Ford Repair Questions? Ask a Mechanic for Answers ASAP
I went one step further. I replaced that terminal with another one out of an old 60 pin connector. It is gold plated and looked good. No change in performance. Scanner still indicates bank 2 injector pulse at zero. Testing pulse with noid light indicates proper operation. Contradiction here. Engine idles smooth, running on all 8. Ligfht throttle in gear, drops injectors listed before. I DO have a substitute wire for the trucks wiring harness in place to eliminate that possibility. I am performing the tests at the ECU plug.
Three ECU's, all with the exact same problem. What could cause the injector driver circuit to fail in the ECU? This is a pretty basic system. Timing and synch done by the distributor and modified by the TFI and sent to the ECU for injector control/fuel management.
It is a 95
on the pcm pin what number pin did you splice into
Let me see if you agree with my next step. Replace the 4 affected injectors, build a new harness for those injectors and replace the ECU.
If you will look back, one of the questions I had was: will an injector cause the ECU driver circuit to overload and burn out?
Thanks Don. I will replace the 4 injectors and the firing side of their harness. I will have to order the ECU. Should be done with the other work by the time the replacement gets here.
FYI: I am also an expert on this site. I amCustomer A.S.E. Master Certified since 1990. I have 40+ years experience in Domestic and Asian Cars & Trucks.
I have replaced the 4 affected injectors, rebuilt the trigger side of their harness all the way to the ECU. (Which had to come from Pennsylvania = Long Wait). Fired the engine with my scanner attached. Still showing bank 2 with zero pulse width. Still drops the same 4 injectors.
Two questions to ponder...
1) What would happen if I tied both banks of injectors together. (firing all 8 at the same time)?
2) What ECU pins are grounds? My wiring diagram in my chilton book does not show me.
Here are my test results.
All 4 ground pind show zero ohms.
Loaded the 4 with an old rotating beacon light, drawing between 5 and 10 amps.
Voltage drop is: Pin# XXXXX = .54, Pin# XXXXX = .64, Pin# XXXXX = .64, Pin# XXXXX = .71.
All these seem to be acceptable to me.
yes all of the ground are with in ford spec. I have gone over and over the wiring. what does the iac motor do when this happens
IAC goes to 100% at start-up. rolls back down to 42 - 45 %. Keep in mind that this is a very dirty throttle body. IAC varies accordingly with TPS changes. CT TPS = 1.07v. TP goes up and IAC follows. IAC has no different reaction when running on 8 or 4, other than normal allowance to maintain idle.
here is the issue injectors 1234 are powered together but 2468 are grounded. so the only thing that can cause 2468 to bow out is the injector to pcm wires. when you over laid the wire did you use a new pin in the pcm connector or the old one and just tap into the wire
I want to make sure we are on the same page. According to my Chilton wiring diagram, pin#59 (white wire) fires injectors 2,3,6,7. Pin# XXXXX (tan wire) fires injectors 1,4,5,8. I replaced injectors 2,3,6,7. Built new wiring harness from those injectors all the way to the ECU. I replaced the pin in the 60pin connector with another gold plated one out of a used connector. Tested the drag on the ECU pin prior to installing it. Everything is clean and tight. My new overlay also bypasses the engine compartment connection on the left fender. All my connection were soldiered and heat shrinked.
In short, not a new pin, but a good used pin with lead wire attached.
Im sorry I was just using the numbers that way as an example your wiring is the same as mine. could you give me the vin # XXXXX I will call the ford tech line tomarrow and see if they have heard of this concern. 1234 are powered together but 2367 are grounded together
Cool, We are on the same page.
I REALLY appreciate your dilligence in this endeavour. It is just after 4:00 here. Time to start shutting down.
FYI: I am a one man operation here. So if some of my relpies are delayed, it's because I am also trying to get other work done at the same time.
sorry it took so long to get back to you. here is the response from the tech line.
From the information listed suspect the vehicle is over 8500 GVW. As per the EVTM page 26-2 this vehicle uses bank fire when controlling the INJs on this engine. The INJs listed are grounded by the PCM pin 59. Please verify how the INJ pulse is being checked(noid light, test light, etc.). If there is a misfire issue present the PCM could stop INJ pulse. The PCM monitors the PIP signal from the distributer for INJ pulse. From the parts that have been replaced the concern is due to a PCM power/ground or an issue with the PIP signal to the PCM. Recommend to check the PIP signal to the PCM(using a DVOM, it should be half of battery voltage). If there is no issue present load test the PCM powers and grounds while performing a voltage drop. If the voltage drop is .2v or greater overlay the circuit being tested and re-pin at both connectors. Document if the vehicle is equipped with any aftermarket components(if equipped inspect the insulation of the components)
Testing for injector pulse is done with a noid light. On the good bank, noid light pulses get brighter and longer as expected. On the failing bank, noid light will start to brighten and then dim down to nothing. There are no aftermarket items on this truck. Even the stereo is factory. I will check powers and PIP signal again on Monday. Voltage drop of .2 would indicate that my grounds are all insufficient. Since my lowest one was pin # XXXXX was at .54.
Is there a common ground for the 4 grounds on the PCM? If not, where would I find them located.
Misfire... There is no noticable misfire occuring at idle.
Here we go again. Just another manic Monday...
I serviced all the grounds. Grounds are good. Power supply is good. PIP voltage is 6.2 volts running. Just under 5 when I pull the spout.
Here is another question. The orange/red wire from distributor to pin# XXXXX what is it for? Taking a reading on that wire: key off = +.02, Key on = -.03, engine running = -.03.
I'm guessing it is the ground for the hall switch in the distributor. And is no help to solving this mystery.
I have no misfire until the injectors drop out.
I am about ready to invest in some C4...
I am going to back burner this one for a while. I need to get some of the stacked up work done to pay some bills. Maybe try to get another truck like this one in here to compare things with.
If you get some other brain storm idea to try, just let me know.
I am finally getting back to this @$%# XXXXX
Just pulled KOEO codes for grins. I have: 654 - Manual Lever Position Sensor fault
558 - EGR Vacuum Regulator Circuit
624 - Electronic Pressure Control Circuit ( Transmision?)
Is it possible for any of these to affect injector pulse?
I also had a code 212 - no tach signal to processor. After running the test a second time, it did not return.
In the meantime, I am going to check every individual sensor to make sure none ore open or shorted.
HI Don, During the past couple of months, I did get a Bronco in here with the same engine code. Swapped computers before the customer took it away from me. My computer worked perfectly in the Bronco. The Bronco computer had the same symtoms in my truck. Did not get a chance to perform any comparisons between the 2 trucks.
Ultimately, I jumpered the 2 injector circuits together and told the owner of the consequences and recommended to trade it off for a new truck. The beast still sits here, the company that owns it is on the fence in it's own future existence. They are not doing much business and may have to close up. They keep hanging on by a thread.
If anything changes or I get lucky, I will certainly let you know.