No start: Fuel line pressure when removed?

[Safety Guy]

I got to work yesterday and went in to change.

When I got out, my stock '92L 5 speed wouldn't start. It caught a little once or twice, then just turned over with nothing left. It sounded to me like no fuel. Cranks strong though.

This morning it still wouldn't start, so I took off the fuel line at the rail and a little bit dribbled out. I got some more out when I lowered the fuel line. I then put the line in a bottle and cranked and cranked. No fuel in bottle.

Seems like a fuel issue. So I put in a new fuel pump this morning.

Still won't start! Still no fuel coming out of the fuel line up front. I just got home from my Dad helping me and I have his truck. I just loaded the truck with more parts, my shop manual, multimeter and an extra VAF (another theory).

Any ideas while I sleep? Any are appreciated.

I'll be reading the manual tonight and doing more tomorrow morning, but I figured I'd ask for ideas. It wouldn't be the inertia switch, would it?

I'll also have to figure out where to check for continuity to the fuel pump. It could be a broken connection somewhere, methinks.

Thanks,

Karl

[muscle_Car1]

Do you have spark? I was trying to figure out the same thing but from the spark side. In my case it was the main relay behind the driverside headlight, It was rusted real bad.

Just a thought, as its kinda the same issue. Parked it, wont start again, no fuel pressure, no spark, cranked great.

[Safety Guy]

Thanks Kemp. I'll look into that. Didn't think about spark.

Karl

[Mike McKown]

The inertia switch would be a good thing to check. The car ran to the parking lot and wouldn't run back out. Maybe somebody bumped it in the lot?

I think the fuel pump is energized by the start circuit while you're cranking the engine then switches to the VAF when you return the key to "run".

One of your fuse links under the hood controls the juice to that pump too, I think(?).

[Safety Guy]

I had Twinstiva towed home today. Inertia switch push didn't work. I checked for spark (yes).

Next I'll try another VAF and the power thingy in the LF fender. I should be able to use the power thingy from Luxstiva.

Karl

[Safety Guy]

Could engine oil leaking into the intace fry the VAF?

Lotsa oil in the VAF that I began cleaning/draining out. However, it started to rain, so I'm in hiatus.

I'll try my spare VAF, which is defective but generally works (something's loose and occasionally cuts out on bumps).

After that I'll try another "power relay" (what I called a "power thingy" before).

Unfortunately, the shop manual doesn't have "troubleshooting" like I thought it would. Gotta find my Haynes...

Since she's not running, it'd be a good time to switch to fuse blocks from my old links, too.

Karl

[Safety Guy]

Dave G came over today and we examined Twin. Checked and rechecked to see if the fuel pump was coming on when cranking (no). Looked in the shop manual for electrical diagrams and/or diagnosis of fuel delivery problems (no).

Was looking at the fuel pump relay under the dash, then I decided to swap the power relay under the hood (LF corner) with Lux's unit.

BINGO!!!!

It was a bad power relay! My next trip to the 'yard I'll grab a couple extras.

Some points for those who have fuel delivery problems:

-fuel pump only runs when engine is cranking
-someone who feels and/or listens to the fuel pump should be able to tell if it runs
-VAF is also a part of the fuel pump electrical circuit, so a bad VAF is another potential problem
-fuel pump relay under dash (manual says mid dash, but mine is on left)
-power relay at LF engine compartment (my problem, as noted above)
-inertia switch could be activated or come unplugged (when I originally got Twinstiva, she was not running, and her problems were unplugged inertia switch and a bad VAF)
-of course, the fuel pump could be bad
-electrical wires either loose or broken (continuity)
-clogged fuel filter or lines could be at fault too, I suppose

Since I pulled my fuel line from the filter and found no fuel moving while cranking, I knew it was a fuel delivery issue. I just had to find the cause, and my electrical checking skills are primitive, at best. The shop manual does have a good description of the whole fuel system and how it works though. Good to know.

If you have other FI Festivas, it helps because you can swap parts from known running cars. For those with carbs, I can't help you.

Karl

[scitzz]

Good Work!

[freshtiva]

"-VAF is also a part of the fuel pump electrical circuit, so a bad VAF is another potential problem"

The fuel pump switch is in the VAF, thats why the fuel pump only works when the engine is cranking.

[Safety Guy]

This was a big relief, especially since I'd begun clearing out my garage to begin some serious car work soon. Having my DD go down was a bummer. However, I was lucky my Dad leant me his Toyota PU truck to use to get to work, etc.

As for Twin's new fuel pump, Kay Sera Sera, as Doris Day would say! She was running on a j/y unit, which will be put away for emergencies. I don't mind enhancing reliability too much, save for the full price I paid at AZ: about $170 for pump and sock. Ouch!

Twinstiva's now at 84+K miles. Still a youngin!

Karl