Tomkat80222

Well, I've had this beast that Tony77 created for a while and have had some fun, but I also have some issues. Nothing has been a big deal till Saturday afternoon. I drove the car in the morning and had no issues. I went to drive it that afternoon and it started real sluggish and was running at 200 rpm then died. The display read low oil pressure. Thought maybe a sensor detected low oil pressure and went into a safety mode. The next morning I got some oil and put in about a half quart to top it off. Started it up and all was well. Went to move it in the afternoon and again the low rpm and dies. Will not restart. Finally give it some gas and it starts. This morning it starts right up. I do have to disconnect the battery every time I leave the car for a while since the stereo drains the battery. Maybe the fuel pump is going??

The Deputy

How old is the battery? Seems strange that it starts good, after having the battery disconnected, but then doesn't start well...after it's been connected all day.

I'd charge the battery, load test, and if it checks out good, charge it again for twenty minutes and leave it connected in the car for the day, load test it again.

Brian.

Tomkat80222

The battery is always on a battery tender and brand new, so that is not an issue.

GregBBRD

One obvious potential isssue:

Each time the batttery gets disconnected, the system adaptation in the LH computer gets reset....which means the system needs time to re-adapt the computer. Perhaps you are not driving the car far enough for this to occur and the LH computer is confused?

Fix the stereo problem and leave the battery hooked up.

A common problem:

The idle stabilizer sticks closed when it is hot. The stabilzer might be working when the car is cold, but once it gets hot and you shut the car off, the stabilzer returns to it's fully closed position. If it sticks there, you will have very low idle until it unsticks...possibly not until it cools down.

Try some WD40 sprayed into the hose leading to the idle stabilizer and let it soak (turn off the car immediately after application.) See if this cures the problem, temporarily.

A really scary problem....unfortunately way too common:

If an automatic, the flexplate can push forward on the crankshaft, making the engine very difficult to rotate. It will crank slow and have a low idle. This will turn the engine into junk, very quickly.

Check the flexplate preload, if the car is an automatic.




There's a bunch of other possibilites, but these are where I would suggest starting, without seeing the car.

77tony

Hi Tom, First and foremost listen to what G.B. suggests above. FYI the last TB, WP, etc., was installed by Herman K and would guess within the last 6-7,000 miles. At that time the flex plate was checked, within spec and PKlamp added to prevent migration. Searched through my old GTS photo pics and below is the result. Would suggest taking your GTS to a reputable auto sound specialist to chase down that bug (sounds like a ground fault) in your sound system and get you back on the road T

The Deputy

Battery was a little over a month old in my 78 when I got it, previous owner said he still had to keep it on a tender or it would go dead, so I imagine it had gone dead a few times. I guess, it's easier to throw a tender on it...than to find the issue.

Found the glovebox light was staying on, repaired...system checked out good...no drain.

Battery, even disconnected would not hold a charge over night, it had been drained dead to many times already. Doesn't take more than four or five times of a battery being drained completely...to ruin it for life.

Since you know you have something draining the system, and the battery has possibly been run down, I'd still have it load tested, just to take it out of the equation.

Good luck,

Brian.

Tomkat80222

GB, I was wondering about the brain resetting. This happens in older Supras and takes some time to relearn AF mixtures. Especially when you have modded the engine. This is the first time this has happened, so I thought that by '94 they had figured out how to store the data when the battery is disconnected. I was concerned about the flexplate when I couldn't get it to start since it would not turn for long. I could hold the ignition on, but the starter would stop turning. But when I was able to start the car, it runs smoothly.

I had someone lined up to look at the stereo and now he is injured. I have another contact in the Colorado Springs and will take the car down there some weekend when I'm not taking the kids skiing. One of my sons in in a 20 weeks competitive program, so I have very little time to work on or drive the car in the winter.

When I was not able to start the car, both time the car was not warm. Maybe the cold start injector?

GregBBRD

No cold start injector after 1985, on USA cars.

Sounds like the flexplate "problem" has been looked at and preventative steps have been taken....so if the endplay was correctly measured and there was no problem, you can dismiss that. (I say "if" not to raise paranoia, but with the reality that "final stage" TBF failure has fooled me....several times. Seems that once the bearing thrust bearing gets stuck or has high resistance to movement on the crankshaft, the resistance to movement makes it really tough to measure the actual endplay. Please note: I would not normally bother even going down this mental road, given the information at hand....but the fact that the engine isn't happy about cranking over with a perfect battery concerns me. I would check that battery (as suggested above) and isolate the issue with this....before much more running.)

My best guess, if the thrust bearing is not an issue, would be a sticking idle stabilizer, when hot. That would certainly explain the low idle and low oil pressure light. The slow cranking will not be this, however.

Keep in mind that these cars take time to diagnosis when they are sitting in front of me....it's tough over the internet.

Landseer

Bad battery or battery ground strap will cause all of this. Ignore the apparent newness. BTDT.

Tomkat80222

I started it up today and I did notice the voltage level was low before starting and came up as soon as it started. So this may be the problem after all. I will make sure the battery is fully charged and get the stereo fixed soon. Thanks for all the help.

On another note, the brake light comes on when first started and then turns off as soon as you touch the brakes. No other issues with the brakes. Fluid level is fine.

ROG100

That is what it is supposed to do so not an issue.

77tony

Hi Tom, Check the 928sRus receipts found in file folder I left for you in the GTS. IIRC a new ground strap was installed approx. 5-6 years ago. Wouldn't hurt to check the battery ground strap as Chris recommends to be sure. T

Mongo

Has the car had an intake service yet? Could be the idle stabilizer valve as my 1987 did the exact same thing.

Tomkat80222

I went back and started the car and paid more attention to the volt meter. Turn key to on position and the voltage is just below 12. Fans come on and voltage drops a bit. Turn key to start the car and voltage drops to almost 10 volts. I understand that the volt meter may not be very accurate, but after the car starts, the volt meter reads high 13 volts. I failed to mention that I have a battery cut off. I checked and cleaned the connections on the battery strap with no signs of oxidation. I thought maybe the cut off was the problem and when I was removing the battery strap I did notice the mounting bolt for the cut off was not completely tight. I attached the strap without the cut off and checked the voltage on start up and the reading were the same. So, I just put it all back together and made sure all the connections were tight. I think this has fixed the problem, but I'm concerned about the voltage readings. Is this normal?

SteveG

I think your V readings may be indicating the problem. There are cheap batt cut offs that will wear out. I had one and took it out of the system. If you really need it for security purposes, I would try a new one and it should cost more than $10. Otherwise I would get rid of it. And clean all the grounds.