Hey guys.

Only very new to the forum. My grandfather has upgrade his vehicle recently, so i have taken posession of a 1994 Magna SE 3.0 V6. It has 135,000kms on the clock, Automatic.

It has developed a couple of problems.

The 1st was oil consumption of 20w50 grade oil. I have since done an oil change to Penrite HPR30 20w60 grade, hasnt used a drop. Having a few oil leaks, and previously owned a sigma i expect some oil consumption.

The 2nd, and the most puzzling. When accelerating (hard or soft) it begins to splutter/misfire around 2,800rpm up until 5,000 where it seems to clear itself.

I have replaced the spark plugs, the spark leads, the fuel filter is relitavely new also.

Could anyone give me some advice on what could be causing this, i dont really want to just replace parts randomly...... Also if anyone could tell me how to bring up codes?? which pin etc... needs to be bridged or earthed.

Sorry, for the long post,
thanks guys

First of all, good choice with the Penrite! Undoubtedly the best oil around!

One possible cause of your problem (I think) is a vacuum leak. Have you checked the hoses running to the brake booster, and the emission control hoses on the engine? These hoses are rubber and can perish. If these are cracked, which usually happens around the connections, your engine may be running too lean resulting in the problem in that rev range. Also check the pipe between the air filter and the throttle body. If this has a split in it (check inside the ridges) then this will be bad also! You can pick the hoses and air pipe up from wreckers very cheaply if they are a problem.

When you replaced the spark plugs, did you just replace them with the model number that came out, or did you look it up and ensure the right type was installed in the first place? A wrong type may still fit perfectly but the performance parameters may be different resulting in problems... Don't just put any Magna 3.0 V6 sparkies in, they have to be the ones for the Tr/Ts (I think the TE/TF etc 3.0L used different sparkies?)

Does it do this from when its cold or is it only when it warms up? If the engine runs hot due to a faulty thermostat, blocked radiator etc. you could result in that problem. If the radiator water isn't a rich greeen then a flush couldn't hurt. Use good radiator flush such as Tectaloy Mukowt, then replace the fluid with a good one, such as Tectaloy 90 Plus (which is premixed at 33%), and replace the themostat with a high flow one.

Are the spark plug leads in the correct order? hehe

Is the timing adjusted correctly? Have you tried adjusting the timing by the distributor adjusting bolt? Mark the position with a pencil and try moving it, you can always put it back to where it was if you mark it! Rotating the distributor in a clockwise direction will advance timing. If the adjustable gap at the top of the adjusting bolt is almost non existing it is probably too advanced, if there is a massive gap then its probably too retarded (very unprofessional way I know), I can't imagine having the timing too retarded could cause that problem?...

Thanks, very helpful.

As far as im aware, they are the correct NGK plugs, i had to return once cause they gave me the wrong ones.

All the leads are in the correct order.

It splutters/misfires in any condition. Cold, Running Temp..... needle never passes 1/2 on the temp guage.

I supposed a coolant flush could be an idea, and change the thermostat...... your thinking being its running COLD fuel MAP all the time, or HOT fuel map all the time which ever way the thermostat has/if failed yeah??

I will definately do a full inspection of all the hoses, didnt think of a vaccume leak however im not sure of how this would cause the engine to splutter/misfire. The airbox-to-throttle body hose is fine, i removed it to clean the throttle body..... which did SFA.

I forgot to mention, i have also re-set the ECU by disconnecting the battery, which once again made SFA difference.

I am not overly keen on adjusting the timing......... Think i will leave that to a workshop with the EFI computer for diagnostics.

Could a O2 sensor have failed?? or fuel pump??? Maybe blocked injectors????? is there any way to bring up the engine fault codes???

Could be that you need to put some flashlube or something through it?!

on ignition side of things id could also be caused by the distributor; clean all the connections around it and check for cracks etc in the cap.

Personally it sounds more likely to be a fueling problem.... happens all the time.... i can start my ts and even thoughs its cold and bad for it itll rev out like normal. Temp gauge should never really go far from half so i think your cooling system is fine.....

my bet is that the injectors have never been ultrasonically cleaned which is meant to happen once every 2 years, its an off car cleaning and you'll probs spend 220$ or so doing it; it gained me 13hp atw but i hadn't done it in 300000km's

also having hoses ****ing up can cause weird ****; check pcv valve esp...

all i got

Wow, another $220 every 2 yrs? would the flashlube etc negate the need for that?!

Wow, another $220 every 2 yrs? would the flashlube etc negate the need for that?!

yeah probs ive never felt a difference with those cheap injector cleaners; but also i dont think ill be ultrasonically cleaning 1 times in every 2 years.

Thise samll vacuum hoses can be a pain to see if they have cracks and stuff. Get a can of start ya bastard and spray that around al lyour hoses when its running and the revs will rise when it is sprayed near any cracks

****UPDATE

Problem still there, However if you revv the car in neutral it doesnt misfire right upto 5,500rpm

its not a vacume leak
vacume leaks are noticable at idle not up in revs


most likley the dissy cap

commin problem with them they ark internaly causing a miss under load

if plugs and leads are good the cap needs replacing

if you take the cap off and look inside it you may see white burn marks inside of it

replace the rotor at the same time

I would suspect distributor cap and / or rotor. Once fitted new Bosch rotor and cap, within 1 month experienced prob you have. Refitted old Magna cap and rotor and prob gone. The 2 Bosch parts looked perfect, but 1 or both were no good. Normally one can see where cap or rotor is no good, unless it is carbon tracking. unfortunately Mitsu cap and rotor are expensive. I fitted genuine cap and rotor after my bad experience with Bosch. Cap is not easy to remove, make sure you have instructions, as rotor has to be in correct position in order to remove cap. One of the manuals (think it is Gregory manua) gives wrong position.If your cap is non- mitsubishi, this is probably the cause.

thanks heaps for your help guys. I will get a new dizzy cap and rotor tomorro...... fingers crossed

Hey guys.

The 2nd, and the most puzzling. When accelerating (hard or soft) it begins to splutter/misfire around 2,800rpm up until 5,000 where it seems to clear itself.

I have replaced the spark plugs, the spark leads, the fuel filter is relitavely new also.

Could anyone give me some advice on what could be causing this, i dont really want to just replace parts randomly...... Also if anyone could tell me how to bring up codes?? which pin etc... needs to be bridged or earthed.



I would bet on it being your injectors blocked.

I had almost identical problems in the past 2 months and decided to get the injectors ultrasonic cleaned. drove it in, collected it and forked out $200 2 hours later, and its driving lovely again now, no splutter cough, misfire etc.

First of all, good choice with the Penrite! Undoubtedly the best oil around!

Use good radiator flush such as Tectaloy Mukowt, then replace the fluid with a good one, such as Tectaloy 90 Plus (which is premixed at 33%), and replace the themostat with a high flow one.




Penrite is also 100% AUSTRALIAN OWNED! YaaY

BEWARE of aftermarket coolants. There is actually 3 types, and they all deal with different engine needs. The most common are the red (or orange) and the green.

I recently purchased a 3 litre (concentrate) MITSUBISHI coolant from my dealer which is all the V6's need, cost $30.

Do the "flush" as normal and make sure you turn on the heater so it can get the gunk out of there too.

When flushing the system I always rinse it with clean fresh water then run the engine for again for a while, then empty the fresh water again then pour in the 3 litre mistu concentrated coolant (which requires a topup with additional water).

I usually top it up with some de-mineralised water from my mates still as normal tap (and YES, even rain water) can have some minerals in it that can activate corrosion in the cooling system.

Thise samll vacuum hoses can be a pain to see if they have cracks and stuff. Get a can of start ya bastard and spray that around all your hoses when its running and the revs will rise when it is sprayed near any cracks



WARNING:

NEVER EVER under ANY CIRCUMSTANCE use "start ya bastard" to check for vacume leaks.

I once did this to detect an inlet manifold leak, the engine backfired and set fire to both the can AND my hand.


To detect any vacume leaks, the simplest, safest method is to use a cheap squirter bottle filled with water and a drop or 2 of dish detergent.

I would bet on it being your injectors blocked.

I had almost identical problems in the past 2 months and decided to get the injectors ultrasonic cleaned. drove it in, collected it and forked out $200 2 hours later, and its driving lovely again now, no splutter cough, misfire etc.


blocked injectors cause a rough idle

blocked injectors cause a rough idle

and i lost mid range and top end power

i suspect dizzy cap and or rotor, also check leads and plugs. Tip: get the injectors cleaned and a new fuel filter whislt your at it.

I had this problem wiv my nissan 2.8et efi turbo patrol. (engine mod long story) I had to make an ignition module for the electronic distributor using two 60 amp transistors. It worked too well, producing a spark that could light a small town. It would not missfire when in nuetral but would from about 1200 to 3000. wow was that annoying. I changed the spark plugs about 4 times. It help alittle bit but it would come back with a vengence. Then one night i lifted the bonnet wiv the motor running and saw the leads arcing. Changed the leads proplem gone.
Fuel starvation can also cause leanout missfires. But you should feel the car surging, and a noticeable poping and backfiring in the exhaust. Missfires like yours sounds like electrical.
Hope this helps.