| Author |
Message |
    
Chase Fancher (Roverboy)
| | Posted on Tuesday, November 12, 2002 - 07:58 pm: | 
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About a month or so ago, I installed some Bosch p4's and magnecor 8mms into my disco..
I was expecting some increase in gas effeciency but have found only the opposite by nearly 2-3 miles!!
Any opinions on this?
My D1 has about 75,ooo miles on it.
Could my O2 sensors be at fault?
so frustrating!
Any opinions are greatly appreciated, thanks!
-Chase |
redrover
| | Posted on Tuesday, November 12, 2002 - 09:21 pm: |
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Platinum plugs can cause feedback loops in the efi system. I know for a fact that many late 80's and early 90's vehicles don't like platinum plugs. I always have, and always used copper. Even in turbo'd porsches on the track. |
Jason Vance (Jason)
| | Posted on Tuesday, November 12, 2002 - 10:50 pm: |
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MPG is one of those less scientific measurments around. Unless you can compensate or account for changes in driving style (sunday driving, red-light racing, etc), driving conditions (wind, grade, etc), traffic conditions (lots of lights, highway, bumper-to-bumper, etc), vehicle conditions (tire pressure = rolling resistance, decreased ring performance = blow-by and loss of economy, etc), change in the octane you were using (did you previously use regular, then start to use premium after adding the new plugs and wires?). The list goes on.
Not doubting you at all, but I can see a 1-3 mpg difference in fuel economy between fill-ups just by changing my driving style and routes I frequent, even when I consider my typical driving habits/locations to be the same. |
Chase Fancher (Roverboy)
| | Posted on Tuesday, November 12, 2002 - 11:07 pm: |
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Jason-
After my first fill-up (of the usual octane, at the usual pump, with the usual everything) I noticed a difference. I didn't change driving styles, routes, or anything that would affect the MPG. After my next fill up, again with the usual, I altered my driving style to conserve gas; slower acc, more coasting...I basically drove like my grandma...Again, no big difference at all in MPG, except a decrease...
I've lost around 50 miles a tank...should I call Bosch, get my money back, and switch to copper?
Thanks for the response.
-Chase |
John Moore (Jmoore)
| | Posted on Tuesday, November 12, 2002 - 11:12 pm: |
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I switched in 88RRC to bosch platinum and was happy. Ran better. It it possible the Bosch 4's are fouling? Have you plugged a plug to check it out?
Just a thought?
-John |
Roger Fastring
| | Posted on Wednesday, November 13, 2002 - 01:00 am: |
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I run B+4s w/o a problem. For wires, I run the grey Bosch wires. Ran slightly better than before, with old non-plat plugs and stock 100+mile wires. |
Jason Vance (Jason)
| | Posted on Wednesday, November 13, 2002 - 04:47 am: |
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Cripes Chase...!
FWIW, I'm running the Magnecore 8.5's and +4's on my '95 with no adverse change in MPG or performance. I don't know what year your D1 is, but if it is 94-95 and has the distributor, check the vacuum advance line from the plenum to distributor. Certainly, as you have mentioned, the O2 sensors could be in need of replacing.
A while back, somebody posted the p/n for some NGKs that were bomb-proof. Expensive, too; like $10 a plug, but he claimed they were well worth the money. |
Chase Fancher (Roverboy)
| | Posted on Wednesday, November 13, 2002 - 10:33 am: |
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Well...hmm...
The engine runs very smoothly, so I dont think any sparks are fouling...
Jason - I've got a 97 D1, so there goes the distributor problem.
Any ideas on what I should do?
Could the gap be too large on them?
My friend set them while I was doing the work.... Off the top of my head, I think the manual said around .33-.36. If that being the case, my friend set them at .34. I could be wrong though and I'll check the manual later today.
Man..all I need is worse gas milage!!
-Chase |
joey lafever
| | Posted on Wednesday, November 13, 2002 - 11:35 am: |
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I live in the silicon valley area.. California..
and I have lost nearly 100 miles per tank...:-(
I was told that in these few months gasoline is oxygenated for pollution/smog sensative time of the year.. I have no hard facts but I was told by two different people that noticed it for the past couple of years for these few months.
could be something to look into? I didn't change anything on my truck and it still runs perfect other than the horrible gas mileage.. I will search around for some info and post back..
Joe |
Rick Lindgren (Slacker)
| | Posted on Wednesday, November 13, 2002 - 01:53 pm: |
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Chase, you should definitely verify if somebody tried to gap the plugs. AFAIK the Bosch platinum +4s are factory gapped and shouldn't be changed. If they did get changed, it could be causing a problem.
Rick |
Chase Fancher (Roverboy)
| | Posted on Wednesday, November 13, 2002 - 02:06 pm: |
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Rick-
I've never understood the factory "gap" concept..
are they gapping for each individual car type? We measured the sparks and they were definitely spaced too tight...I think around upper .20's?
Joey-
I would assume that out here in MO they aren't as concerned with air pollution and may not adjust the blending of gas. But that is definitely an annoying possibility..
-Chase |
Jason Vance (Jason)
| | Posted on Wednesday, November 13, 2002 - 02:13 pm: |
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I second that...you do not gap the +4's. You run them as is, out of the box. Other plugs like the regular platinums and copper's you gap per your application, but not the +4's.
That could be your problem... |
Bill K (Bill_K)
| | Posted on Wednesday, November 13, 2002 - 02:35 pm: |
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You dont gap the +4 because you cant do it accurately. You have to live with the preset gap. If thats good for your car, good. If not, T.S. Thats why I use the single electrode Bosch Plat. I adjust the gap to meet manuf. spec. A wrong gap will cause rough running or bad mileage, etc. etc. I would change the plugs to the single electrode Bosch plat or copper. and see what happens from there. |
RJ Clayton (Tozovr)
| | Posted on Wednesday, November 13, 2002 - 03:04 pm: |
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You don't gap platinum plugs because it cracks/chips th platinum...
Factory gapped means there are more than just 1 platinum plug available, not 1 size fits all...you buy the plug that is already gapped for your application...
Check your O2 sensor lately? |
Scott - OZ
| | Posted on Wednesday, November 13, 2002 - 03:47 pm: |
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THE NKG ones are Iridium - I used them in my series one they are about $140 Aust per set (trade price). I was after Bosch Platnum because my series II has them and one thing you dont want to be doing often if you can help it is replacing plugs every 5thou or so miles in an alloy head. Bosh did not reccomend them for my 95 series one however. The Iridiums last for about 40 thousand miles. I bought my series one second hand about 2 months ago. Some ham fisted mechanic had cross-threaded a plug at some point. The trouble with alloy is that it can feel spongy at the best of times when fitting plugs. He screwed it in and created a new thread - something that would be harder to do with a cast iron head. Anyway i had to get a brass insert put in which has worked out perfectly. My 95 does not have O2 sensors by the way - it is open loop. As for MPG I have no clues - the computer is not programable; check however your air filter, stepper motor, O2 if you have them; and make sure the hot wire air mass sensor in the intake manifold is functioning - although that and the stepper would tend to cause rough running if they were shot. God knows!! Drive it like a pussey and watch your MPG increase. Perhaps power is up and as a result you are inadvertently using it!!
Cheers |
Chase Fancher (Roverboy)
| | Posted on Wednesday, November 13, 2002 - 05:09 pm: |
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Well, I purchased the sparks through Rover Connection and I would have assumed that they'd match the correct gapping required by discos. Its really too bad they didn't...
But I would also assume that putting new sparks in would be better than the POS sparks that I had in before, even if they were gapped slightly off.
The sparks I pulled out were horribly darkened and each had different gaps ranging from .3-.5 in spacing.
Thanks guys
-Chase |
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