Skip to main content ↑ ↓
Topic: 1990 351w EFI problem / quesiton (SOLVED) (Read 1986 times) previous topic - next topic

1990 351w EFI problem / quesiton (SOLVED)

1990 ford bronco 351w EFI which everyone else here but me drives.
situation:
I was running up and down the driveway sping ice and the xfer case was in 4wd low range.  Time doing this span about 30min (6 passes in first gear) and the rpms were about 4k up hill and about 2k going down hill.

Problem:
out of no where the bronco would not start.  Engine cranks and sounds like the timing was off or like it wanted to recoil and backfire. No smell of excess fuel. Catalytic is gutted and smog plumbing is unhooked from the heads.  Egr block off plate is in place and no EVP is hooked up so codes are EGR related only.

Testing
Fuel presure is 41psi
installed remote starter and visually checked spark at plug 5 and it was nice and blue/white
checked coolant and found i could not see any at all down in the radiator.
Injecter blink test failed.  I had no pulse going to any of my injectors although i only checked two.
Added fluid but lost precious time in troubleshooting because i had to drive and get a couple gallons.  I was hopeful to test / troubleshoot with the truck warm.

results:
I add coolant and the truck started line nothing was wrong.

Thoughts:
Something cooled down and now it works.

I got to thinking that the ECT was not submerged in enough coolant (perhaps none at all)and the resistance went low enough in the ECT to the point that the EEC prevented the injectors from firing.  Is this likely?  I think the ECT acts as a fail safe but I never really knew what the end result would be when you have one over temp.  I would suspect the the T-stat was dry until i added fluid.

Anyone know if my failing the blink test was a result of an ECT being too hot makes sense?

ANYHOO,, Lets just say someone around here needs to not neglect checking fluids ,, its easy and quick.

1990 351w EFI problem / quesiton (SOLVED)

Reply #1 –
anyone?

1990 351w EFI problem / quesiton (SOLVED)

Reply #2 –
This isn’t your problem but over the summer I had similar problems w/my 5.0efi 88 bronco out of nowhere it would shut off mostly on the hwy. I couldn’t figure it out, just let the truck cool down and it will start again. My symptoms mostly came on hot days too.
Soo. One day a was thinking I couldn’t figure it out and then it hit me it was like the car was starving for fuel but I new I had a new fuel pump and filter and then it hit me I CHANGED the fuel tank in the winter and broke one of the lines going to the sending unit so I replaced it w/a repair kit but it was in there kind of awkward but it was fine so I left it and forgot it. Long story short hot summer day and exhaust and awkward line well it kinked enough to stave the engine of fuel.
Sorry I no this don’t help but some times its where you least expect it.

1990 351w EFI problem / quesiton (SOLVED)

Reply #3 –
Quote from: jcassity;200378

I got to thinking that the ECT was not submerged in enough coolant (perhaps none at all)and the resistance went low enough in the ECT to the point that the EEC prevented the injectors from firing.  Is this likely?  I think the ECT acts as a fail safe but I never really knew what the end result would be when you have one over temp.  I would suspect the the T-stat was dry until i added fluid.


Don't think this would be a issue on a 1990... AFIK it'll run till it melts... The newer systems shut off every other injector so the engine can run without coolant...

1990 351w EFI problem / quesiton (SOLVED)

Reply #4 –
Sounds like the pick up coil in the dist is getting "hot" and breaking down.

 It would cause a no inj pulse and erratic timing.




SCT Tuned by Me(Greg@SpeedyDyno.com)

E.T. 10.28 @ 136.5 MPH 1/4 mile: List of Mods; 351 EFI, AFR heads,AOD,Rousch 13in frt brakes,11in rear brakes, AirRide Tech air ride system, Sub frame connetors,2400 RPM stall, 3.50,BBK shorties,T62PT Turbos  air to air intercooled, Home built kit.
Car weights 3705lbs without driver:burnout:

1990 351w EFI problem / quesiton (SOLVED)

Reply #5 –
Quote from: 5.8fastcat;201012
Sounds like the pick up coil in the dist is getting "hot" and breaking down.

 It would cause a no inj pulse and erratic timing.


Yep same thing happened to my 95 T-bird. It's probably the stator in the dist.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

1990 351w EFI problem / quesiton (SOLVED)

Reply #6 –
its probably due for one anyway,,although no code.  Ill just put a new one in there.  Time to have fun again with the gear.

1990 351w EFI problem / quesiton (SOLVED)

Reply #7 –
found the problem,
A few years ago I deleted the upper intake coolant lines.  The lower TB coolant line leads to a three way fitting at the lower intake, one of which was hooked to my TB.  I had it pluged and clamped but water showed up a couple days ago on the engine pretty much all over.

I've repaired that problem with no issues again.  Evidently the coolant saturated several connectors so since my coil is up on the engine (saturated as well, and the tfi was wet, Ill assume thats where my injector signal went,, straight to ground.

1990 351w EFI problem / quesiton (SOLVED)

Reply #8 –
Believe it or not you had a problem like me
Sometimes you gotta sit back and think and look whats going wrong.
 

1990 351w EFI problem / quesiton (SOLVED)

Reply #9 –
the first time this happened, i did a lot of looking and thinking.  the coolant wasnt visible last time and i suppose thats due to the nose of the car on a huge incline in granny low with lots of time for evap and also low coolant would have made the small 1/4'' hose pretty much empty at that time.