Got what I believe to be a 13b from an 86-88 NA in a 1982 Vanagon Westy camper. More info on this in my introduction.

The good news is, the engine runs and sounds good but won't start on its own and likes to die easily. To get it to start, I have to try 2 or more times with starter fluid then maintain a high idle, revving often, until it warms up. Once warmed up, it will usually idle fine. Until recently, the most I've tried to drive this bastard setup was in and out of the driveway but two weeks ago, I did a test drive down the road only to stall it (my fault) on the return trip. After that, it refused to start so with the help of neighbors, we did the push of shame back to my house.

For months now, I've lurked on this forum, watched countless videos about rotaries and tried to learn as much as possible. My background in engines is air-cooled VW's and carburetors. EFI is a foreign concept to me so I'm looking for advise to try to get this engine running before I give up and try to find a shop (if I can find one) willing to work on it. This van has been siting since 2006 and the most that has been done to the engine so far is an oil change, new fuel filter and spark plugs.

Where should I start? Anything else I should just replace now? There will probably be many dumb questions so I appreciate any help. Thank you.

 

This is super cool! Link your intro thread and add more pics!
You have a heavily modified stock intake system.
When cold, there is a "thermowax" system that cracks the throttle open to increase rpm. It is still attached in your other picture, so it may just need some adjustments.
In the mean time, you can just tighten the throttle cable to keep it running.
I'd go through everything fuel related: get rid of any 2006 gas in the tank, pull the fuel injectors serviced, check fuel pressure if you can
When rotaries stall, they often flood. Pulling the EGI fuse and cranking will usually clear it out. Put fuse back in and try again.

 

 

The person I bought it from drained the tank and replaced the fuel filter but there could still be crap in it. I added a bottle of Seafoam to the tank to see if that would help. Next, I'll check the fuel pressure but after that, I'll need to consult the Haynes manual I found in the van for more help. More than likely, I'll probably take it to a shop but I'll exhaust all my options first.

 

Have you changed the coolant? I'd definitely change the thermostat which would cause it to overheat if you run it too long.
These engines are sensitive to vacuum leaks too. If you get it running, spray carb cleaner around the rubber hoses, intake joints and listen for an idle speed change.
Generally, the lower you can get it to idle, the better it is running.
The Haynes manual will helpful to identify stuff, but most of it has been re-arranged.
FYI the EGI fuse for de-flooding is in the fuse box next to the battery.

 

Thanks for the advise. Hoping to get a chance to toy with it this weekend but it's been raining a lot again.

 

Is it possible to have too much fuel pressure? Just did a test and fuel pump pressure is over 100psi (pegs the gauge). System fuel pressure is 48psi then I hear a buzzing noise and it goes down to 42. The book says fuel pressure max should be 84 and system max 38.

Also, in the top middle of the engine bay photo, you will see a solenoid with a white connection. It looks like the AWS in my book but then my book says it's for 1989 only and I'm pretty sure this engine is from an 86-88. Anyway, there are no hoses connected to it and it doesn't click when I give it power. Ohms were correct for AWS, if that's what it is.

 

Ran a compression test and got around 80psi on both the uppers. Book says 85 is the minimum but the engine may not have been fully warmed up either. It's now hard to keep idling as it pulsates then dies only after a few seconds even when warm. Probably has vacuum leak but I can't seem to find one. Sprayed carb cleaner around the motor but didn't hear any changes in RPM's.

 

The engine will run fine with the extra fuel pressure. I've run a car with 50+ psi and it just runs a little rich. AWS just raises the rpm on startup. As long as the connections are plugged, then it is fine to run without it.

It's more important to have consistent pulses. If using a standard compression gage, hold the valve open to see readings from each chamber. If it starts consistently, then I wouldn't worry about compression too much. Running for a few seconds is usually a vacuum leak or the fuel pump is shutting off after starting. You can force the pump to run by jumpering the fuel check connector, but I'm not sure where it ended up after the swap. N326 is an S4 non-turbo ecu, so it's a safe bet everything matches that.

 

Went out this morning and played with the vacuum hoses and water thermo valve. Valve seems to work but I did find a vacuum leak so I fixed that. Van wouldn't start on it's own but fired up quickly with starter fluid and idled on its own and stayed running for ten minutes without hiccuping or stalling. Drove it to the side of the house to wash it. Later, it started on its own after 5+ tries then stalled as I was pulling into the driveway. Wouldn't start after that so had to push it the rest of the way in.

When cold and warm (ish), what techniques should I be using to start the motor?

 

Found the reason why it's been so hard to start, besides resolving the thermo wax. By chance, I learned the MAF controls the fuel pump and I noticed that when I tried to start the van, the flap wasn't opening. The fault turned out to be mine because the MAF was not all the way connected. Now engine will start on it's own, though it may take several tries.

Now the motor will start cold and fast idle, relatively smoothly, on its own before dropping idle after warning up. Then the idle pulsates and the motor will stall frequently when I put it in gear and try to move in and out of the driveway. It will sometimes stall at idle but at least it will start back up again. Feels like I'm halfway there now.

Ideas?

 

Well, now I'm back to hard cold starts and still stalling when warm. To get it to start cold, I need to open the MAF flap wide open then it will fire on the 2nd to 3rd try and stay running. Not sure if that means it needs more fuel or air to start but it works. After warm up, the idle will drop and pulsate. Again, I sprayed carb cleaner around all of the vacuum lines and around the intake but there was no change in idle. Then I tried to mess with the adjusting screw on top by turning it to the left but that just made the idle worse so I turned it back to the right until it was seated, which is where it was to begin with. Then I checked the BAC valve and it works but there is no change in idle if I disconnect the power or plug the vacuum port.

What would be the next items to look at?

 

It's really difficult to tell based on the pictures, but this may be a tough one to sort out due to the complexity of the swap.

People will kill me for saying this, but I've never had luck keeping an S4 engine running well on a stock ECU with all the emissions related components. However, I do know some that have. @Derekcat ? Care to chime in?

 

In the last few days, I had the chance to check the AFM and it passed according to the FSM. I also set the TPS to 1k at idle (with cold start blocked off). At WOT, it peaks at 4300ohms and I didn't see any dead spots going between. When I tested the C side of the TPS, it was 3700 idle and 306ohms WOT. Not sure if that means anything or not. One source said it should stay at 5k idle or WOT.

Suddenly, though, I'm getting a lot of smoke coming out the exhaust. This is new and I'm not sure if I screwed something up. When I checked the spark plugs, the leading are both black and smell like unburnt fuel. The trailing plugs are clean and dry. From the smell of the exhaust, it seems to be a fuel, but could also be oil (which would be new as well). This got me thinking that perhaps opening the AFM all the way to get it start is telling the ECU to dump fuel into the motor?

 

Think I answered my own question. After a walk around the neighborhood with the family (with my mind of my van and my van on my mind), I decided to test my theory by first doing the de-flooding technique then I started the van by my old method of using starting fluid. Took several tries, like usual, but it started with far less smoke and it dissipated in a short period of time and it idled on its own again. But a new issue came up. The trailing plugs are not firing and I cant seem to get the motor timed correctly and stay running. It will die when I retard the timing and doesn't like to start in that position. I did take out the CAS and verify the notches are lined up so I think I'm good there.

 

Yes, propping the AFM open is telling the ecu to add lots of fuel.

Nice...

It'll idle and drive around without trailing ignition. Crossing the Trailing 1 and Trailing 2 will be a problem so make sure that's not happening.
Fuel injectors don't like to sit that long and are probably working inconsistently. Sending them out for cleaning would be my top priority.
The ecu modifies fuel and timing for 2 minutes after starting. Make sure you're setting timing after that.

 

Thanks for the tips. My timing light did not activate on either trailing so I need to figure that out. And before I check timing again, I need to find the initial set coupler then try to set the idle and fuel mixture.

 

It's been brought to my attention, through a PM, that the secondary injection on this motor has been modified. Can anyone add to this? It would explain why I was having a hard time finding the fuel pressure regulator and why the routing for the fuel lines don't line up to the FSM.

 

In case you aren't already using it, the manual is available online. Foxed.ca - Mazda RX-7 Manuals

The intake has been modified to eliminate the middle section of the 3-piece intake. Probably to reduce overall height. It's also where the injectors originally mounted.
Looks like they cut the secondary fuel rail in half and mounted each to the sides of the intake. As long as everything seals up, it should work.
Your pressure regulator is on the fuel rail section at the firewall side of the engine.

 

Yes, I downloaded the FSM a while back and it's been a tremendous help but sometimes diagrams don't always transfer well into my brain. Now that I know the secondary has been modified, I can see how the dynamic chamber has been changed to accommodate it. Now I'm curious if the PO did this or if it was part of some kind of kit for a Vanagon. Fortunately, there is no signs of leaking fuel and it seems to function. I'm guessing this was done to save space but without seeing a stock FC in person, it's hard to comprehend.

Today, I thought I made some progress but this motor likes to disappoint. After a family outing to see the tulips in Skagit valley, I was able to locate the ISC so I can try to tune it to see if that will help it start and idle better. It took several tries to get the motor to start with starting fluid but eventually it warmed up and idled, though it was surging. Once warm, I connected the ISC then adjusted the idle, which made a difference and helped it smooth out. Then I tried to adjust timing but I was not able to retard it far enough (counter clockwise) to get the yellow mark to line up. It's about 2-5 degrees advanced but the CAS is bottomed out. Then I tried to adjust the idle fuel mixture but there must a problem with it because no matter how I turned it, there was no difference in idle. Regardless, it was idling better than is has in a long time so I left it as is and took out the ISC jumper. I was ready to try and drive it around the neighborhood but it was dinner time so I had to wait. After dinner, I went back out and it started right up so I let it warm up again but it went back to surging and stalling often. I tried one more time to tune it with the ISC but it made no difference. The motor was plenty warm and even made the electric fans engage. Ugh!

Forgot to add, there is a clatter coming from (or near) the check valve on the air control valve. It wasn't doing that before.

 

With no one in town willing to work on my motor, I'm resigned to tear into myself. Normally this would be fine but I have two small kids so free time for such endeavors is limited.

I've tested as much as I can test and have done a lot of research. The motor is running lean, either due to a vacuum leak(s) or lack of fuel. Fuel pressure is good, all vacuum lines are attached and look fine, AFM tests good, replaced water thermosensor, checked grounds, thermowax and fast idle are working and checked compression again. Front and back are within 5lbs if each other and no low readings.

I think my next step is to have the injectors cleaned and tested then install with new seals. Should I replace the intake seals in the process?

Btw, here is a short video on my compression results.

 

Was that video slowed down? That's extremely slow cranking speed.

Overall, you've done a great job persisting and doing your due diligence. All though....your statement about the timing concerns me. There is no reason you shouldn't be able to get the timing marks to line up per factory specification. That is, unless, the pulley had been swapped, modified, or the CAS was incorrectly installed. Only once timing is spot on, would I move forward.

 

It was slowed down so I could catch the actual readings. When I did it the first time, the needle flopped so fast it was hard to make out. As far as timing, resetting the CAS is on my list of things to do (along with many other things).

My VW friends keep ridiculing me for trying to get this motor to run. "Put a TDI in it", "change to a Subaru" etc. Doing this would actually require a lot more work to swap. Everything is already set up for this S4, plus it's such a cool modification.

 

On Thursday, I tore into the motor and took the injectors to a local diesel repair shop. They cleaned and tested them and said they were good. Ordered new injector seals, intake gaskets and a BAC valve gasket. The job went smoothly until it came to the middle intake stud, nearest the primary fuel rail. The nut was difficult to access until I removed one of the oil injector nozzles.

The manifold extension should now be called a "spacer" and the surge tank has several modifications. One issue I'll need to resolve is the original builder moved the air temp sensor into the freeze plug, due to the original location interfering with the primary fuel rail. The metal in the plug is very thin making it impossible to really tighten the sensor. I'm thinking my only two options are to either drill a new location and plug up the hole or install a locking nut on the inside of the surge tank with a dab of Loctite.

When ordering the injector seals, they came with Pentle caps and fuel screens. Not sure if my injectors have Pentle caps already and where do these screens go? Lastly, all four injectors should be he same correct? I separated them just in case.

 

The rebuild kit for the injectors came today, and with the help of a video I found, I learned how to remove the screens with a screw and a vice. The lower seals were rock hard so hopefully the new ones will help. And the Pintle caps were a pain to remove but have been replaced.

Intake gaskets also arrived from Atkin's today, which was super fast. Need to replace all the old fuel lines and small coolant lines then I can put it all back together. Hoping this will make a difference.