My 1.8 L-Jet, continued, sorry Options

[jd66921]

Hi

I've posted about my car before, sorry about asking more again!

I have a '75 1.8l L-Jet that I drove from LA to TX a month ago. Since
then it has assumed the position of many 914's, resting too comfortably
in the garage!

I'd like to ask several questions in hopes of stirring it from its slumber!

History:

1. The car ran fine from LA most of the way home. Toward the end, it
wouldn't idle, and generally wasn't "right".

2. I have replaced virtually all of the vacuum lines on the car. Most are
plugged now.

3. I have pulled the injectors and had them cleaned and flow checked. All
OK within 1%, was 10%

4. Compression (cold) is a little low, but consistent, 90 psi on all cylinders.

5. #2 exhaust is not getting hot. I have changed the plug and the plug wire.
No change. Plug is wet with fuel.

6. All the rest of the cylinders look a little rich, black. No fouling. Air leaks
indicate lean, right?

7. The car will not idle. It starts, rev's, and then dies. I can save it with the
throttle. It "seems" like it wants to go to a high idle cold.

8. Fuel pump runs continuously. Fuel pressure is over 30 psi all the time and
does not seem to drop as the engine "dies".

I am sorry if the description is out of order. Okay, the questions:

Questions:

1. Do you think the car should idle, however badly, with one dead cylinder?

2. What is the matter with cylinder #2? I changed the plug and the wire. It is
getting fuel. Oh yeah, dwell and timing have been verified. Dizzy cap is new.

3. How far open would you expect the idle screw on the throttle body to be? One
turn, two turns, more?

4. The mixture control on the air flow sensor is totally closed. How far open
would you expect it to be?

5. There are small backfires at the air flow sensor. I know this is bad.
What is the cause of these? Vacuum leaks? Why the backfires?

I am SO tired of this crap!!

Thanks,

Jeff

[ClayPerrine]

Where in Texas do you live?


If its close enough, I will come take a look.....

If you live in El Paso.. forget it!

[jd66921]

Where in Texas do you live?


If its close enough, I will come take a look.....

If you live in El Paso.. forget it!

Almost as bad, Corpus Christi! Actually 35 miles North of Corpus. Do you fish?
My boat is sitting in the canal right behind the house!!

Jeff

[ClayPerrine]

Where in Texas do you live?


If its close enough, I will come take a look.....

If you live in El Paso.. forget it!

Almost as bad, Corpus Christi! Actually 35 miles North of Corpus. Do you fish?
My boat is sitting in the canal right behind the house!!

Jeff

Nope.. but the beach is cool....

[Brando]

Now would be the perfect time to perform a full service on the car. A properly tuned 1.8 will run smooth and idle properly.

The first thing to do would be replace your points, rotor, cap, plug wires, plugs and maybe your coil if you have no receipt or written history from the PO of this being done.

Also replace ALL of the proper vacuum lines in the engine bay. It is best to replace them one at a time as to not get confused where they go. I highly reccommend getting a silicon hose kit, or buying proper silicon hose sizes from an outlet. They do not dry out, get brittle and crack like the OEM rubber hoses and cloth-covered rubber hoses. A big vacuum leak could be underneath the oil filler neck. Replace that cork gasket. Also replace the rubber gasket inside the cap on the oil filler. Replace that large cloth covered rubber hose that goes from the oil filler to the intake boot.

Follow that up with an oil change and valve adjustment. Be sure to replace your valve cover gaskets.

Then set your timing. Timing is set with both vacuum lines disconnected from the distributor (and plugged), idling at 950±50 RPM (I set mine at an even 1000), 7.5º After TDC (or is it before? I forget, I just look for the timing mark) Anyhow, you'll see the timing mark with a light in there.

Another tip that was mentioned by Captain Crusty, is to take off your air intake boot, clean it very well, and apply black silicon RTV over any small cracks and other joint areas.

The 1.8 L-Jetronic system is very sensative to vacuum leaks. It is an air-metering system. Any air leak behind the air flow sensor will cause a lean condition because of "false" air in the system.

To answer your questions:
1. Do you think the car should idle, however badly, with one dead cylinder?
The car will not idle properly at all with one dead cylinder.

2. What is the matter with cylinder #2? I changed the plug and the wire. It is getting fuel. Oh yeah, dwell and timing have been verified. Dizzy cap is new.
Dizzy cap is new. How are the points? The lobes of the cam on the distributor shaft? Is one flat? Rotor? Tried with a brand new spark plug wire ?

3. How far open would you expect the idle screw on the throttle body to be? One turn, two turns, more?
The idle screw should be loose enough to let it idle at 950-1000 RPMs with the timing properly set. When setting the timing you may have to adjust this, but after the timing is properly set, use it to set your idle correctly. Another trick I learned to prevent a leak here, is to put some teflon plumber's tape over the threads of the screw and thread it back into the Throttle Body. This will prevent it from backing out.

4. The mixture control on the air flow sensor is totally closed. How far open
would you expect it to be?
Never saw one that worked on the AFS... Basically it's a fine tuning for mixture. You would need a flexible gas analyzer to know if the adjustments are working. You can use it as a rough guesstimation to lean/rich by tone of the engine as it's running. But without proper emissions testing equipment you won't be able to tell how your adjustments affect the car's running state without making a drastic adjustment (all the way in, all the way out).

5. There are small backfires at the air flow sensor. I know this is bad.
What is the cause of these? Vacuum leaks? Why the backfires?
Backfiring up through the intake manifold? When you start the car, do you press in the gas pedal? That is a big no-no with L-Jetronic, as if there is a backfire in the intake manifold you could destroy the AFS. The little spring-loaded door will fly back the way it is not supposed to, bend, and be permanently broke. Any other reason why... I'm uncertain.

There ya go. Feel free to poke holes in my reply peoples (IMG:style_emoticons/default/smile.gif)

[nycchef]

don't know if this helps . having many of the same problems with my 1.7. do you mean the fuel pump stays on longer than a few seconds when you try to start the car? mine did that turned out the po hot wired it.

[So.Cal.914]

I think brando covered most of it, if I were you and after as long of a drive as you

took I would adjust the valves first thing. Screwed up adjustment can cause all of

the symptoms that you mentioned.

[Dave_Darling]

Are you, in fact, getting a spark on the #2 plug? You can use a spare plug to check; tape it so the threaded part (or the outer electrode) is touching a ground like the fan shroud. Plug it into the #2 plug wire, and have an assitant crank the starter. You should be able to see a nice fat white spark.

If you don't, then you've got a pretty good idea that the problem is in the ignition.

Find a "noid light" at your FLAPS. Plug it into the injector connectors to see if it flashes when the starter is cranking. See if #2 is different. (Does it stay on all the time?) If so, you've got a pretty good indication of a problem.

--DD