S4 SE (88 sale year, manu. in 87)
Auto Trans
Emissions rack removed including airpump, retained BAC, looks to be using an S5 radiator, and the PO installed some type of fuel cut switch.

New rebuild using RA Apex seals, apex seal springs, corner and side seal springs, corner seals, oil control rings, and soft seals / o-rings, and oil pump off an s5.

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I've just finished rebuilding and installing this engine, it is stock other than the subtle mods mentioned above.
I have new NKG 7's for trailing, and '9 for leading plugs installed.
I cranked the engine over for 10 seconds 3 times, prior to attempting first start.
I squirted a good deal >1oz of 10w-30 in each leading plug hole prior to start (I know 2-stroke is better, but the shed was locked today, and key was not available.)
I turned the key, with the fuel cut switch in the position I believe to be ON, it's not labeled.
The car started right away, with tons of smoke (I assume from the oil)
The engine idled somewhat smoothly at around 2000rpm, but wavered slightly. So to prevent it from stalling, I held it at about 3000 with gas pedal.
The car ran for 20-30 seconds, and then very abruptly shut off.
It didn't stutter or shake before hand, like it were running out of gas, it simply shut off.
I tried starting it a few more times with no luck.
I then pulled the plugs and egi fuses, and proceeded to unflood the engine with 3 starts, and 10 seconds of cranking each.
I squirted what felt like less, About an ounce, of 10w-30 in each leading plug hole, replaced the spark plugs and wires.
Then tried starting it once more.
The car started and ran for what seemed like less time than the last, leading me to believe that the car might only be running on the oil, and then dieing once that burns up.

I tried the same method mentioned above with the fuel cut switch in the opposite position.
The car did not start, and the Cooling Fan light on the idiot light cluster stayed on, and the stock electric fan turns on. I know this fan is related to the EGI circuit, but am still not sure on exactly the switch was wired.

On the same subject, the radiator has a coolant sensor on the top. it looks like a wire was ran to connect to that sensor, and then the one wire sensor on the filler neck, connects to a red wire than runs back through the firewall, to the fuel cut switch I think.

These were the only two non-stock looking connectors that I ran into, and there were only two stock connectors cut off of the wiring harness.

Anyway, I'm going to mull over it a little more, just wanted to put this up in case anybody has an idea of where I can look.

My current plan is to get out the multimeter, and find out for sure what position on that switch is "on"
Second I'll get the compression tester out and get definitive numbers on each chamber, so I know what I'm working with.
Verify that injectors are working. Most likely by tying them to the fuel rail with wire and seeing if they spray.

I have already verified that the plugs are firing, but I guess that was verified by the 30 seconds of running.

On a side note, the only light that has been on in the idiot cluster is the brake light (Handbrake is set), and the "Add Coolant" light for just a moment. I've also checked coolant levels, they are find, and the coolant light has not come back on.

Not sure if it's relevant, but when I pulled the engine, I did remove the wiring harness from the car.

When I re-installed it, I connected 3 connectors to the ecu, and 2 connectors in the passenger kick panel. They were both rectangular and yellow.
There is a white two blade connector down there that i could find a connection for. No idea what it is, but just in case it's vital and I don't realize it.

Any other areas I should investigae?

 

Have you verified operation of the fuel pump?

 

Have not. It's now on my list or things to check. I'll be heading back out to the barn after a bit, thank you for the suggestion, I'll let you know what I found out.

 

Ok, just got back in.

Determined the ON position of the switch, it's for now being left ON.

Confirmed that the pump is delivering fuel to the rails, I removed the FPR from the secondary rail and turned the key for a sec and fuel came out in large quantity.

Confirmed spark on leading and trailing, as mentioned plugs are new.

Compression test showed 60psi on each face, low, but I thought rebuilds were supposed to have low compression for a while, and this one has less than 60 seconds of run time.

I confirmed the injectors are delivering fuel.
I went through typical de-flooded the engine (just in case)
I disconnected the coils, removed leading and trailing plugs, and cranked it over. Got a nice mist out of each plug hole, it's gas.

Only thing I'm considering now is timing.

When I initially stabbed the CAS, I alighted the right most (Paint is rubbed off, but the corners are yellow) timing mark, and aligned the dot on the CAS gear and held the (pardon my french) "spinny thing" in position, making sure it was lined up.

Any other suggestions?

 

Did you forget to put in the injector diffusers? That is a common symptom of flooding and fresh rebuilds dying in <1 minute.

 

Yes, I'm sure. Though it's something I did not know, I'll be sure to remember that in the future, thank you.
Any other suggestions / areas I should look at?
I'm going to triple check for vacuum leaks, but doesn't seem likely as the engine ran smooth for the short time it ran.
I'd like to check timing, but don't know how since I can't keep it running.

 

Make sure the AFM is plugged in and checks out per the factory service manual instructions. Also check for leak(s) in the air intake piping.
http://wright-here.net/cars/rx7/manuals.html

 

You need to do a fuel PRESSURE test. just to be sure.

 

The car won't run on oil alone. Jump the test connector to ensure the fuel pump runs continuously and try again.

It sounds to me like a vacuum leak. My rebuild would do something similar, start and run okay for a few seconds and then die. The difference being mine would start up easily time and time again, just wouldn't keep running. It was an air leak.

 

AFM is plugged, in, I have not tested it, but will do so when I get back out.

I don't have a fuel injection pressure tester. From what I've seen they are like $50 at the local auto store. If I don't figure out the problem by Friday when I get paid, I'll most likely purchase one, I imagine it will be useful in the future.

I got it to start again, this time it ran for almost a full minute, using only a small squirt of oil to help with compression / lubrication.

The engine jumped up to about 2k after starting initially, and I gave it some throttle to take it up to about 3k, I held it there, but it started getting smoky, so I re-positioned myself so I could roll the window down a little, and let the rpm drop to about 2.5k. This is when the engine died. I tried giving it some throttle to get it back up, but failed.

The only thing not capped is the split-air tube, it's still running to the cat, but the airpump is removed, and thats because I was under the impression that without an airpump, that becomes a dead hole.

I will get it back apart and check again after trying to start it again. The last time it ran, it seemed to be doing better than the time before.

The housings were used, but appeared to be in great shape, and I know compression numbers are fairly low, perhaps it is just taking the seals time to bed in?


I have a video that is being uploaded now, shows start, running, and then stalling.

I'll also jump the test connector and try another start.

 

i didn't read if you had a check engine light on or not?

 

No. The check engine light only comes on with all the other lights when starting, no other time.

We has video
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Honestly it sounds like it's running out of gas. With that being said, I would bypass the fuel cut relay and wire the fuel pump straight to ignition power. That would eliminate the fuel cut relay. Just my opinion.

 

I've been going over some wiring diagrams, I'm going to check the voltage at the pump, then, if under 12v, I'll run through the circuit checking at each connector, to try and find the bad spot.

I know the grounding on the car is not the best, I had to replace both battery terminals, and run a grounding strap to the chassis and then the block to get the starter to crank at a decent speed.

I'll post my results

 

Seems extremely reluctant to start. If you're using a regular dial compression tester you're just not going to get a valid result, even with the bleed pin removed or held in. You can use those testers to verify a dead chamber but that's about it.

Can you keep it running if you have your foot on the throttle, or does it die regardless of what you do? If it dies regardless, it does sound like a fuel pressure issue. Jumper the fuel pump test connector near the airbox and try again.

 

Ok, well the storm has hit, and it's been decided that we're gonna stay inside and get drunk for a while, if the storm clears up I'll get back out there.

I tested the voltage at the pump. I have a cheap analog voltage tester, but the voltage with the test connector jumpered and the key was about 11v (Hard to tell with this cheap POS, I need a new one)
Yes, it was a cheap harbor freight dial compression tester, I wasn't really looking for accurate numbers, just uniform numbers on all faces.

The engine originally died because one of the apex seals was stuck in the rear chamber. On this same gauge it showed 45 on all faces on the front, one pulse of 30 on the rear, and two nominal pulses.

So just using that as a guide, the engine ran before the seal stuck, with 45 psi per this tester on the front, and I'm now getting 60 on every face per the same tester, I think compression is better than before the rebuild.

I'll try starting at seeing how long I can hold it at 3k. It died earlier because I took my foot off that gas a little when I was rolling the window down (Was getting smoky)

But it'll be a bit, I'm a little faded right now.

 

it's been said AFM, and i'll say it agian, can you physically verified the operation of the AFM door?, what does it do when yo prop it open with a screw driver? or just wiggle it a bit? maybe the DOOR is seized?

 

I will triple check after the rain passes, but I did check the brown output wire to the fuel pump circuit, was getting 12v with the fuel pump test connector jumpered and the key in the "on" position. If your thinking that the physical door is stuck, should be easy enough to check. I'll also check that next time I get out there.

I'd like to go out and put a little more oil in, start it up, and hold it at 3k rpm as long as I can, just to see if the engine is super low compression. Keep in mind, the P/O said it started and drove fine prior to the morning it wouldn't start. I found the problem internally, it was a small nick in the apex seal groove. I sanded it flat, and am now getting better compression.

I know that 60psi is in the lower end of compression, and you'd be hard pressed to get an engine started with only 60psi compression.

Could it be possible that the seals need to bed in for a while before the compression builds up to a reasable level?

 

what was the nick in? the rotor housing? or the rotor? I see the seals are new. either way, unless you replaced what was nick'd. you're ****'d.

 

The apex seal groove in the rotor had a nick that caught the apex seal.
I sanded it down, and the seal I put in moved freely up and down without the slightest hitch.
Plus, if that nick were the cause of any sort of issue, i would have poor compression on two faces of the front rotor, all are giving an even 60psi at last check. So, even though possible, not probable by looking at the symptoms.

I'm looking into the fuel pump a little more, only because I can't hear it when it's supposedly running, that does sound like it could be the problem, and still plan to check the AFM to make sure it's functioning.

 

even if the doors isn't stuck,the AFM still should be ohm'd out, and voltage test'd per FSM.

and how did the nick become to be with out the housings getting nick'd also? did someone try to put a wrench in the exhaust port to get the flywheel or front hub off.

 

To get you off the AFM, here are the readings.

E2<->Vs=200ohms
E2<->Vref=200ohms
E2<->THA=2700ohms
E1<->FC= Open

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E1<->FC
Door Closed = Open
Door Open = 0

E2<->Vs
Door Closed = 200
Door Open = 200

These look normal per FSM, the only poor reading is E2<->THA, it's only 300ohms off from spec, and could be the fault of my cheapo multimeter.

As far as the nick, i don't know, but the housings were perfectly smooth, no gouging or scratches, no flaking chrome, no imperfections that I could see. Like I said, that was the only internal damage I found, and it sanded right out.

 

i've seen a few engines do what your video shows....i think it is a large vac leak, like a hose missing or a large split in it. smoke it. it'a an easy tell, just blow some cig smoke up our intake., keep doing it like you think your filling up the engine with it.

 

Your right, it does sound like a vacuum leak, I just can't think of where it would be leaking from.
I'll try the smoke test tomorrow and see what happens.

 

hey is your oil pressure gauge broken? cause in that video it looked like you had no oil pressure.....