Need a 5-OH whisperer

[drecords]

Alright -- whole story for maximum entertainment and diagnosis potential:

-Leaving TWS #34 took a long time to start, cycled ignition switch and it fired up and drove onto trailer.
-Once returned to Red Mist Racing world headquarters, wouldn't start to back off trailer.
-Pushed her into the shop, put the cover on and didn't touch it for 3 weeks, pulled shocks off for rebuild and did alot of other things non-racing related.

-Fast forward to today. Tried swapping TFI module, and ignition coil, still no start. Have 12V at the coil.
-.15V at the TPS sensor with the ignition on.
-Used a noid light in the #1 injector and am seeing no indication that its seeing a PIP signal (no flashing on crank). Have 12V at fuel injector red wire, points to a bad PIP.
-Bought a new distributor thinking the PIP was bad, put it in and tried to start it. Car still didn't start, however when I stopped cranking I could hear the fuel injectors clicking away and the coil had a spark. After this event, no more spark was seen for the rest of the day.
-I pulled the TFI connector and took OHM readings on all the pins -- none indicated a break in the wiring though 2 had higher resistance.
-Check engine light illuminates when I turn on the ignition which indicates to me that the computer is getting power.

Dunno where to go from here, guess i'll use the light to get the CEL codes and go from there. :confused:

[marshall_mosty]

I don't think it's a smoking gun, but the stock EEC-IV strategy needs approx 0.98V on the TPS with the throttle closed.
Also, check your chassis grounds at the back of the engine (head to firewall) and the computer ground inside the car.

[Wade]

1. Out of fuel? Check gauge mounted on fuel rail. Should be in the 35-40psi range after priming the ignition circuit on/off/on.
2. Tripped circuit breaker? You car has a painless harness with circuit breakers that can be reset by the driver. See if any of those are popped out. (should be the second one from the left?)
3. Check the Orange ground wire (ignition/TFI ground) that should be mounted on the back bolt of the upper intake. I was thinking that you had moved this to some other location?
4. Fuel pump priming? See #1. Perform on/off/on switching of ignition circuit and listen for pump whine.
5. What about all those wires you melted at TWS near the passenger inner fender? It appeared those were for the O2 sensors, but could also be Mass Air Flow Meter related. Did you actually fix those at the track, or was it a "track fix" that needs to be re-addressed?
6. Since you pulled the distributor, recheck the ignition base timing. It is possibly a tooth off. It is easy to "miss" by one tooth. Put the engine at TDC on number 1 based on the crank markings and then see if the rotor is pointing to #1 on the cap. Remember that #1 is marked with a sharpie, not the actual #1 stamped on the cap.

Good Luck. Wade

[drecords]

I don't think it's a smoking gun, but the stock EEC-IV strategy needs approx 0.98V on the TPS with the throttle closed.
Also, check your chassis grounds at the back of the engine (head to firewall) and the computer ground inside the car.

I'll check grounds, I have confirmed they're tight by wiggling but will put a wrench in them.


1. Out of fuel? Check gauge mounted on fuel rail. Should be in the 35-40psi range after priming the ignition circuit on/off/on.
2. Tripped circuit breaker? You car has a painless harness with circuit breakers that can be reset by the driver. See if any of those are popped out. (should be the second one from the left?)
3. Check the Orange ground wire (ignition/TFI ground) that should be mounted on the back bolt of the upper intake. I was thinking that you had moved this to some other location?
4. Fuel pump priming? See #1. Perform on/off/on switching of ignition circuit and listen for pump whine.
5. What about all those wires you melted at TWS near the passenger inner fender? It appeared those were for the O2 sensors, but could also be Mass Air Flow Meter related. Did you actually fix those at the track, or was it a "track fix" that needs to be re-addressed?
6. Since you pulled the distributor, recheck the ignition base timing. It is possibly a tooth off. It is easy to "miss" by one tooth. Put the engine at TDC on number 1 based on the crank markings and then see if the rotor is pointing to #1 on the cap. Remember that #1 is marked with a sharpie, not the actual #1 stamped on the cap.

Good Luck. Wade

#1. Pump primes, pressure comes up to 40 then falls back off to 0. This is what has me confused, I have no spark and seems no signal for fuel pump to remain on. CEL illuminates which indicates comp has power.

#5 barbequed wires have been checked and no issues found there, though it is suspicious that this problem developed within 24h of that event.

#6 in my experience even when off a tooth I get a spark...not the case today. No spark, no fuel injector pulse but have 12V on supply side of each injector.

[Trublu]

Carb

[marshall_mosty]

Fuel pump will only prime for 3 seconds until the engine starts, then it will continue to run.

[marshall_mosty]

You may want to redo the orange TFi ground, or at least sand it with some 500 grit to make sure it's grounding properly.

[marshall_mosty]

Do you have a spare computer to try?

[drecords]

Do you have a spare computer to try?

I don't, I pulled it and checked resistance on computer ground, checked that the EEC relay was functioning correctly. Also interesting is that the computer appears to have power with the EEC relay unplugged.




You may want to redo the orange TFi ground, or at least sand it with some 500 grit to make sure it's grounding properly.

Moved it back to the intake bolt, no change. Connection is nice and tight.

[drecords]

Found an A9P computer to try -- its the auto computer but from what I've read on the interwebs it will allow me to start the car and rule out the computer. Hopefully sort that Wed night

[marshall_mosty]

Try changing out the main relay.

[drecords]

Try changing out the main relay.

Talking about the EEC relay? -- I had one in the spares box which I tested and confirmed working (12V applied across the coil resulted in 0 resistance across the ignition wire) and installed.

[Alien]

#1. Pump primes, pressure comes up to 40 then falls back off to 0. This is what has me confused, I have no spark and seems no signal for fuel pump to remain on. CEL illuminates which indicates comp has power.


How does the FORD Vats/Pats whatever work? Isn't there something funky about it being really difficult to bypass on the 5.0, integrated with the fan control or something silly? IIRC, GM has a ground for the fuel pump and a signal to ecm for the injectors.

[ShadowBolt]

This is most likely not your issue but several times I have had my 4.6 not want to start (even though it was turning over fine) after sitting in the off season because the battery was down just a little. I sounded like it was plenty hot listening to it spin the starter but for whatever reason it would not get any fuel or spark. In the case of the 55 the fuel pump will not even prime when I turn on the key unless I have over 12 volts. After charging the battery to a full charge it will start just fine. I even tried push starting once and with the battery at 11.5 volts it would not start.

JJ

[marshall_mosty]

How does the FORD Vats/Pats whatever work? Isn't there something funky about it being really difficult to bypass on the 5.0, integrated with the fan control or something silly? IIRC, GM has a ground for the fuel pump and a signal to ecm for the injectors.

Ford EEC-IV (87-95) didn't have VATS/PATS. The injectors and fuel pump relay both rely on the computer to ground the circuit, which is why the grounds are so important...

[drecords]

This is most likely not your issue but several times I have had my 4.6 not want to start (even though it was turning over fine) after sitting in the off season because the battery was down just a little. I sounded like it was plenty hot listening to it spin the starter but for whatever reason it would not get any fuel or spark. In the case of the 55 the fuel pump will not even prime when I turn on the key unless I have over 12 volts. After charging the battery to a full charge it will start just fine. I even tried push starting once and with the battery at 11.5 volts it would not start.

JJ

Jerry, I've had the same issue with #34 on the dyno....no start due to dying optima. I've had it sitting on a tender since TWS so battery should be optimal.

[drecords]

Ford EEC-IV (87-95) didn't have VATS/PATS. The injectors and fuel pump relay both rely on the computer to ground the circuit, which is why the grounds are so important...

When I pulled the computer last night I checked resistance to ground of pins 40&60 which are the ground pin and got 0 ohmses

[Fbody383]

I've had it sitting on a tender since TWS so battery should be optimal. Unless the charger or battery is bad. Voltage?

[mach1]

I followed my troubleshooting guide and it said "Replace Windsor with LS engine", not sure what that means??

[Pranav]

I followed my troubleshooting guide and it said "Replace Windsor with LS engine", not sure what that means??

Fixes everything.

[marshall_mosty]

My troubleshooting guide this offseason said to replace the EEC-IV system with a FAST XFI system...

[dtanker65]

Carb

[marshall_mosty]

Carb

Bah... knuckle dragger...

[drecords]

My troubleshooting guide this offseason said to replace the EEC-IV system with a FAST XFI system...

Ill take things I wish were CMC legal for 100...


Carb

The thought has crossed my mind more than once as I pick through this EFI harness.


I followed my troubleshooting guide and it said "Replace Windsor with LS engine", not sure what that means??

It means we're doing it wrong...

Hopefully borrowing an A9P computer tonight to rule that out. We'll see. On Wade's recommendation also going to go over everything another time and hope I'm missing something stupid.

[Fbody383]

Fixes everything. Fixes it so well... AI even said "stop it."

[Supercharged111]

A9P has a different timing curve than A9L, if you decide to keep it you'll want a dyno cert with that EEC.

[drecords]

A9P has a different timing curve than A9L, if you decide to keep it you'll want a dyno cert with that EEC.

Yup... planning on just using the A9P borrowed computer to rule in/rule out my computer as failed.

[mach1]

Yup... planning on just using the A9P borrowed computer to rule in/rule out my computer as failed.

Do your homework on the o2 harness before you switch computers, I think it fries leads on the PCB of the ECU if you go one direction but not the other.
Also, open your ECU and replace the caps, 2 out of 3 on mine literally fell off when I touched them.

[Supercharged111]

Do your homework on the o2 harness before you switch computers, I think it fries leads on the PCB of the ECU if you go one direction but not the other.
Also, open your ECU and replace the caps, 2 out of 3 on mine literally fell off when I touched them.

This does ring a bell, but was that a MAF only thing? The details are fuzzy, but I do recall auto and manual having different O2 hrnesses now that you mention it.

[drecords]

This does ring a bell, but was that a MAF only thing? The details are fuzzy, but I do recall auto and manual having different O2 hrnesses now that you mention it.


Do your homework on the o2 harness before you switch computers, I think it fries leads on the PCB of the ECU if you go one direction but not the other.
Also, open your ECU and replace the caps, 2 out of 3 on mine literally fell off when I touched them.

I'll do some googling, thanks gents!

[Matthew Smith]

Another option is to disconnect the O2 harness completely (to avoid firing the ECM), install the A9P computer for troubleshooting. This will help you determine if it is the ECM. One last step before starting with a bump starter (attached to the stater solenoid, not the ignition switch) check your TPS/Key on with the new ECM. Should be in the 90s. If it is let her rip!

[Matthew Smith]

I missed your statement about the TSP reading .15 volts. I would perform the TSP test, it will confirm if the ECM is bad. Here is a link for the test; http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/throttle-position-sensor-tests-2#1[/URL] If it points to the ECM and you find you need an O2 harness for an automatic, let me know and I will see if I have a spare one.

[drecords]

I missed your statement about the TSP reading .15 volts. I would perform the TSP test, it will confirm if the ECM is bad. Here is a link for the test; http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/throttle-position-sensor-tests-2#1[/URL] If it points to the ECM and you find you need an O2 harness for an automatic, let me know and I will see if I have a spare one.

TPS was showing .15V so swapped out with a new one. Now reads 1.05 Key on engine off and getting correct signals per test above.

Swapped out ECM's and confirmed it's not an ECM.

Throwing Hail Mary and thinking I might have a bad TFI harness connector. I lengthened the wires when I did the TFI Relo before TWS. New TFI harness shows up tomorrow at the local O'Reilly and I'm optimistic it's my issue.... We'll see.

[drecords]

Figured I'd update you guys on what ended up being #34's ailment. After swapping computers, verifying all the sensors from the various interwebs troubleshooting guides for the EEC-IV I found this little gem of a guide. http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/ignition-control-module-tests-1

Turns out the PIP sensor was bad which is what I suspected, then the warranty distributor had a bad PIP sensor, used this LED test to diagnose and it's running again on distributor #3. Now to fix all the other crap that I still have to before MSRH.

Many thanks to all who provided some input, especially to Matt Smith who helped via lots of PM's with different stuff to check.

Any other EFI guys have a class legal replacement distributor they like over the O'Reilly's one?