I have a problem with my 89 LX.

[g0dspeak]

So I bought the car about a month ago now. I have replaced the thermovalve and air cutoff diaphragm unit with good ones from another carb, a refurbished distributor, and a new valve cover gasket.

When I got the car, it ran like shit. And then it started getting worse.

It doesn't matter where I have the dizzy, (right now its just about in the middle)

The car still runs horrible, it will fluctuate from 1.5k rpms up to 4k rpms.

I have no vacuum leaks. Each vacuum line is connected to the correct spot.


Also, in the original documents that I have, from when the car was new, the owner took it to the dealership and complained about problems such as the car was 'dieseling' on shut down (which is still does it..) and idle problems.

Has anyone else experienced any of these issues?

[Dr_Snooz]

Are you using a timing light or just eyeballing it? You need a timing light.

If you're getting dieseling, either there is a lot of build up in the combustion chamber or your carb is getting tired.

[g0dspeak]

Are you using a timing light or just eyeballing it. You need a timing light.

If you're getting dieseling, either there is a lot of build up in the combustion chamber or your carb is getting tired.

I was just eyeballing it just to try and get it to somewhat idle. I have a timing light.

I'm sure the carb needs rebuilt, i'm probably going to do a weber conversion later down the road though.

It seems that just about when the car was new it started having a high idle problem, I have multiple receipts for work done, it's had the dieseling issue since 2000.

When I get back from hunting this weekend i'll take a timing light to it.

[Dr_Snooz]

It's a good idea to set everything to factory spec when diagnosing. Set the timing and then see where you are. There are people on here that know how to diagnose the different parts in these carbs. I would just rebuild the whole thing or do a Weber swap, if that's legal where you are.

[g.frost]

After you get the timing set, & warmed up, Check that the Choke is fully opened. Those symptoms are also familiar to a failed choke opener. ( and running rich)

[g0dspeak]

It's a good idea to set everything to factory spec when diagnosing. Set the timing and then see where you are. There are people on here that know how to diagnose the different parts in these carbs. I would just rebuild the whole thing or do a Weber swap, if that's legal where you are.

Will do.

I was hoping to do a weber conversion soon. There are no emissions whatsoever in montana.


After you get the timing set, & warmed up, Check that the Choke is fully opened. Those symptoms are also familiar to a failed choke opener. ( and running rich)

Alright, i'll see what happens.

[A20A1]

Check the fuel cut-off solenoid at the back of the carb, it might be allowing fuel into the carb after the ignition is off, causing dieseling, high rpms will also result in dieseling.

1.5K-4K in gear or in Neutral?

You might still have a vacuum leak, but they can come from the gaskets, diaphragms like the brake booster, faulty valves, solenoids, air bleeds, not just the vacuum lines themselves.

This is just and rough write up but to stabilize the idle temporarily you may want to disconnect the idle diaphragm by the throttle cable by unscrewing the adjustment screw or removing the push rod, also disable the A/C idle boost diaphragm, if necessary remove the throttle cable from the carb linkage. Plug any hoses/lines you disconnect.
After all that you can run the idle solely on the throttle stop screw.
Warm up the car fully, Check that the choke is open and adjust the idle, then check the ignition timing.

If the idle is still erratic you may want to check the float level. Don't forget to blip the throttle every now and then with your hand. Some float valves leak and cause flooding of the fuel bowl which usually will flood the engine but I suppose it could also cause dieseling given the right conditions.




I was just eyeballing it just to try and get it to somewhat idle. I have a timing light.


Understandable
I've eyeballed it in the past using the indentations left from the bolts on the distributor housing itself as a reference point. :)

[senor honda]

+1 on the fuel cutoff solenoid at the back of the carb.
I swapped it out from a junkyard carb. Solved my dieseling problem.

Later I added a manual switch to use as a fuel shutoff.
as a backup if the ignition-off doesn't kill the engine.
At the same time I added a manual radiator fan switch as a backup
in case the normal wiring doesn't cut on the radiator fans.

A further tip:
I periodically walk through the junkyard and buy new parts
for my car from crashed cars, bag them and put them on the shelf.-Bob

[senor honda]

His quote:
After all that, you can run the idle solely on the throttle stop screw.

I have used this trick to get my car home when the throttle cable broke.-Bob

[g0dspeak]

Thanks for everyone's replies, I currently have the timing set I believe. or at least close to correctly set. I have the idle adjusted to about 1k rpms. The car still deisels and stalls 90% of the time when I drive it, every time I push the clutch in or go to stop at a stop sign or light, the engine will immediately stall out.

This weekend I will try what you suggested, A20A1.

Bob, I have a 88 a20a1 carb I got from the junk yard, i've already used the air vent cut off diaphragm off it, i'll try replacing the fuel cutoff solenoid with one from the junk carb.

Thanks!

[g0dspeak]

Alright so I removed the push rod from the idle. It runs on the idle stop screw now. The idle still likes to fluctuate from 1k-1.5k up towards the 2k range, in neutral.

While driving the car, it acts and feels like it is starving, when i feather the throttle it picks back up, i'm going to check the fuel cut off solenoid later, I also have a spare one from a junk yard carb, not sure if it works but always worth a shot.

[Oldblueaccord]

Make sure you have the timing set with the idle speed correct for your car (any car really). If your setting it at 1000 rpms or higher the advance maybe kicking in and giving you a false reading.

Possible the throttle shaft is so worn you can't get it to stay consistent and the vacuum leak when you step on it will effect greatly how it runs. Very very common on older carb cars. I have several atm that do it.


wp