


If Bosch plugs work for you, great, have at it.


If you have drivability issues, It's smart to swap them out with OE plugs as a foundation for a good diagnosis.

i have been waiting all morning to hear Chris post. hehe.

 

[Chris-St Louis]

Its hard to get the "Tone" of a post. Were you waiting in a good way?

I'm just waiting to have to defend myself.

Fun Points about Spark plugs on a Hot Rod Fast and Furious guy web site Cut and paste.


Looks like I'm not the only one.





Bosch Platinum
I hate these plugs. They have a weird center electrode that is flush with the insulating porcelain. What happens is that this electrode quickly erodes so it ends up being a depression in the porcelain, making the spark shoot out of a hole. Sparks like to propagate from sharp edges so I think they have a hard time getting out of this hole.

These plugs will absolutely not work for long in high compression, high rpm, boosted or NOS applications. They are marginal on a stock engine. In my experience they work OK for a few thousand miles then start to idle roughly and on modified engines misfire under load. It amazes me that an OEM level supplier like Bosch can make pieces of crap like these.

Bosch Plus 4
Although I have not had any experience with them, others have reported that they suck, including one source that I respect very much for information. These plugs have an unusual design with 4 ground electrodes much like a rotary engine plug. Personally I hate Bosch plugs so much, I will not test these!

 

[garrett]

Its hard to get the "Tone" of I post. Were you waiting in a good way?

yes. i was going to post before you, but knew you would be happy to see this one.

 

[S Marks]

...I choose Bosch +4s based on some other threads I've read (but overall my impression was people either loved them or hated them). I hate them.

I read many of the same things you did prior to changing my plugs in my '99 DII. But there were too many stories like yours so I decided to stick w/ the stock Champions. Glad you were able to figure that out prior to dropping any more scratch. You shouldn't have any issues w/ the Magnecores.

 

[mnwolftrack]

Yes, Bosch sucks for making this plug. But I honestly didn't think they could make it run THAT badly. I figured, new spark plugs = better. WRONG! New spark plugs = poo in a rover!

I still have to solve the initial problem of the SES light coming on and lower compression on #6. I erased codes last night just before going to bed. I didn't bother writing them down this time because they were all +4 issues.

I got about 10 miles on my way to work this morning and the SES light came back on steady (whew) this time. I was engine braking downhill in 2nd gear when it came on. As when I intially bought this D2 almost 3 weeks ago now, the light only seems to come on around idle but I'd want to test it a little more before I'm solid in my answer. I haven't checked the codes yet, but I'm willing to bet it's only PO306 which is the cylinder with lower compression (140 vs. the others at 190). All the baddies caused by the Bosch plugs are gone (rotten eggs, horrible idle and miss, flashing SES light, wet plugs). I cannot say enough how much better it runs without those $(%*(! plugs.

Yes you were right Chris (no flaming coming from me either), and I bow down to you!

 

[garrett]

Yes, Bosch sucks for making this plug. But I honestly didn't think they could make it run THAT badly. I figured, new spark plugs = better. WRONG! New spark plugs = poo in a rover!

I still have to solve the initial problem of the SES light coming on and lower compression on #6. I erased codes last night just before going to bed. I didn't bother writing them down this time because they were all +4 issues.

I got about 10 miles on my way to work this morning and the SES light came back on steady (whew) this time. I was engine braking downhill in 2nd gear when it came on. As when I intially bought this D2 almost 3 weeks ago now, the light only seems to come on around idle but I'd want to test it a little more before I'm solid in my answer. I haven't checked the codes yet, but I'm willing to bet it's only PO306 which is the cylinder with lower compression (140 vs. the others at 190). All the baddies caused by the Bosch plugs are gone (rotten eggs, horrible idle and miss, flashing SES light, wet plugs). I cannot say enough how much better it runs without those $(%*(! plugs.

Yes you were right Chris (no flaming coming from me either), and I bow down to you!

bow? he likes kneeling.

but really i can't imagine #6 at 140 psi being your issue. i'd be lucky if all of my cylinders are producing 140. that is a pretty solid number.
there has to be some other shit going on.

 

[mnwolftrack]

It's not so much the absolute value of 140PSI that bothers me, it's that all the other cylinders are about 190 +/-3 PSI, so that #6 is about 25-30% less. While 190 seems high, I consistently get the same numbers across the board and just to be safe I bought a brand new actron compression tester and I get the same thing. #6 is the only one that fluctuates, and I've gotten everything from 120 to 145PSI. I got 120, 125, 130, 140, and 145 (145 only with adding a bit of oil in the cylinder). And unlike the other cylinders, #6 takes longer to max out. For example, if it was going to max out at 140 it might go up to 125 first, then hang for 3-5 seconds, go up 5-10 PSI and hang, go up and hang, etc... The gauge is not sticking either, because only #6 does this, and both my gauges show this. The other cylinders would go up to about 5 short of their individual max right away then take a few more seconds to go the remaining 5PSI.

 

[jsonova99]

Speaking of stock spark plugs, what is the part no. on them? I'm getting ready to change mine, and I'm just going straight to OEM, no messing with Bosch for me. By the way, is the general concensus still Magnecor wires? If so, what size is recommended for a bone stock D2.

 

[garrett]

Speaking of stock spark plugs, what is the part no. on them? I'm getting ready to change mine, and I'm just going straight to OEM, no messing with Bosch for me. By the way, is the general concensus still Magnecor wires? If so, what size is recommended for a bone stock D2.

check out STi wires too. for the $$ i think they are at least as good as magnecore. i have both.

 

[Chris-St Louis]

I'll take your bowing..... Kind of making me blush.

Now, if you were one of those girls stuck in mud.......

 

[mnwolftrack]

Stock D2 plugs should be Champion RC11PYPB4. They were in mine originally (and I even put the old ones back in because they spank the Bosch plugs), and that's what the manual calls for.

My only difficulty was that none of the stores in my town carry this plug or even have it listed in their books or on the Champion website. One place even told me this plug doesn't exist because Champion doesn't do part #'s in this fashion. Yet strangely enough I had 8 plugs in my hand with this # and my owner's manual says it on page 179-ish. Eventually I will just order stock replacement plugs from a Rover specialist/dealer.

Regarding Magnecor, I don't think I read any negative responses about those, and I bought mine from www.ultrarev.com for $72 shipped. I think the most common wires are the 8mm and are slightly bigger than stock, while the 7mm are stock size. The 8mm are a tight fit into the wire looms. I drilled mine out and they fit nice now. Be aware with whatever plug wires you go with that you will not be adding horsepower (read magnecor's website). I've seen some spark plug wire companies claiming 5-10 HP gains. Even the best wire will only allow the engine's spark system to deliver the maximum spark the coilpacks are capable of.

I think the magnecor's are cheaper than stock rover wires too. I'm not putting down other wire brands, I just know that the Magnecors have a good reputation (outside of Land Rover too). Now if we were talking about spark plugs, I definately know of at least one brand I would slam....

 

[jsonova99]

Stock D2 plugs should be Champion RC11PYPB4. They were in mine originally (and I even put the old ones back in because they spank the Bosch plugs), and that's what the manual calls for.

My only difficulty was that none of the stores in my town carry this plug or even have it listed in their books or on the Champion website. One place even told me this plug doesn't exist because Champion doesn't do part #'s in this fashion. Yet strangely enough I had 8 plugs in my hand with this # and my owner's manual says it on page 179-ish. Eventually I will just order stock replacement plugs from a Rover specialist/dealer.

Regarding Magnecor, I don't think I read any negative responses about those, and I bought mine from www.ultrarev.com for $72 shipped. I think the most common wires are the 8mm and are slightly bigger than stock, while the 7mm are stock size. The 8mm are a tight fit into the wire looms. I drilled mine out and they fit nice now. Be aware with whatever plug wires you go with that you will not be adding horsepower (read magnecor's website). I've seen some spark plug wire companies claiming 5-10 HP gains. Even the best wire will only allow the engine's spark system to deliver the maximum spark the coilpacks are capable of.

I think the magnecor's are cheaper than stock rover wires too. I'm not putting down other wire brands, I just know that the Magnecors have a good reputation (outside of Land Rover too). Now if we were talking about spark plugs, I definately know of at least one brand I would slam....

I've run into situations like this before with the rover where parts "don't exist" at your standard parts places. As far as wires, not looking for HP gains, just looking to keep that V8 running strong, quiet, and trouble free. I'm in the middle of doing my 60k service myself. I don't drive the Rover daily though, so I'm just doing it at my leisure when I get time. I have most of it done, but this is the job I;ve been dreading. OUt of curiousity, how did you get the old wires off of the coil packs and the new ones on?

 

[vray]

Here is what Robison Service says about plugs:

? All pre-1999 Rovers can use the Champion RN12YC spark plug. It's widely available at auto parts stores. We prefer the 12 to the 11 heat range the factory recommends. In other countries these plugs may be offered as N12YC or N12. They are OK also, but we suggest changing them every 15,000 miles.

? Newer Rovers with the Bosch engine management use a special platinum Champion plug. Quite a bit more expensive, available from your dealer. RN12YC can be fitted in a pinch.

 

[jsonova99]

what about Roversnorth and Atlantic British, do they sell these plugs at all? I didn't see them on the online catalog. Actually RN does sell a atuneup kit with plugs and wires, but I've heard some people say the OEM wires aren't that good. The kit is also like $250

 

[mnwolftrack]

I did *technically* find a set of plugs at a locally owned store, and I think the code was RC12MC4 ( also called the 318), I bought them but I haven't installed them yet. I was going to do a search on Dweb to see if anyone else used this plug. The NGK part # was 5555 for their double copper nonplatinum plain plugs, but I didn't get those. I haven't searched, but since the old OEMs were such an improvement over Bosch I will get new OEM's. I'm shooting for exact OEM!

 

[andrewv]

Well, now that it's better, I'll beat Chris' offer of $1,500 and go all the way to $2,000

 

[apg]

Plugging along

I use the Champion RN12YC in the '96 Disco as well as the '72 Series III...hell, I even use tham in my sailboat and that has a little Atomic 4 engine with all of about 25 horses. I tried the Bosch "Platinum Plus" plugs in the '72 a while back at it absolutely hated 'em. I mean, here is a low-compression engine of 1950's technology designed to run on third-world, 70 octane petrol and it was tough as hell to start in cold weather. Re-installed the old Champions, and it was back to it usual first spin start.

No, I don't like Bosch plugs either....

Cheers