6G Celicas Forums

Excellent report Syaoran. Good thread too with the differences between the emissions systems and efi.



This article is hugely illuminating for me. I've never had problems with any ignition system and never learned much about it. This article had the basic information I needed to understand Syaoran's post.

So I understand that when switching to ems, Celicas with factory batch injection should at least fit the old style distributor? And the reason is for it's cleaner signal and overall better design?



This post has been edited by H8TRAIN: Dec 30, 2013 - 9:48 PM

Not really a better design. The newer distributor is of a better design.

The way it works though is not the traditional way and therefore the majority of EMS won't like running on it properly.

This only applies to OBD-1 Celicas, however, as far as we know because OBD-2 Celicas also have a crank trigger for OBD-2 reasons. The distributor in this case can act as a cam sensor if desired to run full sequential injection with an EMS capable of doing so, since the distributor generates a pulse every 1st(or 4th) spark, indicating TDC IIRC.

As I showed in an image in the OP, the 93+ distributor has 2 wheels, one with a single tooth (TDC indicator for the cam I believe) and the 4-slanted teeth wheel which is a trigger wheel apparently decoded by the Toyota ECU.

The previous distributor is not better by any means, it just is what is needed to run an EMS without hassle. Personally, I could never get it running right with my MS2, since I always had startup issues with the car firing at the wrong time because it couldn't tell precisely when TDC was occuring.

I would try to get a static crank signal though, and then use the distributor for a cam signal and ignition purposes if desired as well.

There's a couple options you have, with regards to the ignition setup, since you can:
1. Keep the stock distributor to run the ignition with an EMS controlling the coil with an internal igniter in the ECU (megasquirt has one in their MS2, MS3 ECUs), while using the distributor as a cam sensor and running the stock OBD-2 crank sensor setup (requires oil pump, oil pump timing gear and crank sensor to do this if pre-obd2)

2. Use the older distributor as both crank and cam sensor using the 24-teeth trigger wheel for you crank signal and 4-teeth wheel for cam. Most ECUs will require you to remove a tooth from the crank wheel, or eliminating 3 from the cam signal trigger wheel. Run a standalone coil system like MSD coils, 420a coils, etc.

Post is a little winded, hope you can understand it

Here in bold we are talking about the same distributor in both the obd1 and obd2 cars? Does the ob2 celica cal have a timing gear on the balancer or on the oil pump? Thank you for great reply Syaoran. I do need bits clarified tho. And think of all the future researchers!




Here are you saying that you never go the previous distributor to work or that you never got the newer version running right?



What's a static crank signal? What you describe here is described below as "option number 1"?



(not directly related to the quote I found this unclear thruout the thread) So a 96 obd2 celica has the cas on the oilpump, and uses the same distributor as an obd1 car? Is this only true for CA cars so they can use sequential fi?



I read your story about your mr2 friend who used the older dizzy and ran fine. But as I pointed out above I saw a comment from you about perhaps it not working so well. The verdict here looks like the old distributor with megasquirt on batch fire is good to go?

Thanks again, Syaoran!

You're welcome. Anything I can do to see more Celicas on EMS and less on SAFC, I'll do it. XD

Excellent. That all will help alot! I've read this thread several times and the information is hardly sticking. It's relieving to have things clarified that way. Compatibility conversations of any type give me a headache and I don't know much about ignition (or efi) on top of that.

I finally go around to reading this thread and wanted to bring up a few points.

1. There is nothing wrong with running a boosted engine with a distributor. All 3sgtes run perfectly fine with them. COP is great, and its an option with an aftermarket ecu, but saying that its a bad idea to use a distributor is really false. I'm also running the stock 3s distributor on megasquirt with zero starting issues or anything like that. Having said that, the cam signal on all Toyota distributors has a pretty high amplitude, and you have to use pull down resistors in the circuitry to get it to show up. I had to use a 33k resistor to get a perfect signal. However MS2 deals with the signal path of the cam signal differently than the DIYPNP that I am using. Almost no one was able to get the cam signal to pick up on a standard MS2, however with the DIYPNP unit, its just a matter of adding a resistor to pull the voltage signal down.

2. Pressure 2 engine was originally from a Cali Spec OBD2 car (it was actually my old engine), however when we swapped that motor in, we used his stock 94 harness, ECU, and distributor. So his engine made 300hp on a normal 94 OBD1 ecu (and an insanely high factory NA ignition map).

Now correct me if I'm wrong (I probably am since its been a while since I worked on a 5s), but I was under the impression that only the 7afe distributor came with the built in coil. I remember 98 5sfe having a separate coil, and I thought Presure2's 94 had his own coil as well. The only reason why we used his distributor was because the harness plug key was different.

This post has been edited by lagos: Jan 3, 2014 - 2:33 AM

art, the 94-5 "cali" spec cars came with the external coil, and had sequential injection, the "federal" spec cars had the internal coil and batch fire injection.

Oh I see. So thats why you had an external coil on 94 electronics.
So the simple solution to this issue would be to just swap to a Cali spec distributor and coil, and you could easily run Megasquirt or any other EMS with sequential injection.

I have a 1994 5sfe, but the motor has been replaced with another 5sfe. they had to trim the bell housing so the oil pan would fit, so I'm sure its not the same as the original.
also I noticed that it has a crank sensor, but the plug is just hanging there with no where to plug it in to.
yet the dist cap has only 4 wires, so I assume that the coil must be inside it.
where is the identifying numbers so that I could have Toyota look it up?

Just look on your firewall under the igniter to see if you have a coil there with a think black coil wire going to your distributor cap.

This post has been edited by lagos: Jan 4, 2014 - 3:20 AM

You mean this?


That's what I've been saying. Either you get that, or you get a crank sensor setup from the last revison 5s/cali-spec obd2

Yeah, pretty simple solution. I think its a better way to go than the crank sensor setup since you don't have to take off the crank pulley and lower cover to get to it.
Then just get a DIYPNP kit, and use a 33 or 51 kohm resistor to bring the signal down, and everything will work. Id love to see someone do a 5sfTe setup like this.

This post has been edited by lagos: Jan 5, 2014 - 9:00 PM

interesting. Im wondering if this might be a problem that the FIC is having. It is constantly fighting with the stock ECU

Most likely.

Thanks for this write up, it makes me glad I have a '91 5SFE without the 98+ distributor brick

I am building a 5SFTE MR2 and i'd like to get your opinion on what the best ignition option would be for somebody that is using an AEM F/IC piggyback. I ask because this thread seems to focus on standalone EMS systems so far.

I also made a different thread about adapting a motorcycle CDI system for a 5S, just to explore the possibility.