OustedFairlady

Try number two. My original post on the General Rotary Tech Support forum got no replies in a couple days, so I'll try here.

I recently picked up an '87 TurboII. 107xxx miles, one owner, garage kept, and generally babied by the previous owner (incidentally, she's 65 years old).

The car has exhibited signs of flooding, namely difficult/impossible to start, huge amounts of raw fuel on the plugs, etc. I've done some research and found that the AFM is likely bad, as the fuel pump turns on when the key is turned to the "Run" position.

I performed the deflooding procedure; pulled the plugs, spun the engine over for 10 seconds or so to remove excess fuel, put a bit of ATF in the rotor housings, and spun the engine over. The car started up on the second or third revolution.

Obviously, this means the engine was flooded. I performed a compression test with a standard tester when the engine was cold, before getting it running for the first time, and it showed 110psi on the front rotor, and 90psi on the rear. I'm unsure if running it has helped any (It ran for around an hour and drove around 2 miles). I haven't tested it at operating temp yet.

In any case, I've done a few minor things here and there to try to find out what problems it has. It doesn't overheat, and runs just around a third of the way up on the scale as far as temperature. The car has an odd idle, but won't die if I take my foot off the throttle. It has no issues idling for extended periods of time, just starting. It will idle for quite a while between 12-1500 RPMs, and then eventually will drop to around 800RPMs. When the idle drops, the quality of idle diminishes tremendously, and the car begins to shake. This leads me to suspect the compression on the rear rotor as being the culprit, as this is a common symptom of low compression on piston engines. If I'm wrong, tell me! I've not worked on rotaries before and this is all based on things I've read on the forums, not real world experience!

I drove the car briefly today, and put around 2 miles on it. I've noticed that the engine is slow to rev, and when the throttle is blipped, engine speed falls slowly. A classic symptom of a rich AFR, IIRC. The car exhibits a marked lack of power (3500RPM takeoff on a very light grade, otherwise it tries to stall), will not build boost, and above 20% throttle, will not climb past 3500RPM. I suspect the TPS is on the blink, although I haven't tested yet. I've read about the dreaded 3500RPM hesitation, and as I have only just gotten the car running, I haven't had a chance to correct the problem yet.

All that said, my question is thus:

Based on the information above, would it be the opinion of those more wizened than I that I need to buy apex seals, etc., and replace internal parts? Or would this set of problems point to a less drastic repair?

Forgot to mention...

The P.O. allowed the car to sit up for several years. I have no idea how many times the car was cranked in the period of time it sat, but I'm assuming it wasn't. Last date of inspection was 2004. The P.O. asserted that her growing arthritis pain made it too much of a bother to shift the manual transmission, and she preferred her automatic car.

ericgrau

iTrader: (1)

www.aaroncake.net => "RX-7" has some general information. Also information on what to do for a car brought out of storage.

The early high idle is normal, but the rough idle at 800 isn't. You should compression test it with the check valve removed or disabled so you can see all 3 values (from 3 triangular rotor faces) on each of the 2 rotors. There are 2 spark plugs per rotor, IIRC it doesn't matter which hole you use. The 3800 rpm hesitation comes from lag in the secondary fuel injectors kicking in at 3800 rpm, usually caused by ECU problems caused by poor ECU grounds rather than the injectors themselves. Maybe yours aren't working at all? I dunno. If your engine doesn't flood again I wouldn't worry about that. Hopefully it was from storage. Just take care of the plugs and oil while you're changing out all the fluids and so on; do all of the scheduled maintenance regardless. Unless you find out the car is toast. A rebuild (opening the engine for any reason) will be $3000 or more. Most symptoms of a bad engine are the same as piston engines except the parts and method of fixing it are different. And there are a lot of electrical problems (substandard electronics) so if you're lucky then the rich running problems are from one of those and not engine trouble. Or from the old gas or AFM or who knows hopefully.

The lack of power is worrisome so you may want to compression test first, figure out how much it'll cost to fix and make sure you have the budget and decide whether or not you want to continue from there or start with a car in better shape.

OustedFairlady

I'm assuming my previous test values of 110 and 90 are going to be incorrect, then? I didn't hold the check valve when testing previously.

The car continues to flood, very nearly instantly. The car has new plugs, oil, coolant, etc. This is the thing that annoys me the most, as it requires me to pull the plugs, clear the rotors, and inject ATF into the housings every time I wish to start the car, whether warm or cold.

The lack of power is by far the worst thing. It isn't simply a lack of power. It's nearly the total absence thereof. As in, on a slight incline as you might find in a driveway, the car tries to stall. It cannot, let me repeat, cannot make it up a pair of ramps, and barely moves on flat ground.

Tomorrow, I'm going to mix up some two stroke oil and fresh gasoline and see if that helps. I've been told that a failed Oil Metering Pump could possibly cause a similar issue?

I'll also check into the car's grounds. I found one loose, dirty ground on the firewall. Where would I commonly find dirty or missing ground connections?

Also, I read a post by "RotaryDoctor", IIRC, that mentioned that if the fuel pump activates with the key on but the engine off, it points to a bad AFM. Is this correct? If so, my car has a bad AFM, as the pump does indeed turn on. Any pointers on repairing rather than replacing the AFM?

1SWEET7

iTrader: (1)

The flooding symptoms sound like leaking or clogged injectors, that would also cause the car to stumble when driving it as well as having problems revving. You say it sat for a long time, I would have the injectors cleaned and flow tested. Did you drain the old gas before starting it? Change the oil and fuel filter? General tune up stuff? Sitting wreaks havoc on cars if they aren't started often. Did you probe the fuel pump connection at the left rear shock tower to make sure it was coming on or did you just hear it? Get to know the search function on this site and you will find most of the stuff you need.

OustedFairlady

The fuel tank was removed, cleaned, and reinstalled. Fuel pump has been replaced, as well as fuel filter, plugs, wires, etc. Oil changed. I've searched high and low on the forums, and while I've found some things, my issues seem to somehow encompass all of it at once.

Not to sound as though I'm being somehow belligerent, but I'm pretty familiar with online forums and the general rules of use, as I'm a pretty steady member of the HybridZ forums and a few others. Searching is the rule of thumb, I know, and after a week solid of searching, here I am. I wouldn't have posted this if searching had fulfilled my need for information well enough. Sadly, searching has failed to do so.

Fuel injectors was something I was suspicious of. I wasn't sure, but I wanted to rule everything I could out before buying a set of injectors or sending them to who-knows-where to get them flow tested and cleaned.

ericgrau

iTrader: (1)

110 is good and 90 is acceptable on the compression test IIRC. Ya you should retest while holding the check valve to make sure you get 3 high bounces. Don't use ATF to deflood if you can help it, it can cause damage. Or at least run the engine immediately after to clear it out, which I'm sure you're doing anyway. A failed OMP would cause a lack of lubrication leading to blown seals; if it had one it might already be too late and I think it's compression wouldn't be so high. And s4's tend to be better than s5's for the OMP. www.aaroncake.net also has a regrounding guide.

I'd get a used AFM cheaply from a junkyard or the forum classifieds if you need one. Also make sure it is level not turned 90 degrees though I doubt the old lady touched it. Searching the forum for something like AFM cleaning might yield some info too; it might be a matter of unsticking some stuck parts IIRC.

IMO you might as well send the injectors to get cleaned, who knows how old they are anyway. I think a forum search could reveal some options on where to ship them to. To help your search I think people use phrases like "sent my injectors out to get cleaned". It is possible after sitting so long that the injectors and lots of other parts are covered in varnish. You might want to gamble on a big name fuel system cleaner like Chevron. Probably too weak for major problems like the injectors though.

1SWEET7

iTrader: (1)

http://witchhunter.com/ is where I sent my injectors. They have great turnaround times and it's pretty cheap. They also give you before and after flow data to see if one or a few weren't working. I had to clean my AFM recently because the flapper had become stuck slightly making my fuel pump turn on with the key to on. Take it off and make sure the flapper moves freely when you press on it. Buy some AFM/MAF cleaner from a parts store and go to town on it. You can also Ohm test it to see if it passes OEM spec. You can find the test procedure in the FSM.

OustedFairlady

Alright, thanks for the info. I forgot to mention that I had indeed twiddled with the AFM and the flapper door opens smoothly and without any catches. I'm suspecting an internal problem then?

The car had never been disassembled when I pulled the UIM off. All factory clamps and hoses were on it. I assume the car was never touched, except possibly for regular scheduled maintenance, such as the oil filter (is/was genuine Mazda), the air filter (again, Mazda), and spark plugs and wires (aftermarket; likely <insert random parts house here> brand). It does have NGK-R plugs.

There is quite a bit of the whitish corrosion that appears when aluminum parts are allowed to sit, and now I recall that the AFM wiring had been tampered with. Two "jumpers" were wrapped around two of the wires going into the plug. They weren't connected to each other or anything else. I'm suspecting some enterprising "technician" attempted to solve some problem by entirely the wrong method.

As for the fuel pump cycling on, it doesn't stay on. It comes on for a second or two, presumably to prime the car's fuel system, and shuts down again. I had originally assumed this was normal behavior, until reading a thread that mentioned that it shouldn't come on.

I'm going to add 5 gallons of 2stroke oil + midgrade fuel to the car, with the mixture slightly high on the oil side, as the car has a quarter tank in it at the moment of fairly fresh gasoline. If this helps, I'm going to suspect the OMP, although I can see how a failure would've made itself pretty apparent by now.

Oh, and the ATF does NOT stay in the car for more than ten minutes before startup. Usually I start the car up immediately and allow it to burn off the ATF. I'd prefer to use an alternative means to help compression, and I think I may put a little fresh motor oil into the engine in lieu of ATF as a means to clean/start it.

ericgrau

iTrader: (1)

As long as the UIM is off (if it's still off) I believe there's a hard to reach grounding wire there (check the guide in the link), the ECU ground i.e. the most important one, and if any of the vacuum hoses or fuel lines are leaking or hard as plastic (they should be rubber) it's a good time to replace them. Also check the fuel pulsation dampener for leaks (also under the UIM I believe), or replace it anyway since it only lasts ~100k miles and that might not be accounting for age. Probably ~$100 or so new. It's a common problem leading to engine fires. The ECU ground is a common cause of the 3800 rpm hesitation, another common problem.

Dunno much about fixing the AFM but I do remember that the guide involved opening it up. (searches around) Ah here I have the guide in my subscriptions: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/how-clean-out-your-afm-black-goo-stuff-681449/

The Factory Service Manual in the FAQ can provide you with a lot of helpful info on wiring and everything else.

OustedFairlady

Alright, thanks. The UIM is back on the car, but it's relatively easy to remove, so I'll pull it off again next week. I read about the ECM ground there, but only after I reassembled it, so...again, it'll have to be disassembled.

The FPD doesn't seem to be leaking in the slightest, and the hoses are still fairly supple. No major cracking. I'd like to delete much of the emissions components, as we haven't the slightest bit of emissions testing here in MS, so I'll wait to replace lines until then. I deleted the throttle body thermowax and heater. I didn't think it'd cause any issues, as it's regularly 80+ degrees here from mid march to september.

ericgrau

iTrader: (1)

I suppose you'll be certain that's not the cause of your injector problems, though they could simply be clogged. Up to you if you do all that now or wait until you're doing something else there.

OustedFairlady

Well, I'm leaning more and more towards sending the injectors off and having them cleaned regardless, as it's only $20 per injector, and I have four other cars to drive.

I do have about a hundred 440cc injectors from my various supras lying around...would they serve as a stand in injector well enough for me to troubleshoot the car or will it cause any issues even at idle or part throttle operation under no boost? All of my 440s are in good condition, and use the same or similar plugs as the RX7 injectors, since these 550s are supposed to be plug-n-play upgrades for 7MGTEs.

OustedFairlady

Forgot to mention, I made a little progress today. I started the car this morning and it fired up on the second revolution. No flooding. I was very pleased.

It ran for around, oh, 45 minutes, and I drove the car around and put a few miles on it. Still no power, still has the 3800rpm hesitation. I brought it back into the shop. It idled between 11-1200rpms. Exhaust temperature at the tailpipe seemed extremely high, although the cat(s) weren't glowing. I suspected the engine is running extremely rich, causing the cats to get hot, and my suspicions were somewhat justified when I found my FPR vacuum line loose. I'm guessing this caused the high idle and rich fuel mixture, at least in part. I couldn't see it with the intercooler on, and only did after removing it.

I checked the AFM for goop, since my air filter's rubber has turned into rubber glue, and found none in the AFM housing. I'm going to do a resistance check on the AFM tomorrow and see if I have any bad or damaged circuits.

I'm put some fresh gas in the car and in the morning I'm going to pull the UIM, clean all the grounds, replace any damaged wiring, and start replacing any bad vacuum lines I find.

Welp, that's it for today. Maybe I'll post a picture up! In fact, I will. Sorry for the crap picture quality. I'll try to get better ones in the morning.

OustedFairlady

Update:

The car is attempting to run correctly now. I removed the UIM, cleaned all of the grounds, and checked all of the vacuum lines. I came within an inch of yanking the rat's nest, but I'd rather get the car running correctly and then start modding.

Cleaning the grounds partially fixed the 3800RPM stall, although it didn't do the trick completely. I also have a TPS that's on the blink, but it works well enough, I think, to drive. It was tremendously out of adjustment, and after readjusting it, the car seems quite a bit happier, if a bit high on the idle.

That semi-solves a few issues, and now, I have another that I'd like to fix, but I'm not sure where to start.

When I shut the car down, it absolutely will not start immediately after unless I put oil or ATF in the housings to kick the compression up a bit. If the car sits for around 20 minutes or so, it will start up fairly easily. This is regardless of whether or not the car runs for 2 seconds or 2 hours. If it hits, it will not start afterwards.

Any ideas as to why?

OustedFairlady

Waited thirty minutes and tried starting the car. I ran it earlier until it warmed up thoroughly, and it made good oil pressure, ran at a good temperature, no issues, no fluctuations in idle (although idle was at 1200rpm). Now, the car attempts to start, but no joy. Car is still warm, so I tested compression. 110-115psi per rotor, even pressure pulses on all faces. I'm ruling out compression.

I read during my searches about a possible problem with heat soak in the CAS? Anyone have any experience with that?

1SWEET7

iTrader: (1)

Never heard of heat soak in the CAS. I still say get the injectors cleaned, it can't hurt at least. Good to see your getting acquainted with the UIM removal process. You can do it pretty quick after a few times. I just hate that damn coolant hose.

OustedFairlady

No more coolant hose. I got rid of it. I'm fairly quick at removing the UIM now. Took me about thirty minutes.

I only read about CAS heat soak once, somewhere on the forums, but I can't remember where. I'm going to send the injectors off soon for cleaning. The car doesn't have a gross lack of power now, it seems. Just won't start after I shut it down. It's odd. Any ideas?

IanS

iTrader: (4)

Sounds like sticking injectors to me. It seems as though they arent closing completely and any excess fuel pressure is being bled off when you shut down causing a flood in the engine. This would explain your lack of start up after you shut down.

OustedFairlady

Would this be near instantaneous? Even if I shut it down and IMMEDIATELY restart, it won't do it. I'll have to make a video of it.

OustedFairlady

Just drove the car again. Same exact set of problems. Will not start after running, lack of power, 3500rpm STALL (as in, the car just stops. it's like an ignition cut at 3500RPM). I haven't spent any money at this point. I've repaired what I can, so now, I'm going to get a set of injectors, or send mine off for repairs. I'll likely buy a set from eBay or something.

I'll be doing a fuel pressure test tomorrow, just to see if the car loses fuel pressure through an injector. I know it'd only tell me if there was a leak and not where, but I'm just going to assume a bad injector before a bad pump and get them. If the pump was bad, I'll just replace it too.

alritzer

Is the engine hot when this happens? Maybe check the water temperature sensor. If its bad the ecu will try to start the engine with too much qas.

OustedFairlady

Well, sorry for the lack of any sort of updates...

I figured out what the problem was. The front primary and both secondary injectors were all stuck closed. I.E., no fuel at all. It was running all this time on the rear rotor.

I installed a set of supra 440cc injectors for the time being, just to get the car to move, and it runs alright. Not well, just alright.

The idle is all funny now. It tends to surge, which makes me think vacuum leak, so I'm going to delete the rat's nest and as much of the vacuum stuff as possible, as well as check all of the hoses. I'm also thinking that the 440s aren't supplying the engine with nearly enough fuel, so I'm not driving it much. I put 93 to help offset the lean mixture and cut down on detonation.

In any case, I'm definitely sold on the rotary. I had intended to put a piston engine of some sort in it, but that idea flew out the window the first time i drove it.

OustedFairlady

My frustration level is coming to a head.

I pulled the UIM again today, to replace an extremely leaky secondary injector O ring. After replacing said o-ring, the car is again running on a single rotor, doesn't idle, and refuses to stay running. I am incredibly aggravated.

I'm suspecting the rat's nest is Culprit #1 in this case, as the car exhibits some symptoms of either a massive vacuum leak or a collection of small vacuum leaks.

The TPS is plugged in, all vacuum lines are plugged in, the injectors are working just fine, and the plugs are all firing. The engine revs slowly, bogs horrible, doesn't run right, and dies unless it's made to idle, and is difficult to start, to boot.

Any ideas? I'm all out here.

When I pulled the car into the shop before removing the UIM, it ran fairly well. Wonky idle, but both rotors making power and the car was revving as it should. Maybe I screwed up somewhere, but I'm just not seeing it. It was a straightforward procedure; remove UIM, install o-ring, reinstall UIM, crank. Now I'm getting nothing, again.

Help!