Aerostar 4.0, changed coil, still has a persistant miss, ideas?

[chrisofna]

Changed my coil because I had a miss and 2 of the plugs had gas on them so I figured hey, the coil must be bad. So I changed it but it's still there. I unplugged the MAF and it didn't change idle or how it ran at all. Any ideas?

[Movin]

Those are bad for vacuum leaks..Safety thing..you replaced any bad ignition parts
right? Wires, plugs and cap..No possible sparks. Have a fire extinguisher handy
in case you might have missed something. Use a can of carb cleaner spray or a
unlighted propane torch..direct fuel near possible vacuum leaks with engine idling.
When fuel is near a vacuum leak the leak will pull the fuel into the engine and smooth
out the engines rough idle. Repair leak and retest. Absolutely do not do this if you
are not confident about sparks. There are other methods such as vacuum hoses
in your ear and directed toward the possible leak but do not use these as ear damage
could happen. Please look carefully first as this id the safest method.

Other possible causes you have not checked yet include compression, damaged crank
sensor, valve seal making carbon in injector pocket, and faulty injector or circuit.

I absolutely did not suggest soaking 100% of your brothers clothing in a full can
of carb cleaner and burning them in front of the house while he is in the shower.
Just load that van and get gone!

[chrisofna]

Well, it's definitely cylinder number 5. We can manually click the fuel injector, but fuel isn't going into the cylinder I think. Maybe the computer isn't firing it. We got spark and compression. Any ideas?

[M3NTAL]

Sounds like its clogged happen on my Harley truck, Try to clean it or get one at the yard

[200KGPGTP]

Ignition control module?

[chrisofna]

Checked. It's good.

[chrisofna]

Sounds like its clogged happen on my Harley truck, Try to clean it or get one at the yard

Well I'm in trouble if so, cause I can't remove the engine to take it out.

[Movin]

They come out..without pulling engine
make a hole big enough to pull the plenum
through at the front of the engine.

[FestYboy]

do you have power to that injector?

[Movin]

The injectors are fired 3 at a time. The red wire supplies power and the tan
wire with whatever color stripe is grounded by the computer, 3 at a time.

Have you identified which cylinder is dead ?

You will need to know that so you can replace only one injector. You will
need a upper plenum gasket and patience to remove the upper plenum.

If you have to test the injectors, you can leave them clips to the fuel
rail, lift them from the lower intake and put a paper towel under each
injector then crank the engine to make them squirt fuel onto the towel

Unplug the primary of the coil and take all safety precautions with fuel.

It is kind of a drag to pull all that so you want to make sure you have
spark and compression in the dead cylinder before doing all that...I hate to
say it again, but no vacuum leaks!! either.

It is fun diagnosing stuff, keep us informed!!

[chrisofna]

There is about an inch between the firewall and the plenum, and the plenum has studs going through it, I don't see how it's going to come out without the engine at least lowered. It's definitely number 5, it's the only cylinder that doesn't change the miss at all when you remove the spark plug wire. It has spark and compression (120 across the board) on that cylinder. Where did you get the info that 3 injectors fire at the same time? I can't find that information anywhere.

[FestYboy]

it's called batch fire, my fiero has it too. that's why i asked about power to the injector.

[Movin]

I usually strip what I can off the front, bungees are useful to hold things
back out of the way. I have not dropped mounts but that might make it
easier if you are using non powered ratchets.

Info...I pay for access to all manufacturers published information and
access to a data base of common problems with vehicles experienced
by techs. I did not see your year in this thread, I used '90.

[Damkid]

Moved to the repair help section where it belongs

[chrisofna]

I have alldata too, lol. It makes stuff a lot more simpler than what it is.