Maroochy

Looks like the '84 GSL-SE is sick again. The motor had a total rebuild by a good rotary shop about 700 miles ago, but after about 500 miles it began acting up. Only a little at first, but it steadily got worse. The in-dash voltmeter reads low, even though the brand-new battery is kept fully charged to about 12.9V, as measured with a multimeter across the terminals. On the car's in-dash voltmeter, it reads 9-10V when not running but key in the ignition. It reads 11-12V when the car is running, due to the alternator. So I'm losing at least 2V whether the car is on or off. If I rev the engine, sometimes the voltage goes up slightly and stays up. When the directional is on, the voltage drops a little rises a little, drops a little, rises a little, etc. in sync with the blinking of the directional. If I lower the power windows, the voltage drops and the window motors lug.

At the same time the voltage issue popped up, the car starting running rough at startup. The revs would bounce up and down, it'd stall out if I didn't get on the throttle immediately and hold it there for a few moments, and the car would run richer than it normally should. ​​​​​​Sometimes the starter would have to spin a few too many times to start the car, even though the battery and starter were good. It didn't matter whether it was a cold start or a hot start. But after I'd start driving, the car would run fine. I'd pull to a stoplight and have no stalling problem, and the idle was rock steady at about 750 RPM. But if I turned the car off and started it up again, the stalling/richness problem would come right back. I drove it as little as I had to while I checked out a few things, but it got worse. The voltage kept dropping lower, and it started spewing more oily blue smoke out the exhaust while it idled at startup. It got to where there's a bad misfire now, so it's off the road. It went through more than a quart of oil in the last 50 miles. Which makes me worry about the rebuild.

As of this past spring, I'd checked the TPS and MAF, and they were well within spec according to the FSM. Also checked out the IAC and throttle body, and they functioned as they should. Also got both nice and clean. Fuel injectors were freshly rebuilt not long ago, and I'd replaced both connectors. When the motor was rebuilt, the idle was set (with the TPS, idle screw, etc.) and the car had no startup problems or unsteady idle for the first few hundred miles. The spark plugs, spark plug wiring, distributor cap, and distributor rotor are all only about a year old/<1000 miles old. There's some white powder on the contact points of the dist. cap and rotor, but I believe it's just a little oxidation I can clean off. The electrical grounds in the engine bay look fine and clean.

I know electrical problems can cause all kinds of running issues, so I'm hoping that when I track down the voltage drop it'll take care of the idle/stalling/richness/ oil consumption. Before I start going through everything wire by wire, is there anything in particular I should check out first?

diabolical1

iTrader: (3)

Have you checked the alternator?

Maroochy

That was my next guess, too. I've got a new one in a box here, and I took the old alt off this afternoon. I'll update tonight, as soon as I can get back out there.

Maroochy

Update: the new alternator didn't change anything

diabolical1

iTrader: (3)

Check to see if you've blown the ENGINE fuse.

GSLSEforme

What is the charge rate at the battery when running,engine/engine bay is cold. It SHOULD be about 14 volts,maybe slightly,no less. On cold engine 14.3-14.5 is optimal. Alt belt is tight enough? If battery readings are not within specs outlined,put positive lead of voltmeter on alternator battery output connector at alternator(thick white/red wire). What does it read,should be very close if not same reading taken at battery . Post your results.

Pull the dipstick and smell the oil for gas. All symptoms may be related. The oil consumption may be related to the hard start,rough running which sounds like it may be flooding on shutdown possibly from a leaky injector. Enough gas gets in the oil and it thins the oil enough that it can get past seals and burn,again the symptom of blue smoke from tailpipe. Put dipstick back in and check oil level,if enough gas has gotten in the oil it will raise oil level in engine

GSLSEforme

Pull ALL the plugs and inspect. Misfire you speak of could be fouled plug(s) from flooding(?) oil consumption.

LongDuck

GSLSEforme is on the right track (*as he usually is!), but I would recommend a few other things you could look at;

1) When starting, does the starter sound slow? The big wiring on these cars have to carry a current in spite of being almost 40yrs old. If you've never replaced the battery main leads for (+) and (-) then you should consider doing that as good maintenance. I installed a big *** negative ground directly from the battery (-) to the alternator bracket using one of those generic Battery Cable kits at Autozone of the desired length which solved a lot of dimming lights and other low voltage problems I was having. The cable runs along the wiring path of the stock loom just on top of the A/C bracket. Also, the (+) lead which goes to the starter is a 3ft long section which is exposed to the elements under this side of the engine and can get internally corroded, causing all kinds of starting problems.

2) Is the battery sized properly for the vehicle? When available, I ran a little dinky Optima Yellow Top meant for a Prius Starting battery because it weighed about 30lbs (vs. 45) and that left front corner is already overweight. It worked for about 9yrs without problems, but at the end it just died completely. Point being, if you have the right sized battery in there, and are sure it's fully charged - that's a good first step. A brand-new battery, fully charged, off the rack should read 13.8v. Hooked up in your car, it should still be above 13v before it hits your voltmeter, but keep in mind that the -SE voltmeter on the dash isn't exactly a precision device.

3) Running rich on startup is expected, as that's how the -SE works with the Double Throttle Butterfly valves in the intake to effect a choke function. The Thermowax Pellet uses engine coolant temp to mechanically open these choke plates in the intake once the engine is warmed up. The other method looks at the Coolant Temp sensor at the back of the Water Pump to define when the engine can come off of the startup map for Fuel Injection pulse duration. If that sensor is bad, the ECU will think the engine is cold all the time and spray more fuel. Normally, that startup sequence runs for 60sec on initial start with a standard rich map, and then the ECU monitors Coolant Temp via the sensor to drop out of startup mode. What's your mileage been like lately? You would notice this, trust me.

4) At a minimum, you're going to want new plugs in there. NGK BR8EQ14's are what most of us are running, and expect to replace them annually, as they will foul. You can clean them up once or twice, but by then the spark gap is off.

5) Have you shared this information with the engine builder? If the car was running really well when you got it back, if they're local, it might be worth a trip back to them to have them take a look at it. Personally, I doubt it's the engine that's the problem here.

Good luck, and you have some good leads to check out (pun),

Maroochy

Much appreciate all the collective effort. Thanks for chipping in, fellas. I forgot to mention I'd checked the fuses when the issue popped up, and none are blown. I also checked the oil a few times as the problem worsened (and when I kept having to add oil), and I didn't see or smell any gas in it. The oil on the dipstick looked normal. The alternator belt is new and tight, too. I'd assumed the plugs are fouled now because of all the blue smoke and misfire, but haven't pulled them yet. ​​​​​​I use BR8EQ14's normally, and that's what's in the car. I may as well order a new set. The battery is an Optima Red Top 35, 660CCA, and in good shape. The starter sounds ok and starts quickly, except for a rare few times where it's been slow to start, which only happened when the voltmeter read particularly low.

I know the SE runs a bit rich on startup by design, but before the car totally crapped out, the idle would smooth out as the engine temperature reached normal. So it's at least functioning to the degree that, after a cold start, it'll settle down once the engine hits normal temp, but I get the same stalling problem on hot starts, too, when the engine is already warm. When the issue got worse and the voltage dropped lower, I laid off using the car anymore than I had to, but I didn't notice any particularly huge change in MPG. I'm not confident in ruling it out, but it wasn't any enormous difference that knocked me over. I called the engine builder, but he said he had a ton of cars he'd have to get through before he could look at mine, and he's 150 miles away. So at least for now, I don't want to flatbed it out there just to sit for weeks. I'll get back out there tonight to measure the voltage at the alternator's positive.

diabolical1

iTrader: (3)

For your voltage issue: I like what LongDuck said (Item #1 of his post), so maybe look into doing what he described.

For the other issues: (1) are you still running original cats? (2) have you checked you oxygen sensor?

LongDuck

"Gee, I should get rid of some of these ground wires..." - Said nobody who has ever owned an RX7.

Maroochy

Good idea to check the alternator at the positive. With the car off, I got 12.5V. So it'd seem the battery cables are ok, and the issue is downstream of the alternator.

As far as the cat, I doubt it's on its original. I'm the fourth owner of the car, but a year or so ago I had an exhaust shop check everything out down there, and they said everything looked good. I haven't run the car enough with its problem to screw up the cat that quickly.

GSLSEforme