low end power disappeared?

Topic: low end power disappeared? (Read 21093 times) previous topic - next topic

low end power disappeared?

Reply #120 – January 02, 2015, 01:02:33 PM

Quote from: ThunderbirdSport302;442322

Unless it was a GM vehicle, I don't see how the engine or any mechanical part could care any less whether the EEC tells it that it's going to pulse the injectors sequentially, or in either bank of 4 (or 3, if it's a V6).

Elaborate..? :)

Not calling you out, I'm sincerely curious as to why the distributor of all things made a difference in regards to bank vs sequential.

Or maybe I've forgot all the stuff I picked up back in the very early 2000's when I was researching doing an HO swap on my '92 F series..

Quote from: jcassity;442335

one question I never could get answered..

the finned windows that pass through the stator magnetic field...... does the eec keep the injector triggered on when the stator is in the "open window" or the "closed" window.

something tells me the eec is turning on a given injector when the magnetic field on the stator has an open window ,, the metal fin passing in front of the stator determines the time the next injector to fire in line is off.

To answer both of these: The "odd" window on the distributor is used as a reference for #1 cylinder TDC. The other slots are only used as counters - when the odd slot passes, the EEC knows it's number 1 TDC. It then counts seven more pulses and knows the next one will be #1 TDC again. It's sort of a primitive camshaft position sensor (indeed, in distributorless versions of the 5.0 and 3.8 there is actually a mechanically driven camshaft position sensor that bolts in place of the distributor). Without that odd slot the EEC will not know when to fire the injectors. It'll still fire them, but not at the right times. This results in the fuel pooling in the ports and will usually result in a lean condition, especially at low RPM (at higher rpm the air is moving fast enough that the fuel doesn't pool as much). Think of it like running a car with a bad fuel pump by pouring gas directly into the throttle body. It'll run, but it won't run right.

As for the injector triggering, it has little to do with the position of those windows. The injectors are triggered by the EEC-IV, and their "on" time depends on calculated engine load (determined by RPM and MAP readings, or MAF readings in a MAF car), desired engine load (based on TPS data), and inputs from the O2 sensors (to finely tune the mixture). The window position tells the EEC-IV what position the engine is in, and therefore which injector to fire, but the EEC uses the other inputs to determine how long to fire the injector. The injector for a given cylinder will start to fire just before the intake valve opens, regardless of engine load, but the amount of time it stays open is determined by the EEC (close again almost immediately for idle or coasting, stay open longer for higher loads). The EEC then looks at O2 sensor data to see what kind of job it did, then adjusts the injectors based on what it sees (a lean signal from the O2's will cause more fuel, a rich signal will cause less fuel).

In fact the windows in the hall effect sensor are used to control two different things at two different times. For any given cylinder the EEC will fire the spark plug as the piston is getting close to TDC on the compression stroke, then it will fire the injector about one crankshaft revolution later, or half a distributor revolution later, as the intake valve is opening for the intake stroke. The "odd" window is not required or used for ignition timing. There is only one coil, so the EEC-IV basically just fires the coil four times for every crankshaft revolution (or each time a window appears in the hall effect sensor). The EEC uses inputs from the hall effect sensor to determine when and how often to fire the coil, inputs from TPS and MAP to finely tune when and for how long (advance, dwell), and the physical position of the rotor button inside the distributor cap determines where that spark goes.

The Jeep 4.0 liter uses a hall effect sensor as well, but it does things a bit differently. It only has one window in the hall effect sensor (half the rotor thingy is solid, the other half open). Their EEC just needs that simple "on/off" signal and a crankshaft position sensor signal (not present on Ford 5.0's), and figures out everything from there. A common failure in the Jeep engines is the crank sensor. When this goes bad the engine will not start, because with only one window in the distributor sensor it can tell that something is at TDC but doesn't know what. I've had a bunch of those Jeeps and came up with a very simple way of testing the crank sensor. Remove it from the engine but leave it plugged into the harness, turn the key to "run", and move the sensor back & forth near any steel or iron surface. If the sensor is good it will pick up that motion and will prime the fuel pump and turn on a bunch of relays on, which you can hear (if you've got a spark tested in the coil wire it'll fire that too).

low end power disappeared?

Reply #121 – January 02, 2015, 01:20:54 PM

Quote from: Aerocoupe;442338

With the compression numbers he posted on #1 all he needs to do is plug off the spark plug hole on the #1 cylinder with some wadded up paper towel and roll the motor over by hand. It will pop the paper towel out on the compression stroke. From there you can use a thin screw driver and continue to roll the motor by hand until TDC is achieved. This is done by feeling the piston move up the cylinder with the thin screw driver. It will top out, there will be a dead spot where it will not move, and then it will start to fall. TDC is whrn the piston no longer rises. I would be shocked if this does not end up with the pointer showing zero on the balancer. From there drop the distributor in and time it.

Darren

As simple as it gets. It's not that difficult.

low end power disappeared?

Reply #122 – January 02, 2015, 02:29:16 PM

Quote from: ThunderbirdSport302;442353

A T5 HO car with 3.55 gears has no trouble at all breaking the rear loose. I could even do it at a roll if the tires were cold.

That was with AOD stock. I forgot to mention that. Yeh stick is easy to do.

low end power disappeared?

Reply #123 – January 02, 2015, 07:47:33 PM

Here is a tip. Go on the net and find a TDC whistle and forget the TOILET PAPER

Make sure you get one that screws in

http://tools.boxwrench.net/top-dead-center-whistle.htm

I have to tell you that my DROP top can melt the tires off the car and it is an auto tranny

low end power disappeared?

Reply #124 – January 02, 2015, 11:19:39 PM

well now that's on my list to be hanging on my tools wall real soon

low end power disappeared?

Reply #125 – January 03, 2015, 05:57:16 AM

Is this the guy that worked on your car??

low end power disappeared?

Reply #126 – January 03, 2015, 10:47:24 AM

HaHaHa! Bit out of focus but looks familiar (maybe seen him in the mirror). I put in those spark plugs and engine runs a lot smoother. I think I'm almost there. Going to play with the timing a bit more and install the high flow pump. Thanks again everyone for the great advice and discussion!

low end power disappeared?

Reply #127 – January 03, 2015, 10:55:59 AM

Quote from: TOM Renzo;442391

Is this the guy that worked on your car??

OK. You mad me laugh!

low end power disappeared?

Reply #128 – January 03, 2015, 11:20:07 AM

Quote from: marianadeeps;442396

HaHaHa! Bit out of focus but looks familiar (maybe seen him in the mirror). I put in those spark plugs and engine runs a lot smoother. I think I'm almost there. Going to play with the timing a bit more and install the high flow pump. Thanks again everyone for the great advice and discussion!

I'm glad it runs better with the new plugs. See you have to read the instructions that come with the heads. You can't assume that they take the same spark plugs

. Actually the spark plugs are even different between E6 (SO) and E7 (HO) heads. Most aftermarket aluminum heads (AFR, Edelbrock Trick Flow) use the Autolite 3924 or Motorcraft AGSP32C.

Stick a better fuel pump in it (155lph or 190lph), some 93 octane gas, and bump the timing to around 14* base. Should run much better :).

low end power disappeared?

Reply #129 – January 03, 2015, 10:09:02 PM

Very happy you are making good progress. That is Herbie my lap DUMMY and mentor on car issues. He always agrees with me.