Engine Running Rich

[Ricker]

Attachment 38472

Ok. I've checked about everything I can think of without really finding anything wrong. Fuel injectors clean and checked, idle 775 RPM, timing good, new micro-switch, filters, spark plugs, wires, rotor & rotor cap, high voltage coil, all vacuum hoses replaced. It has not passed the Colorado Emissions testing. The old spark plugs were all black. From this I assume it is running rich. In addition the car was initially sold in IN. It is now 5,280 feet in CO. I have read a number of posts on how to adjust the mixture; basically checking the dwell of the Frequency Valve (swigging between 30 - 50, average 40) when the engine is idling and running at temperature. But I'm not sure where or how to get to the mixture screw. I believe it is under the cap centered in front of the Fuel Distributor (toward the rear of the car).

So for "fuel adjustments for dummies", is this the right thing? How do I get the cap off? Is it screwed in? I think it is pressed in or what? Can I just grab it with some pliers and pull? Can I get a screw driver under it and pry? I believe a long 3 mm Allen Wrench is used for the adjustment. What do I get to plug it up with afterwards?

Next, how and specifically where do I connect the dwell meter up to? Does anybody have pictures?

If this is set right my next replacement is the Catalytic converter.

I really want to be able to do this and understand it. Driving to Texas or finding a local garage is my next choice.

Thanks!

[sdg3205]

You'd have to carefully drill it out.

Before you do, you need to confirm your lama system is actually working. It may be that it isn't, in which case that would be your first step.

Does the frequency valve buzz? if you unplug it, does it throw off your idle?

[Ricker]

Yes. It buzzes and if you disconnect the wire the idle is terrible.

[DMCMW Dave]

You'd have to carefully drill it out.

?

DO NOT just drill it out. People do this and damage the housing. You need to drill a small hole in the center of that plug and STOP when it hits the steel disc at the bottom of the aluminum plug. Then thread in a sheet metal screw and use that to pull the plug out.

If you try to drill through it, you can round out the hole to be too big for a plug, get metal shavings in the engine, or drill through and damage the adjuster. Or all three on the same car!

[sdg3205]

thats a good sign.

check mixture with a dwell meter. stick the probes in the molex connector at the bulkhead with the car at operating temp and see what you get.

[sdg3205]

DO NOT just drill it out. People do this and damage the housing. You need to drill a small hole in the center of that plug and STOP when it hits the steel disc at the bottom of the aluminum plug. Then thread in a sheet metal screw and use that to pull the plug out.

If you try to drill through it, you can round out the hole to be too big for a plug, get metal shavings in the engine, or drill through and damage the adjuster. Or all three on the same car!

hence the word "carefully." figured we'd cross that bridge if it became necessary.

EDIt - Dave, I also would not try and give advice on something I have never actually done. That's all you!

[Ricker]

I think before I go through the trouble to removing the plug, I will check the reading. Perhaps it is something else and I'll get out of doing it. I need to go get a dwell meter. I still do not understand how or where to hook it up to. Maybe once I get the meter I will understand better. Sometimes I can't see the obvious.

[Bitsyncmaster]

I think before I go through the trouble to removing the plug, I will check the reading. Perhaps it is something else and I'll get out of doing it. I need to go get a dwell meter. I still do not understand how or where to hook it up to. Maybe once I get the meter I will understand better. Sometimes I can't see the obvious.

Yes, get the meter first before you drill the plug. There are a few ways to read the dwell. Make sure you check your reading by pressing the wide open throttle switch. Your reading should be very close to 55 deg. If not your meter is hooked up wrong.

[Ron]

I think before I go through the trouble to removing the plug, I will check the reading. Perhaps it is something else and I'll get out of doing it. I need to go get a dwell meter. I still do not understand how or where to hook it up to. Maybe once I get the meter I will understand better. Sometimes I can't see the obvious.

Here Ya Go:

How To: Set Dwell
How To: Remove Anti-Tamper CO Plug

[Jonathan]

So for "fuel adjustments for dummies", is this the right thing? How do I get the cap off? Is it screwed in? I think it is pressed in or what? Can I just grab it with some pliers and pull? Can I get a screw driver under it and pry?

D - Fuel Emissions and Exhaust Systems.pdf

See if you can open this attachment. It is section D from the workshop manual, the fuel and emissions section. It explains in section D:04:03 what to do with the tamper proof cap (page 23 of 46 in the PDF file).

I believe a long 3 mm Allen Wrench is used for the adjustment. What do I get to plug it up with afterwards?

You can use a golf tee to plug it afterwards or a wad of bubble gum, or get one of these from DMCH:

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

Next, how and specifically where do I connect the dwell meter up to? Does anybody have pictures?

Have a look at this short video.



I think the consensus was that Bob's dwell reading wasn't right since the needle generally isn't supposed to stay stuck on 43 like it is in the clip, but it does show you clearly where and how to hook it up.

If you look through that workshop manual section, on page 35 of 46 (D:04:15) explains the testing steps to ensure your Lambda system is doing what it is supposed to be doing. If you go ahead and do that stuff, please share your results as I have done those tests before myself and wasn't too clear on what the results told me.