I drained 10 gallons just for the odd chance. Nope. still idles rough

I will drain all fuel out, pull filter, flush tank with something, reconnect and try again.

 

Maybe try a smoke test or other way to find what may be a tiny air leak.

 

car idles rough but better with most of fuel out. could this be Fuel Tank Press Sensor fault ?

what does one perform smoke test on, just the connection from air filter to TB ? I have a cigar I need to smoke.

 

I will empty fuel tank, flush tank with some new gas, change filter, add 5 gallons of new gas. and see what happens.
Also pull stuff away to look at tank. Maybe I can access FTPS

 

FTPS signal is 3.3 v. with gas cap on or off.
it would give 4.9 v at high pressure and 0.2 v at low pressure.

 

emptied the tank and FTPS still reads 3.3 v, that seems to be wrong, anyone have knowledge of the sensor?

 

disconnected FTPS, no real change but I got the error code for the sensor which I guess is a good thing
more tomorrow

 

I did a smoke test with a cigar and hand pump, smoke coming from lower part of intake manifold???
coming from underneath both sides.

 

photo ?

along a gasket junction, or…… ?

hard to visualize exactly where you are meaning (for me).

Z

 

the smoke was faint but appeared to come from intake seals, all of them

that does not make sense to me

I will do it again when I get some cheap cigars

maybe the engine breather hose cracked on its own?

 

If you mean between the base of the intake manifold and the head then you have a serious vacuum leak due to failed intake gaskets. They are essentially o-rings and they do get hard and flat over time. They are not very expensive, and fairly easy to replace.

 

engine breather hose looks fine

I replaced those gaskets in 2020. when I had to do valve job on the car.

would spraying MAF cleaner at them while idling engine be a discerning event?

 

I use brake cleaner, and yes, that's how I found some kind of weird crack in my intake. Spray between head and base of intake and if the car stumbles, you're on to something.

 

more smoke from some cigarillos. and the leaks are coming from 3 injector seals. I just had them checked out and I reinstalled them. maybe I did not push the seal down far enough !

 

I learned from my mechanic mentor 55 years ago, one does not need to use a flammable spray such as carb or MAF cleaner to detect an intake leak.

just plain water in a spray bottle will do just fine, and it will cause a change in the idle speed, no problem. And with water there’s zero danger of causing a fire.

Z

 

could I have dislocated those seals by blowing on the tube I used for the cigar smoke?

tomorrow I will reseat them and see if the car is better

 

No. My guess is that the injectors aren't attached correctly at the clips at the top where they attach to the fuel rail. DO NOT ask how I know this.

The clip fits into grooves in the injector body, ensuring the injector is the correct "length" from the rail. So, when you bolt down the rail the injector seats firmly into the intake seal. I suppose it's also possible that the rail wasn't bolted down tightly and has worked itself loose. That might cause similar symptoms.

 

yes, I had pushed the injectors too far up into the fuel rail and the catch caught on the wrong slot.

put in 2 gallons of previous gas and now idles much better at around 900. but I do not know why this all started. I will put fresh 5 gallons of gas in and see if that helps

 

After all this I suspect the FTPS is faulty, as noted earlier the voltage does not change from 3.35 volts whether empty or full tank. Current voltage is 3.35 V
with empty tank and gaS CAP OFF.
Does any one know how the FTPS interacts with the vapor recovery system?

 

so I slid the tank about an inch out of its position and was able to pull FTPS out. connected to DVM and with a hose I barely added some pressure and voltage went up, sucked on tube and voltage went done

that is opposite from what wiring diagram fig 04.1 states

anyone seen this before