Severe stuttering/hard misfire

Matt

Member
Hi all
Just bought this as abit of a project, I'm not familia with jap cars, I had a 200sx but other than playing with it I never had a single issue so I didn't learn about the sr's foybels lol, I took it down the road by my work to see what's what & its stuttering/hard misfiring under any kind of load (was wondering about the knock sensor) it has been sat for 12 months.
It's got an apexi ecu & controller, z32 maf, fmic, adjustable fuel pressure reg. can I code scan it with the apexi?
Any ideas anyone
 

Matt

Member
It revs perfectly & cleanly at stand still & has fresh fuel in it, & levels are correct. I'm going to buy a service kit inc plugs after xmas

Thanks
 

PobodY

Moderators
Staff member
Checked for any fault codes? - Maybe it's not that easy with a PFC; you might need to connect it to a PC.

Throttle position sensor? - My first guess would have been a boost leak, but you say it's otherwise fine.

Was it running well before you bought it, or was it a bargain because it doesn't run?
 

Matt

Member
I knew the car before I bought it, It was running well before it was parked up a year ago & I had it running before I bought it, took it for a quick blast up the road & at that point stuttered briefly then went ok but I barely got into 2nd gear. I bought knowing it need some work.

Thanks
 

Matt

Member
Also it's more of a stumble/misfire than a boost leak, it won't even pull to near the redline
 

fubar andy

Moderator & N/W Rep
Staff member
I had similar to this.

Changes all my ignition system (dizzy leads coilpack plugs etc) and it went away.

Check the dizzy for "build up" that's always a good start too!


...also check the plug gaps!
 

Matt

Member
Sounds like a plan! I'm itching to get working on it but can't till after xmas :(
Where's the best place to go/makes to go for, for the parts you listed?
Thanks
 

Fast Guy

Moderators
Staff member
Check all the boost hoses, sounds like you might have an air leak somewhere.
I had a hose come off once and it hated trying to rev whilst trying to drive home.
 

PobodY

Moderators
Staff member
That was my logic too; I've had one of the small vacuum lines come off and it idles fine, but really doesn't like any boost.

Hopefully if it was running fine before it was parked-up it's just a matter of freshening things up and blowing the cobwebs out. - Oxidation in the distributor could be plausible; there's enough to get a gentle spark, but not enough to get a big one.
 

Matt

Member
Great I check those out, got some things to go out now. Need to learn how to use this apexi controller once it's up & running again, I'll probly take it somewhere for a proper set up too

Thanks for your help
 

johnny gtir

Well-Known Member
You tried a new set of plugs in ? Are they gapped right ? Sounds like could be something simple like that to me. It might rev standing still but blow out on boost
 

Matt

Member
Plugs were my first thought as I've had a similar thing on a cossie, but I haven't chance to touch it yet with it being bloody xmas lol I'm going start with checking/gapping the plugs & dizzy/rotor arm

Thanks
 

PobodY

Moderators
Staff member
You tried a new set of plugs in ? Are they gapped right ? Sounds like could be something simple like that to me. It might rev standing still but blow out on boost
I had this problem before. - You couldn't notice it driving, but when it was on the rolling road you could see the power die as the spark blew out.
 

Fast Guy

Moderators
Staff member
Another thought possibly, Any water in the plug wells? This used to be a common problem a few years back after rain.
 

Matt

Member
Fixed this Fitted new plugs, leads, dizzy cap, rotor arm & coil pack. & upon stripping found a lot of corrosion where the main coil lead pushes onto the dizzy. Now that fixed 70% of the running issue. I then found out more about what happened to it before it came of the road so I fitted the stock Ecu & injectors back in & it's now "near" perfect.

Thanks for all your help
Matt
 
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