sleestak240

My '87 22R-E has been having cold start issues for a while that I've been trying to diagnose, but I have had little success. After leaving my truck 7-8 hours overnight, the first start of the day is a little rough, with the RPMs coming up, dropping below 400 once, stuttering, and then popping back up to a normal idle...I don't have to give it any gas to help it out.

I've adjusted the TPS to get rid of a diagnostic code #11 (truck idles great and gets better throttle response now ), replaced the cold start timing switch, and cleaned the cold start injector pretty thoroughly. Resistance across the terminals everywhere checks out. I'm not quite convinced that the injector is actually functioning properly, so I'm going to do a check this weekend after I leave it overnight. Is there a way to safely activate the cold start injector off the truck without the special service tool?

I've searched several places for solutions and haven't had success with anything. From the Toyota Service Manual I have, it looks like the auxilliary air regulator could be another part of the system I might want to check out...but considering that it's kind of a PITA to get to, I'm wondering if anyone here has ever seen one of these acutally fail? What about the water temp. sensor (seems to be indicating reasonable resistance values).

One last question...could this be a symptom of a leaky head gasket? I see no obvious signs of serious head gasket problems...no smoke from exhaust (just some water), no oil in coolant or serious coolant usage, the truck does burn some oil. I put about 1/4-1/2 quart of Castrol GTX High Mileage in every 3-4 weeks.

This is a little long winded...but any suggestions?

4Hummer

You can add 12 volts to the Injector for short burst and see if it engages.

Or take it to an injector Shop and have them test and clean it.

84sr5yoty

If the truck starts immediately, than it's not the cold start injector or the time switch. The auxiliary air valve has full control of the cold idle RPM's.

I'm only familiar with the 83-85 22re air valve designs, so I can't give you any advice other than to follow the FSM instructions on testing it. I believe yours is incorporated in the throttle body, vs. the older design that has a separate valve below the intake plenum and manifold.