Fuel, air, spark...but still no start. Is it user error? Am I *that* dumb?

[RayRay]

Throwing myself at the mercy of the Repair Help Forum. I'm wound up in knots, head spinning, having a reeeally tough time here.

93 fuel injected, 5-spd, ~350k miles, bought a year ago after ~5 years in a barn, and have put ~4k miles on it since then. Ran reasonably well, had the common random power loss issue, but unsure if that pertains since it always randomly went away as fast as it came.

A month ago it lost power while driving, felt like it was on 2 or 3 cylinders for about a mile (felt different/worse than the usual random power loss), then died and wouldn't restart. I have fuel (plugs are wet), I have spark (tested each one individually & watched em fire...three had nice hot spark and one was mediocre...dunno if that's a thing or not), and it's getting air (tested the Batt+ and the REF from the VAT connector, they had 6.35v and 6.5v respectively, and I think that's good, right?).

Codes were 8, 9, 10, and 17.

Tested the VAF by replacing it with a used one *thought* to be good...didn't work...might still be the problem but I'm stumped where to go with it.
Tested the ECT by dipping it in warming water on the stove...watched it go from 2000 ohm cold to 255 ohm at 180 degrees, so I believe it's good.
Tested the VAF connector for voltage as stated above.
Assuming a bad O2 sensor won't stop it from starting.

Poured gas down the booster's vacuum tube into the intake, and after ~10 seconds of cranking and vigorous stomping on the gas pedal, the engine roared to life, as high as it could go, and then just as quickly died again. Repeated the experiment and got identical results.

I've put in new plugs, wires, cap, rotor, and fuel filter, since it was time for all of that anyway, to no avail. And now...after a month of searching and reading and more searching, I'm just stumped. :banghead:

Any help GREATLY appreciated!

[ryanprins13]

The random power loss followed by how it died was exactly what happened to me. Could be a different problem for you but for me it was whatever was in the distributor that sends a signal to the coil that quit. I replaced my distributor with a used one and it was fine after that. iirc i still had spark but it was coming at the wrong time or weak or something.
Anyhow, could also be a loose wire or ground, but if you have a spare distributor try it.
My random power loss was like 1/4 secomd at first and gradually got longer over about a year and was almost a full second when it would happen just before it died and wouldnt restart.


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[chrisofna]

Check compression and timing.

[FestYboy]

^ this, we need those numbers.

[TominMO]

The random power loss followed by how it died was exactly what happened to me. Could be a different problem for you but for me it was whatever was in the distributor that sends a signal to the coil that quit. I replaced my distributor with a used one and it was fine after that. iirc i still had spark but it was coming at the wrong time or weak or something.
Anyhow, could also be a loose wire or ground, but if you have a spare distributor try it.
My random power loss was like 1/4 secomd at first and gradually got longer over about a year and was almost a full second when it would happen just before it died and wouldnt restart.

This is also symptomatic of corrosion building up where the disty wire plugs into the coil. Disty caps get changed regularly, so it doesn't happen much there, but the coil is usually on the car for the life of the car. Pull the wire and clean the tip off with sandpaper, then do the same with rolled-up sandpaper in the coil connection.

[bravekozak]

Gas must be squirting out of the injectors.
Air must be getting sucked into the engine.
Spark must be at the tip of the spark plug.

Gas + Air + Spark

Check for proper firing order.
Advance the timing a little more.

[bhazard]

If it fired on gas dumped into the intake then it must be a fueling issue. Make sure the pump is working and the injectors are firing.

[firebush357]

Need to add compression to that equation, I found that out first hand lol

[firebush357]

If it fired on gas dumped into the intake then it must be a fueling issue. Make sure the pump is working and the injectors are firing.

There is a test connector near the brake booster that when grounded will turn the Fuel pump on. Would it make sense to ground that and then try to start to see if the VAF is sending the signal for fuel? Might help eliminate a few things

[RayRay]

wwwooowww...I am *so* grateful for all the help, guys...sincere thanks!!!!!!! :-)!!!!!!! I'm *extremely* limited financially and physically (and mentally at this point!) but I'm committed and Will Not Give Up On This Car. I just hope I can keep up with yall.

As requested, here are the compression test results:

1 - 141
2 - 150
3 - 137
4 - 149

This is actually marginally higher than the results from a year ago. I use "Restore" brand Engine Restorer in the silver cylindrical can every oil change, so I'm not surprised. Been using it for >15 years...but that's for another thread.

I've read a thread titled "Engine cranks, but will not start" posted by krock26 on 8/12/2015. In it was this post from William:

I had a Similar problem with my b6d and turned out to be the coil.
I had spark. But the spark was orange. I swapped it with a spare and it fired right up. I was so shocked I had to swap back to the other coil to see of it was really the problem or just a Coincidence.

I realize it's a different thread, but does anyone think it could be this simple? I have white spark from 1 & 2, orange spark from 3 & 4, and the spark seems to be strongest at 1 and weakest at 4, dropping gradually.

Regarding timing, I don't have a timing light but thought I'd at least remove the top timing cover to check the cam timing...but had to stop due to physical limitations. Got two of the bolts out, will work on the other two again asap. Was able to pry it back and view the timing belt which looks good (from that view, at least). Have read that it's rare for a Festy to slip a tooth, and given that it ran smoothly (albeit at wide open throttle seemingly) with gas poured into the intake (as mentioned above), I'm not inclined to blame a cam/timing issue. I could be way off track though...

[firebush357]

I am not saying you should do this but it may shed some light on the situation. When the car I was working on was 1 tooth off I was getting numbers similar but I could still get it started by moving the distributor all the way to the right or left. It wouldn't run well but it would start and halfway idle.

[ricko1966]

If it fired on gas dumped into the intake then it must be a fueling issue. Make sure the pump is working and the injectors are firing.

If it starts on added fuel your compression is fine. You are in time, Your spark is strong enough. You have a fuel related issue, like bhazard said,Bad fuel pump, out of gas,no injector pulse etc.

[ryanprins13]

Can you check your fuel pressure? Iirc there is a shrader valve on the fuel rail.

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[WmWatt]

dirt in the gas tank? clogged screen?

[RayRay]

UPDATE - FIXED / SOLVED

First and foremost...my most sincere thanks to everyone for their assistance, and my apologies for the delayed update (took me till yesterday to determine the problem, thanks to health issues). The problem was fuel delivery...but not what I was expecting, and therefore, not what I was looking for. I tend to only find the solutions I'm looking for, so I was missing this the whole time...heh...

The power wire to the fuel pump had been re-routed by someone in the past, and it's new path allowed it to rub gently and eventually rub through the rubber coating. It'd short and lose power to the fuel pump, and then vibrate an inch or so over and no longer short out, and then it'd vibrate some more and bounce back to shorting again. The car has a pretty serious vibration problem, thanks to worn mounts up front plus a huge hole in the exhaust pipe under the cabin. The wiring to the fuel pump wasn't secured nor protected well enough, and it caused the fuel pump to cut out intermittently, all while parked in the same spot. Unsure if this could have been going on while driving, as it did indeed have random and short-lived power losses, but no dying on the road (until the day it died and wouldn't restart).

The way I finally figured it out was while looking at the fuel pump wiring and not finding anything wrong, probing and testing the wires and getting good signal, but then after many days and many attempts to start it, I noticed a newly empty fuel filter (I have a clear secondary filter to help eyeball what state the primary filter is in, and it was full when I first started this post). With an empty fuel filter, I re-tested the pump wiring and sure enough, no power. That led to chasing the wiring from the pump forward, and ultimately found the offending worn spot in the power wire.

This does make me wonder why a grounding of the fuel pump power wire didn't cause a fuse or relay to blow. I don't have the schematics in front of me (and I tend to forget things if they're not right in front of me), so I'll be returning to the books for that answer, unless anyone chimes in with an answer or any other hints / advice pertaining to this whole debacle. Note that this car has >350k miles on it, with a history of being abused by jerkface previous owners who did things like cut the black code retrieval connector from the under-hood harness and wrap the exposed end up into the rest of the harness with electrical tape. Why would they do that? Who knows...but I'm not impressed with their long term thinking...heh...

Again...my most sincere thanks. The tips provided above were what led me to checking out the fuel system...and that's what led to finding the offending wiring issue. Cheers! :-)