Hey folks,
my car just recently developed the following symptoms when started cold. Once warmed up, no problems.

The car: '94 manual, 47k miles, Pettit ECU, DP, RB-Duals, Intake, Greddy SMIC.

Starts up without problems, same as ever, no smoke other than condensation, also as it always has done.

The idle is quite lumpy when the car is in neutral, seems to miss and there's a little pop associated with it each time. Also seems to rock the car a bit.
In gear with the clutch down it all smoothes out. Clutch state doesn't cause a change while the car's in neutral.

When going from in gear to neutral it's very pronounced, lot's of popping from the exhaust for a couple seconds, then it settles. I can hear an air "whooshing" sound start when going to neutral, which I assume is the airpump. It goes away again if I put it back in gear.

I have the "DaleClark Moo Eliminator" installed and was wondering if the holes I have in it aren't large enough, could it cause this? I've had it in for a while and it hasn't done it before, so I doubt it... but I removed it for now to test it anyhow, need to let the car cool down first though.

While in neutral the vac seems to be low, about 2-3 in/Hg less than while in gear. Guessing that's caused by the missing. Again only a problem while cold.
Vacuum at 1000rpm when coming down during warm up is 18+, once warmed up it's just over 17 at 1000rpm, a little higher if the car's in gear.

Spark plugs are a little over 2k miles old. I'll be pulling them to see if anything's up with them. Gonna wait with that until it warms up a bit though, concrete at freezing temps isn't all that much fun.

Hoping for any suggestions on what to check.
It's not the MAP sensor, checked that first thing


TIA

 

Check your clutch switch. Sometimes the spring breaks down, and the white "pin" doesn't pop out.

 

Both clutch switches look ok. Plungers push-in and pop-out.
Will need to take a multi-meter to them to make sure if they indeed work correctly.

I thought about clutch switch as well but didn't think it would be an issue, since in neutral there doesn't seem to be a difference wether the clutch is in or out.

Well, better to rule it out for certain.

 

MAYBE something with the neutral switch on the tranny as well. Clutch switch/neutral switch both are a factor there.

The anti-moo shouldn't be a problem, I wouldn't think. I just drill 4 or 5 small (like 1/16") holes - no problemo.

Dale

 

TPS would be my guess... check you voltages from the plug there.

 

Chalk up another one to the spring in the clutch switch.

One springless ball point pen later and idle is as smooth as it's always been. Not that it means all that much on a cold 13B...

The spring actually had enough left to push the plunger out a bit, but not enough to get it to the contact point to close the circuit. When I took it out it pretty much fell apart.

Thanks guys.