Suggestions taken about haunted electrics

[NightFlight]

Hi,

The electrics on my 1991 Seca worked fine until a few months ago, since then they've been pretty odd.

1) Battery keeps going flat (down to 4 volts charge), I was about to replace it when my mechanic said it was an old generator fan belt slipping & not charging, so that was changed. No improvement. Total Russian roulette on starting the car.

I've ditched the 1st mechanic (too many bad things there). A separate one checked the current from the generator to battery & pronounced it fine. So getting a new battery next week.

But there are other things I wonder about.....

When the car is idling it sits at 600RPM and all electrical systems are on half power. It wasn't like that before a few months ago.

Often when left on its own it will cycle between 600-700 RPM and the headlights, radio and any other electrical system will go closer to full power at 700RPM.

But these are only basic electrics like running lights, interior light & radio.

If I rev the engine over 700 RPM then all systems run at full power, including the headlights, electric windows etc.

There doesn't seem to be enough juice being supplied for even basic electrics below 700RPM. This is certainly even before bringing in a real heavy like Aircon, that saps everything and even slows down the engine noticeably while driving. Aircon used to be a fuel guzzler but didn't affect engine performance appreciably (no ageist jokes pleez! ;) ). But anyway haven't been running Aircon for weeks, that's not a major issue here.

All these changes in the electrics happened after there was a service done where the ignition lead set and cap were changed, along with a new set of plugs installed, again, some months ago by the original mechanic.

The engine has run fine since then but the electrics have gone to hell along with the battery which is about a year old.

[chef]

Hi,

The electrics on my 1991 Seca worked fine until a few months ago, since then they've been pretty odd.

1) Battery keeps going flat (down to 4 volts charge), I was about to replace it when my mechanic said it was an old generator fan belt slipping & not charging, so that was changed. No improvement. Total Russian roulette on starting the car.

I've ditched the 1st mechanic (too many bad things there). A separate one checked the current from the generator to battery & pronounced it fine. So getting a new battery next week.

But there are other things I wonder about.....

When the car is idling it sits at 600RPM and all electrical systems are on half power. It wasn't like that before a few months ago.

Often when left on its own it will cycle between 600-700 RPM and the headlights, radio and any other electrical system will go closer to full power at 700RPM.

But these are only basic electrics like running lights, interior light & radio.

If I rev the engine over 700 RPM then all systems run at full power, including the headlights, electric windows etc.

There doesn't seem to be enough juice being supplied for even basic electrics below 700RPM. This is certainly even before bringing in a real heavy like Aircon, that saps everything and even slows down the engine noticeably while driving. Aircon used to be a fuel guzzler but didn't affect engine performance appreciably (no ageist jokes pleez! ;) ). But anyway haven't been running Aircon for weeks, that's not a major issue here.

All these changes in the electrics happened after there was a service done where the ignition lead set and cap were changed, along with a new set of plugs installed, again, some months ago by the original mechanic.

The engine has run fine since then but the electrics have gone to hell along with the battery which is about a year old.

Sounds like a stuffed alternator.A new one should fix electrical problems.

[Rolla Boy]

Sounds like the timing is off to me...

Your idle should be 800rpm...

600rpm is too low and will be causing loss of power supply to your electrics...

[NightFlight]

Sounds like the timing is off to me...

Your idle should be 800rpm...

600rpm is too low and will be causing loss of power supply to your electrics...

Every expert I've spoken to has a different explanation for this one.

It hasn't been helped by the budget for the last six months being blown by the car's original mechanic playing extremely dodgy & time consuming games that have completely missed this electrical problem or whatever it is.

I've been to two different mechs since him just fixing problems caused by the first one, and he's a very well respected one on the Northern Beaches.

ANYWAY, if the idle speed at 600 RPMs (& it sometimes cycles up to 700) is too slow, where is the fault causing that? What controls the idle speed?

So at present it's either

1) The alternator, possibly the low speed phase?

or 2) A timing problem causing the idle speed to be too low.

Whatever it is it's affecting other systems: in the last hot month the cooling fan failed to engage in time and the radiator coolant boiled, blowing out the radiator at points where someone had stabbed the radiator with a screwdriver. (I can guess who, or at least one of his idiot apprentice techs, probably when the oil filter was last changed)

The radiator's got to be replaced as well now....

So I've either got to get the alternator or whatever controls the timing replaced to get the electrics right.

The battery is unlikely to be at fault then, no point replacing that?

Edited March 14, 2010 by NightFlight

[CHA54]

have you got a 4afe or 4afc? If it's a 4afe then open the throttle bypass screw up until the idle is at 800rpm when hot, then switch the aircon on and adjust the AC idle-up valve until the idle is 850rpm.

[NightFlight]

Sounds like the timing is off to me...

Your idle should be 800rpm...

600rpm is too low and will be causing loss of power supply to your electrics...

OK so did my own voltmeter test on the system:

1) Before start battery is at a lousy 4.3 volts.

2) Start engine (with the help of a charger).

3) WTH! Idle RPMs are now at 1000! Havn't seen that in months. Has it been lkistening to you Rolla?

4) Anyway I rev the engine to 2000RPMs for a few minutes and check the battery voltage: 13.5 volts.

5) Next I run a few systems, electric windowup & down a few times.

6) Battery voltage check: now 6.5 volts. - That's notta good is it? What does that mean?

7) Rev engine again for more minutes at 2000RPMs & battery returns to 13.5 volts.

8) Idle speed settles to 900RPM. It's not doing the 600-700 RPM shuffle today.

Keep it at 900 RPM.

9) Run Blower fan for 3 mins (not aircon) - battery down to 10.4v

10) Run Aircon with fan at max & coldest setting for 5 mins - battery goes down to 9 volts. Turn off engine & battery goes down to 5 volts.

11) Leave idling at 900RPM and battery comes back up to 13.5 volts after 5 minutes.

12) New knocking sound I haven't heard before from engine, sounds like popping steam, but the coolant is fine.

13) Anyway leave for a few minutes and engine starts fine on battery power.

14) Try again and no start. Battery now down to 5.5 volts.

What to make of all THAT......

There seems to be recharge current getting to the battery.

It looks like the battery just isn't holding a charge reliably.

But the idle speed of 900RPM is like back before the electrics went whacked after that service. What does control that?

Edited March 14, 2010 by NightFlight

[NightFlight]

have you got a 4afe or 4afc? If it's a 4afe then open the throttle bypass screw up until the idle is at 800rpm when hot, then switch the aircon on and adjust the AC idle-up valve until the idle is 850rpm.

It's a 4A-FE.

I went out to the car again after leaving it to cool for about 10 minutes.

Battery now at 10.4 volts, it is all over the place, was 5.5v just after I last switched off.

It just managed to start on that. Does it stress the starter system starting under 12v do you think?

The idle RPMs are now back to 700.

Did another 4 starts, (battery held this time, but no load on it between starts). Yes revs back to the recent performance: starts actually at 1000RPM & then drops off to 700RPM. It held at 900RPMs all through those tests. No idea why.

Should have restarted the engine to see if it was a one off for that for all that testing, still it does show performance at a 900RPM idle.

You'll have to direct me to the throttle bypass screw & the AC idle-up valve.

Edited March 14, 2010 by NightFlight

[NightFlight]

have you got a 4afe or 4afc? If it's a 4afe then open the throttle bypass screw up until the idle is at 800rpm when hot, then switch the aircon on and adjust the AC idle-up valve until the idle is 850rpm.

Here's the 4A-FE engine.

Can anyone direct me to the throttle bypass screw & the AC idle-up valve?

[NightFlight]

Do these test results say yay or nay for the battery?

Sounds like the timing is off to me...

Your idle should be 800rpm...

600rpm is too low and will be causing loss of power supply to your electrics...

OK so did my own voltmeter test on the system:

1) Before start battery is at a lousy 4.3 volts.

2) Start engine (with the help of a charger).

3) WTH! Idle RPMs are now at 1000! Havn't seen that in months. Has it been lkistening to you Rolla?

4) Anyway I rev the engine to 2000RPMs for a few minutes and check the battery voltage: 13.5 volts.

5) Next I run a few systems, electric windowup & down a few times.

6) Battery voltage check: now 6.5 volts. - That's notta good is it? What does that mean?

7) Rev engine again for more minutes at 2000RPMs & battery returns to 13.5 volts.

8) Idle speed settles to 900RPM. It's not doing the 600-700 RPM shuffle today.

Keep it at 900 RPM.

9) Run Blower fan for 3 mins (not aircon) - battery down to 10.4v

10) Run Aircon with fan at max & coldest setting for 5 mins - battery goes down to 9 volts. Turn off engine & battery goes down to 5 volts.

11) Leave idling at 900RPM and battery comes back up to 13.5 volts after 5 minutes.

12) New knocking sound I haven't heard before from engine, sounds like popping steam, but the coolant is fine.

13) Anyway leave for a few minutes and engine starts fine on battery power.

14) Try again and no start. Battery now down to 5.5 volts.

What to make of all THAT......

There seems to be recharge current getting to the battery.

It looks like the battery just isn't holding a charge reliably.

But the idle speed of 900RPM is like back before the electrics went whacked after that service. What does control that?

[Dave89]

Lead-acid batteries (like the ones found in cars) dont like being discharged too low, you've got to remember the battery is only there to start your car, after that the alternator should supply more then enough power for all your car systems.

It takes a huge amount of current for your starter motor to turn your engine and start your engine firing.

Charge voltage is around 13.5-14.5 volts, so if you are reading that (which you are) then that means your alternator is charging your battery, and if it wasn't supplying enough charge current then your "alternator light" on your dashboar would illuminate.

-That charge voltage is what is read when your engine RPM is higher than idle...such as 2000rpm or higher.

The longer/higher you run your engine, the more power that is generated by the alternator is which to charge your battery....

As i said batteries dont like to be run down to low, if you've read anything less that about 8 volts then your battery cells are possibly getting damaged, so if your battery has spent a lot of time discharged, my recommendation is get a new battery, if you run big stereo's, amps, subwoofers, suggest getting a bigger battery?

the dimming lights/"half power electrics" is because you are drawing more current then the battery/alternator can output, so if thats because your idle speed is too low and your battery can't hold a good charge because the cells are damaged.

Wind up your idle speed a little and replace battery.

Also, a good sign of a dieing battery is "sluggish" starting of the engine, batteries will also perform worse is cold weather than in warm weather.

[NightFlight]

Lead-acid batteries (like the ones found in cars) dont like being discharged too low, you've got to remember the battery is only there to start your car, after that the alternator should supply more then enough power for all your car systems.

It takes a huge amount of current for your starter motor to turn your engine and start your engine firing.

Snip

Also, a good sign of a dieing battery is "sluggish" starting of the engine, batteries will also perform worse is cold weather than in warm weather.

Thanks for that Dave89.

Actually reading Toyota's own material about the electrical system, the battery does have a bit more to do than start the car. It does have a hand in power regulation and also gets called in at low speeds when heavier electrics are turned on.

This may explain some of the odd behavior of recent months, as well as that caused by the rev problem.

Toyota's "Toyota Charging Systems" pdf file goes into it.

Anyway I got another tech to come over & do a thorough test of the electric systems.

He thought the battery was fine at first (loose battery connector lecture). Then the battery died after acting like a little angel for a few cycles. Big surprise! ;) The battery is going:

I like the look of the new Century NS60 to replace it.

Alternator tested fine at all stages: phew!

The low rev problem was more complicated. It is actually pretty erratic, and is much worse when the car is idling in DRIVE than in PARK (pretty nasty at traffic lights).

It varied from a start at 1000RPM, dropping to the 600RPM level I'd often get at those traffic lights.

The tech's verdict is that the THROTTLE BODY needs cleaning.

He wants to wait for the radiator to be replaced before he does that though, & I'm in the market for the replacement that.

So it's come down to 1) Replace the battery 2) Replace the stabbed and exploded radiator and then 3) clean the throttle body.

I hope that gets the dear auto back to it's former reliability!

TOTALLY RANDOM STAR TREK REALISATION:

BTW. I just thought - you know how they always used gadgets called "Tricorders" on Star Trek. I wondered why they called them "Tricorders" since they seemed to record fricking well over thousands of weird type ****.

Possibly they are an in joke on the Voltmeters that all present day techs carry as their basic portable "Sensor" equipment: which are in fact TRICorders: measuring voltage, current and resistance.....

Bring that up at the next party that has the right crowd present.. but only the right crowd