Hot weather misfire
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Hot weather misfire
Hi Z Gurus,
I have an 82 zx (NA).
Today was 33 degrees C in Melbourne. (this is pretty warm weather but I'm too lazy to do the conversion). My Z was running ok, but I noticed two things...
1> The fuel pump was noisier than usual.
2> The car had a very slight misfire under load between 1000 and 2000 rpm.
The car hasn't behaved like this before. Once up and moving the miss wasn't noticable and the engine sounded and ran the same as usual, but I noticed the misfire while moving slowly (traffic etc). The miss isn't there when idling so it's hard to check for in the garage. When at full advance, the car seems to be running great.
Besides the obvious checking of plugs, leads, blown gaskets etc, is there anything which i should be checking related to heat? The car wasn't overheating, oil temps and pressures are fine. The car is pretty much stock, and I service it regularly.
Thanks if anyone can suggest anything - we are heading into a long hot summer here and I want to be able to take the top off and cruise to the beach regularly without worrying about reliability.
iksteh
What Rust?
I have an 82 zx (NA).
Today was 33 degrees C in Melbourne. (this is pretty warm weather but I'm too lazy to do the conversion). My Z was running ok, but I noticed two things...
1> The fuel pump was noisier than usual.
2> The car had a very slight misfire under load between 1000 and 2000 rpm.
The car hasn't behaved like this before. Once up and moving the miss wasn't noticable and the engine sounded and ran the same as usual, but I noticed the misfire while moving slowly (traffic etc). The miss isn't there when idling so it's hard to check for in the garage. When at full advance, the car seems to be running great.
Besides the obvious checking of plugs, leads, blown gaskets etc, is there anything which i should be checking related to heat? The car wasn't overheating, oil temps and pressures are fine. The car is pretty much stock, and I service it regularly.
Thanks if anyone can suggest anything - we are heading into a long hot summer here and I want to be able to take the top off and cruise to the beach regularly without worrying about reliability.
iksteh
What Rust?
Guest
Posts: n/a
Re: Hot weather misfire
thanks -
I've read elsewhere that the N42 head on a newer block (as
I have found in my car) is a bit more prone to detonation
so your call sounds right to me.
can't find anything else wrong so I'll go with
optimax on hot days - think this is highest octane on
the market at the moment.
do L series motors have any probs with too high octane?
I know in the VG series, running excessively high octane
fuel would cause a hard buildup around the ports. It's
still the first thing I'll try.
iksteh
What Rust?
I've read elsewhere that the N42 head on a newer block (as
I have found in my car) is a bit more prone to detonation
so your call sounds right to me.
can't find anything else wrong so I'll go with
optimax on hot days - think this is highest octane on
the market at the moment.
do L series motors have any probs with too high octane?
I know in the VG series, running excessively high octane
fuel would cause a hard buildup around the ports. It's
still the first thing I'll try.
iksteh
What Rust?
Guest
Posts: n/a
Re: Hot weather misfire
PULP/Optimax is the only way to go - L6's run a bit average on LRP & ULP will require timing alterations to prevent pinging. You should check all ignition components if you're not confident about the condition, fuel filter too.
Although it may not feel like it [img]/w3timages/icons/smile.gif[/img], the L6 engines in the Z familes were a 'performance' engine & need > 95 RON. Especially with all the extra additives that are in the fuel now & the fact that the EFI system is pretty primative (relatively speaking).
Ben
Adelaide
Sth Australia
IZCC#1902
240Z L31ETT
L28ET MR30 Skyline
FJ20ET DR30 Skyline RS-X
Although it may not feel like it [img]/w3timages/icons/smile.gif[/img], the L6 engines in the Z familes were a 'performance' engine & need > 95 RON. Especially with all the extra additives that are in the fuel now & the fact that the EFI system is pretty primative (relatively speaking).
Ben
Adelaide
Sth Australia
IZCC#1902
240Z L31ETT
L28ET MR30 Skyline
FJ20ET DR30 Skyline RS-X
Guest
Posts: n/a
Re: Hot weather misfire
Thanks for your help guys..
similar weather today and a tank of optimax and I didn't have any problems. I changed the fuel filter as well since it seemed a simple task and might help if the problem was dirty fuel.
I do normally run on premium, avoid LRP at all costs. I'll treat my L28 a bit better in future. And re the comment about the L6 being a performance engine? there was never any doubt
I bought my Z with the intention of doing an RB25 or RB30 swap but i've grown to love the nature of this motor and plan to stick with it (or maybe an L28ET). Has anyone ever mounted a crossflow head on this thing? seems the biggest drawback.
I ramble... thanks for the suggestion.
*gone driving*
iksteh
What Rust?
similar weather today and a tank of optimax and I didn't have any problems. I changed the fuel filter as well since it seemed a simple task and might help if the problem was dirty fuel.
I do normally run on premium, avoid LRP at all costs. I'll treat my L28 a bit better in future. And re the comment about the L6 being a performance engine? there was never any doubt
I bought my Z with the intention of doing an RB25 or RB30 swap but i've grown to love the nature of this motor and plan to stick with it (or maybe an L28ET). Has anyone ever mounted a crossflow head on this thing? seems the biggest drawback.I ramble... thanks for the suggestion.
*gone driving*
iksteh
What Rust?
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