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Discussion Starter · #1 · (Edited)
I have a brand new MSD ignition for my 4.0 TJ including the blaster 2 coil and all plug wires that's been sitting on the shelf for about a year. I was just wondering if anyone is running this set up on their stock 4.0? How do you like it? Is it worth the time to put it on mine or will it not make much difference?
 

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In Da Faaaaaace!!!
1988 YJ
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I'd do it! Better spark and you can open the gaps of the plugs.

Just don't get jolted by it....hahaha I have a few times and it hurts!
 

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Discussion Starter · #3 ·
Yeah, I was just wondering if anyone was running this exact setup what they though of it.
 

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331 Posts
I have the MSD Off Road 6470 on my 98 4.0 TJ. Also using the Blaster 2 coil, MSD rev limiter and the 8910 tach adapter.

I like the set up. It seems to smooth the motor out at the lower RPMs and it certainly doesn’t hurt it on the big end. Whether it’s worth it or not it is up to you. I like playing with that stuff and I think it helped the overall performance, if ever so slightly.

Also using the rev limiter. The MSD unit can lower the stock rev limit but not raise it. Currently my limiter is set slightly lower than stock as the MSD unit works much smoother than the stock one. That and the 4.0 really has no business being around 5,200 rpm anyway.

After installing this setup I started getting a PO351 code, no CEL, just a code whenever I checked even though it ran great. Installed the 8910 tach adapter and that problem went away. MSD tech said “The 8910 Tach Adapter is basically a "dummy coil", it restores the "kickback" signal that is normally produced by the coil when it fires. The ECM commonly uses this signal to monitor the status of the ignition.”

Good Luck
 

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Discussion Starter · #5 ·
Great info! Thanks. Did you notice a change in throttle response at all?
 

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Yankabilly
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I beg to differ I bounced my wifes old yj off the limiter everytime I was in the throttle. It loved being in the rpms that motor came alive around 4,500 rpm. Also your valves don't even think about rotating until the engine is above 3,500. That is why so many 4.0's have idle issues is because of the carbon build up on the valves. The MSD will help with that as well
 

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Discussion Starter · #7 ·
I beg to differ I bounced my wifes old yj off the limiter everytime I was in the throttle. It loved being in the rpms that motor came alive around 4,500 rpm. Also your valves don't even think about rotating until the engine is above 3,500. That is why so many 4.0's have idle issues is because of the carbon build up on the valves. The MSD will help with that as well
I believe you bounced off the rev limiter in everything you have ever driven, probably even that old Bolens!:teehee:
 

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Great info! Thanks. Did you notice a change in throttle response at all?
I think it does a little bit. The 6470 fires each plug 3 separate times when it fires (below 3000 rpm) and, as has been stated here, you can open the plug gap significantly. At idle I believe the engine runs a little smoother and it comes off of idle nice.

“B” is correct in that the motor really comes alive around 4,200 rpm. Especially if you have done all the intake and exhaust mods (cold air intake, throttle body, manifold, high flow cat and muffler). I love running my TJ through the gears and have resigned myself to the fact I will be picking my crankshaft up off the ground some day. I have found the rev limiter to be most helpful when I run through a mud hole and knock the transfer case into neutral with my right knee. I never heard a noise like that before.

I am looking at the billet rockers for a spring project. Looks like it would be fun. Of course when I get that done I will spend all day idling through the woods. Must be a Jeep thing.
 

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Discussion Starter · #9 ·
The one I have is the 6al, don't have all the number right in front of me. I already have the cold air intake and a flopro muffler, getting ready to get the high flow cat here real soon. I think I'll go ahead and get it installed maybe this weekend. I think I just need to order a harness to make it all work.
 
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