89 toyota truck starts up after sitting all night and I drive 30 min to work and I go into work and tuck sets for 10-xxx minutes the tuck doesn't want to start up( almost like it starved for fuel). Eventually starts up but then runs super rough, sputter and hard to hold idle etc.

also noticed when it gets wet out or humidity here in NC is high the truck doesn't like to idle and acts like it's almost missing on a cylinder or something .

months ago I replaced my fuel pump, just did the spark plugs, also got rid of the smog stuff and capped the lines etc and seemed to ru. Good just idles low but overall good little truck...

advice pleaee

 

Start with basics. Fix^^ this first.

No issues starting in cold morning?
See "how Cold start injector works". This only applies while cranking.
Also check temp sensors. Those need to be cleaned at least once every 31 years Clean to bare metal, threads and all, and threads where they mount.
Also search hard cold start and rough idle. There is already a thread on that.

 

No issues starting on a cold morning but I'll ch ca the other sensors as you said and give it a try. Thank you

 

well, no offence, but i dont agree with just fixing a low idle first.
Because that would mean mucking with idle speed, when the reason for the low idle could be something else, like spark quality,, timing, or fuel or compression, and i would place a monetary bet that part of your desmogging didnt inlcude changing the idle settings, or changing the amount of air going in to the engine at idle.

This new issue sounds like a humidity related spark problem.
before you do anything that costs money, go out at nighttime, open the bonnet, get a spray bottle and spray a fine mist of water over the HT leads, dizzy cap, and all ignition components in the dark. I repeat, a fine mist (not flooding the engine bay lol). Watch for sparks.
If you see sparks, u are leaking high voltage. this often happens when the air is so humid that it cannot hold moisture any longer so it becomes very easy to transmit high voltage electricity over relatively small distances.
Like from HT leads across to steel mounting points or brackets etc.
U may notice it slowly gets better as the engine warms up, this is because the engine creates an area of heat around it which (in simple terms) dries out the air, both in and around the distributor.

 

lots of possibilities here.

could be as simple as no residual fuel pressure, which affects warm starts much more than cold starts. if this is the root cause, it can be "solved" by turning the key to "start" but NOT pressing down the clutch pedal for one second, then press the pedal while still holding key in start position (warm starts only - for cold starts, use "normal" procedure).

 

I like Thommo's suggested practical test^^^. I would do it, too.
hookerpilot47, Pls note someone else in this forum was seeing arcing from high tension (HT) wires to metal.

Withuot knowing This suggests that idle needed to be checked after the last thing hookerpilot47 did.

Yes. To eliminate doubt on pressure regulator, Wallytoo, a few others and I installed pressure gauge piggybacked on CSI.


This vacuum switching valve (below) controls fuel pressure regulator.


I don't exactly know when ECU does it but when valve exposes FPR to atmospheric pressure fuel pressure goes up as in this video:
https://photos.app.goo.gl/Xb8jVERhPA8JfpPx1

 

Gents,
did what you recommended and squirted the high tension cables no arching but when I sprayed on the top of ththrottl body where all he vacuum lines connect the engine dropped Down a ton on rpm Ns began to sputter and spit. Could any of you post some pics on how you routed your lines de-smogged . Do have a line that is left open and I thought that would keep the fuel pump pumping but I maybe wrong. Can you assist me ?

Should I readjust the idle after I square that away after I verify I have no leaks on the throttle body / intake area.

Thankd in advance

 

Well... looks like you have a vacuum leak. Look, feel listen to where it may be at.

 

 

hmmmmm well then. that was an unintended success in finding something hah
i recon uve forgotten to plug something on the throttle body and your going to find it now and kick urself.

 

What you all think? Advice or did. Do something wrong

 

What you all think? Advice or did. Do something wrong

 

Looks like your Fuel Pressure Up VSV is missing on one of those pics.
See this and
See Scope's explanation here.

 

id be trying to spray water in a very small spray around each hose infividually and see which makes it stumble. looks like uve tried to use hoses that are a bit loose and zipties em haha. good try, but it never works with vacuum hoses.

 

you all rock

 

Thanks, but what is a "Jen Hose"? Both sides of a hose are the same, It doesn't matter which ends are connected as long as they're connected to correct fitting.
What was reversed? Care to share to help other owners in the future?

 

ahhh ok, so it was also sucking in air through that reverse fitted hose?
yeh whats a jen hose? do u mean reg hose?

 

you all were right, the hose you labeled in red was hooked up to the other connector and the open air was chasing the changing in fuel pressure . Silly mistake for sure but makes sense in order to keep the fuel pump pressurized . I'll send pics in the am when it's daylight

 

We always appreciate fellow members updating us on what fixed their problems. (Others merely "walk away" without leaving information that may help others in the future.)

Actually,
1) If the hose marked in red above were not hooked up, your intake manifold would be sucking air; that's a major vacuum leak. That causes stalling or idling issue.
2) If the wire hose marked in blue were not hooked up, it exposes a mechanism in the fuel pressure regulator to atmospheric pressure (higher than vacuum) and raises the fuel pressure, but you would not see that without a pressure gage.

 

after I drive it 30 min or so then it’s sets for 10-xxx number of minutes it won’t crank hardly at all. I don’t know this is got me scratching my head, is the fuel rail losing pressure after it sets and then I have air in the system ?