lights flickereing

[ITSME4G63]

Hey guys,

I've noticed this problem jsut yesterday, I dont know if its really a problem but here ti goes:

Sometimes at idle or when I drive I notice the faces gages lights kind of flickering, not on and off, but pulsating more like it, and then I see my boost gage light does the same, my fuel pump makes a different noise whenever the pulasting happens and even if I turn the dome lights on theyre affectred by it too . what could it be?

 

[JayJones]

Do the lights get dim at idel and brighter while moving?

 

[luv2rallye]

Bad alternator (internal regulator or rectifier shot).

 

[GTM]

Hey guys,

I've noticed this problem jsut yesterday, I dont know if its really a problem but here ti goes:

Sometimes at idle or when I drive I notice the faces gages lights kind of flickering, not on and off, but pulsating more like it, and then I see my boost gage light does the same, my fuel pump makes a different noise whenever the pulasting happens and even if I turn the dome lights on theyre affectred by it too . what could it be?

Dirty battery cables, bad battery, failing alternator, B+ lead loose on alternator, loose mains fuse. And a bunch of other possibilities.

Cheers,
GTM

 

[ITSME4G63]

Yeah the alternator went out last week, so we replaced it with one that came out of a dsm with 88k miles. Ill check the battery grounds today thanks. any more input appreciated.

 

[GTM]

Yeah the alternator went out last week, so we replaced it with one that came out of a dsm with 88k miles. Ill check the battery grounds today thanks. any more input appreciated.

Woops, another obvious condition missed. Check alternator belt tension. What was wrong with the other Alternator, maybe you should take a close look at the battery putting too much load on the system. Do you have radio amplifier?

Cheers,
GTM

 

[ITSME4G63]

battery is like half a year old, according to the turbo timer, the voltage is anywhere from 13.8 to 14.2 its jumps around, unless the turbo timer dont read battery voltage and I just sounded like a dummbass

 

[GTM]

battery is like half a year old, according to the turbo timer, the voltage is anywhere from 13.8 to 14.2 its jumps around, unless the turbo timer dont read battery voltage and I just sounded like a dummbass

I don't know where you got the numbers but that is within spec.

Do check the plug and wires for the field circuit on the back of the Alternator.

Was the old Alternator doing the same thing or had it failed for other reasons. You can go to one of the chain auto part stores and have them check for free. I'm trying to get some history here to determine if you have another problem which keeps taking out Alternators. How long has this been going on if that's relevant.

Cheers,
GTM

 

[ITSME4G63]

well the old original alternator took a shit, I think it just took a shit cause it took a shit, was old, but with the old one, my face gages (speedo rpms etc) would dim soemtimes. and one day I turned the car on and all the dash lights were on, aww shit the alternators bad. After driving around back and forth to skool all day adn then somewhere else with my mom I was going to my friends house (in order to change the alternator) running off my abttery and finally it gave away. So we got the alternator off another talon (parts car)and put it on my car. Had to push start it and it fired right up. The lights werent pulasting or anythin then and my face gages didnt dim no more. I just noticed this pulsating on saturday.

 

[GTM]

...
The lights werent pulasting or anythin then and my face gages didnt dim no more. I just noticed this pulsating on saturday.

I'd look for problems with grounds, engine/firewall, body, transmission, dash. Harness connectors, fuse box. Spray with WD-40, loosen and tighten a couple of times, harness connectors pull apart and reseat. Does the radiator to core support have one?

Cheers,
GTM

 

[ITSME4G63]

I have to check, one this is too though, that the fuel pump doesnt have that progressive hummm, its a pulsatign humm for example normally it would be like :


hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

but now its like



humhumhumhumhumhumhumhumhumhumhumhumhum

the only thing not affected by this is the cd player, the lights on it dont pulsate/dim, its a aftermarket sony one, even the light on the turbo timer pulsates.

 

[GTM]

I have to check, one this is too though, that the fuel pump doesnt have that progressive hummm, its a pulsatign humm for example normally it would be like :

hummmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

but now its like

humhumhumhumhumhumhumhumhumhumhumhumhum

the only thing not affected by this is the cd player, the lights on it dont pulsate/dim, its a aftermarket sony one, even the light on the turbo timer pulsates.

Yup, bit confusing. The CD will have a good regulating circuit design so it produces a pure stabalized DC circuit so the disk doesn't spin faster or slower just for these reasons.

Really, about the only circuit that I can think of is the meter regulator which is pretty elementary in design. If you know how a turn signal flasher works this is much along the same lines. You will have to look at a manual / schematic, look at the temp gauge and follow it from the sender back through the gauge to the power source. Hopefully you will see something labeled regulator, other gauges such as oil pressure and gas gauge will also be tied into this unit. The problem I'm having with this is the gauges draw very little current whereas the fuel pump would be on the magnitude of 10x.

Alternator brushes don't behave this way, neither do diodes, the alternator voltage regulator yes, but why now. You didn't hook jumper cables up backwards for a moment??

A shorted diode will give something like a 60 cycle hum not pulsating. See if you can find some test information on the voltage regulator.

Cheers,
GTM

 

[ITSME4G63]

nope i didnt hook jumper cables up, we push started the car, would a bad or failing fuel pump cause this?

 

[NeoStreamGSX]

not the fuel pump. it is the alternator. needs to be replaced w/ a new or rebuilt one, not another used one. your voltage regulator is bad...not good to drive on cause what you dont see is your fuel pressure not staying constant because of ur fuel pump is not getting consistant voltage.

 

[GTM]

...
would a bad or failing fuel pump cause this?

Yegads, a fuel pressure check should have shown low pressure.

It's been 20+ years since I've seen one that did this BUT yes!!!

The commutator gets bad and the brushes start to skip over the bad section. Frequently the pump will stop on the bad spot and you can give it a smack with a hammer which will jarr the brushes enough to start. Combined with pressure regulator resisting or rails having to fill. Only when the pump gets warm is this happening.

Cheers,
GTM

 

[ITSME4G63]

no, its pulsates nonstop, the fuel pump does it even if its cold or not. That pulsating hum, it synchronizes with the lights pulsating.

 

[GTM]

no, its pulsates nonstop, the fuel pump does it even if its cold or not. That pulsating hum, it synchronizes with the lights pulsating.

Understood, I didn't write it that clearly. I've got a half dozen problems going at the same time and it's hard to keep score.

Beg, borrow, or steal another pump new or used. I don't know what these look like so don't know if they can be serviced. Presumably they run in gasoline including the armature and brushes which helps keep them cool. So running them low on gas can speed up the failure incidence. As I mentioned before it's been a long time since I've seen one behave like this and it just escaped my memory until you prodded me. I'm not comfortable with saying 99% certainty this is the problem but it makes the most sense because it fits the conditions you have offered. You can dig around the wrecking yards looking for one that maybe has been changed.

Cheers,
GTM

 

[ITSME4G63]

Ive been itching to put a new fuel pump in this car, and this just made it better for me, I will try to have the new one in this weekend.

 

[GTM]

Ive been itching to put a new fuel pump in this car, and this just made it better for me, I will try to have the new one in this weekend.

If the pump is outside the tank don't forget to pinch off the inlet hose with vice grips etc, don't kill the hose with too much pressure or you will be draining the tank. Also don't let it go down your shirt collar or on your crotch for you will have something to explain to you wife or girl friend... If it isn't primed it wouldn't hurt to prime it a bit, you can use gas or kerosene. You can pull the starter solenoid wire and hold in crank for 10 or 15 seconds just so you can flush the system a bit, if close to filter change now is the time.

Have fun, let us know how it goes.

Cheers,
GTM

 

[NeoStreamGSX]

there is no need for a fuel pump change. what you need to do is change the ALTERNATOR.

 

[thebird_19]

I agree with the alternator problem. I don't see how a fuel pump can cause lights to flicker. It definately sounds like an electrical problem and since in didn't start until you change the alternator, that seems like the obvious start point. It could be charging but skipping or hanging a bit. I just put a new one on mine, because it had a good voltage readout, but it and a hang spot. Corroded battery cables can do it to and it could be inside the insulation where you can't see it, so you might want to check that.

 

[butane]

there is no need for a fuel pump change. what you need to do is change the ALTERNATOR.

^^^ AGREED!
Or at least take the car to get the electrical system tested.
I ran into this problem on my 1G a while back (2+ years) and you know what ended up solving my problem? Replacing my battery post connectors and checking all of my grounds.

I am baffled at how this turned into a thread where you blame a fuel pump for voltage irregularities..?!?! Does not compute.. not one bit.

 

[GTM]

^^^ AGREED!
...

I am baffled at how this turned into a thread where you blame a fuel pump for voltage irregularities..?!?! Does not compute.. not one bit.

I don't suppose it could be experience????

I did explain in an earlier post how an why I've switch from alternator to fuel pump. Gonna be a lot of virtual beers moving around on this one. hehehe
................

Here are a couple of quickies to isolate which end of the car he needs to spend money. Put your hand on each while the engine is running. (nonono not at the same time) With a listening device ... mechanics stethoscope, screwdriver, wooden dowel place on the component in question other end at ear.

With a fully charged battery, take the B+ lead off the alternator and start the car. Loosen or remove the drive belt and start the car.

Lastly, take the starter wire off the selonoid and turn the key to crank.

Certainly one of those will produce positive results and can be done in under 2 minutes.

Cheers,
GTM

 

[butane]

I don't suppose it could be experience????

Maybe, but you are not the only one on this board who has been working on DSM's for years and years. Myself and countless others on this board have been too.

IMO, this dude is asking a relatively simple question and you are complicating things. Plain and simple.
The sound from the fuel pump is most likely the fact that there is low voltage to it causing it to whine. I have seen it on a few DSM's and the alternator is to blame 90% of the time.

What he needs to do:
- Have the alternator checked out and replace if necessary.
- Check belt tension and tighten if necessary.
- Have the battery checked out and replace if necessary.
- Clean the battery terminals and replace the post connectors.
- Check the ground wires everywhere.

If none of the above yields any results, THEN he can start poking his ear around the engine bay with a wooden dowel attached. Speaking of which.. can you elaborate on this:

Here are a couple of quickies to isolate which end of the car he needs to spend money. Put your hand on each while the engine is running. (nonono not at the same time) With a listening device ... mechanics stethoscope, screwdriver, wooden dowel place on the component in question other end at ear.

With a fully charged battery, take the B+ lead off the alternator and start the car. Loosen or remove the drive belt and start the car.

Lastly, take the starter wire off the selonoid and turn the key to crank.

No offense but it is pretty incoherent. I understand a little bit about what you are trying to convey but for the most part, I don't understand what results these tests are expected to yield. I am not being mean at all but if you are going to give advice, it needs to be displayed in a way that people can understand.

-JP

 

[butane]

Perhaps the difference is I did it for a living or does that not qualify. Now just for the record so you will feel justified I have looked under the hood of exactly 2 running DSMs, 1 was my son's and the other his friend's.

Congrats on being a mechanic. Unfortunately, that doesn't mean anything (does not qualify). Parrots can be taught to speak english too.. Does that mean they are humans, no. I was merely trying to help the guy who originally posted with this problem, I.E. getting you to explain your testing procedures a little better. The bad part is that you took what I said as an opportunity to start talking $hit. Fair enough.

It took you longer to write your response than it would have to make at least any one of the tests which would locate the problem. I thought they were fairly concise and self explanitory but for your edification when an alternator exhibits certain malfunctions they will sing or produce sounds. With limited tools and facilities you use what's available including touch for they will impart a vibration rather than smooth operation. Either you have not been around enough alternators or not listening.

My whole point is your post looked like something a 9 year old would write. Your "procedures" were nothing but a couple of sentences slapped together in a half-assed manner. I'm sorry but you REALLY need to be more clear in posts like that. We are all happy that you are the end all be all of alternator knowledge but if you really want to help at least give the guy steps to follow. Not this:

"Here are a couple of quickies to isolate which end of the car he needs to spend money Which end of the car??? WTF are you talking about??. Put your hand on each while the engine is running. EACH WHAT?(nonono not at the same time) Not at the same time what? the rear bumper and the front bumper??With a listening device ... mechanics stethoscope, screwdriver, wooden dowel place on the component in question other end at ear. What component? The battery is in question. Does he listen to that?

I'm always open to ideas and the most cost effective and efficient method to solve a problem. What I offed was no expense, took 2 minutes to conduct.

If they made any sense, sure. Have at it. But speaking of cost effective, all of the major chain auto parts stores offer free battery, alternator, starter testing, etc. etc..

While I fully admit that I am getting old and don't always remember everything I ever learned I seriously doubt that we are on the same playing field. I was invited to be a Wiseman not a wise arse, you can view my profile, view the threads and come to your own conclusions. It's unfortunate that some people just have to try to run someone down to try to bolster their own cause or inadequacy.

Your profile means nothing to me. Just because I never post here means nothing. I am much more active on the regional list. AND was very active on DSMTalk.. Honestly, you have no idea how many local DSMs have been fixed in my garage. More than 2, I can tell you that. And I wasn't trying to run anyone down. I posted because I literally JUST (within 3 days) fixed this problem on another DSM. I was trying to save this poor guy from falling down the "Check a bazillion things and ignore the most obvious" hole that you were helping him down.

As for your question about the wooden dowel it's common knowledge they make instruments out of wood because it has sound transmitting qualities. A 1/4"-3/8" dowel bought from the hardward store for 59¢ makes a valuable tool for performing a variety of tasks including listening for all kinds of sounds. But you knew that and of course why a metal tool poses certain hazards. In larger sizes they can be used for removing and installing seals, bearings, gears etc. just as a 2x4 and a 5 lb sledge has it's uses for breaking loose rusted pistons loose.

I know wood is a great tool when doing maint. on a car. I am a huge proponent of using wood for seals, etc. What I am saying is (again) what is the point of *listening* to your alternator when you can take it to get tested for free and get a REAL answer as to the voltage output. As opposed to putting your ear on it and listening for sounds.

As long as I'm on my soapbox it's people with attitudes that cause experts to abandon trying to help people here. I looked at your profile "Test Engineer/Net Admin." I owned and operated a national networked BBS for 12 years straight, built my first modem over 25 years ago and wrote the code to operate it. So I guess it's the "Test Engineer" that allows you to be more qualified than this old fart that ain't had the benefit of no fancy schools that give me a title.

The community doesn't need a bunch of self proclaimed "experts". What they need is help fixing their problems. People like you let their egos get out of control to the point where they cannot take any constructive crits. I was offering up advice to the original poster and to you in how you approach posting your "procedures". Thats it. Instead you decided to flex your (assumed) cranial muscles and make us younger guys feel like idiots. If you have some kind of strange domination thing toward other men, that is your business but I HIGHLY suggest you learn to take some advice instead of firing back with a bunch of insults.

And Now I will borrow your soapbox...
WTF does my job have to do with anything? You think your dick is bigger because you ran a bunch of BBS for 12 years? Big deal. I am 24 and know more about DEC and VMS systems than most guys that have been using them for 20 years. Not to mention operating systems that have been released since those dinosaurs. And I used to walk to work in 2 feet of snow.. up hill both ways.. with one shoe and no lunch. I think that is how it goes.

Either way, if you want to continue this chat, take it to PMs. We've broken the rules enough..

4. No getting off-topic - if you're not replying to the thread starter, take it to PMs/email or start a new thread.