G-man

iTrader: (2)

I’m about two bolts away from removing the dash from my stock 85 GS so that I can replace the wiring harness with an 85 SE harness so that I can (hopefully) run my rebuilt 13B motor. The harness had a couple of minor repairs but over all it’s in good shape (I’m rewrapping it as I inspect each section).

However, I’m starting to get cold feet and I’m hoping that some experts out there can help the hobbyist here – to reassure me before I start ripping out a perfectly functioning GS interior and electrical system. Before I get too far, I’m wondering if you could take a look at the rebuilt engine I have (see pics attached) and tell me if I’m doing the right thing.

My intention is to take this engine and wire it to the SE harness & ECU.

What I know about the engine. The original engine was a 13B from an 85 SE but after I got it back I was told it was basically a mix of S4 and S3 parts. As you can see the Auxiliary Port Actuators are gone, Air Control Valve is gone, Anti-afterburn valve is gone and the Oil Metering is gone (have to run premix), and it’s supposed to have a mild street port.

What I want to have when everything is back together is a reliable, weekend car. I’m not concerned with making X hp or racing or whatnot. I’d like to keep most of the emissions if possible as well as the EGI system.

So, can I accomplish my goal with this engine and the stock SE harness & stock ECU that I currently have despite missing the components as describe above? Or should I leave the perfectly working electrical system as is and look at other engine management systems??

Please help.

By the way, I've already upgraded the fuel system (new pump, lines and tank) to handle the FI system.

Thanks.

Rx-7Doctor

iTrader: (13)

As far as keeping the emissions you have already blocked off the most important portion which is the ACV which means you cannot run a catalytic converter. Without the air pump and the ACV there is no air to the catalytic converter which means it will be destroyed in a short amount of time. Also the 5th 6th port actuators gone will take away from the HP when running the EFi. It may not have as much of an affect if you were going with a Carburetor.

If you want to keep the emissions and have the engine run as it was intended to then get your self another lower manifold that does not have the ACV blocked off and put the 5th 6th actuators on.

If you want to retain your stock harness then put a aftermarket carburetor on it such as Holley, Weber, etc.......

Keith13b

iTrader: (6)

I can't quite see what S4 parts were ever used in that rebuild.... also I've never seen the ACV plate welded on like that before. I guess that really prevents leaks.

Anyway - you can keep the EGI w/o emissions as I did that for several years; but you will need the SE wiring harness AND computer to do so, along with all the intake parts (AFM, TPS, U & L manifolds, etc.)

For the actuators, I always remove them anyway, even on EFI applications as I find that more often than not, they stick in the closed position and the actuators are not consistant. The loss of low rpm torque is almost un-noticable.

Unless you already have all the parts to do the complete swap (sensors, brackets, intake, etc.) I would just put a carb on it if you want complete reliability. The whole reason I ripped out the fuel injection on my car was all the unreliability of the electrical connectors. They would get lightly oxidized and would give high resistance and the computer wouldn't respond correctly. Usually unplugging and re-connecting the connector solved the problem.....but it drove me nuts and acted up at the worst possible time. The EGI gave me some laboring starts and uneven idle (not bad, but not smooth either) and seemed to "run outta gas" per-se' at high rpms. The intake was just too restrictive.

I tossed on a Dellorto and "holly hell" is the only way to describe it! The power increase across the whole rpm range was quite noticable, the idle was dead on perfect. Smooth as silk compared to the sometimes choppy EGI. Like RX7-Doctor stated, I now had enough bottom end to not notice any power loss due to the 6-port actuators removed, and infact it seemed to have more bottom end then with the functioning actuators w/ the EGI.

The EGI components are over 25 years old and I would have a hard time justifying keeping them if reliabilty is your main concern. A standalone would be a better bet but will cost more. The carb is the cheapest (and easiest) alternative. The decision is just up to you. If you are a traditionalist and RX-7 purest - keep the EGI and tune it up - as many on this forum would love you for it. Just looking for a reliable car and to keep it cheap - get a carb. If you have some cash and want the ultimate in tuneability - get a stadalone.

Rx-7Doctor

iTrader: (13)

In my experience the EFI system of the SE however old does function just fine.

If you had an issue running out on top end then you either had a fuel volume issue, TPS out of adjustment or AFM out of specs plus the fact that the 5th 6th port actuators are designed to optimize HP through the whole RPM process.

Intake leaks are another issue after so many years from the gaskets cracking. This is one of the biggest causes of a choppy idle as well as the AFM getting out of adjustment after time.

The starting issues were normally contributed to poor battery cables, especially the grounds. After I had replaced the grounds and the main cable the engine would start every time on the 1st try even in below freezing conditions.

Once the system is put back in good operating order the EFI is very smooth, makes HP like it is supposed to and gets way better fuel economy than putting a carburetor on it.

As far as the electrical connectors. I have not found that their is an issue from corrosion but from old brittle connector ends on the injectors and the coolant temp sensor for the ECU. They would crack from age and heat and the clips that would retain them in place would no longer stay. Once you replaced the ends you were good to go with no more issues. This is not an uncommon issue with connectors of that type after 20 plus years.

Keith13b

iTrader: (6)

My real problem was having driven a friends street ported motor in the past (lol).........but, yes, I went through 3 TPS', 2 AFMs, and one computer. This was all in the late 1980's to early 1990's when the parts were still quite expensive and the cars warrenty ran out. My AFM was over $600 from a wrecking yard.....to put things in perspective. You can see how my frustration with the EGI system went south quickly. I originally bought the car at the dealership so I always had the warrenty work done on it as well as any tuning and repair work performed there. Only the dealer touched my car until the warrenty went out and I was left to repairing it myself due to the sheer costs involved. The TPS was needing adjustment constantly and having the dealer do this got expensive for them to "use their computer" to do it.

So true - the LIM to motor gasket has failed several times on me making a very lopey idle. Hylomar is your friend!!!! Also the vac line to the brake booster......But my agravation was that the EGI would fluxuate +/- 50 rpm - I'm assuming based on input from the O2 and OAT sensors.

I was quite fortunate to not have the dreaded cable issue. My starting issues were the car would crank over 3-4 times before starting (5+ in the winter)- based on loss of fuel pressure at the injectors (gotta love those pulsation dampeners). This didn't fair too well with heavy loaded electrical systems (stereo) and factory alternator and fuseable links...meanining the starter would kill the battery quickly after a lot of short hops in the car. I got very good at pushstarting the car..... I finally upped the battery to a higher CCA and added the FC alternator and fuse box - amazing difference. I'm sure thats why the FC's came that way. Too many customer complaints.

The EGI is a great system that runs a lot smoother than the stock Nikki carbs ever did. Keep in mind that FI cars were not that big in the 1980's, so it is a piece of history to have it still on there. Thats why so many people swear by it.

mikeric

iTrader: (20)

Some of the high horsepower guys running big boost weld their entire manifold just so then they get leaks they have less places to check. It looks like someone was modifying that manifold to run boost.

G-man

iTrader: (2)

First of all, thanks for everyone's input on this. It's helped a lot.

I think my first move will be to remove the LIM to see what else might have been modified. I will post pics when I do.

I have all the sensors, intakes, etc for the complete SE FI system so if it's just a matter of putting a WTB ad for a new LIM and actuators/valves I feel better about proceeding with tearing out the dash and replacing the wiring harness and ECU. My wife thinks I'm absolutely crazy for doing this by the way...

I appreciate the input on the FI vs carb debate..but I'm sort of set on keeping it semi-traditional. I'm replacing most of the lines and all the gaskets as I put it back together as well as cleaning all electrical contacts. I'm hoping this will minimize problems when I eventually get it running and need to tune it.

Hoping to prove my wife wrong on this,
g-man

G-man

iTrader: (2)

So here's a couple of pics with the LIM off. It looks okay to me - but what the hell do I know. Anything look out of place? to you? I also posted a WTB ad for a LIM with the actuators and ACV in the Canadian for sale section. I guess I should also be looking for a set of auxiliary sleeves.

Directfreak

iTrader: (2)

Keep in mind it is simpler, and more power can be made when using a carburator (Weber/Dell'Orto) than a stock EFI system. Plus, it looks beautiful.

Keith13b

iTrader: (6)

Man its been a while since I saw a stock motor stripped down, but is that a partial P-Port?... I've never even seen one here in the states, but it sure looks like it to me.....Or maybe I'm just an idiot - but I don't remmeber having to use liquid gasket material in that area....

Again - I have no clue and I am unfamiliar with the partial P-Port. However, I just checked a spare LIM I have and that area is dead spot in the LIM - and those holes look pretty deep into the rotor housings....and they have a gasket material on them. You might want to take a closer look at the area w/ the red/orange gasket material. See if it goes all the way into the chamber.

Just my .02 cents.

If by chance it is, I would doubt the factory EGI could be used - but get advice from others. Until a few years ago I never have heard of a partial P-Port. So take my statements with a grain of salt.

Directfreak

iTrader: (2)

I didn't even look at the pics before - Yes, that's a Semi-Perfpheral Port.

Keith13b

iTrader: (6)

If we are correct, I'd recommend you do some homework on that porting and see what options you have for it. It appears clearly to me that the motor was designed for some boost......ANy idea what rotors were used?

G-man

iTrader: (2)

Really? I had to do a little research on what a p-port is - so I'm a little more educated now. I think you're referring to the intake on the rotor housing where all the red/orange silicone is. The hole does go fairly deep but not so far that I can see the rotors. There seems to be openings at the back of the holes that lead somewhere...

I'm pretty sure the guy I got it from said that the original SE housings were trash so he used S4 housings and rotors.

The LIM that I have from the SE basically covers that entire section so it's completely blocked off when the LIM is installed with the gasket.

Will the blocked peripheral ports be an issue if I use the SE LIM?

j9fd3s

iTrader: (3)

those are FC rotor housings, one is S5 one is S4, which is not so hot. irons are s4 NA.

the hole in the rotor housing is for coolant on the FC turbo, ideally they should be blocked off with a freeze plug, but the orings work too, you just have to cut the gasket out if its paper.

Directfreak

iTrader: (2)

How can you tell?

Nismo Convert86

iTrader: (7)

Front has a Knock Sensor boss above the trailing plug (S5) and the rear does not have it (S4).

Directfreak

iTrader: (2)

Ah, I didn't notice the earlier pics with the spark plug side facing the camera.

G-man

iTrader: (2)

This is getting interesting in a not-so-good sort of way.

With this new information - what options do I have for an intake? Can I still run a stock SE system or am I just asking for trouble with this franken-wankel (a "Frankel" ?? )

j9fd3s

iTrader: (3)

i had an S4 engine in my SE and it was GREAT. made good power everywhere. the replacement was a stock gsl-se engine with 89+ NA rotating assembly, and the s4 motor had it beat everywhere except under 2000rpms.

the s4 had bigger ports than the gsl-se

G-man

iTrader: (2)

Did you use the stock SE ECU for the S4?

j9fd3s

iTrader: (3)

yeah it was an s4 block, everything else was stock SE

Keith13b

iTrader: (6)

@j9fd3s: Did all the manifold bolts line up okay? I've never mix/matched different year parts. Did you use the S3 injectors?

j9fd3s

iTrader: (3)

the only thing that doesn't work is the air injection ports on the 86-88 NA's are in the end housings, everything else is in the center.

so with the S4 engine it'll never ever pass smog ever.

everything else bolts right up.

G-man

iTrader: (2)

I've been doing a little reading about Haltech solutions. I think I need to drop the illusion I have about keeping emissions (not required here in Ontario). However with this system I believe I can still keep the semi-stock look I'm looking for with the use of the SE TB and intakes. It would also allow me to tune this monstrosity.

I wasn't able to determine if it was still necessary to remove the dash to install this type of system. Can anyone enlighten me on this?

Thanks

Verneuil

You could also try Megasquirt ECU. http://www.diyautotune.com/ ppl have used these with rotarys. Its cheaper than a HalTech and offers more features at the same time.