No Spark or Fuel During Engine Crank

[thundley57]

Was this PU coil from NAPA's 'Gold line'(top of the line)?
Did you ever get a better meter?
LG

The PU was their Echlin brand and was the most expensive one they offered. Yes, did get a new meter.

 

[Lumpy Grits]

OK-That's a good brand.
Did you disconnect the battery POS(+)before the install attempt?
What meter did you buy?
LG

 

[thundley57]

I've convinced myself for now that the problem is in the Howell supplied ECM. I've got spark (tested all the cylinders and have a good strong spark to each), I've got fuel as evidenced by the fuel shooting through the injectors while trying to start. The engine tries to start but acts like it's flooded and there does seem to be an unusually large amount of fuel flowing through the injectors while cranking.

Spoke with Troy at Howell tech support this morning and after explaining the original problem (dist PU coil) and the current symptoms he recommended replacing the tach filter to the ECM which he suspects was fried at some point during the ignition problems. It's a $50 part so I'm back to throwing money at the problem but at this point I don't feel like I have a choice. If this doesn't work he recommended a new ECM which is $AMC 150 . I will report back after replacing the tach filter. If anybody has any other ideas where I should be looking I would love to hear them as I'm missing out on prime Jeep season here in CA! Thanks!

 

[thundley57]

OK-That's a good brand.
Did you disconnect the battery POS(+)before the install attempt?
What meter did you buy?
LG

Disconnected the neg side of battery while installing. I should have said that the meter was "new to me" and is on loan from a friend (can't remember the brand and I'm not currently at home). The funny thing is that I'm getting almost identical readings from it that I get from my own meter.

 

[Lumpy Grits]

Does the tach-filter just run your tachometer? If so, take the tach out of the circuit and try to start.
Make sure the borrowed meter has a fresh battery in it.
LG

 

[thundley57]

Does the tach-filter just run your tachometer? If so, take the tach out of the circuit and try to start.
Make sure the borrowed meter has a fresh battery in it.
LG

No, according to Howell it runs straight into the ECM.

 

[Posi]

Troy has been working at howell for over 20 years, although a nice guy he still takes the shot in the dark approach to fixing FI issues. He also has a difficult time customizing chips.

Is this an ignition problem, or a tach filter/ecm problem?
Why throw money at it on a guess.
There is an easy way to find out.

Remove the white tach wire from the negative side of the coil.
With a test light hooked to the positive post of the battery, key on, touch and remove the test light to the end of the white tach wire. Each time you touch and remove the test light the injectors should spit fuel (simulated a spark).
If it spits fuel you have an ignition problem.
If it does not you have a tach/emc problem

If your fuel injectors do not spit fuel.
You have a problem with my tach filter or ecm.

The next test will tell you if it's the tach filter or ecm

With the test light still hooked up, and key on, touch and remove the test light on pin B5 at the ecm.
Although you won't see the injectors fire working inside your rig you will hear the pump running. If the pump runs the issue is the tach filter. If the pump does not run you have a bad ecm.

Hope this helps.

 

[Torxhead]

Frying the tach filter does sound interesting, along with just how it was done. Anyway, If you are having an issue with a rich start you could disconnect an injector.

 

[007]

Troy has been working at howell for over 20 years, although a nice guy he still takes the shot in the dark approach to fixing FI issues. He also has a difficult time customizing chips.

Is this an ignition problem, or a tach filter/ecm problem?
Why throw money at it on a guess.
There is an easy way to find out.

Remove the white tach wire from the negative side of the coil.
With a test light hooked to the positive post of the battery, key on, touch and remove the test light to the end of the white tach wire. Each time you touch and remove the test light the injectors should spit fuel (simulated a spark).
If it spits fuel you have an ignition problem.
If it does not you have a tach/emc problem

If your fuel injectors do not spit fuel.
You have a problem with my tach filter or ecm.

The next test will tell you if it's the tach filter or ecm

With the test light still hooked up, and key on, touch and remove the test light on pin B5 at the ecm.
Although you won't see the injectors fire working inside your rig you will hear the pump running. If the pump runs the issue is the tach filter. If the pump does not run you have a bad ecm.

Hope this helps.

WOW!

 

[Posi]

Frying the tach filter does sound interesting, along with just how it was done. Anyway, If you are having an issue with a rich start you could disconnect an injector.

I fried my tach filter when I power washed my Jeep after a day of wheeling. I had those glass fenders without the splash guard the metal ones have. Some water sprayed into the engine bay, not realizing I started the engine to park the Jeep in the garage.... well, didn't start.

Another way to deal with the rich start issue is to hold the accelerator pedal to the floor. That action gives the ecm a flooding message and shuts off the fuel to the injectors.

 

[thundley57]

Troy has been working at howell for over 20 years, although a nice guy he still takes the shot in the dark approach to fixing FI issues. He also has a difficult time customizing chips.

Is this an ignition problem, or a tach filter/ecm problem?
Why throw money at it on a guess.
There is an easy way to find out.

Remove the white tach wire from the negative side of the coil.
With a test light hooked to the positive post of the battery, key on, touch and remove the test light to the end of the white tach wire. Each time you touch and remove the test light the injectors should spit fuel (simulated a spark).
If it spits fuel you have an ignition problem.
If it does not you have a tach/emc problem

If your fuel injectors do not spit fuel.
You have a problem with my tach filter or ecm.

The next test will tell you if it's the tach filter or ecm

With the test light still hooked up, and key on, touch and remove the test light on pin B5 at the ecm.
Although you won't see the injectors fire working inside your rig you will hear the pump running. If the pump runs the issue is the tach filter. If the pump does not run you have a bad ecm.

Hope this helps.

Will definitely perform these tests and report back, thanks again Posi!

I fried my tach filter when I power washed my Jeep after a day of wheeling. I had those glass fenders without the splash guard the metal ones have. Some water sprayed into the engine bay, not realizing I started the engine to park the Jeep in the garage.... well, didn't start.

Another way to deal with the rich start issue is to hold the accelerator pedal to the floor. That action gives the ecm a flooding message and shuts off the fuel to the injectors.

I tried this as well and although the flow diminished somewhat, it did not completely stop the fuel flow which is another reason why I am suspecting the ECM.

Frying the tach filter does sound interesting, along with just how it was done. Anyway, If you are having an issue with a rich start you could disconnect an injector.

Good point. I actually tried this but disconnected both injectors hoping I could clear out some of the excess fuel although it didn't start even for a second. I will try disconnecting one injector only.

 

[Posi]

I tried this as well and although the flow diminished somewhat, it did not completely stop the fuel flow which is another reason why I am suspecting the ECM.

It can make the injectors do funky things. When my tach filter went bad the injectors were alternating fuel spray. I have my thoughts on what the problem is, but once you preform the tests you will know for sure if its ignition, tach filter, or ecm.

 

[thundley57]

Troy has been working at howell for over 20 years, although a nice guy he still takes the shot in the dark approach to fixing FI issues. He also has a difficult time customizing chips.

Is this an ignition problem, or a tach filter/ecm problem?
Why throw money at it on a guess.
There is an easy way to find out.

Remove the white tach wire from the negative side of the coil.
With a test light hooked to the positive post of the battery, key on, touch and remove the test light to the end of the white tach wire. Each time you touch and remove the test light the injectors should spit fuel (simulated a spark).
If it spits fuel you have an ignition problem.
If it does not you have a tach/emc problem

If your fuel injectors do not spit fuel.
You have a problem with my tach filter or ecm.

The next test will tell you if it's the tach filter or ecm

With the test light still hooked up, and key on, touch and remove the test light on pin B5 at the ecm.
Although you won't see the injectors fire working inside your rig you will hear the pump running. If the pump runs the issue is the tach filter. If the pump does not run you have a bad ecm.

Hope this helps.

Ok so I tried this test and yes, the injectors spray fuel when tapping 12V to the white wire. Does this definitely mean that it's an ignition problem though or is it possible that a bad tach filter is telling the ECM to inject the wrong amount of fuel?

I also tried disconnecting one of the injectors as Torxhead recommended but with no real improvement.

If I disconnect both injectors, open the throttles wide open and crank the engine over a few times to clear out the cylinders, it will start up after I reconnect the injectors but just barely runs and then dies. I still think it is too rich. I removed all of the spark plugs which were basically pitch black with soot further indicating a rich mixture.

Would the spark plugs being fouled like this be enough to weaken the spark enough to prevent it from running? When I grounded a plug and turned the engine over the spark looked fairly weak to me (orange rather than a nice bluish color). I then hooked my spark tester up (basically a test spark plug) and the spark was definitely stronger. This may seem like a no brainer to some of you but I'm getting tired of throwing money at this thing and don't want to buy new plugs if I don't have to since these are almost new.

I also bypassed the coil resistor wire and fed the pos side of coil with 12V while key is in the run position thinking the extra voltage may get the engine up to full idle but no go...even though it seemed to help slightly.

So again, I have fuel and spark, double checked the timing by turning the engine over until the timing mark was at 8 deg advanced then turned the distributor until the rotor was pointing at #1. Also double checked the resistance across the violet and orange distributor wire spades and got 590 ohms. The resistance varies widely though if I crank the engine while testing but returns to 590 when stopped. Is this normal?

Sorry for the long posts guys, just trying to provide all the information to give you guys that are better than me on this stuff some more clues of what I'm missing.

 

[007]

Dumb question...."a n y" chance the O2 sensor has an issue?


Sent from my iPhone using Tapatalk

 

[Torxhead]

Dumb question...."a n y" chance the O2 sensor has an issue?


Sent from my iPhone using Tapatalk

O2 sensor controls fuel mixture, and does not function until it gets to a certain temp. This should not keep the engine from starting, although I am by no means an authority.

 

[Posi]

You have an ignition problem.
The tach filter is a small circuit board, is it possible that the board is sending a bad signal, it's possible, but I doubt it. Typically their either good or bad.
Use a wire wheel or some other method to clean your plugs good.
While the plugs are out disconnect the fuel pump rely or clamp the inlet fuel hose at the TB, and clear the engine of fuel.
After the engine is cleared, and plugs are clean install the plugs and see if the engine fires.
If it doesn't we can address the voltage drop to the emc.

 

[Torxhead]

A weak spark was mentioned, so maybe a new set of MSD wires would be good. Howell recommends using the Champion RFN14LY plugs, which is a pretty hot plug. I like the little cooler Auto 985s though. Along with the large distributor cap or at least the smaller cap with brass inserts. I did notice that the wiring harness comes with #18 fuel pump wiring which is pretty weak to pump fuel with the way I see it.

 

[thundley57]

A weak spark was mentioned, so maybe a new set of MSD wires would be good. Howell recommends using the Champion RFN14LY plugs, which is a pretty hot plug. I like the little cooler Auto 985s though. Along with the large distributor cap or at least the smaller cap with brass inserts. I did notice that the wiring harness comes with #18 fuel pump wiring which is pretty weak to pump fuel with the way I see it.

Brand new set of MSD wires were installed several months ago. Purchased and installed Autolite 985's today. Installed the larger Ford distributor cap & body last year when I bought the Jeep. Fuel pressure is the specified 12 psi.

You have an ignition problem.
The tach filter is a small circuit board, is it possible that the board is sending a bad signal, it's possible, but I doubt it. Typically their either good or bad.
Use a wire wheel or some other method to clean your plugs good.
While the plugs are out disconnect the fuel pump rely or clamp the inlet fuel hose at the TB, and clear the engine of fuel.
After the engine is cleared, and plugs are clean install the plugs and see if the engine fires.
If it doesn't we can address the voltage drop to the emc.

As mentioned above I sprang for some new plugs just to make sure, cranked the engine over with plugs out to clear the cylinders, installed the plugs & wires and still the same problem. The engine starts but will not come up to idle speed and then dies. I tried disconnecting one of the injectors again to lean the mixture out and it seemed to run better but still wouldn't come up to idle. Voltage at the positive side of coil is just under 11 volts while cranking and about the same in run position because I still have 12V jumpered to the coil to maintain full voltage while in run. This is with a brand new battery that has 13.6 volts before cranking. Does this voltage drop seem normal?

It still seems to me that there is gobs of fuel being pumped into the TB while cranking and then the subsequent weak run but I can't be sure. Spoke with Troy at Howell again today who isn't ruling out an ignition problem but is adamant that a faulty tach filter could cause the ECM to send the wrong fuel mixture to the injectors. Could be that he's just trying to get me on a parts buying spree (already purchased a filter which is on its way).

I'm getting so frustrated with this thing...PLEASE help!

 

[Belizean]

Have you looked at the timing chain and gears?

 

[Posi]

I don't think Troy is sending you on a buying spree, but he isn't trying to save you money either by suggesting the problem “could” be the tach filter "or" ecm without offering any diagnostic tests to confirm it.


When I diagnosed my tach filter I preformed the same test I suggested to you (key on, touching power to the white coil wire). My injectors did not spray, (yours did), the non-spray told me my the tach filter or the ecm was faulty. I next touched power to B5 pin on the ecm and the injectors sprayed fuel. This told me the tach filter was bad. I replaced it and the engine ran as it should.


As I previously mentioned the tach filter is a circuit board and it's possible some components in the filter are working, and others are not so lets do the next test.


Compare the injector spray from your previous test (when you touched the coil white wire with the test light) to the injector spray when you touch B5 pin on the ecm. You will need a helper to touch pin B5 while you inspect the spray. Is the volume the same or different from when you tested the white coil wire?
Key is on with both tests, test light connected to the + battery post. Same as the white coil wire, just touch the B5 pin on and off.


Also, do you mean 12.6 battery voltage? Your posting 13.6, unless it just came off a charger.