Help: 22R Engine Dieseling Problems

[22RYota]

I Got a 89 Toyota 2WD Mini Truck with a 32/36 carb, The problem is everytime I shut the ignition the motor seems to run for a few seconds and then shuts off, sometimes it sounds like the gas is spitting back to the intake.... Since I can't get the the timing to be 0degrees BTDC, I got it on 5 degress, its weird because it doesn't want to go back to zero, maybe it could be that vacuum advance unit on the distrubutor, or maybe the carb is to lean??, carbon deposits??? or maybe the timing is just f*cked or vacuum leaks... Help guys I need to solve this problem... Thanks

[GregoryM]

Too many rpm at idle is the first thing to check. Adjust curb idle to specification. Idle mixture screw should be adjusted for "lean best idle". Initial timing should be set according to proper proceedure: vac. advance disconected and plugged, correct idle speed. 5 degrees initial sounds about right for your engine. After tightening down the distributor, increase rpm's and observe if the timing advances smoothly. This should get you in the ball park. Good luck.

[GeneralBenson]

my 22re does the same thing. but ti constantly idles atleast 1000 rpm, then it will go for 3-4 seconds after ignition is off. why does it idle so high?

[Billy_The_kid29]

reasons for dieseling:
1 idle speed to high
2 ignition timing incorrect
3 incorrect spark plug heat range
4carbon build up in combustion chamber
5 valves sticking
6 bcdd or ficd system not operating correctly
7 valve clearance incorrect
8 intake air leak
9 egr system not operating correctly
10 fuel shut off system not operating correctly


reasons for high idle:
1 sticking throttle cable
2 choke opened excessively at idle
3 idle speed incorrectly adjusted
4 valve clearances incorrectly adjusted
5 dash pod out of adjustment

[SpeshalK_82]

My 32/36 carb does the same thing. But, with my idle screw backed all the way out it still idles at about 1000 rpms's. My local toyota man told me that many weber carbs diesel back and that you can purchase an anti dieseling solenoid that will correct that problem. I haven't purchased one yet. But if you can get your idle anywhere below 1000 your truck should shut off fine.

[GregoryM]

GeneralBenson: Note the original post refers to a carburetor. Your engine is fuel injected. Your high idle rpm's could be related to the throttle position sensor. The trouble shooting sequence is different from a carburated engine so you will have to proceed accordingly.
SpeshalK-82: If your curb idle screw is all the way backed off, an anti-dieseling solenoid (throttle positioner) will do nothing for you. Check for vacuum leaks, initial timing, stuck throttle blade(s). Good luck, guys.

[SpeshalK_82]

GregoryM- when i turn the mixture screw down, the idel does drop below 1000 rpm's where i want it, but the pickup doesn't idle quite as well as i would like. If i were to start with the mixture screw all the way down tight, about where should it be set at? how many turns approximately?

[GregoryM]

The idle mixture screw should be approx. 2 turns out from lightly seated all the way in. You can fine tune it after the engine reaches normal operating temp. Note that this is not the "curb idle" screw which adjusts the position of the throttle blade at idle. There is also an adjustment for the idle position of the secondary throttle blade as well. Anti-dieseling throttle positioners were indeed used on some Weber/Holley applications for emission control but, I don't think they are needed in most after market conversions. Once your idle mixture is adjusted properly, then adjust idle speed with the curb idle screw. I prefer to adjust the idle speed to around 700 rpm. If you still encounter run-on after shutting of the ignition, you may have some more serious internal wear or damage issues. You can set the parking brake and just engage the clutch with the transmission in gear while shutting off the ignition and the engine will stop. We used to do this in the old days when we ran ridiculous cams in muscle cars. The dang things would barely want to idle at 1000 - 1200 rpms! LOL

[SpeshalK_82]

Thanks GregoryM-
I am currently letting out the clutch and turning off the key to kill the engine. I will work on resetting my carb mixture screw and idle screw. One question. where is the adjustment located for the secondary throttle blade?

[GregoryM]

The adjustment screw for the secondary throttle blade is in the base plate and can only be adjusted from underneath. The carb. must be removed from the manifold and a small slotted set screw is accessable from the bottom. Although anything is possible, it probably doesn't need to be touched. BTW, Holley 4 bbl. secondaries are adjusted the same way. I hope this helps you get that 32/36 working a bit better. It is a great carb. and a huge improvement over the stocker.