Heap Light On, RPM Drops !!

[siangmh]

Head Light On, RPM Drops !!

Hi all sifus, newbie here, please help me, thank you a million in advance.

Car:

yr2000 P.Wira 1.5(A) EFI sedan


Problems:

1) When i switch on head light, my RPM drops significantly, worse if combine with a/cond compressor running + engage in D gear + car stagnant (eg stop during red light), even worse if sudden brake, rpm drops so low until engine like wanted to stall anytime. When idling in N level without a/cond, RPM is ok, around 850, running smooth & steady as before.

2) Fuel consumption worsen after recent installations (see below) :<


What recently did to my car:

1) change alternator to non-ori 90A type (ori is 80A), -ve terminal of batt dismantled for half an hr while installation, after installed immediately tested that it charging batt @ 14.x V while head light & a/cond turn on. I didn't change alternator belt, just use back d ori belt.

2) change both head light bulb twice, fr ori Philips to Narva 4500k, after few days then change back to ori philips, both (60W/55), also tried installed HID for few minutes for demo by accs shop, then uninstalled it.

3) change fog light, left side fog light wire cut & rejointed, as d lousy accs ppl cant pull out the wire's socket-joint thru bumper hole

Besides, the moment when turn on key to ignite engine, i can hear a sound like belt squeeking, only last for 0.5 second then gone when engine starts running.Dunno which belt, but i suspect its d alternator belt. :<

So, Sifus, what problems is this? wiring messed-up? tuning out? belt too tight/loose? ECU reset? (0.5hr disconnect batt can reset ECU already?)

Pls advice

 

[xavier]

You can try to adjust the idling nut. Increase the RPM for idling by a bit, say 1/4 round, anti-clock wise. Ur situation was similar to my idling situation, but after increasing the idling by a bit, it was ok. Urs, 850, can increase to 950 liddat, coz if u put into D with brake, the RPM should drop to about 850 liddat.

Then you can go buy the belting spray less than rm20 from Enos, spray on the belts. That should get rid of the belt squeeks. If not, can also use WD40.

Just my 20 cents. Hope it will help a little.

 

[siangmh]

Thank Xavier Bro.

I think if increase idling just like that can't cure my problem. Last time when engage D gear, the RPM dont drop so much, only little bit, even a/cond kicks in also no problem. Besides, last time the ECU smart enough to hold-up higher RPM when engage on a/cond.

All the while 850 RPM (tuned by PDA look-a-like gadget by Mech) is very stable. If adjust higher, then increase fuel consumption yet cant solve the root cause of the problem?

Regarding lubricant for belt, i dont think that shld be as primary solution, bcos before this there is no belt sound at all. Besides, the belt sound is less then a second, just happen when d starter crank d engine....dunno if its due to tension or not?

How Mech knows how much tension (for belt) is good enough when they install alternator? Guessing only right?

 

[howiechoo]

use wd40 on belt is a stupid idea..it will crack ur belt when it dry and hot...

 

[xavier]

Stupid??? Who's stupid???!

use wd40 on belt is a stupid idea..it will crack ur belt when it dry and hot...

Tai Lor... Me and my friends have been using WD-40 for a long time already la... I have been spraying it on the belt once a week or once in 2 weeks on the same car for 2 years plus! My old car, for another 2 years plus before I sold it. Only change the blet when it's old. Besides that NO PROBLEM leh... NO CRACK... PLUS NO BELTING NOISE@!

U sure will crack meh? What makes you say so? What chemical inside will make it dry and crack? Maybe yours crack la, not mine . Nyways, can use other more specialized belting spray mah. Hmmms... :shades_smile:

 

[siangmh]

Peace Bro :shades_smile:

About my problem, my guess is :

~ Alternator not installed with the right belt tension, probably too tight, as i was told by mech if belt too loose, belt sound will be consistently there (true?)

~ As batt disconnected for half an hr, ECU reset already? so engine tuning out also? but turn on lighting shld not affect tuning right? or lighting cables messed-up by accs ppl hence distord RPM when on lighting?

So, either 1 or both of above lead to consumed more engine power to drives those few inter-related pulleys, or out-tuned timing, hence wasted power & increase fuel consumption.

My previous fc is ave. 420km/[email protected], Best hit is 470km. (KL Jam 2 hr daily Mon-Fri, 2 pax on board, weekend 95% tmn road, lagi teruk. RM70 used to last about 1 week only)

Now, ONLY 300+km !! (for previous 1 week) sob sob...

Based on past experience, general mech no good in dianogstic in these kind of problem (wiring/tuning related), too difficult for them, either no knowledge or no gadget to identify what is d causes, usually just simply say this or that part faulty need replacement thats all...wasted $$ thru their trial & error, yet no guarantee can solve problem or not......

Me even have 1 night dream about my car problem until tidur pun tak lenyak...

Any Sifu can shed some light on whats wrong & solution.......or recommend a really skillful mech to me, preferbly located near to old klang road.

Thank a million in advance!! Thanks for reading as well, sigh.

 

[huakenny]

Tai Lor... Me and my friends have been using WD-40 for a long time already la... I have been spraying it on the belt once a week or once in 2 weeks on the same car for 2 years plus! My old car, for another 2 years plus before I sold it. Only change the blet when it's old. Besides that NO PROBLEM leh... NO CRACK... PLUS NO BELTING NOISE@!

U sure will crack meh? What makes you say so? What chemical inside will make it dry and crack? Maybe yours crack la, not mine . Nyways, can use other more specialized belting spray mah. Hmmms... :shades_smile:

to spray belt..there is another product to use...specicif for belt only...forgot the name...it is a sprayer...for belting only...can get it at spare parts shop around rm30 per can

 

[huakenny]

since u done so many things...just re-check all the things u hv done....

 

[siangmh]

since u done so many things...just re-check all the things u hv done....

Thanks huakenny tai kor.

I intend to send for wiring / timing checking, but very busy these days, somemore dunno where to find good Mech....:sad_smile:

Have u heard these kind of problem (i.e. lighting on, RPM drops) b4? Is it Wiring problem? or Tuning problem? or both?

 

[huakenny]

hmm...try to measure ur car voltage wit engine ON...and then ON all the electronic components n see the volt reading...

i suspect ur headlight dim due to insufficient volt...high resistance or alternator not enuf charge...since u juz change it...

my2cent...

 

[minikar]

Headlight on, rpm drop. How bout aircon on?

 

[siangmh]

hmm...try to measure ur car voltage wit engine ON...and then ON all the electronic components n see the volt reading...

i suspect ur headlight dim due to insufficient volt...high resistance or alternator not enuf charge...since u juz change it...

my2cent...

I did measured once after installed 90V alternator, reading batt charging about 14.XX with head light on & air cond (level 2) on.

So, is this reading good enough?

but one thing didn't change is when turn on a/cond, the head light will be slightly dimmer, the brightness difference is very very little and i thought it happen to all other protons, right?

If belt too tight, do u think it will drag/burden on engine? do u think loosen it a bit will be good idea? If were to be loosen a bit, by how much tension? judge by feeling?

Or shld i also add lubs/grease on all pulleys that involved? it could slip the belt also right if too much grease?

 

[siangmh]

Headlight on, rpm drop. How bout aircon on?

Yo minika bro,

a/cond does reduce the RPM, combo with head light on, teruk lar...:confused_smile:

When i sudden brake, not harsh one lar, the RPM would just drop so low untill engine want to die like that. Scare scare if really put load on my car & sudden brake during up hill climbing, die lor then......

If on a/cond alone without headlight, RPM drops a bit only, & RPM wont drop too low when sudden brake, it drops also back to idling range only, wont go lower.

So when on headlight at night, no good driving already :<

Have u experience head light on & RPM drops before? heard of it?

 

[siangmh]

Me cant take it no more, dont have the heart to see my car fall sick like that :_:

So i am going to send it for repair @ Saturday, see whether got luck to solve it or not, else just waste my $$ this weekend......

Hope luck is on my side...

 

[minikar]

My own experience:
If I on both, the engine almost die off at critical stage. I am in the same situation as you are in now before it get critical. >>>> one my valve toasted. Indication? Smell of petrol in exhaust, temp get slightly higer than normal. Or do compression test.

Not sure bout yours. It might also be the alternator/ air-con compressor dying soon, getting tighter and tighter on load.

 

[siangmh]

Bro minikar,

Mine tell me which valve ur talking about? is it one of the 12 valves on engine top? spoilt in what sense?

Will a near-to-kong alternator give these sort of problems (head light on, RPM drops)?

 

[siangmh]

Update:

Done tuning with PDA look-a-like gadget, cleaned TB, adjust a "screw" in TB, install back my old 80V alternator, lower d timing by twisting the electronic distributor clockwise......then d distortion of head light to RPM is now minimise, still there though, but minimise liao, engine wont want to stall like previously....

Is everybody's head light on will also lower their RPM? Please share with me....

 

[minikar]

Bro minikar,

Mine tell me which valve ur talking about? is it one of the 12 valves on engine top? spoilt in what sense?

Will a near-to-kong alternator give these sort of problems (head light on, RPM drops)?

yes is the (at least) one of the 12 valves leaking.

 

[staralliance]

Could it be caused by the throttle body ?

Thats why the RPM is so low ?

just my 2cents.

 

[siangmh]

Could it be caused by the throttle body ?

Thats why the RPM is so low ?

just my 2cents.

Dont think so lar. Bcos after wash the TB, problem would only reduce to:

1) Idling with a/cond on, then switch on head light, then RPM will still drops. If no a/cond then ok lar...

after wash TB is slightly better then b4, but much improve is only after i change back to 80V altornator, dunno due to what factor lar :Not_Impressed: ....... maybe d 90V altornator, maybe belt too tight....