32 Gtr Stutter

[indeedy man]

hi guys,

have a problem i am hoping someone can help me with.

the car will stutter ie. revs will stop building just for an instant on full throttle over about 5500rpm all the way to redline. feels like something is momentarily pulling the car back then releasing then pulling back again and again. the problem seems to be worse the colder the surrounding temperatures are for example at night. on a hot day the car will actually rev fine all the way to redline.

the problem isnt AFM, have alredy tried changing them over. car has been rebuilt and run in just recently. it also has new spark plugs and all that jazz. rebuild uses mostly stock items except for a slight overbore requiring larger pistons (larry perkins racing series). also computer has been reset twice now.

any help would be greatly appreciated

thanks

[blur]

tried swapping coil packs?? sounds a bit like an engine miss at revs. bit wierd its better when warm, but who really understands the magic of electricity!

[heller44]

What were the plugs gapped to?

[indeedy man]

forgot to add the car has had a diagnostic done and nothing came up.

incorrect spark plug gap was my first guess too. i dont know what they are gapped to as a workshop did this. i thought they might be too wide but the guys there assured me that wasnt the case.

keep those ideas comin

thanks

[smasha]

Sounds like coilpacks. if you have stock items, they may be getting on and cracking.

There's a really good deal in the For Sale section on Splitfires too.

[Mr GTS4]

check both knock sensors are plugged in. same thing happen to my gts-4. once i plugged them back in she pulled to redline

[Beer Baron]

take it back to the workshop and have them fix it.

[sewid]

<standard sounds like coil packs reply>

Splitfire is your friend.

[indeedy man]

last night i got as far as swapping igniter packs found one of the plugs was very loose however 2day the stutter is back.

when it stutters there is a loud pop from the exhaust. would coil packs produce this? also i thought that if the coil packs were playin up it would affect the car when driving normally not just when at high revs?

anyway if sum1 could clear that up 4 me that would be great

thanks again

[Gav]

last night i got as far as swapping igniter packs found one of the plugs was very loose however 2day the stutter is back.

when it stutters there is a loud pop from the exhaust. would coil packs produce this? also i thought that if the coil packs were playin up it would affect the car when driving normally not just when at high revs?

anyway if sum1 could clear that up 4 me that would be great

thanks again

The pop is most likely backfiring (ignition of the unburnt fuel in exhaust pipe) from ignition failure in one or more cylinders.

My guess is also on coil packs not providing enough voltage (resistance across the plug gap is greatest under peak load). Try borrowing a good coil for someone and substituting one at a time.

Could also be a cracked insulator on a spark plug or cracked plugs on the coil pack harness. Also check that the harness ground lug is clean, connected properly and grounded tightly.

[indeedy man]

hi guys,

it doesnt seem to be my coil packs. swapped them with a freinds ran his in mine and mine in his gtr and both cars ran fine.

a new problem is developing now which i guess is caused by this miss or ignition failure. when idleing the car will suddenly drop revs and sound like it is under heavy labour. when it does this there is heaps of smoke coming from the exhaust which i am gussing is unburnt fuel.

hardest thing is the car wont play up all the time so it is very hard to get my mechanic to look at it.

again any help would be great

[Hungryhippo]

ive got almost exactly the same problem with my suzuki.normal boost is fine.if the car is around85 degrees or higher is fine on high boost but if the temp drops lower on full boost it has a stutter.taking the car to the mechanic this arvo so ill see what he says is wrong with it and let you know

[indeedy man]

thanks hungryhippo look forward to it heheh need help

[Nathan_G1]

fuel pump might be on the way out......i had fuel pump problems when my 32 did that, replaced it and the filter and hosing and she came sweet as.......try ur fuel pump of filter......u might be getting fuel starvation

[Benno31]

I get the same thing when I use full throttle. According to my PowerFC it is detonation.

Time for a tune for me.

[jager]

reckon the prob could be either fuel pump or fuel regulator

had similar issues with gts-t and i just got a gtr fuel pump and re-tune

[Hungryhippo]

dont know if it'll help or not but it turns out it was my spark plugs. Apparently suzuki coils and hks spark plugs dont get along so well with each other. Put some NGK plugs in and the problem disappeared.

[markk]

I had a similar problem. Turned out it was crank angle sensor.

[arbess]

Ive been in indeedy man's car and when it happens it just a small miss of a heartbeat for the engine. The fuel pump seems to sound ok when you put your key on ignition.

meesa thinking it could be electrical.

[trust_33]

i have a 1995 R33 gtst and it has the same problem...at nite it stutters after 4500 rpm till limiter but during the day its fine.. might be leaning out due to the cold air??