winstarman

(See final post for resolution)

Argh! Truck (87 22r 2WD - no mods) fires up just fine and warms up but as the engine warms and the idle drops down it idles rough - to the point where if I lower the idle speed to OEM specs it stalls out.

Work done so far:
New carb from National Carb
Wires, cap, rotor, plugs
Timing checks out OK per FSM
Checked for vaccum leaks - none found

Before I put it up on the jack stands and did this work as well as a bunch of other work it was idling rough and backfiring through the exhaust (not the intake). At this point I'm thinking it's got to be ignition related - perhaps a bad distributor or a weak ignition coil??? Any suggestions would be greatly appreciated - I'm having fun working on it but I'd at least like to be able to drive it!

swampfox

Have you checked the egr valve ?

winstarman

I have not - what should I be looking for?

swampfox

The valve can stick partly open which can cause it to idle rough. I Have had a smog pump on a small block Chevy go bad ,and cause it to back fire intermittently.If it has one on the motor try unhooking the belt.

slow-mo

You very well may need to further adjust the new carb to your engine. The rebuild people will set the idle mixture screw to a standard setting, like x-amount of turns out, but because your engine is worn, the vacuum draw will be different from engine to engine. Therefore you will have to tune the new carburetor to the old engine.

The Toyota repair manual will tell you how to do this.

Oh, also check the fuel level in the float bowl. Make sure the fuel is in the middle of the sight glass.

winstarman

I've got the egr block plates on order and will respond once thats done. The float level might be a tad high, but I dont believe either that or the idle mixture isnthe problem. ive followed the fsm directions on both idle mix and speed but none of that has had any impact. The folks i talked to at team yota said my symptoms sounded like a stuck open egr.

winstarman

It appears the main issue was the EGR valve being stuck open. I purchased the block plates from YotaShop.com (http://www.yotashop.com/egr-block-off-plates-22re/) but it looks like my troubles aren't over.

winstarman

after dealing with this for months the truck does drive better, but appears to be running VERY rich (lumpy idle, high fuel consumption, bucking, strong gas smell). When driving, with the clutch in and decelerating, the idle is very high and then finally as I come to a stop the idle drops and quite often the engine stalls out.

A good friend of mine came by and helped me try to determine the cause - everything checked out OK -

We did the following:
Checked the choke
reset the timing (double checked to make sure new distro was installed correctly)
Checked plugs - a bit black, but not bad.
performed compression check 150-160 across all four cylinders
thoroughly checked for vaccum leaks (none found)

I plan on checking the AAP again (carb is less than 1 year old) but am at a loss as to what else could be causing the issues. Any help would be greatly appreciated.

winstarman

This appears to be resolved. Turns out the stock specs for the idle mixture screw and idle were WAY off on my reman'd carb from national carb. Ended up needing to only have the idle mixture screw backed out about 2.5 turns. Once that was done the idle was easy to adjust and it now purs like a kitten (which it should after everything I replaced.) Symptoms were rough & fast idle, surging during acceleration, stalling when decelerating as well as a tendency to sound like it wanted to backfire out the exhaust. All this was topped of by horrible gas mileage. Lesson learned is that the original problem was probably the EGR valve and maybe a carb tuning - in retrospect I don't think the carb needed to be replaced (but at least it's done!)

Thanks to those who helped out.

Farmhouse

Good follow-up with repair and symptoms. I am dealing with similar issues and it is nice to get some closure at the end of a thread.