starts, but wont stay running, help

[Wolfchant]

ok, so here's the deal, last night i finished dealing with ignition issues, now it'll start, but it runs really rough, and will not stay running on it's own, i have to hold my foot on the pedal to keep it running

also, the exhaust is black ish and leaving a black sooty deposit on the snow

1990 351w

it also has 2 of the old spark plugs in still, passenger side of the block towards the firewall, because i just can't do em in this cold, and there's almost no clearance, but what's scaring me more, is the fact that anywhere under 1000rpm, i have a red warning light come on my dash, it's shaped like an engine, and says engine under it, what does that mean, how worried should i be?

[Wolfchant]

anyone? i'm desperate here, i have to have it moved from where it is by tomorrow, or it gets towed and impounded by the city, i can't move it anywhere if it wont stay on long enough for me to drive it

[Jasonhughes2009]

I have the same year and engine and i've never had a light like that, mine literally just has the words check engine and thats it, however i had somewhat of the same problem, the two things i would say to replace and are super easy too, the mass air flow sensor and the idle controller, start with the idler though, let me know if you need a picture of where it is and ill get one too you

[BroncoRN]

you need to pull codes from your engine to tell you what that light means!

[goober]

those 2 plugs could do it for sure. 2 bad cylinders and a V8 will run like dog crap. you didn't mention when you replaced the wires and cap either, for some reason these trucks like to eat plug wires, I've put more in my bronco than any other vehicle I've ever owned.

ditto on the codes!!!

[Jasonhughes2009]

Originally Posted by BroncoRN

you need to pull codes from your engine to tell you what that light means!

probably should have said to do that first!

[theramsey3]

Check fuel pressure and change those two plugs. make sure the fuel pressure regulator isn't leaking gas into the intake by pulling the vacuum line off of it and see if there is any fuel present if so replace it.

[BroncoRN]

Trust me it'll run on 4 cylinders and stay running - won't drive but it'll idle.

[jopes]

pull codes

and how long has it been running like this?

[fordfreak93]

checked your timing

[Wolfchant]

nevermind guys, it was my own fault, because of the cold, i had a loose plug wire so it was firing on 7 cylinders, and for the record, there's the check engine light, and then either just to the right of it, or the left of it, there's a red warning light shaped like an engine block, it does not say engine under it , i kinda cross eyed when i first looked at it, but google tells me it only lights up when there's a huge issue, for example, when your engine is running on 7 cylinders due to a loose plug wire, what it means is that there's a critical issue with the engine, and you should turn it off as soon as possible, and repair as needed, thanks for all the replies though, it's nice to be on a forum with as much activity as this,

i also noticed though, while driving to park my truck in my grandma's yard until i register it, that the oil pressure gauge seems to work intermittently, what seems more probable, bad ground, or bad oil sending unit? if it helps any, my headlights and highbeams also seem to have a mind of their own

[goober]

just something to check on your headlight problem, see if the battery has been set down on the passenger headlight wires... That happened to mine and it was grounding out on the battery tray and causing the lights to go crazy every so often...

the multi-function switch (headlight dimmer/wiper washer) switch is pretty notorious in these things as well. But at 60 bucks or so for one, I'd look at everything else first.

Originally Posted by Wolfchant

nevermind guys, it was my own fault, because of the cold, i had a loose plug wire so it was firing on 7 cylinders, and for the record, there's the check engine light, and then either just to the right of it, or the left of it, there's a red warning light shaped like an engine block, it does not say engine under it , i kinda cross eyed when i first looked at it, but google tells me it only lights up when there's a huge issue, for example, when your engine is running on 7 cylinders due to a loose plug wire, what it means is that there's a critical issue with the engine, and you should turn it off as soon as possible, and repair as needed, thanks for all the replies though, it's nice to be on a forum with as much activity as this,

i also noticed though, while driving to park my truck in my grandma's yard until i register it, that the oil pressure gauge seems to work intermittently, what seems more probable, bad ground, or bad oil sending unit? if it helps any, my headlights and highbeams also seem to have a mind of their own

[Wolfchant]

i'll double check that on monday, i had the battery out to charge it before, and i didn't put it really all the way back in the tray and tighten the hold down, so it may have bounced around due to the rough roads and jumped onto the wire (the city is really cheaping out on snow removal this year)

as for the oil pressure gauge, im still stumped, been using search, but i haven't found any info other than that the oil sending unit is a bit difficult to get at

[4GIRLS]

Lots of threafs on this topic but this is closer to my issue. When cold, mine will fire fine them sputter and die if I dont keep my foot on the gas. Yesterday it really shook for about 10 seconds.

My difference is I get white smoke, just for a second. When its warm I have zero problems.

Just did all the tune up stuff, cap, rotor, wires, plugs, timing, a freeze plug, some vac lines, etc. Do you think my issues could be the same? Just wondering if maybe some new revelations have happened.

[BroncoRN]

Tps or IAC - check both sensors

[4GIRLS]

Originally Posted by BroncoRN

Tps or IAC - check both sensors

replacing both tomorrow. We shall see what happens...... Crossing fingers.

[4GIRLS]

TPS and IAC replaced, hooked up a new MAP, no fuel in vac line.... Nothin, still doing it. Seems to fire easier on second attempt but will start and die every first try when cold. She smells like she's running rich to......

Im over throwing money at guesses......

[BroncoBuff777]

Originally Posted by Wolfchant

ok, so here's the deal, last night i finished dealing with ignition issues, now it'll start, but it runs really rough, and will not stay running on it's own, i have to hold my foot on the pedal to keep it running

also, the exhaust is black ish and leaving a black sooty deposit on the snow

1990 351w

it also has 2 of the old spark plugs in still, passenger side of the block towards the firewall, because i just can't do em in this cold, and there's almost no clearance, but what's scaring me more, is the fact that anywhere under 1000rpm, i have a red warning light come on my dash, it's shaped like an engine, and says engine under it, what does that mean, how worried should i be?

Everyone should start their thread my saying "i pulled codes and". This is the first step that should be done, unless you didnt know about it.

[jopes]

This topic is 2 years old!

[4GIRLS]

Originally Posted by jopes

This topic is 2 years old!

But it's common and many of us are still looking for help or maybe someone has finally figured out the most likely culprits. This thread has the best info on forum that I could find.