Gevo

So the last problem was solved, new injectoe and engine runs great. On to the next problem. Sorry this turned out a little long, I need some advice!!

I was adjusting my tps, I dont really know what the heck im doin but I figured I should start by adjusting the throttle stop screw to its correct position. I wasnt entirely sure so after some reading around I adjusted the stop screw to just hit the tab when the butterfly valve is completely closed. I did that and realized my idle was now way to low, I turned the idel control screw and at some point it started not making a difference. I figure this is the end of the effective zone. Problem is my idel is like 400, way to low.
Also when I just begin to give it gas it stutters a tiny bit. Then on releasing throttle it stutters and sometimes shuts down.

Im 99.9% sure I dont have a vacuum.leak. I checked it a bunch of times with carb spray.

Then I thought to isolate the egr, no change. Then I pulled a vac hose off of the pair valve and let there be a vac leak purposely, the idel started to run much better with the extra air.

Now im trying to figure out my next move. Timing is at 10 btdc. I feel its running a bit rich and the idle air going in isnt enough, how can I adjust the timing to compensate? I know that question almost doesnt make sense, but I also remember when playing with timing the engine would idle faster when setting spark 14 or so btdc.

Please your thoughts!!

hyo

iTrader: (1)

i found out that if you adjust the idle screw and it doesnt change the idle, that usually means you have a leak in the intake area. what my problem ended up being was the intake manifold had a leak because i had forgot to tighten one bolt.

also when you are doing timming are you jumping the pins? the check like should be blinking or on.

Gevo

Well I replaced an injector today and so I put the plenum back with a new gasket and the bolts all tightened to spec +4 lbs.im 99% sure its not a vac leak in the intake area.

And yes I do jump the pins.

Punchy

http://personal.utulsa.edu/~nathan-b...93throttle.pdf

Gevo

Punchy, I have that section printed out and by my side everytime im working on those components. However im glad you brought this up.

Some things are unclear to me in the fsm.. my 91 3vze does not have a throttle openner, right? Also I dont understand what step 5 is saying. It refers to an air valve and idle screw. Is the air valve the butterfly valve in the throttle body? According to step 5 is the engine supposed to run with the idle screw al the way in from the air it gets through the air valve? In my own world I set the stop screw to the butterfly valve when it is fully closed, then adjusted the idle only with idle screw. If I put the idle screw in all the way the engine dies.all the way out max idle is under 500.

ksti

There is a o-ring on the idle air screw that gets hard and brittle and will affect idle adjustment. Replace it and see if you can adjust idle.

Gevo

Interesting, I will replace it. Although, I doubt it's causing my issues.

I have a feeling it's my own lack of knowledge in adjusting a throttle body that is the problem.

Gevo

I searched some more on here and found my answer to the throttle openner question, unfortunately that doesn't solve any of my issues.

If one of you geniuses can tell me what to do, i have today to fix it.. tomorrow mechanic.

Gevo

Ok Guys, I think I've got her figured out aftr reading about throttle bodys in general.. etc.. I just want to know if anyone can tell me what is the proper idle speed for the 3vze when the idle screw is screwed in all the way. THe SM says (sort of repettitively) that is should drop below idlespeed, and then again it should drop below idle stop. I have no idea what that means.

Thanks!