'89 2.9 won't start. vacuum?

[RonD]

spark seems fine now. still no fire though (or very little) will check the fuel pressure.

what pressure reading should i be looking for?

'89 should have 30-40psi at the rail

 

[Josephus]

Ok, spark *seemed* fine, but it may have been weak. At least it was there.

In any case, fuel pressure was about 43 psi once I actually got the gauge to find it ( i had to keep from tightening the fittings down all the way on the schrader )

So, I went back to spark. Put in new plugs- no change.
Checked resistance on the plug wires- all b/w 6 and 8 kOhms. Too low??

Next I check cap/rotor, and finally fuel injectors?

 

[Josephus]

I still have no clue on the vacuum...

 

[Josephus]

Got back around to the truck and had a little breakthrough...

I sprayed gas directly into the intake and it fired up! Stayed lit too! This is strange to me since the ether test failed pretty miserably.

It will now start if it's only been sitting for a few minutes. But otherwise it's back to the no-start condition and i have to spray more gas into the intake. Fuel pressure still good.

lesson learned: just b/c ether doesn't work does NOT mean you don't have a fuel problem...

 

[RonD]

Never ran into that, spray gas working and starting fluid not working, may be an issue with that can of starting fluid.

If fuel pressure is good it could be the injectors are not vaporizing the gas, build up on the nozzles may just be dripping the fuel in the intake, so if cold the engine won't fire up, once warmed a bit it will.

What idle RPM is it at when first started and then after running a bit what does it drop to?

 

[Josephus]

idle wanders a bit, but i'll check...

 

[Josephus]

finally got the running codes off.
12, 21, 42, 13, 74

i'll be replacing the ECTS

 

[Josephus]

Replaced ECTS. wouldn't start cold, but after warm up i let it sit for a couple hours and came back and it started. I think that's an improvement.

Can someone explain how the fuel injection works in this engine? Do the injectors spray a mist or a stream? And is it straight into the cylinder or into some pre-cylinder intake chamber? Wiring diagram indicates it's a "bank to bank" system where 3 injectors are wired together. That makes me think there's some pre-chamber where the fuel is injected.

 

[Josephus]

Started cold twice today, so that's great. Now the problem is when it warms up it really starts to have trouble. blueish/blackish smoke (not a ton).

cold idle is b/w 6-800 rpm. Warm idle is in the floor. stalls out. i have to goose it to keep it alive after i've driven just a few miles.

added 1/2qt atf. transmission was shifting really bad but doing better i think. the engine running rough doesn't help though. it seems to downshift kinda late at stops.

 

[RonD]

The fuel injection is Batch fire, so on a V6 3 injectors open at the same time, PCM alternately opens the 2 "sets" of injectors.
Fuel is sprayed into the intake, so not directly injected into a cylinder.

This is similar to how a carb worked, the Batch fire setup keeps intake full of fuel/air mix regardless of which cylinder's intake valve is open, just like a carb did.

On the end of fuel injectors is a pintle or nozzle, it is usually a plastic cap that diffuses the fuel into a spray, these do get dirty and can cause fuel to drip instead of spray, this reduces fuel to air ratio in the intake.
Injector cleaners like Seafoam, or the additives in premium fuel, help keep the nozzles clean.

I am sure you have done all the regular fuel trouble shooting, fuel filter and Fuel Pressure Regulator(FPR) test.
FPR's are operated by vacuum, so at idle when vacuum is highest the FPR's diaphragm is pulled open so extra fuel is sent back to the tank via the return line, this keeps the fuel pressure at about 35psi.
You should test the FPR's vacuum line for fuel, if diaphragm leaks, fuel is sucked into the intake, and test if unhooking FPR's vacuum line changes fuel pressure, it should, fuel pressure should be between 30-35psi at idle then jump up when vacuum line is removed and FPR closes.

 

[Josephus]

Good info, Thanks.

Should i be able to remove the vac line from the FPR? Or just from the intake end of the line?

 

[Josephus]

what's the most affordable fuel pressure gauge?

 

[Josephus]

while i was checking the fpr i pulled the pcv to see if it would rattle. It does a little, but feels kinda stuck. the rubber grommet is absolutely toast (well, more like jelly)

 

[Josephus]

3rd self-reply in a row

replaced pcv- no help.. not even spraying gas into intake.

I cleaned the grounding points (except the engine grounding point- couldn't reach it- need a lift)
tried again- no start.

I pulled the TFI, It ohmed out good, so i put it back. no start

Checked the spark- looked good on drivers side.

I pulled the plugs, they were wet and black. Cleaned them up and replaced. Engine starts.
Idles around 4-500 pretty rough. Guess i'm running pretty rich right now?

 

[Josephus]

or could it be timing? I haven't checked timing yet.

I have cleaned out the IAC a few days ago. no apparent change.