LagunaFC

So the other day I was trying to start my car and it wouldn't start. My first thought was that it was flooded so today I got out and did the unflooding routine (removed EGI relay, cranked with WOT, etc...). Eventually the car started, but when it did it was vibrating like mad and idling extremely rough, and eventually stalled after about 15 seconds. Now it wont start, like its flooded again. I'm about to go out and try the unflooding procedure again, but I suspect something else might be the culprit. Last time I ran the car it ran perfectly with no issues at all. I checked if the ECU was throwing any codes and got nothing. The car is a '94 and almost completely stock (intake, downpipe, cat-back exhaust, and a few reliability mods). Any suggestions? Thanks in advance.

grimple1

iTrader: (1)

compression test it. also what did the plugs look like when you pulled them?

RENESISFD

iTrader: (13)

It was probaly running on only one rotor. Do the deflodding procedure again and see if that helps. Did you take out the spark plugs? Were they wet? When i had my fuel injectors cleaned the primary injector on the front rotor was stuck closed and the car idled like a v8 with a monster lift cam. lol it shook really bad. Hope this helps.

John

LagunaFC

Thanks for the info guys, I did the deflooding procedure again, and it still idled very rough for the first few seconds, but after a while it calmed down and ran fine. This was yesterday, and the car ran fine all day today. . . until tonight. I was driving down the road and I downshifted into second and gave it some gas, when the vibration suddenly returned, but this time the car still ran. I pulled over and the car stalled, so I consider my options. I end up deciding to see if the car will drive since I'm so close to home (5 blocks), and to my great surprise it actually starts, but the vibration is still there, it really does feel like I'm running on one rotor. I managed to get home in the end, and I'll update again tomorrow when its light out and I've had a chance to take a closer look.

Anyway judging by this recurrence it sounds like its more than just simple flooding now, so any suggestions as to what might be causing this? Could my motor be on its last legs? I really hope I didn't damage anything choosing to drive home the five blocks.

EricRyan

iTrader: (4)

Hmm, maybe check your connections at the MAP sensor, both the electronic connection and the vacuum hose connection. I know when I blew the hose off at WOT, it acted similar to what you're describing.

Neilguy

Sorry dude, i couldnt find any entries or helpful info in alldata in the limited time before i got tired. i'll check again tomorrow when i have time.

LagunaFC

Update: I ran a compression test today, rear rotor was very low (90psi) but was still three equal peaks, should that warrant a rebuild? Front rotor looked fine at 115psi. Old spark plugs were pretty fouled so I replaced them since I had new ones lying around. After that I fired it up and it still runs like ****, no power, lots of vibrating. Is there an easy way to check the fuel pressure and injectors without ripping out the rats nest? I just had my injectors cleaned about 1k miles ago, but its possible that they've managed to gum up I suppose. . .

grimple1

iTrader: (1)

did you check the MAP sensor connections? there's a little hose on that has been known to pop off. once it comes off it'll run like crap and exhibit the symptoms you're talking

Also, any chance of a vacuum leak in the rat's nest? While the car is running, take some carb cleaner and spray it around the hoses and see if the idle changes. If so, there's a vacuum leak in there somewhere.

About the 90s. If it's equal then that'd rule out what I was suspecting (apex seal problems).

TSXtasy

I just sent my motor off for a rebuild, similar compression (80 on all 6 faces). didn't vibrate like yours, but did run like crap and wanted to stall at every stop light. turned out to be side seals.

LagunaFC

Thanks for all the info, I checked the MAP connections and they were all fine. I think I'm just gonna bite the bullet and get it rebuilt, it's a high mileage original motor so its overdue anyway.

DaveW

IMO, 90 psi is on the very low end of acceptable compression. While it does not, in itself, warrant a rebuild, and should not cause rough running, if you are having starting problems, then it is a judgement call. In the NA rotaries, the engine will always run great, right up to and past the time when low compression causes starting problems. That, to a somewhat lesser degree, also applies to the FD.

Also, I would look very thoroughly for some other cause of the rough running - if it starts, low EQUAL ON ALL FACES compression should not cause rough running.

LagunaFC

Yeah, I dont know why but I have an instinct that the 90 psi isnt the main factor in the problem. Since I tested the ignition and compression, the only other things it could be are a fuel or electrical problem I guess.

Under what conditions does the PCME cut fuel or ignition to the rear rotor? I remember seeing a graph somewhere showing load vs. RPM and all the different operational regions, is it possible that something is "tricking" my computer into thinking it should be cutting fuel to the rear rotor? Or that my PCME is fried?

I've already decided to get the rebuild, but I still want to diagnose the problem so I can avoid it in the future.

mulder9927

i just rebuilt my fd and it ran fairly well for a min then would stall after about 3-4 min. then it started flooding so i cleared the flood and got it started and kept it running but it reeked and if you took your foot off the gas for a second it would die instantly. it seems to be getting worse the more i work on it, its also running very rough, any ideas for me?