Chasing the Herky Jerky Gremlin on my 83SC...

[Carl83911]

Ok, this is kinda adding up in cost but have to keep going until I find out what the heck is making my car jerk during accelaration on any gear. I feel like a bobble-head...

This started about a month ago and so far I've spent abourt $2k.

Old Mechanic:
diagnostic
new cap/rotors/plugs
replaced WUR with a good used one (according to my mech)

New Mechanic:
have injector o-rings and seats replaced then sealed (this fixed my idle issue)

He found that my rings have hardened and shrunk and cracked from age that when he forced smoke through my (intake?) there were geysers of smoke shooting out from the rings.
He also found a .06mm leak on my airbox which he sealed with epoxy. No need to change yet (according to him) to save me about $1.5k in r&r

what next to tackle:

valve inspection and adj (last adj @ 45k)
clutch?

new set of ignition wires? I believe I still have the original with the mesh cover.
should I go Magnecore or stay with oem?

Anything else I may have missed?

I'm hoping for just sticky valves. my clutch seem to be ok. It not slipping and my pedal travel is normal.

Any feedback is welcomed.

Thanks folks.

Carl

[Scott R]

Whats the condition of the distributor? I've had this issue and it turned out my advance weight springs were broken (pads that they rest on broke) and the advance pod was shot.

[lonewolf]

does it jerk only when you floor it in any gear or with or does it do it with any amount of throttle?

hot and cold it acts the same way?

[Carl83911]

Originally Posted by lonewolf

does it jerk only when you floor it in any gear or with or does it do it with any amount of throttle?

hot and cold it acts the same way?

Yes, hot, cold, any throttle.

[Carl83911]

Originally Posted by Scott R

Whats the condition of the distributor? I've had this issue and it turned out my advance weight springs were broken (pads that they rest on broke) and the advance pod was shot.

Scott,

thanks for the reply, the Mech did check the distributor and it's ok.

[lonewolf]

have you had any charging issues lately?
does it rev smoothly when sitting ? and only jerks under load or does it shutter when you try to just rev it .

[lonewolf]

if the car idles ok
under the pass seat is the lamba brain,right beside it is the relay for it .
with the car idling unplug the relay and the car should have a noticeble roughness and will not rev right. if you unplug it and nothing happens they try a new relay.and make sure you have +12power to the relay.

[Carl83911]

Originally Posted by lonewolf

have you had any charging issues lately?
does it rev smoothly when sitting ? and only jerks under load or does it shutter when you try to just rev it .

It only jerks under load.
Throttle response when idling is good. No hesitation.

[Carl83911]

Originally Posted by lonewolf

if the car idles ok
under the pass seat is the lamba brain,right beside it is the relay for it .
with the car idling unplug the relay and the car should have a noticeble roughness and will not rev right. if you unplug it and nothing happens they try a new relay.and make sure you have +12power to the relay.

I will definitely check this one out.

thank you

[lonewolf]

I think the relay is ok, that's not it .because it idles and revs smooth when sitting .
if the relay was bad it would not be smooth at any time

[lonewolf]

I should have started with this first.
tell how the car was running right before this happened.
had you just done anything to it or had any kind of issue big or small?did you just finish a long drive ?
Left the headlights on. anything that happened, may be nothing to you but to some one trying to diagnose
all info is important .

[Carl83911]

Originally Posted by lonewolf

I should have started with this first.
tell how the car was running right before this happened.
had you just done anything to it or had any kind of issue big or small?did you just finish a long drive ?
Left the headlights on. anything that happened, may be nothing to you but to some one trying to diagnose
all info is important .

__________

Car was running well before this began other than idle was a bit low and irregular when cold. Once warmed up all was well. then,
My original cd unit died. My car just died at an intersection and couldn't get it to start. had it towed in and Mech told me it was my CDs. Replaced with a permatune and matching coil.

My ignition wires look pretty old. but I inspected last night with the lights out while car was running and there was no fireworks in the engine bay. that probably doesn't tell me if my wires are firing 100%.

[lonewolf]

ok,so we're clear.
Car ran fine for some time and then roughly a month or so ago the CD and coil were replaced.
then car was back to normal for how long? or did the jerking start right after that.

[ivangene]

Subscribed

[mca]

If the jerks started after the permatune install, you have your answer.

Regardless, send the CDI out to be fixed and go back to original coil.

Can you borrow a Bosch CDI from someone locally?

[lonewolf]

MCA is right.
permatunes have been known to act up shortly after being installed.
was gonna say the same thing .did you get to keep your old CD? and coil?

[Carl83911]

Originally Posted by mca

If the jerks started after the permatune install, you have your answer.

Regardless, send the CDI out to be fixed and go back to original coil.

Can you borrow a Bosch CDI from someone locally?

_______________

If it is the new PT, wouldn't is also act up when revving up while on neutral. The throttle response is spot on. Only when in gear is when I have the isues. I can probably try to borrow a friends CDI.

thanks for your input.

[Carl83911]

Originally Posted by lonewolf

MCA is right.
permatunes have been known to act up shortly after being installed.
was gonna say the same thing .did you get to keep your old CD? and coil?

_____

Damn, I should have asked for my old CD and coil back. I didn't think of that. since I had them replace it with a new Pematune and coil, they didn't need the core. (!!!1.....slapping forehead)

the car was ok up until last week. So I'd say it was running good for about 3 weeks after the new PT and coil were installed. But like I mentioned to my response to mca,

I would think that revving during neutral would also show a bad permatune? wouldn't that be the case?

[Cdnone1]

Have you been adjusting your mixture while you have been taking care of all your vacuum leaks and control pressure problems.
Your mixture could be way off and causing you problems
Steve

[Carl83911]

Originally Posted by Cdnone1

Have you been adjusting your mixture while you have been taking care of all your vacuum leaks and control pressure problems.
Your mixture could be way off and causing you problems
Steve

No, i left that to the mech.