Topic: Ignition upgrades for TBI 2.5L?

[Matt vs YJ]

Hey folks,

I'm new to this forum, so forgive me if this has been discussed before, but I haven't found much info through searching or the FAQ.

I'm in the process of rebuilding the engine in my '89 YJ and I'd like to do a few upgrades as well. I plan on using the Hesco RVB04 Cam, but other than that I'm not doing anything too extreme. I already have a CAI, and exhaust upgrades are in the near future.

I'd like to do something with the ignition system, if possible. Those of you that have the TBI system know that the ignition coil is kind of integrated with the ignition control module, making it a chore to find a direct replacement.

It looks like it may be possible to modify the ICM and run jumper wires to new coil, such as the MSD Blaster type coils. Has anyone had an luck with that?

I've heard that the ignition system is very similar to Ford system, so maybe there's an upgrade possibility with Ford parts.

I "accidentally" sold an MSD box that I had (left it in the trunk of my old car), and was hoping to use on the Jeep.

Any help or ideas would be great. Again, this is referring to the TBI system, which is quite different from the MPFI systems that have the ignition control in the PCM.

Thanks, Matt

[Mr_Random]

It IS different???

OH crap... gotta plan some more (and spend more money) now... I'm starting (late planning, early gathering) my MPI swap.

Well, thanks for warning me about that (without actually meaning to!).

Can you specify what is different between the two?

Sorry I hijacked and didn't help...

[Matt vs YJ]

Can you specify what is different between the two?

Seems like just about everything is different:

The engine harness, dash harness, gauges, alternator, PS pump, Intake manifold, fuel pump (in-tank), water pump, valve cover, vibration damper...

You can see why I decided to keep the TBI. Besides, I just finished spending a bunch of money getting it running right before a piston blew, so I'd be wasting the money I spent on sensors if I switched to MPFI. I'd rather just buy a newer Jeep, instead of doing a swap...

Prior to the upgrades (rebuild), I was fairly satisfied with the power. So, while I'm in there I'm just gonna do a few simple upgrades to make it run better and smoother.

[Mr_Random]

Seems like just about everything is different:

The engine harness, dash harness, gauges, alternator, PS pump, Intake manifold, fuel pump (in-tank), water pump, valve cover, vibration damper...

You can see why I decided to keep the TBI. Besides, I just finished spending a bunch of money getting it running right before a piston blew, so I'd be wasting the money I spent on sensors if I switched to MPFI. I'd rather just buy a newer Jeep, instead of doing a swap...

Prior to the upgrades (rebuild), I was fairly satisfied with the power. So, while I'm in there I'm just gonna do a few simple upgrades to make it run better and smoother.

Woo, makes this project more fun! My 86 XJ has too many one-off parts in the engine bay, replacing everything is NOT cost effective for me. I could get strictly junkyard or used parts, but even then, I could do better by getting used newer parts!

I'm glad most of these things are cheap... I'll continue researching... after work, gotta make the money to make everything work!

[Matt vs YJ]

Any other ideas for TBI ignition upgrades? I'm sure there's gotta be someone else that decided to stick with this system.

[Mr_Random]

Any other ideas for TBI ignition upgrades? I'm sure there's gotta be someone else that decided to stick with this system.

There are quite a few (people) out there, but I haven't heard of any TBI ignition upgrades. Do you know how it is specifically different from the MPI systems?

There ARE all those MSD/other brand ignition upgrades and stuff, but I thought they also applied to the TBI ignition...

I don't know, good luck though! I'll try to help in any way...

[chardrc]

i have the tbi 2.5l but i haven't done any ignition upgrades yet... unless you count putting new cap, rotor, wires, and plugs in (all of the "middle grade" aka like stock at the parts store)which helped alot since i found that the previous owner had the wrong spark plugs in it

[Matt vs YJ]

Yeah, I've done all the standard replacement stuff last fall. It made a little difference, and Champion Truck plugs seemed to work a little better too. What I'd really like to do is get a high energy coil so I can gap the plugs a little wider.

[chardrc]

yjmechanic used to have a tbi 2.5l and was the guy to ask about the tbi system. he was even making his own throttle body spacer. but then he sold his jeep for a mpi 2.5l jeep... and he hasn't been as active since.. that i notice at least. maybe if you / we could contact him e may have done something with the ignition coil and what not.

[chardrc]

yjmechanic used to have a tbi 2.5l and was the guy to ask about the tbi system. he was even making his own throttle body spacer. but then he sold his jeep for a mpi 2.5l jeep... and he hasn't been as active since.. that i notice at least. maybe if you / we could contact him e may have done something with the ignition coil and what not.

my bad it was Guardian7 not yjmechanic....

[Castr8r]

FWIW...   I'm running a Blaster coil and really can't tell much difference from the stock coil.  My experience has been that Champion plugs are consistently better to use in AMC/Chtysler products.  With the stock coil, I could open up the gap to .040" with no problem; with the Blaster coil, I could probably go more but I don't think there would be much gain.  I mounted my Blaster on a home made bracket on the fender where the distributer wire would reach with plenty of slack.  The stock coil is energized thru spring clips that contact the  stock coil when it is put in place.  I used some standard push on connectors I had from a previous project to slide over the spring clips, and ran a pair of wires to the coil.  To keep it neat, I wire tied them to the radiator brace, leaving a little bit of slack "just in case."   Hope this helps.

[Matt vs YJ]

FWIW...   I'm running a Blaster coil and really can't tell much difference from the stock coil.  My experience has been that Champion plugs are consistently better to use in AMC/Chtysler products.  With the stock coil, I could open up the gap to .040" with no problem; with the Blaster coil, I could probably go more but I don't think there would be much gain.  I mounted my Blaster on a home made bracket on the fender where the distributer wire would reach with plenty of slack.  The stock coil is energized thru spring clips that contact the  stock coil when it is put in place.  I used some standard push on connectors I had from a previous project to slide over the spring clips, and ran a pair of wires to the coil.  To keep it neat, I wire tied them to the radiator brace, leaving a little bit of slack "just in case."   Hope this helps.

Great info! That's just about exactly what I had in mind. I have a Blaster coil laying around somewhere, but it sounds like it may not be worth the trouble.

However, I'm gonna be getting that MSD box (6AL) back from the guy I "gave" it to. It turns out that they make a wiring harness to plug into the stock TBI module/coil. Maybe the box combined with the coil will make a difference. I know it helped an old Ford 302 I had a few years ago.

[Castr8r]

Matt - let us know how it works out.  I have an old Jacobs Ign. set up for an AMC V-8 that I've thought about piddling around with.  I like the idea of multiple sparks at low rpms; it worked on a Javelin I had.  Just a hotter coil by itself doesn't seem to help much, in my opinion, but adding the multi-spark ability should make a noticable difference.

Brakes woek best when the wheels are in contact with the ground...

[Matt vs YJ]

Just a quick update before I head to the beach for a week of relaxing and cruising in the Jeep 

I haven't got the box yet, but I did go ahead and wire up a brand new Blaster 3 coil and gapped the plugs to .045. As Castr8r said, it didn't make much of a difference, but it may have a little more power in the lower RPM range. I hope the box will help a little more. I'm actually hoping to improve my gas mileage, but more power is ok too.

I was testing out the 4wd (stupid vaccum disconnect ) on a gravel road last night and in 4Lo my brakes actually couldn't hold it still while idling in 1st gear. I think that's partly due to the inertia ring allowing it to run down under 300 rpm without stalling, but I feel that the ignition had something to do with it too.

[pioneer4x4]

any updates on the ignition set up for the TBI set up, I also have the tbi and want to upgrade ignition. who makes the wiring harness for the coil? MSD? is the harness for the coil or the box? never been exposed to multiple spark boxes before.