rdharper

Why have we eliminated fuel pump/pressure?

thook

No we haven't. I'm just guessing. Troubleshooting is still pretty new to me and I am in the process of learning the mechanics of how motors operate. I was talking with a friend of mine this afternoon and that occurred to me....fuel delivery. It also occurred to me if it was a vacuum leak it wouldn't have run very well when I first started the motor....if it started at all. Is that correct?
Anyway, fuel delivery. I'm thinking maybe a sensor since it runs worse as it warms up...the temperature seeminly being a factor. Is it possible that the motor is operating, getting fuel, from the cold start injector from the start, and as it warms the fuel is being cut off?
If it were the fuel pump, wouldn't it have trouble starting or difficulty running early on in the warm up cycle?
The fuel press. regulator is new, but there is a vacuum line running from where the EGR valve was and I plugged it off with a screw. Maybe that was not the right thing to do? If not, what do I need to do with it? I've asked and searched and twice I was told to just plug it....the line that is. No pun intended!

rdharper

Before we go down that path, let me recheck something you said earlier on. I thought that you'd said when you disconnected the TPS, and before you retimed it, that it was maintain idle, not dying. Is that true?

In otherwords, if it has seen at least one setup among the several thousand you've tried, which has not resulted in it cutting off, the problem is probably not fuel, fuel delivery.

If it is fuel, there are lots of guys on this board that have much more experience troubleshooting fuel problems on 2nd generation trucks. You get into things like air in the line, fuel filters restricting flow against usage, but letting it sit allows it to rebuild fuel availabe for another (frustrating) cycle.. etc.

One thing I can tell you in troubleshooting... simplify the problem where ever you can. For instance, don't change a bunch of things at once. And as I've said, leave the TPS disconnected until you sort out the engine dying problem.

thook

Yes, I did say that. But, the problem has returned. Regardless, like you say there was a point it didn't die. Okay...simplify. Leave TPS disconnect and sort out first things first.
Sorry, Richard...I've been multi-tasking making it difficult to keep track of what's happening. I will have to start logging my results.
So, is what you're saying that messing with the timing could be causing this?

suprathepeg

Yea at this point it is a good idea. You will never get it to run well without the TPS but it will run. I don't know much about the AFM system but I experianced almost the same thing as you are describing this week. It was an easy fix as I had a hose clamp come off of my intake tube causing the AFM not to send the proper reading. I can't remimber if you said anything about the AFM in past but you might look there. And for the record the write-up on 4crawler's site wont work with the 3.0. You might try looking at the FSM.

thook

Okay, so the latest results.
After thinking about how long our vehicle sat before another motor was put in and it was running, I figure things were a bit gummy. We already had a vacuum flush run on the upper part of the motor and ran auto-rx through the crank after the motor installation. So, that was out of the way. Today I replaced the fuel filter figuring it couldn't hurt and probably needed it. Once I got the little PITA out, I blew on it to test and no air would go through! So, I put in a NAPA Gold/Wix and now the motor is idling smoother and isn't dying anymore. On the test drive, it had alot more get up and go....climbing hills at record pace, for this 4rnr anway. The only thing now is a little sluggish on idle return if you hit the throttle and let off. I haven't tested the AFM yet, but it looks sparkly clean. Which raises a question! Is there any adjustment to be made since the air box and ISR mod?
Anyway, I'm running a can of seafoam through the fuel on 1/2 tank to see if that will help any. Tomorrow, I will drive to town and all around and do the hoky poky and see what happens. Plus, I am making a several hour trip this weekend. So, I'll see how it all goes and post back.
Thanks again and again for all of the help fellas!

rdharper

There is a dashpot just to the left of the end of the throttle cable. Its job is to specifically slow down the drop in rpms when you let your foot off.

It could be sticking, dropping your rpm's too slowly, among other things.

thook

Ah! I wondered about that. I'll have to test it, then.
Thanks Richard! There may be an end in sight 'fore too long!

thook

Does anyone know where I can find a gauge to test the fuel pressure on this system? I have been looking all around!!!! I found a kit at Harbor Freight, but it doesn't mate up to Toyota (bosch, jetronic ?) systems. I can't spend more than twenty on this. Thank you!

thook

thook

Hello all....again!
Sorry to bore anyone to tears with this, but I made an interesting discovery.

Took a trip to Tulsa, OK (about 250mi. round trip) and CEL came on....code 26. Air/fuel too rich. Ran a number of tests as suggested on the FSM. O2 sensor, cold start injector, ECT sensor, the AFM, replaced fuel filter, ran cleaner through the fuel system....all to no avail as far as solving the problem.
The AFM tested fine on the ohms, but I noticed the fuel pump was running with the ignition on tonight. Reread this thread and this post particularly:

And the response:
He suggests checking the flapper. I know what that is, but what should I look for? Here are the specs when I tested the AFM:

VS-E2: 314ohms
VC-E2: 280ohms
THA-E2: (@ ambient temp. of 85*F) 1.7k ohms
FC-E1: Infinite

Now, I know there is a circuit open relay to test that can cause the pump to run, and I will test it also. Couldn't hurt, and atleast I'll know. But, how can the AFM test good and still be bad? Anyone have an idea of what's happening here?

TNRabbit

It's not that the AFM is bad, but maybe that the flap is stuck open. Take off the air filter and look up into the intake. That's where the "flapper", as 84sr6yoty so eloquently put it, is located. That flap is open when the engine is running, an so therefore could be telling the ECU that a running engine is present, therefore causing the fuel pump to run. The engine temp sensor can cause a rich fuel condition because the ECU is then richening the mixture to compensate for the cold engine. You can still get codes even those these sensors/meters test OK because of a bad connection or short in the wirign to those parts. Hope this helps!

You need to rename this post; as it's taken on a life of it's own, you should call it "the incredible '92 3vze that refused all efforts at troubleshooting" or some other appropriate name...

thook

BTW, ruled out fuel press./delivery. I called the mechanic who did the fuel system flush and at that point fuel pressure checked out fine. I found a gauge at harbor freight to test it myself a couple days ago, but the cheap gauge gave no reading...sat at 0psi....which is impossible because the vehicle will run. I plugged the gauge into the fuel input line from the tank (the only place it would go) and even with a slight leak the mechanic said it should still read something. Regardless, his readings were at 48psi before he replaced the press. regulator and on spec afterwards. Between now and then, it should still be just fine.
But, back to the AFM.....
Is there a good way to clean the inside where the flapper is....if it is sticking? I will search.

thook

LOL!!!!!!
Hey TN,
I didn't realize you were on and had posted. My puter is taking forever to load pages 'cause my wife is downloading some big file...we're sharing bandwidth. Tried replying to your pm, but it won't even load those pages under the present cirumstances. I'll get back with you on that, though.
Well, thanks for the tip....and the new thread title! Ha! So, what does this mean, man? Replace the AFM? Can I check those wires with a meter? You know I'll read up on it if I can just run some tests.

thook

Found this, TN!
https://www.yotatech.com/forums/show...t=AFM+cleaning

So, on an unrelated note...."V" does stand for "vane", but not in VAF. So, you weren't totally off. Know what I mean?

TNRabbit

I sprayed TB cleaner directly into mine. I would suggest taking the entire intake hose off as it is probably FILLED with oil goo from the PCV (I know mine was when I took it off for the first time @ 192k miles!). You have to keep the revs up while you do so. I ended up using two entire cans of cleaner (cheapo WalMart off brand).

thook

Pulled the air cleaner off, and everything is clean as a whistle under the AFM. There is this little probe sticking down that's plastic and greenish yellow in color. On one side, there is some discoloration....like that of a terminal jacket having burned from a short. I don't know what I'm looking at, but would you, TN, or someone have some reference for this? Is it normal or indeed a short? Maybe someone would be so kind as to look at theirs for comparison?

Pulled the TB off...again.... and looked in there because I found oil towards the top of the intake tube near the TB port....again. And, of course, there was oil in the TB and inside the plenum. It had especially collected at the port where the EGR valve used to be....puddled. I think I've asked this before, but is this okay? I know the vent tube from the valve cover is the source, but it seems to me this is not desirable at all. ???

Onward through the fog.....

thook

One more thing, does it matter the direction the TPS is pointing when being set? The terminals facing the intake or away from? I know...I've asked this before, too. I called the dealer and they say they've never seen one come in that did not face the intake plenum. However, he said if it worked facing away, then fine. I only ask again because his answer was vague....that he really didn't know. It would be nice if were true because then I could easily verify a hand adjustment with a meter.

TNRabbit

TPS terminals face the intake.

Oil in the intake is a constant problem; some have put a container inline between the valve cover & intake hose to collect the oil/goo.

thook

Okay on the term.'s. It's interesting, though....I wonder why in the Haynes manual they would picture it facing away from? No matter...

Yes, I read about that container trick. So, the oil is common and not a malfunction of some sort then? Just poor design?