Megasquirt..

[SilverXJ]

Since my PCM is making the engine hesitate I had a thought to look into Megasquirt. The PCM still operates the gauges fine, so I could use the PCM for the gauge cluster.

What sensors on my 2000 XJ would work with MS? Crank, cam? Can MS control the voltage regulator or the electric fan?

I am just trying to get a feel for what has do be purchased/replaced/modified, etc.

-Chris

[TurboTom]

I use a GM water and air sensor , stock Jeep TPS, a modified Jeep dizzy and no Idle air motor. MS-II will control the AIM but I don't need one.
No cam or crank sensor, or coil pack. Just the dizzy and an MSD box that the MS-II controls
My alternator is a 2001 model that came with my engine, I use an inexpensive Dodge voltage regulator wired in. Just ask for a voltage regulator for a 1978 Dodge D-100 with a 318.

[Plechtan]

A unichip would probably end up being similar money compared to a preassembled megasquirt. Easer install , but tuning would be a problem unless you found a local shop. You can buy a cable and Hesco will email you changes you can load yourself. The megasquirt use to not do sequential injection, they said it was coming last time i looked.

The Unichip will plug in, the megassquirt will require allot of wiring and maybe changing sensors. I think you may have a problem with your coil packs as well, you may have to change back to a distributor.

A similar solution the the megasquirt is the Haltech E6X, which will soon to be replaced by the Sprint 500. It has 4 injector drivers and 4 coil drivers. You would run batch on your injectors ( same as megasquirt) and wasted spark using the factory coil pack. You would have to add a 36-1 trigger wheel to your damper to trigger the unit. One nice thing about this unit is that it will directly drive a IQ3 dash, so the instruments are not a problem. If you have an automatic the Jeep ECU does send the VSS signal over the can bus to the TCU. This could be a problem.

[SilverXJ]

I don't want a unichip as I can't program it myself.

I don't want to change my dash and I can't afford to invest in new sensors. And I forgot that MS can't do sequential.

Guess it will be a stock PCM with a tune and the Apexi.

[TurboTom]

Why would anyone give a squat about sequential ??
There is no power or economy to add from this.

[SilverXJ]

Why would anyone give a squat about sequential ??
There is no power or economy to add from this.

On an MPI system using anything else is just damn dumb. Lets fire an injector in to the back of a valve when its not even close to opening. And yes there is power an economy benefit, maybe not a power benefit.

As usual, thanks for your contribution.

[lafrad]

Why would anyone give a squat about sequential ??
There is no power or economy to add from this.

On an MPI system using anything else is just damn dumb. Lets fire an injector in to the back of a valve when its not even close to opening. And yes there is power an economy benefit, maybe not a power benefit.

As usual, thanks for your contribution.

On the new hemi's, the sequential fire injectors are specifically time to fire all their charge on the closed intake valve... from the factory.

Only when the injector duty cycle gets above 25% is there ANY fuel being injected when the valve is open. In these applciations, I would venture to guess that it would be difficlult to tell via engine behavior if the inectors were batchfired or sequential fired.

[SilverXJ]

On the new hemi's, the sequential fire injectors are specifically time to fire all their charge on the closed intake valve... from the factory.

Yes, but it is still timed it isn't a random time when the valve is closed. Using batch injection you can't time it very well so you could be squirting when a valve is closed or open.

[1bolt]

From what I've read there's very little benefit to sequential, most of it is while idling, and very light throttle, a couple foot pounds off idle and while cruising with very little load. The reason OEM's do it is for emissions and CAFE regs. We don't care about a .5% improvement in fuel economy, or a .5% reduction in emissions but OEM engineers salivate over them because CAFE and emissions regs are averaged over their entire production. Power wise (and this plays into the whole fuel injector size thing), batch fire is happening most of the time anyway... There's not much (if any) one for one timed injector pulse matching the valve opening event going on. In fact one of the things that happens with a wet valve is the fuel is sheared/vaporized out of the bowl and off the valve during low valve lift, just like an annular "booster" venturi in a carburetor. The low lift valve opening causes fast localized velocities around the curtain area ripping fuel into the chamber and shearing it into smaller droplets, which vaporize easier under compression, and then burn better.

fun reading: www.speedtalk.com

[Plechtan]

I am looking into uning a Haltech Interceptor to do what a unichip does and have somthing that you can program yourself. The Haltech will not accecpt the Jeep crank sensor, but it can function as a standalone ignition controller. It will modify the map sesnor input to the ECU similar to the Apexi. It would require a different crank signal, but i think this could be done cheaply by bolting a trigger wheel to the harmonic balancer.

[SilverXJ]

I am assuming the Haltech uses the crank sensor for an RPM reference? The Apexi doesn't play well with the crank for RPM, but it works well with the cam sensor.

[TurboTom]

Why would anyone give a squat about sequential ??
There is no power or economy to add from this.

On an MPI system using anything else is just damn dumb. Lets fire an injector in to the back of a valve when its not even close to opening. And yes there is power an economy benefit, maybe not a power benefit.

As usual, thanks for your contribution.

And just how much dyno time have you spent to find this out??
I have about 17 years of testing this stuff, and Variable cam timing.... but I must be "Damn Dumb"
I made 500 Ft/bs and 450 HP on a Turbo 4.0.
What does your Sequintial engine make????
Stop reading the internet ...and do some testing.
Sorry.. I am just getting really tired of keyboard experts.

By the way, I have never seen a timed carburated engine... think about it!

[Plechtan]

Tom is right, at full throttle an injector will fire 85% of the time, but the intake valve is open about 25% of the time. Sequential will probably idle a little better, but from a performance standpoint, it really doesnt make must difference.

[the_wrench116]

The Apexi doesn't play well with the crank for RPM, but it works well with the cam sensor.

little off topic should one decide to use an apexi afc II you would wire it into the distributer??? even on OBD-1??
thanks in advance.

[PolloLoco]

I am looking into uning a Haltech Interceptor to do what a unichip does and have somthing that you can program yourself. The Haltech will not accecpt the Jeep crank sensor, but it can function as a standalone ignition controller. It will modify the map sesnor input to the ECU similar to the Apexi. It would require a different crank signal, but i think this could be done cheaply by bolting a trigger wheel to the harmonic balancer.

You referred me to Haltech in another post so I got interested and started looking around their site. The Interceptor is not listed as being a supported model (yet). When do you plan on buying it? I'm thinking this might be my best option. I will be able to adjust the timing (and hopefully advance it, unlike the FTC1) and adjust my fuel (like the Apexi and PSC1). I'm going to let you be the guinea pig.
Let me know how it works out for you, I may end using a Haltech. I don't even know how much it costs or where to buy one.