Goss

This is my 89 3vze. Very sluggish, but that's for another day. Truck idles fine in park, neutral and reverse(auto trans). Put it in drive and it will slowly go dead. I'm putting a pic of the truck and the location on the missing vacuum line.

right now, I'm just wondering where the other end of the line connects to, and what is the purpose of that line. Any help would be appreciated.
Thanks in advance.
Roy


In this pic, three vac lines coming from one connection, but one lines is missing.

Sturmcrow

If you are talking about that plug in the middle of the photo, it is supposed to be there. I think maybe it plugs into cruise control or some other factory option, if you have it.

That connector just to the right of the vacuum plug is your cold start injector. That wire looks kinda messed up. If it is not working, you will have pretty hard starts, though I do not think it would die later (after starting).

You may need to read up on the TPS and VAFM and how to check them both out.

Goss

you are correct. the vacuum port above the lines labled #1 and #2 actually has a "cap" over where a line would go. never noticed the end was closed off.

Anyway, to restate something in my initial post, the engine idles fine in reverse with the brake on. Putting it in drive makes it sound like a harley on a cold start. Lopes like it has a 3/4 cam in it then dies. Cranks like it is new. I'll check the two suggestions you gave and see what happens. THANKS!!!

Roy

Goss

ok...i've done a little reading on the two subjects(tps and vafm). Would anyone be able to fill me in on how either one of those can tell if the truck is in reverse or drive? From what i could glean from my reading(and a little logic), throttle position and airflow should be causing this in reverse just the same as drive.

would there be anything else to look for? I have a mechanic bud of mine that is gonna look at it this weekend.

thanks.

Sturmcrow

Personally, I think TPS and VAFM are somewhat kneejerk responses whenever there is a problem with engine power or idle. You could still check the signals coming from them with a voltmeter to see if they are within spec. The FSM will tell you how to test them, and a quick search will net you the FSM for your truck.

I am certain that someone more knowledgeable than me will chime in, but I think there are two main places that you could look. Obviously the transmission knows what gear it is in, and so does the ECM. It is possible that you have a frayed wire somewhere or a faulty ECM that is causing your problem. You might want to check the signals from the TPS and VAFM at the ECM, rather than checking them at the plug.

Getting away from the electrical side, there could possibly be a problem with the linkage between the throttle and the tranny, but I am not sure how that would cause the problem you are seeing.

bone collector

first off... any check engine lights?? that picture you posted shows that the cold start injector wiring is messed up, which will affect your engine performance before it gets warm. Second, is there any vacuum leaks in that general area?? check for leaks with a propane torch that is unlit and the engine running. if the engine revs up there is a leak in that area. Toyota's have miles and miles of vacuum hoses that can cause problems. Third, since you say that it idles better in reverse than drive, leads me to wonder if you have a transmission problem. When is the last time you changed the fluid and filter??

ksti

You mentioned "sluggish" it's possible that's why your idle is wonky.
What have you done service wise lately?
Have you checked for stored codes?
Do you have an Factory service manual?
Does the idle change only when applying brakes?

Goss

WOW...you guys are insane. Ya'll sound like me when people call about laptop and pc problems(yeah, I work on computers). I'll get right on those things guys and let ya'll know.

Thanks again.