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Discussion Starter · #1 ·
I AM HAVING BAD MISFIRING ON MY NAT, (NATURALLY ASPIRATED SINGLE TURBO) 450 BHP. MY LOCAL MECHANIC SAID IT WILL BE THE SPARK PLUGS OR THE HT LEADS NEED CHANGING. THE BAD MISFIRING AND A FUEL SOAKED STEAM FROM THE EXHAUST OCCURS FOLLOWING A SHORT FAST RUN OF ABOUT 7MILES.
IF I AM JUST STARTING FROM COLD AND JUST A QUIET RUN ALL IS OK, VERY SMOOTH?
THE MAP SENSOR AND CRANK SHAFT SENSOR HAVE BEEN CHECKED.
THE HT LEAD THAT FEEDS THE DISTRIBUTER CAP SEEMS TO COME FROM A COIL? BUT THE ITEM MIGHT BE MORE THAN JUST A COIL, IT IS A FUNNY SHAPED THING?
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since you have a distributor you definitely have a single coil, and that is what you have pictured above. Also check the distributor cap itself, since it’s a wear item, the distributor rotor, your spark plug wires, and the plugs (and gap) themselves
 

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First, turn off your caps lock please.

Second, Do a compression and leakdown test. Those symptoms are consistent with damaged pistons from poor tuning. What ECU & fuel system upgrades are in place to support your 450hp setup?
 
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Blue Thunder
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Third, do some research here on what the various parts under your hood are and what they do.

The answer to your question is no. Since you have a GE that still has a distributer, you don't have a COP arrangement like the GTE.

B
 

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Discussion Starter · #5 ·
Hi Guys i am a newbie to your Club Forum, it is much better than my previouse Club where i was a Member for many years.
I have owned my 1996 Mk4 from new, i bought a NA manual and my Brother bought a TT auto at the same time.
In 2015 i had a NAT Conversion at "Rocket Dog Racing" in Cardiff, I had to do this as my Brother was putting out circa 230BHP on his auto and mine was just 220BHP. So i got 452 BHP out of my Conversion and took him for a ride, i enjoyed it. lol.
Basically i had a stock ECU with an Emanage blue piggy back, a Garrett T4 turbo with a 55mm wastgate spring controlled, a 3 inch HQ stainless steel down pipe and 3 inch exhaust system and silencer "Concetua" street clutch, AFR gauge, boost gauge and oil temp gauge. Oil Cooler, large aircooler. twin rear axle torque bushes.Battery cooling box and more, some items were replaced by me, and some extra items were added as well.
In the past 7 years i have covered just 7,000 miles and the machine has been great apart from some minor problems.
However in the past few months i have had to replace the cylinder head gasket, replaced the OEM one, (very thin) with a "Conceptua" racing 4 layer one, the oil seals failed in the turbo, and the turbine veins distorted due to an exhaust to turbo gasket disintegrating damaging the turbo. because i made it myself from aluminium sheeting, i should have checked the temp spec.!
After this the car ran great like a rocket for 4 weeks, then the current problem raised it's head,as per the title above, i am struggling with it.
Symptoms: after say a 7 mile fast run the engine starts to misfire badly and a dense plume of petrol mist comes from the exhaust and 80% of the power has gone, i could just limp home.
A close friend of mine in Nantwitch who sorted a seriouse fuelling problem on my Brother's TT, gave me some tips on the phone last week. No1. Change plugs NGK cold ones gap 0.72mm. failing this, No2. Test the MAP sensor.No3.Check the ECU temp sensor. No4. Check all rubber pipes, all sizes for tiny splits on not connected well.
So i would value the opinion from other Club Members.
 

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Is it always in limp mode now, or just after a drive?

Pulling the plugs, check, and replace (if they are old or worn) is always a good place to start. If you suspect a mechanical issue and the spark plugs are already out, i would do a compression test for a piece of mind.
 

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Hi Guys i am a newbie to your Club Forum, it is much better than my previouse Club where i was a Member for many years.
I have owned my 1996 Mk4 from new, i bought a NA manual and my Brother bought a TT auto at the same time.
In 2015 i had a NAT Conversion at "Rocket Dog Racing" in Cardiff, I had to do this as my Brother was putting out circa 230BHP on his auto and mine was just 220BHP. So i got 452 BHP out of my Conversion and took him for a ride, i enjoyed it. lol.
Basically i had a stock ECU with an Emanage blue piggy back, a Garrett T4 turbo with a 55mm wastgate spring controlled, a 3 inch HQ stainless steel down pipe and 3 inch exhaust system and silencer "Concetua" street clutch, AFR gauge, boost gauge and oil temp gauge. Oil Cooler, large aircooler. twin rear axle torque bushes.Battery cooling box and more, some items were replaced by me, and some extra items were added as well.
In the past 7 years i have covered just 7,000 miles and the machine has been great apart from some minor problems.
However in the past few months i have had to replace the cylinder head gasket, replaced the OEM one, (very thin) with a "Conceptua" racing 4 layer one, the oil seals failed in the turbo, and the turbine veins distorted due to an exhaust to turbo gasket disintegrating damaging the turbo. because i made it myself from aluminium sheeting, i should have checked the temp spec.!
After this the car ran great like a rocket for 4 weeks, then the current problem raised it's head,as per the title above, i am struggling with it.
Symptoms: after say a 7 mile fast run the engine starts to misfire badly and a dense plume of petrol mist comes from the exhaust and 80% of the power has gone, i could just limp home.
A close friend of mine in Nantwitch who sorted a seriouse fuelling problem on my Brother's TT, gave me some tips on the phone last week. No1. Change plugs NGK cold ones gap 0.72mm. failing this, No2. Test the MAP sensor.No3.Check the ECU temp sensor. No4. Check all rubber pipes, all sizes for tiny splits on not connected well.
So i would value the opinion from other Club Members.
Checking the MAP sensor and temp sensor is sound advice. I'm not sure how your car is configured, but if it's set up on speed density only (air intake and MAP sensor inputs only, no mass air sensor) then the rubber pipes/intercooler couplers cracking and failing would cause a low boost or no boost condition but the car would otherwise run and drive fine.

But if your car is still using a mass-air sensor, then a large boost leak would very much cause the sort of problem you're having.

A clear, whole picture of your engine bay would be very helpful to assess your setup.
 
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