'86 idle problems
 

Hey guys,

I'm looking at a 1986 911 Carrera for pretty cheap. However, the guy says that it misses at idle. Fuel injection is one of my weakest points when it comes to knowledge. How expensive could this fix get? What should I check when I get there? I'm sure there's lots of stuff it could be, and you probably need more info to make a real estimate, but I'm looking for a roundabout number that I can use. Thanks.

Alan

I am sure you will ask him about it's maintenance record but check if he replaced:

1. Cylinder Head Temperature Sensor (Temperature Sensor II) Upgraded Double Wire

If he will allow you to removed the hot air intake (it's the 1.5 foot long funnel type thing secured by a screw/s on top and hose clamp on bottom) then you will see a cluster set of three plugs. You will find an off white plug the CHTS, look at the wire to see if it is the original single or double wire. $75, 2 hours and a special tool. Search for CHT replacement.

2. DME Relay

If you want to invest $30, I'd say buy one and swap out the DME relay when you test drive it alone. If this is the culprit, you just fixed his car and he may want more for it. Just my $.02.

It is located under the driverside seat and pulls right off. It is a 1" X 2.5: black box secured by a bolt and a plug going to the ECU flat metallic box the car's brain.

Baby should idle at 800 RPMs.

Our babies are more electrically challenged very rarely mechanical so I would check the electric components first.

Search our host for the Fuel Injector's cost for DIY.

Best wishes,

Get the car inspected (PPI) and don't try and guess at what the problem is. We've all BTDT and bought stuff we didn't need. You can chase electrical stuff all day and then find out it wasn't electrical. A couple hundred bucks now might save you thousands later...and that would apply either to repairs or purchase price or both.

I fully intend on getting a PPI, but I'm trying to figure out what to expect. I don't know if this helps in the diagnosis, but he says that it misses at idle, but it "goes away as soon as you drive off from a dead stop." We'll see, I guess.

Alan, you are taking the right approach with the PPI. Could be as simple as the ICV as well as the other suggestions.

I also sent you a PM, check you Pelican mail box when you get a chance.

Todd