What is this? throttle linkage

[SDHNTR]

I have had this problem that two Toyota independent shops have not yet been able to solve. 1988 22re. My truck starts great when fully cold after sitting over night, and it starts great when fully warm after having just been run. But if I run it up to warm and then let it sit for a while, it starts hard every time. It will either crank for a long time or start, then immediately stumble and die. Fuel pressure has been checked and it's not the problem. I think it is air flow. I have figured out a way to work around this and if I step on the gas pedal just a tiny bit while cranking, it starts right up easily. Which is why I think air flow.

So I started inspecting the throttle linkage to figure out exactly what happens when I step on the pedal a bit. Doing that is what makes the car start easily so obviously I went looking there for a solution.

I found this little nut, that adjusts a stud that seems to sit on top of a valve and shuts it down or opens it when you step on the pedal. I'm assuming this controls air flow into the throttle body. When I hold the gas pedal down a bit to make it start, I noticed that this little stud comes off this valve and allows it to open. So I figured, what if I take a few turns off this nut, thus allowing the valve to sit open just a bit.

I did that and it seems to start better now, but I haven't driven it enough to say for sure. So what does this valve do exactly and am I on the right track here? Anything negative that could happen by taking a few turns off this nut? Thanks.

 

[turboSR5]

That is for your dashpot, all it does is keep your throttle blade from slamming shut when you let off the gas pedal. The screw you are pointing to is just to adjust how soon, or late the dashpot gets depressed after letting off the throttle.

 

[SDHNTR]

So it would have nothing to do with starting then right? Hmmm, not sure what to do next.

 

[turboSR5]

I would check out your AFM and do a vacuum test on your EGR.

 

[off-roadtoyboy]

You say that it is an 88, that year they ran an idle air control valve. If you say that it is lacking air on start up you may want to check the passages in the Throttle Body and the hose that comes out the bottom 1st, blow them out with starter fluid. 2nd you need to check the idle air control valve, it right under the throttle body (that hose that I said to check goes right to it) a factory service manual will tell you check the the resistance on the back side of the IAC valve at certain engine temps. see where all that gets you.

 

[SDHNTR]

Good suggestions, but I just replaced the IAC. I thought that might be the culprit and swapped it out. Didn't help. The hose is clear and I gave the throttle body a thorough cleaning too. Did the EGR vacc test and it works as it should.

What is a good way to check the AFM?

The only reason why I say it is air flow related is because if I tap the gas pedal, or hold it down a bit as I crank, it immediately fires right up without hesitation. That tells me it is an air flow issue. Make sense? So what is that telling me?

It only does this after the car has been run and set for a while and is luke warm. I cannot tell if it is a temperature issue, or a sitting for a certain amount of time issue.

 

[off-roadtoyboy]

The manual will tell you how to check the AMF. yes and no it sounding like a air flow, because when you puch the throttle your also telling the computer to add fuel by way of the TPS. every time I think of something els that it could be another item cancals it out of the pic. Work on finding out if it is a time thing or temp.