Idling high (1000) after working on clutch slave

[DrJeff]

My car is now idling (even when warmed up) at 1000. Before I had to mess with the clutch slave it was idling around 750 to 800. I figure I bumped something. Any ideas? Since its hard to see what's what on the backside of the engine, I'm just hoping someone can point me in the right direction.

[jmettee]

Assuming you left the K-jet components on & "didn't touch" them, I'd say you might have knocked off a vacuum line. Most likely, it's the vacuum line going to the vacuum advance on the distributor....but I hope you didn't dislodge any of the lines going to the vacuum switch under the intake (in the VOD) or you will be pulling the intake to put a hose back on. I fear this may be where the problem is though due to proximity to the slave cylinder.:thumbdown:

These are the lines illustrated on the decal under the engine cover. I'd check all other connections first. If you find the lines going under the intake, you should be able to lightly pull on them to see if any are loose.

[Jonathan]

Here's the vacuum routing decal:

17702

Confirm the electrical connections on top of those components are okay as well.

Make sure something like this is still in place:

http://store.delorean.com/p-6399-plug-removeable.aspx

[David T]

Also check the electrical plug to the vacuum solenoid. It is very important you put the hoses on correctly to the vacuum solenoid. It matters which one goes where. Make sure the throttle arm is setting the idle micro too. You may have to adjust the quadrant arm a small amount longer.
David Teitelbaum

[DeLorean03]

Make sure the throttle arm is setting the idle micro too. You may have to adjust the quadrant arm a small amount longer.
David Teitelbaum

+1 on this. This was my issue when I got done with my waterpump change job.

Does your idle start good, and then as the car warms up does the idle begin to increase?

Here is the throttle arm/idle microswitch area courtesy of SpecialT
Auto. With the engine off, pull the throttle spool back and release it slowly. Make sure you can hear the "click" of the idle microswitch being engaged. If you hear it engaging, you should be ok.

17707

Do you know for sure that your throttle plates are completely closed behind the "W" pipe that connects to the intake manifold ?

[jawn101]

Also check the electrical plug to the vacuum solenoid. It is very important you put the hoses on correctly to the vacuum solenoid. It matters which one goes where. Make sure the throttle arm is setting the idle micro too. You may have to adjust the quadrant arm a small amount longer.
David Teitelbaum

Another +1 on this. Exactly the same thing happened to me when working on a project at the back of the engine. That electrical connection to the vacuum solenoid doesn't connect very positively and can fall off if disturbed. Disconnecting that advance would give exactly the symptoms you described.

[DrJeff]

Excellent advice. I'll check it out tonight and see if I can get her purring like normal. Maybe if I'm lucky I can get an endoscope picture of it. I've been very fortunate that the engine has been no problem at all since I bought the car a year ago.

[Cartman]

Agree, althoug I have never worked on a delorean, I have vorked on the k-jet before. And it seems like you have puld of a vacum hose or 2 :)

[jawn101]

Excellent advice. I'll check it out tonight and see if I can get her purring like normal. Maybe if I'm lucky I can get an endoscope picture of it. I've been very fortunate that the engine has been no problem at all since I bought the car a year ago.

No endoscope required for this one, you'll see it plain as day if you just lean over the top of the engine. The vacuum solenoid is mounted right to the mixture unit at the top, easy to see. Should have two (properly routed!) vacuum hoses and a 2 pin electrical connector - either a white plastic trapezoid or with a black rubber boot if yours hasn't disintegrated yet :)

My bet is the connector fell off and is laying right next to the solenoid, probably resting on a mess of fuel hoses or your heater control valve.

[DrJeff]

Okay, it looks like the connector to the vacuum solenoid had come partially off - enough to lose connection. The boot is still there. The vacuum houses were all still in place, look original but still in one piece. No doubt time for a refresh.

Thanks to everyone on the forum for the help.

[jawn101]

Okay, it looks like the connector to the vacuum solenoid had come partially off - enough to lose connection. The boot is still there. The vacuum houses were all still in place, look original but still in one piece. No doubt time for a refresh.

Thanks to everyone on the forum for the help.

Sweet. So when you plugged it back in, the idle went down I assume?

[DrJeff]

No such luck. Went for a test drive after posting. Idled cold at 1000, but even after warming up (she settles nicely at the first temp dash) she's still running at 1000. Dang.

[DeLorean03]

Test your idle microswitch as referenced in my original post. Did you have to move either of the two screws in this picture at all?

17724

If it's not that, when it idles at 1000, have you tried just revving your accelerator pedal fast and hard really quickly just to see if maybe your throttle cable is sticking ?

[DrJeff]

Fixed! I replaced the short vacuum hose from the vacuum solenoid. The hose looks fine but it probably wasn't hanging on to the solenoid nipple as well as it should have been.

Car starts up good, starts around 1000 idle, drops to around 750 after 30 seconds or so, albeit after a little bit of hunting.

I got enough silicone vacuum hose to do the rest on the next pull apart - very soon for going EFI.

[jawn101]

Fixed! I replaced the short vacuum hose from the vacuum solenoid. The hose looks fine but it probably wasn't hanging on to the solenoid nipple as well as it should have been.

Car starts up good, starts around 1000 idle, drops to around 750 after 30 seconds or so, albeit after a little bit of hunting.

I got enough silicone vacuum hose to do the rest on the next pull apart - very soon for going EFI.

Kickass man. Good work, it's always nice when it's easy.

Be careful though - there are a couple different diameters of vacuum hose in the system. Once I realized that I went with a vendor's silicone vacuum hose kit just so I wouldn't be stuck hunting down tiny pieces of 10 different types. Of course if you're going EFI maybe your vacuum system is changing as well, I don't know what all is involved with that :)

[Bitsyncmaster]

Kickass man. Good work, it's always nice when it's easy.

Be careful though - there are a couple different diameters of vacuum hose in the system. Once I realized that I went with a vendor's silicone vacuum hose kit just so I wouldn't be stuck hunting down tiny pieces of 10 different types. Of course if you're going EFI maybe your vacuum system is changing as well, I don't know what all is involved with that :)


I think that small hose was 3mm ID. It's not easy to find that size hose locally.