Still the same problem with EFI

Hi together.

After doing these and those...all new parts and complete new engine control harness...the problem stays the same.

All 8 injectors firing twice per revolution...

I don't know where to search for the failure anymore. It's It's bewitched.

YouToube Video

I have some strange values, in my opinion, between ingintion run, ignition Start and battery plus...both are low ohmic...I don't know if this is common...

I have a 302/347 stroker with a 351W cam and 351W ECU...
Can the cam be the problem? Or maybe in combination with my distributor? I'm currently not sure, if the distributor is from a 351W or a 302...it's also a new part, including the TFI module.

Maybe it's a problem of the missing emissions control. I have removed everything...but I have had the same problems only without the EGR vent...so I don't believe that this is a part of the problem...

Maybe my test is wrong, cause I have connected the leds directly to the ECU outputs (58, 59) and ignition run. Same procedure when connecting to battery plus instead of ignition run...

Hmmm...can it be "normal" that all 8 injectors firing together while the engine is cranking? Only for starting purposes?

I'm helpless...sorry for that wired theory...

It may be a crank mode for cold starts. I do notice that it appears to fire at #1 and #6 rotor positions both banks at the same time.

A couple of tests, first, unplug the crank signal wire from the starter relay and use a push button jumper switch to repeat the test with the key on and see if both injector banks still fire together every crank revolution. If they do not, then the double pulse is a start item, if they still do then there is definitely something strange going on.

Second, regardless of the first test results, unplug the coolant temperature sensor (light green with yellow wire and black with white wire, in coolant passage front of intake) and put a 3000 ohm resistor across the connectors in the plug. This will cheat the computer into thinking the engine is warm. Then repeat the first test, if the system now alternately triggers the banks, see if you can get it to start and run (maybe poorly) like this. At that point I would check the coolant temperature sensor resistance from the chart I sent.

Hi Bill,

Thanks, I will perform these things. But I don't understand what I should connect with a switch together...

"and use a push button jumper switch to repeat the test with the key on"

EDIT
OK...sometime it takes a while for understanding...I've got it:
1. remove Starter relay signal cable from the regarding post at the relay
2. Connect a switch between battery plus and starter relay signal post
3. Turn ignition switch to "run"
4. switch the signal to the starter relay to simulate the engine is running...

How does the ECU is knowing that the engine is running? If I disconnect the signal from ignition Start from the starter relay, the starter motor won't turn and also the distributor will stand still and give no signals to the ECU, or am I wrong?

In the beginning, as I have run the engine, I have done a cam break-in. Although not knowing the problem at this time, the engine was at temperature and runs rich as hell...assumed that my problem was not the old engine harness, the problem is still the same...

another theory 
Does the injectors have a "real" plus and minus? As far as I know they are only inductors, so it's not possible to wire them wrong...assumed they can be miss wired, maybe it is possible that the bank, with e.g. one miss wired injector, gets its current flowing over this injector while the ECU triggers the other bank...

Ok...while writing this, It comes in my mind that I haven't currently connected this whole circuit...the LEDs are directly connected to the ECU pins...so the reason must be somewhere else...sorry for the wrong-way-theory...

Hi Bill,

everything stays the same. Although with 3k ohms for the water temperature and external starter signal...I don't understand this holy sh**.

Isn't it possible that the 351W cam is the problem? It has another ignition order than the 302 cam. I use the original 302 distributor...
I use this cam: SummitRacing
And this distributor:
RockAuto


In my understanding the ECU gets the pulse for firing the injectors from the TFI module.

So as there can be nothing wrong on the output side of the ECU (Pin 58 and 59), cause there are only LEDs directly connected to them, the error can only be caused by the information the ECU gets as input.

So that's my theory...now I stuck by analyzing, cause I don't know where to start...

Maybe there is a failure in the Analysis, cause although if I do the cranking with external voltage I have read that the ECU knows the rpm of the engine...so maybe it also knows that the engine is not running

So I will connect also the injectors together with the leds and see what's happening, when the engine runs...

But I hope someone has a better idea before...

Rene', when you crank the engine using the key, there is a start signal sent to pin# 30 of the computer and also to the TFI module (which should be a gray one if it is a Motorcraft one). There are 4 TFI modules, two are distributor mounted and two are remote mounted (driver's side inner fender). They are similar except for one item, the gray ones use a starter trigger to increase the dwell time when starting, the black ones are called CCD for Computer Controlled Dwell.

A few posts back you were checking wiring and raised a question regarding the white/light blue wire. This is fed from two different sources in the ignition switch. The reason for this is Ford used one front harness for all gas engine trucks in 1985/86. The Duraspark (non EEC engines) required a resistor in the coil feed which is the red/light green wire, the white/light blue is connected in the harness to the red/light green with a resistance wire. When starting, the red/light green wire is fed 12V through the ignition switch, once the truck is running, it reverts to the resistance. On the EFI trucks the red/light green and white/light blue are connected together, but, the red/light green becomes brown with pink.

The reason I wanted you to disconnect the starter signal wire from the relay and use a push button switch to activate it (battery+ to the start signal pin) is to take the wiring used for ignition feed in starting out of the system to simulate the engine started and running. As an FYI, basically all EFI systems trace their design back to a Bendix system used unsuccessfully by Chrysler in 1958, they sold the design to Bosch who fixed the problems. Many of the older Bosch systems used a cold start injector that was not controlled by the computer. Later ones simply increase the time and possibly the pulse frequency. When I was checking and setting up the system on my 1986 Chrysler convertible, I discovered that when starting the engine cold, all 4 injectors pulse together, but once running go back to a sequential system (1342). This is how the cold start works. That is why I want to see if simulating a running engine will change the pulse sequence of the injectors.

Hi Bill,

thanks for this Information. I'm don't stop learning while writing with you. I have found a book (PDF) named Ford Fuel Injection & Electronic Engine Control from Charles O. Probst. Very interesting things inside. 440 pages that also tell how the EFI-System works inside...but also there I have't found a solution. By the way, do you know this book?

OK, back to the Problem:

First about what I use:
- 1989 351W ECU
- Distributor from Cardone (Same article number for 1986 302 and 1989 351W)

I still have my original distributor from Motorcraft with Motorcraft TFI. I wanted to replace the HAL Sensor inside and save the refirbished distributor as spare-part.

Only to be sure:
If I use a 1989 ECU from the 351W I have bank-fired injectors for sure!

OK, I still need something to continue. I'm out of ideas where to search now. The following possibilities
are still in my mind as reason for the behavior:
- Problem with my cam from the 351W
- Something wrong with the Ignition-switch or the regarding circuit
So, that's it - End of ideas.

The problem with the cam is something I only hope I'm as wrong as I can be...

I still can't imagine what's the reason for letting the ECU fire both channels simultaneously. As I have nothing between the output for both channels, I only can imagine that the ECU gets wrong information.
So as I also can't imagine what information this could be instead of a wrong signal from the TFI.

So also FIY: I have seen that the injectors get one short (about 1 sec.) pulse when turning the key. Short time after the fuel pump has build up pressure. Also all 8 simultaneously. But I think this may be normal to have some extra fuel for starting...so that's my explanation.

So how could I continue? The truck stands now over a year since bought...I only planed to change some simple things...now look what I've got...
Same thing with my CJ7...bought it, runs about 4 month...then new engine and everything new...this seems to be a curse...

Rene' did the original distributor run? If so, plug the harness in to it, don't bother to install it. With the key on, spin the distributor shaft and see if you get the double pulse of your two test lights. If you do, I would suspect the computer. I do not recall my son's F150 or any other I have worked on firing the injectors at key on.

When you do this, note if the fuel pump is running all the time the key is on, or just an initial cycle followed by running when the distributor is spun.

Was the original computer bad or did you change to better accommodate the larger engine?

Hi Bill,

Yes, the original distributor runs. Also the original ECU. As this failure coming up after reassembling the engine, I have changed every sensor and also the distributor and the ECU to find the error...all the same ending...both injector lines firing together...

As I haven't connected the injectors, the pump can run as it likes...should have no effect, since the refurbished injectors close correct...what they do, cause I have checked this before.

And yes, as I thought my 302 computer is maybe bad, I've bought the one for the 351W cause it fits better to my 347 stroker specs.

I will try this with my old distributor, but I don't have much hope, cause I have had the same failure with it before...that's the reason to replace it...

Ok, don't forget there are several wiring changes from 1986 to 1987 and later.

Hi Bill,

I don't understand what you mean.

For the ECU, I have used your 1987 Pinout list. The sensors seems to have the same connectors.

The reason to change all these parts was, that my original setup already has done the same error. Nothing that I have changed solved this problem. It stays the same, no matter what I've replaced...

So, that's the reason for me to target something that I have changed by reassembling the engine...only the cam stays left.

My problem is, that the engine runs...very rich, but it runs...no backfire or other ignition problems...so actually also the cam can't be the problem...

So maybe, that's what I don't know, the error was there from the beginning, when I've bought the car. Cause the setup I've bought have had so much deposits inside, two cylinders without compression and a wired exhaust construction, maybe the carbon stays inside and don't comes out of the tailpipe...

Assuming this, only the ignition key circuit stays left untouched in my opinion...

Cause if two different computers and two different distributors and also two different parts of each sensor all do the same, it can only be the wiring. But regarding the engine control harness, I also have changed it...so what's left?

Oh, I forgot...my ECU gives on KOEO test an error 95 back...secondary fuel pump circuit...this error wasn't there before...I also get a bunch of errors from the emissions control parts...is there any way to fool the ECU that they are there? But this is optional and not so important, currently...

Ok...that's interesting...maybe I should crank more than 20 secs. And see what's happening...

To Bill: it seems it is like I thought...the ECU knows if the engine is running...



So maybe I should  do the test with my old distributor by rotating it with a drill to get some rpm simulated...do you think this can work?

That was my thought on the double pulse. Now, one other question, actually a couple. MAP sensor, is the vacuum line connected to a direct vacuum port on the manifold, it should be a 1/4" (roughly 7mm) line with no taps or restrictions? Second question, if you disconnect the vacuum from it with the engine running, does it change the running, either faster or slower and the obvious rich exhaust? If on the second one it improves slightly or no real change, then the MAP sensor is bad.

On the fuel pump, we can try solving that later.

Hi Bill,

Ok...Regarding to your questions about the MAP, you think I should run the engine and skip the test with the distributor driven by the drill...

My MAP is also new. With the old wiring harness it has made no difference...

About the connection of the vacuum line, I have to check. I have replaced the original lines 1:1 with silicone lines...

So only for understanding my lack in translation:
I have a MFI-fired system, cause not every single injector is triggered. MFI means: bank-fire. 4 injectors in parallel.
So the book says that while cranking all 8 injectors firing simultaneously, two times per distributor full rotation...do I understand this right?

Sorry, I was out in my garage working on my Chrysler convertible. I do understand, and you are correct on the MFI description, MFI standing for Multi-Point Fuel Injection. One thing in dealing with this, you have confirmed a suspicion I had regarding the starting mode on these systems as regards injector pulsing.

On the vacuum line to the MAP sensor, the original ones Ford used were a fairly thick wall, reinforced rubber connecting a hard plastic line to the MAP sensor so it couldn't collapse at high vacuum. My Chrysler has a similar setup, except that it has a solenoid valve so it can check barometric pressure at idle by momentarily switching to an open to atmosphere source (needed so boost limit isn't exceeded). If your silicone rubber lines are soft, they may be collapsing and not giving a correct signal to the MAP sensor.

I'm scanning through but have not noticed a couple basics overlooked. the 351 distributor will not fit in the 302. it is taller and uses a larger oil pump shaft. they do the same thing just fitted to different sized parts. as far as firing order of the 351 cam, it is as simple as wiring the spark plugs accordingly. one thing that ford did in 1986 was to use the 5.8l cam in the 5.0 and calling it a 5.0 H.O. . the fitment is great. however, the cam that you have is an increased cam for the 5.8 and therefore a big increase for a 5.0/302. as for the electronics, I would use all things 302 unless the bank fire would double a cyl and skip another. remember that the ecu and all of the sensors have no idea what size engine they are on. only what afr, exhaust gas output, map and other sensors read. results are all they care about. in many cases hard parts need to be replaced in order for the proper range of operation to be measured. for example. if you were to have a colder thermostat then the ecu will never reach its most efficient range. if the cam overlap is " drafty" then it will allow raw fuel to get past. if the cam lowers manifold vacuum, then the map will always think the throttle is open or a leak exists. I'm afraid that you may have exceeded the ecu with your engine design. you certainly are pushing its limit. not a bad part or a bad build but not exactly compatible with fords management systems.

Hi Bill,

I will check my setup regarding the vacuum lines. The silicon hoses I use are only specified for vacuum applications. As far as I remember, these silicon hoses (also when very felxible) are build for turbocharged systems in racing cars and able to resist very high vaccum without collapsing...but I will check the specs.

So everyting points to run the engine and have connected a LED to each injector port of the ECU, to see what they do. Maybe it's time for "real-life" checking...

Hi, you are right about the distributor of 302 and 351W. I have overlooked one different number while comparing.

About my cam: increased? summits writes "stock replacement"
About my ECU: I have installed one from a 1989 351W. As far as I know the lookup tables are different to the 302 to manage the greater displacement, so the ECU of the 351W "thinks" it's installed in a 351W and controlls the engine like that.

As I have a 347 stroker, I think my specs more at 351W than 302...that's the theory.
I also still use the stock heads of the 302 and haven't done zero decking while reworking the engine block. As far as I know there are much more aggressive cams available, also as other modificated crankshafts, pistons, pushrods and rocker-arms to raise the compression rate, power, etc...

So I hope, I'm not at its limits, at all. I think I only have build from my 302 a 351W for poor people...

Maybe my current problem isn't a problem at all...more a problem of understanding how the ECU works while cranking and engine not running. So I will check what's happening, when the engine is running. If the both injector-ports are alternating instead of firing both ports two times a revolution, everything is fine.
It's nearly three month ago as I have started the engine. Also my last tests, after replacing the distributor and some other parts were only with disconnected injectors and distributor cap off to see the rotation.