I'm fairly new to rotariies and to EFI (my other financial black holes have carbs and pistons). I need a second opinion, please.

My '86 GXL with an '88 n/a engine was in the shop for emissions (according to mechanic no air to cat - CO and HC way over limit) While the mechanic was letting the engine warm up to do a test "it just died" on him after about 3 minutes of running. They had installed a used ACV I had given them if that makes any difference.

Since then, I can sometimes get it to crank using the standard unflood bag o'tricks (ATF, unplugging fuel pump) but iit won't hold idle - (really rough - barump-barump-barump) you can keep it going with the pedal but it dies when you let off. If you bring the rpm way up it smooths out a little and feels like the secondries are kicking in. When you let it go the rpm falls off quickly until it dies. If I hold it around 1500, the oil pressure hovers around 30 psi, When you let it down below 1000 or so it slowly drops almost to zero. Nursing it around the block it bogs down really bad when you accelerate quickly. (It never flooded before, but then I haven't had it for long.)

I realized that the fuel tank was almost empty during all of this - could a piece of crud from the bottom of the tank have made it up to the primaries and caused them to stick open? Plugs always come out wet with gas. Sounds like an injector problem right?

But here's the kicker - when I was doing an extreme unflooding procedure - had my wife crank with the plugs out to clear the fuel in the chambers- I noticed a big puff of gas coming out of 3 of the 4 plug holes. The #2 trailing plug hole had nothing. I reconfirmed with only this plug out. After snooping around on the forum - that sounds like a side seal, correct? (I don't have a real compression tester in my toolbag) Could it have been bad before and still run OK? Could this have been the emissions culprit in the first place? It does smoke a good bit on start up (white) and a little when warming (grey/black). I wish I knew how it smoked when running on the road I didn't notice excessive smoke before.

Given the sudden onset of symptoms - I think the injector theory is the most likely, but the apparent lack of compression from one chamber has me worried. If it was a vac line or something left unconnected it shouldn't have been running like it was when it died, right? I think I can rule out TPS issues for the same reason.

Any thoughts?

Rick

 

Stuck injector are VERY rare, but easy to prove. Simply remove the upper intake manifold, and turn the key to "IGN". When the fuel system primes, is should immediately be obvious if the injector is stuck (ie. it will be shooting out massive amounts of fuel).

I saw this on a TII. One of the secondaries was stuck, and it would completely fill the lower intake with fuel.

 

Cool. Thanks - I'll give it a shot

 

^^ that's a cool trick

 

hate to bring in possible bad news, but my tII did the same thing then nothing at all, lost 3 apex seals, started as 2 cracked ones and then three (2 on front 1 on rear) and that makes it game over. hope you have better luck.

 

that's a lot of lost apex seals

 

Don't ferget to install the jumper in the yellow two prong connector to bypass the AFM (to allow the fuel pump to run with the engine not running)

 

the fuel gets sucked up from the top. it go's thru a screen unlikely its junk in the tank, #1 rotor trailing and #1 leading are two holes that goto the same chamber, #2 trailing and #2 leading are the same chamber . leading holes will most likely dump the fuel cause they are lower in the chamber, Just get a switch so you can turn the fuel pump off and on, or pull the EGI fuse,(sometimes works) but with a switch you can turn it off as your cranking. then when it catched you can turn the pump back on. there should be no reason to take out the plugs to unflood, takes alot of time! check tps sensor cause i had the same problem with it dieing, at 1500 rpm if its running smooth then at least the primaries are working to a degree, Unlikely that they are the problem, at 3,800 rpm is when the secondaries come on,
also check the airtube that go's from the front to the throttle body. It has to Be hooked up and tight for the car to run, If its off the AFM is not sending a signal to the Ecu, See if you can hold the idle at 1k with your foot, if you can maybe the adjustment for the cable came loose, there are many other reasons it Might not hold idle, if i think of any more ill post it, Im blank tonight.

 

Thanks for the info!
I'm up against some tight deadlines at work so I probably won't get back to it until this weekend.

I'm also going to put together a TPs test light ASAP so I can eliminate that issue.

 

I wouldn't recommend doing that. You just need a little pressure in the fuel system, so you can just switch it to IGN and let it prime for a few seconds. Jumping the test connector makes the fuel pump run as long as the car is in IGN, which could make quite a mess in this case.

 

Good call. Last thing I need is to drench the beast with gas. I might be too tempting

 

Sure, but if you don't use the jumper, how are you going to build fuel pressure by just putting the key to IGN? Maybe I have a concept error here, but I thought for the fuel pump to run (therefore build pressure) it needs: 1) Key to IGN 2) AFM not closed (cranking/running) Installing the jumper bypasses the switch in the AFM.

 

The #2 trailing concerns me. The hole on the housing for the spark on the trailing are quite small. No fuel coming out of the trailing, yet it does come out of the leading, probably means the trailng hole is plugged. It doesn't mean a side seal is bad.

Do a compression check. when you do the rear chamber, test both the leading and trailing. If you get near zero on the trailing and a decent reading on the leading, you will probably need to de-carbon the engine.

 

i would suspect a plugged up injector over a stuck wide open injector but a plugged up injector wouldn't be shooting fuel out of one of the front or rear plug holes during cranking.

 

I'm not going to pretend I have an answer, but is your timing set correctly? My idle was crappy and I had a similar 'bog' when I'd floor it. Turned out that my timing was WAY off.

Good luck

 

do a compression test...

 

A real compression check sounds like one thing I will definitely have to do.
When I had it running, I checked the timing and it appeared to be on (if I am looking at the correct mark). I reset the CAS because it was hard over to the left with no room for adjustment. I'll check again next time I get it cranked.

Does anyone know if the TPS check light method will get you in the ballpark when checked cold? I know you are supposed to check it with the engine warm, but its not cranking right now. I'm afraid I might have goobered up the setting when I first got it cranked after the emissions fiasco. It was idling so rough I started adjusting stuff without thinking (bad habit, I know).

I have the Haynes book, the pictures do help, and I am downloading the FSM tonight.

 

The fuel pump primes for a few seconds when the switch is turned to IGN.

 

The fuel pump won't run unless you put the key to START and hold it there ......Or the engine actually starts and the key is returned to ON (afm switch makes the Circuit Opening Relay's ground)......Or the engine not running and the key is just to ON and the jumper is in the fuel pump check connetor (jumper simulates the afm switch being made).

 

when is the last time you changed your fuel filter (located on drivers side subframe just below your brake booster or so). clogged filter (or full of rust from really old casing) would lower your fuel pressure so that your injectors arent misting they are dripping (think garden hose with finger pressed in end as mist and no finger as low pressure) and voila flooded car. just a suggestion.