Aftermarket Ignition on Distributorless engines

cgrey8 · Post by **cgrey8** » Tue Dec 28, 2004 6:23 pm

The 97 Explorer V8 is distributorless, thus it has 2-four cylinder coil-packs that drive the 8 plugs.

It appears most of the Aftermarket Ignition modules such as the MSD-6AL seem to only work when there's 1 coil, not when there are multiple coils to fire. My understanding of the coil packs is that they actually fire two plugs at the same time. They are connected such that one of the two plugs is on the compression (upward) stroke while the other is on the exhaust stroke. I've heard of this, however I've never actually read confirmation that this is how they work. So I don't know how accruate that info is. If someone can confirm/correct me, please do so.

In either case, whether there are 4 trigger wires or 8 triggers to fire each plug's respective coil in the coil packs? I can't believe that this is the case so I feel there is some MSD module(s) that handle this dilemma? Or perhaps the new ignition systems simply don't need modules....

Comments?

Chris

MercuRanger · Post by **MercuRanger** » Wed Dec 29, 2004 7:26 am

I believe MSD makes a module for DIS systems - check import stuff. And you are correct about the coils firing 2 cylinders (one compression, one exhaust).

Mike

MalcolmV8 · Post by **MalcolmV8** » Wed Dec 29, 2004 9:49 am

And interestingly enough the left and right side of your motor will have different plugs from the factory on these coil pack motors that share 2 cylinders per coil. Check out this link for an explanation.

http://www.miracerros.com/mustang/sparkplugs.htm

MercuRanger · Post by **MercuRanger** » Wed Dec 29, 2004 9:55 am

Even more interestingly, the newer GM's reverse the polarity to the coil on every other firing to promote even wear/material transfer between electrodes.

Mike

cgrey8 · Post by **cgrey8** » Wed Dec 29, 2004 11:39 am

I thought I was crazy when I saw that. I've replaced plugs in about 4 Fords and noticed that some have a disk on the electrode and others don't. The center electrode even looks different between the plugs.

Now I know why...

I've always used the Bosch Platinum plugs. I've never invested in the Platinum 4s, but I am considering them for this engine especially since Advance Auto Parts only specs the Autolite Platinum and Bosch Platinum 4's for the newest GMs. The Bosch plugs, as expensive as they are, are still cheaper than the Autolite Platinums. Personally, I think they are a better plug too, but I got no basis, it just "looks" like it would be better.

Thanks for that tid-bit of info. I'm just learnin' all kinds of stuff from yall. The more I learn, the more I realize I don't know Jack.

Chris

Dave · Post by **Dave** » Wed Dec 29, 2004 4:55 pm

Chris,
Not sure if you have gotten one yet but best invest in the wiring manuals put out by www.helminc.com for both your truck and the Explorer. You might also consider changing back to a Mustang wiring and ignition system. Summit and Jegs both sell wiring installation kits that can greatly simplify the wiring for you. I remember a couple of years ago someone in Texas used the Explorer wiring in an older truck like yours and he ended up with a wireing nightmare, ended up going with a distrubitor system. With the kits, I think that there are only 4-6 wires that need to be spliced, I'll defer to those who have had to deal with the wiring. Just a word of caution.
Dave

cgrey8 · Post by **cgrey8** » Wed Dec 29, 2004 6:43 pm

I can bet that's not bad advice. I hate having to guess what wires do. When it comes to computer controlled systems, unless you know what the wire does, it's absolute guess work to figure it out.

I know most of the under-hood wiring on my truck, but I'm clueless on the engine. Is it best to go to the dealer and buy a shop manual or are there special books on the electrical system that's specific to the electrical that will aide in this endeavor.

It certainly isn't encouraging to hear that DIS ignitions have been attempted before at failure. I would like to keep it DIS if possible, however if it's more trouble than it's worth, it's comforting to know it can be done another way.

If I did go with the Mustang wiring harness, will I need a Mustang computer (or modified chip) too or will the Explorer computer work?

Chris

cjcnomor4 · Post by **cjcnomor4** » Wed Dec 29, 2004 7:10 pm

spend the money on the manuals if you want, i can get anyone wiring diagrams just let me know what you need. i can also get shop manual info too. the explorer and mustang pcms will not interchange. the mustang (up to 95) is eec-4 (60 pins at the pcm) the explorer 5.0 (96 to 01) is 104 pin. the 4.6 explorer (02 and up) is 150 pin. you can run an explorer harness if you want but (due to obd-2 standards) you're gonna run into more "unneccessary" wiring and sensors. if you're going for a factory looking truck without a check engine light its gonna be a fight. your biggest problem will be evaporative emmissions, you will need catalytic converters(or mil eliminators), and most of the other engine controls run tighter specs than the old eec-4 systems. i dont know what year ranger you're working on but if its 98 or newer you would have an easier time than if it were older. my truck is a 95 i'm going with a 92 mustang pcm and harness but the block is from a 98 mountaineer. if you dont mind the yellow light go ahead use the explorer harness if you already have it. i would definately recommend finding the mustang harness and pcm though

cgrey8 · Post by **cgrey8** » Wed Dec 29, 2004 8:04 pm

That sounds like a pain...

I don't mind putting the Rear-O2 sensor bungs in and running the Cats. Like I said, I want the thing to pass smog incase my county goes emission legal.

The truck is an '89 Ranger 2wd with 2.9L V6. The replacement engine is from a '97 Explorer V8 so I will have the problems you are talking about with having needless sensors. As long as I can find the Check Engine Light wire on my truck and on the new engine's ECC, I can connect them.

I know to make it work without a Check Engine Light ON all the time, I'll have to apply more sensors than '89 Emissions required. But if that makes the computer happy, it's better than me trying to convert this engine to a distributor engine with a Mustang 89-93 computer, and loosing a lot of what I already have. Or as you mentioned, using the O2 sims on the Rear-O2 sensors since '89 didn't require that to start with.

The main thing I need to know is what wires from the Explorer Computer line up to the OBD-II connection so I can reconnect it. cjcnomor4 helped me out with a diag but without the engine for me to look at, it's not that meaningful yet. However when the time comes, I'll be looking at it more.

I've seen a diagram of an OBD-II computer's pinout and a description of what each pin is. I could probably start there and get a long way. However if you can get me more detailed prints of both my truck's wiring system and the Explorer's Computer harness, I could probably figure something out from there.

Obviously the computer will need power, switched power (to know when the engine ignition is on), and ground. However it'll also need other things like the "Check Engine" light wire. What are other wires the computer will need from the truck that's not part of the engine or it's sensors?

Chris

MalcolmV8 · Post by **MalcolmV8** » Wed Dec 29, 2004 8:24 pm

I personally got the vacuum and wiring diagrams from www.helminc.com like Dave suggested. I also had some other misc wiring diagrams from a Ford EFI book I purchased online somewhere. I recommend you get more than just the diagrams in the back of a haynes manual.

cgrey8 · Post by **cgrey8** » Wed Dec 29, 2004 9:53 pm

I have a feeling I'll need those at my fingertips. The pneumatics are simple enough I think I can figure out, however the wiring is intimidating without some guidance from documentation as to what's what.

Here's another thought. I know computers also handle shift strength and shift points based on engine load and RPM. This 302 engine came from a 97 Explorer that had an automatic. I'm wanting to put a manual (T5/T56) behind it once it's put in the Ranger. Is this going to pose any problems?

If there are no feedback sensors on the automatic tranny that the computer will miss or recognize are in fault once I get the manual in place, then I'm in the clear. However I highly doubt it'll be that easy. Any thoughts?

Are there any other sensors or other connections like the automatic tranny (i.e. theft detection sensors, fuel pump control, etc) that the engine computer is tied to and will be expecting feedback that won't exist in my application?

I'm hoping these are tasks held by some other computer in the vehicle, however without a complete breakdown of the engine computer's monitoring and control capabilities, I have no way of knowing.

I'm moderately familiar with my 89 truck as it is. The newer vehicles are more complicated and thus have more wires running all over. The DIS, integrated security system, Rear O2s, and tranny are the places I know of so far that my 89 Ranger will differ from the 97 Explorer my V8 came from. Are there any other systems I haven't thought of that will either need to be dealt with or nulled out in order to make the computer control the engine correctly?

Chris

cjcnomor4 · Post by **cjcnomor4** » Thu Dec 30, 2004 6:13 am

the 4r70w in the explorer is electronic and controlled by the pcm. you are going to have to set up your fuel system so the vapor control side can hold a vacuum of 14 in/h2o. its abount 1 in/hg and hold it for 1 minute. that means youll need the vapor mangagment valve (vmv), charcoal canister, and canister vent solenoid (cv), and fuel tank pressure (ftp) sensor (mounted in the tank) from the explorer. youll also need to wire them into your truck. a leak as small as .020" is enough to fail the monitor and turn on the check engine light. at the dealership we have a machine that pumps the system full of smoke pressurized at 1 psi and even then these leaks are extremly hard to find. leaving the gas cap off will turn on the light. the pcm looks to the abs module to get vehicle speed info from the rear wheel speed sensor on the diff. again i'll be happy to help with whatever i can, but its gonna be tough.

cgrey8 · Post by **cgrey8** » Thu Dec 30, 2004 6:52 am

cjcnomor4 wrote: you are going to have to set up your fuel system so the vapor control side can hold a vacuum of 14 in/h2o. its abount 1 in/hg and hold it for 1 minute. that means youll need the vapor mangagment valve (vmv), charcoal canister, and canister vent solenoid (cv), and fuel tank pressure (ftp) sensor (mounted in the tank) from the explorer.

The 89 Rangers had the Charcoal Canister, but I don't have a clue whether the tanks were sealed well enough to hold that tight of a vacuum. 14in/wc doesn't seem that strong (as compared to holding PSIs), but I still don't have any faith in the tank I have matching it even if I got the CV and FTP in the tank. Any clue whether the Explorer tank will fit in the Ranger? Being it's extended cab, there's more room than would be in a regular cab. If all this is mounted to the sending unit, I wonder if the sending unit is the same dimensions as my tank (height and mounting top dia).

cjcnomor4 wrote:The pcm looks to the abs module to get vehicle speed info from the rear wheel speed sensor on the diff.

My 7.5" RE has an ABS sensor and I forgot about that one too. But that's still a sensor that will need to be wired in somehow when I get an 8.8" RE. Are the ABS controllers separate from the main PCM in both the 89 and 97 era Ford trucks? If so, is my 89 Ranger's ABS controller capable of interfacing with a 97 Explorer PCM to give it what it needs?

I figured there'd be more stuff like this. Would a custom chip in the computer eliminate all these extras I don't need? If so, I may save myself some grief doing that rather than trying to appease the 97 Explorer computer with fuel pressure sensors, ABS stuff, Rear O2s, anti-theft sensors, and what-all else I still haven't thought of. However, if there's a way to null out each of these systems either by not connecting them or putting resistive values on the sensor lines, I'm more than willing to do a "fakie" to the computer to make it happy. Thoughts?

Chris

MalcolmV8 · Post by **MalcolmV8** » Thu Dec 30, 2004 11:24 am

cjcnomor4, I had planned on doing a 97ish Explorer swap into my 94 Ranger. My plan was to find a wrecked AWD explorer and convert my 4x4 Ranger to a full time AWD 5.0 Ranger. This would be my daily driver. You post has made me think twice about using the Explorer PCM but without it I'd have to find some other way to controll the transmission. Anyhow didn't mean to divert the thread, that thought just caught my attention.

MercuRanger · Post by **MercuRanger** » Thu Dec 30, 2004 11:33 am

As mentioned before, I think the easiest way out would be using a 89-93 Mustang Harness & ECM with the Explorer hardware. All of these issues will go away. IMO, the only time using an Explorer harness and ECM would be a good thing is if you have an equivalent year Ranger - then things would pretty much plug-in.

Mike