Toyota Liteace 5K Engine Misfire

[Izzie]

Greetings!

As per subject matter, I have isolated the misfire to Cylinder No.3 after a “spark” plug test. I’m getting a No Spark for that particular cylinder.

Steps taken:
1.Swapped the HT wires = no improvement.
2.Replaced the affected spark plug = no improvement.
3.Replaced contact point and condenser = no improvement.
4.Replaced ignition coil = no improvement.
5.Inspected and cleaned the distributor cap and rotor = no improvement.

The distributor is fairly new (8mos old). It was replaced, as suggested by the mechanic, because the van won’t start then.

I went to two auto shops. The first concluded that it needs a top overhaul. In the second auto shop, I request for a (dry) compression test and the results for all cylinders are okay. (No wet compression test was made.) But the second shop also concluded a top overhaul is needed.

I got confused so I did some research and the reasons for misfiring:
1.Loss of Spark
2.Improper Air/Fuel ratio.
3.Loss of Compression.

If we apply the “process of elimination”, I’m still at number one. There is no spark. So why a top overhaul is needed?
I’m at loss here so can anybody provide me some advice? I live in santolan, pasig. Can any fellow tsikoteers refer me to mechanic that’s within the area?

Thanks!

[jick.cejoco]

Check your points gap at four lobes of the distributor cam. Number three lobe might be worn out

[RIPmyBrother]

Hi !

My comment:
"To overhaul the Topend helps only to reduce the misfire problem in the wallet from the mechanic but not your engine".
;-)


Your steps from the trouble shooting where good and logical :shake:
After changing the parts (points, spark plugs, coil), swapping the HT wires and checking the compresion (all cylinder are good) it is logical that the problem is the distributor cap and finger.
Change the finger only because it is better to change it together with the cap (my experience).
You inspected and cleaned it but sometimes you cant see micro cracks in the plastik and this very thin cracks can cause the the spark spark went somewhere (to negative ground).
Please report if that was the problem, thank you.

Regards
Ruediger

[Izzie]

*jick.cejoco

Hmm...you have a point there.

I removed the distributor cap and rotor. Inspected the four lobes and I don't think the number 3 lobe is worn. I cranked the engine (w/o the cap and rotor), and looking closely at the contact point....i don't see much play. Maybe the "air gap" of the contact point needs adjustment? Timing?

*Ruediger

Thanks for the comment. The internet helps a lot and that's where I get the information I need in trying to solve this problem. Especially here in this forum.

As for your suggestion, I will try to look for that "short" by spraying a mist of water on the distributor/HT wires while the engine is running.

Although the distributor assembly is fairly new, I'm thinking of replacing this with another one but this time it will be an OEM. If I can find one though.

I have to double check the timing first before I replace it.

Cheers!

[dr. d]

you used a substitute distributor cap!!??
well, if i were me, i would replace the distributor cap. ...i don't have much faith in substitutes for vital parts.. experience.. but check my comment below first.

inspect the no. 3 tower again. check with an ohmmeter, between the tower outside, and the point inside, to see if it is "open".
also, did you actually see the spark, or lack thereof? if not, maybe you should do it. remove the #3 HT from the sparking plug, expose the metal electrode by pulling it out of the rubber insulating cover (don't pull it out of the cover; push it thru the cover!), and position the exposed metal electrode very close" to the engine (metal). crank the engine. a spark should be seen at the end. if none or very weak, there's something wrong with your spark delivery system proximal to the HT cable's end. this may be the distributor cap or the HT cable.
if you have a timing light or gun, clamp the sensor around the #3 HT cable and see if the timing gun's light fires. if it does not, then your #3 HT is "open".
good luck.

...good old troubleshooting... haven't had this much fun in a long time..

[Chinoi]

Try this cheap screwdriver voltage tester. Touch tip of screwdriver any portion of HTW. Neon bulb will glow from induced high voltage from HTW.

It's simple , accurate, cheap and SAFE.

[dr. d]

Try this cheap screwdriver voltage tester. Touch tip of screwdriver any portion of HTW. Neon bulb will glow from induced high voltage from HTW.

It's simple , accurate, cheap and SAFE.

oo nga, 'no!
now why didn't i think of that?..
alamkuna... walang ganyan pang-kotse noon.. meron ganyan, nguni't pambahay (220V) lang ginagamit noon..

[Izzie]

* dr.d

Oh yes, I forgot to mention that on my first post. I did substitute the distributor cap 3 times. Swapping with the old OEM cap and to a new cap, that I bought BEFORE replacing the OEM distributor assembly. Still no improvement.

Definitely no spark in #3. But will do it again following your suggestion.

Thanks Chinoi for the tip! Unfortunately, the CD-King store here is close. Will look somewhere else.

[Chinoi]

*Izzie

Meron niyan sa Ace Hardware, Electrical Supplies. Maraming mekaniko nagugulat sa tester na naisip ko na iyan.


Actually meron ako mga neon bulb naka dikit sa htw para malaman ko kung may pumapalya.

[Chinoi]

*Izzie

Sorry, hindi ko alam kung carburator type ang engine mo.

Na try mo ba silipin mga kulay ng spark plug gap mo. It migh help isolate your misfiring problem.

[Izzie]

*Chinoi

Yes. The spark plug in #3 is fouled. Spark Plugs for the other 3 cylinders are okay. I have downloaded a pdf file titled "MISFIRES" and according to it:

"If the plug is fouled, this is the reason for the misfiring, but you must still determine what has caused the plug to foul. Heavy, black, oily deposits indicate that the engine is burning oil. The most likely cause is worn valve guide seals and/or guides, but worn rings and cylinders can also allow oil into the combustion chamber. Replacing the spark plug will temporarily cure the misfire problem, but the engine will continue to foul plugs until the oil consumption problem is corrected."

Here's the thing, replacing the plug will NOT temporary cure my misfire problem because I get NO SPARK in cylinder #3 in the first place. If it has a spark and it get fouled, then I can consider that the engine needs to be serviced. (Catch22 perhaps? )

Do note the dry compression test came out okay.

Another type of plug fouling is:

"Carbon fouling, can be recognized by a buildup of soft, dry, black deposits on the plug. Carbon fouling can be caused by an overly rich A/F mixture, overly retarded ignition timing, too cold a plug for the application, or faulty ignition wires."

Will do a spark test tomorrow again. In the meantime lets enjoy the night by welcoming 2015.

Happy New Year to you and to all fellow members in Tsikot.com!!!

[dr. d]

Replacing the spark plug will temporarily cure the misfire problem, but the engine will continue to foul plugs until the oil consumption problem is corrected."
![/QUOTE]

doesn't anybody clean his spark plugs anymore? bakit replace nang replace, when cleaning them used to be the norm...?
ang-luho na ninyong mga bata, a...

[Izzie]

I clean my spark plugs. Gasoline, fine sandpaper, steel brush.

Back in the 80's I used to have the following items to tune up an engine. A timing light, dwell/timing analog meter, spark plug cleaner, feeler gauge, oil filter wrench and the Chilton's Auto Repair manual the size of a webster dictionary!

I only used these items twice before I started to work overseas. The Chilton manual is "the holy grail" of most makes/models of automobile then. It has everything.

All of these items are now gone. The last thing I know (1988), my (late) brother lent it to his (late) mechanic friend.

Whoever has it after is lucky.

[innova2013]

Have you tried using another known working distributor assembly? Possible the fairly new distributor is defective.

If the liteace is for keeps, invest to an electronic distributor. Your car will idle better, run better, and bump a little improvement to your fuel comsumption. I bought mine 5 or 6yrs ago at 3800pesos. Try searching olx if there is an online seller for it.

[jick.cejoco]

the cost of cleaning and re-gapping the spark plugs versus replacing them with new ones is not that much of a difference in cost of parts compared to the cost of labor (time). most newer cars have either platinum or iridium plugs because of this reason plus the reduced chance of stripping your spark plug holes. the plugs now are of the time change type.


btt

try reorienting your distributor by re-clocking it and rearrange the cylinder configuration on the distributor cap to see if it is the engine or the distributor(or cap) is the cause. if by reconfiguration or re-clocking of the distributor transfers the misfire to another cylinder, then it is your ignition that it the problem. for example: since you have a toyota four cylinder, your firing order is automatic 1-3-4-2. re-clocking it could be done by re-assigning cylinder 1 of the engine to supposedly cylinder four of the distributor cap, hence, cylinder 2 and cylinder 3 of the cap will switch position. then see if cylinder 2 which was good now turns misfiring. this engine is a dinosaur and should not be too difficult to figure out. simple old mechanics. think mr. watson

[Chinoi]

I suspect that one of valve seals on cylinder no.3 was already defective and need replacement. Leaking oil on gap of spark plug will be burned and accumulate carbon deposits causing short circuit ofSP gap. Prolonged short circuit on SP gap will result damaged to HTW and also no spark voltage.

[EssB]

Pretty common cause of misfiring on K engines: leaking intake manifold or exhaust manifold gasket... or baka lumuwag lang yung bolts ng intake/exhaust manifold near cyl no. 3.

[shelu]

to erase your doubts, bring the car to your suking shop. borrow distributor and see how it works. if it's ok, then buy one. i do suggest get an electronic dsitributor, less hassle. if you are into diy, there's a toturial on how convert your contact point dist with an igniter. i think i read it here in tsikot.. hope this helps.

[neil.corrigan12]

it is a lack of a firing plug usually, cheack the following
causes:

•Spark plugs
•Spark plug wires
•Ignition coil
•Fuel injector
•Wiring to fuel injector
•Timing Belt
•Vacuum leak or stuck open EGR
•Contaminated fuel or bad fuel pump
•Weak compression
•Blown head gasket

[Izzie]

Hello All!

Last January 1, I found the problem to the misfire of cylinder #3! The contact point gap is out of adjustment. I noticed that both screws that holds the contact point were not tight enough. (It seems my diy mech friend did not tighten it enough so the contact point came loose. )

Without my diy mech friend here (on a holiday) and no timing light or feeler gauge, I loosen the screws and made a guess by visually adjusting it. (I lightly crank the engine first to bring the rotor to "point" (almost) to #1 on the distributor cap before making the adjustment.)

Placed back the rotor and the distributor cap. Check HT wires and when I start the engine...it runs normal! Yes!!! I test drove it and I can say, its back to normal! Very responsive!

Thanks to everyone who helped me out here. Happy New Year guys!