Curse of the Weak Orange Spark

[MikeFleming]

Do you happen to know how the injectors fire individually while being on the same circuit? I'm just curious.

Yep. Sure do.

[MikeFleming]

There are 4 injectors, wired in parallel pairs to two different pins in the EEC. Each of those pins has a 5-lead, current-limited TO-3 electronic driver thingie that controls power (current flow) to the injector pair, completing the ground side of the circuit. One driver controls 1&2, the other 3&4. Or maybe it's 1&4, and 2&3, I forget. And it's not relevant. The only important part is two injectors per circuit, wired in parallel.

All injectors fire on and off at the same time - they're just activated by two different circuits. These are a SDF control - Simultaneous Double Fire system. Required fuel needed is calculated each turn of the crank and half the calculated fuel required is sprayed on each turn of the crank, so two full turns of the crankshaft (aka one 4-stroke cycle) are required to dispense the full fuel amount.

There is no timing or synchronization between fuel spray and piston or valve position or firing order. There's not enough time left in the calculations and engine cycles to do that.

This is true for all turbo EECs of that era (1983.5-1989)

[TheSVOTrust]

Hi Doug

Have to say you have come a long way on SVO's since getting ! I'm not a best guy on mod's or wiring but reading you first post - rewiring for LA3 etc etc... it sounds like you have an issue in wiring/computer etc etc.

I THINK there is enough play in the harness to swap injector 1 and 2 ---- or ------3 and 4. Would that tell you it is an ECC problem / compared to TFI spark issue??

Mark
P.S. If you need a brake out box let me know - I figure I owe you some shipping so it is my turn ! (You know I would send an PE and TPS in the box free too) LOL

[Desert Patina]

That is very charitable Mark. You know I've always been suspect of the `89 harness I rebuilt for the LA3, but its been a champ the whole time. None of my fears about it have come to pass.

Also, my name isn't Doug. Its the other thing I have in common with Mike Fleming other than owning an SVO. (Well the Michael F part at least).

Speaking of, with that information about the injectors then I can say for sure that it is a spark problem. I know they are getting gas, the plug was wet and I smell gas when the plug is out of them. And I know the spark is weak because even at 0.100 it was just a translucent orange light, nothing white like a spark about it.

I have a spare TFI (two actually) that I can try. One is from a junkyard and the other I bought new about a year ago that I hope I didn't throw away. The PIP was bought at the same time, and its the new one that is currently installed.

I did try another test. I took the SPOUT out, and it ran rough but regular. Then I put the SPOUT back in and it worked as well as it did before I took it apart (rough idle, but everything seemed pretty smooth after 2kRPM). It missed a few times, but it didn't fume up the garage so it was burning much better.

I tried again a half hour later, and the improvement was gone.

[TheSVOTrust]

Haha
Yeah I'm getting confused in my old age - or at least with the Canyon Red SVO's in AZ !!! I remember when you got your car from the older man up north right?
Anyway you knew it would come down to spark (lack of it), wiring.

I guess if we are going to view through the screen.....is it timed on the intake stroke? Usually when you see NO REASON (componets/wring ECU problem) it can just be a "mistake". I'm sure you have rechecked your work BUT I'd recheck you work. It is amazing now easy it is to get timing wrong (not on intake or timed to #1 injector pulse) OR even wiring order! (you would think with just 4 it's impossible - But trust me WE all have done it wrong at least once)

Mark
P.S. Hope I'm not leading you down a wrong path but it's free AND needed to be confirmed before going to parts !

[Desert Patina]

I replaced the TFI. Unfortunately I couldn't find my new one, so I used the junkyard one. The good news is it idles on its own now, and revs just fine.

The idle is rough, but then again I've been suspicious that one of the previous owners put a hot cam on it.

Time to put it back together and put it on the road.

Thanks again for y'alls help.

[Desert Patina]

It still seems sluggish in responding to the throttle. But if it warms up, revs high enough, it goes away. Its even having more trouble idling now especially when it warms up.

Smoke is coming from underneath the Turbo or exhaust gasket.

Before I had the 2-3 cylinders sharing, and milled the head and put a new Felpro gasket on it a while back. It might still be sharing, and that would explain why those cylinders are having more trouble firing.

It might just be year and a half old gas too?

[Desert Patina]

Checked the torque on the heads (it probably had enough of a heat cycle from me revving for about 10 minutes it the other day), used the new multimeter to adjust the TPS (it said the old close throttle position was 1.4 volts, now its set to .92) and validated it has a nice thick white spark.

The TFI was definitely the culprit.

The engine is still sputtering, what is the likelihood that nearly 2year old gas is the problem? If so, just empty the gas and replace the filter?

Thanks,

[JTurbo]

Gas in the tank and maybe the injectors need to be cleaned up? Throw a partial can of seafoam in the tank to see if that helps clean out the fuel system.....

[Desert Patina]

I have Sta-Bil, B-12 Injector Cleaner, and Iso-Heet standing by (to be joined with 5gal of fresh gas). I'm hoping that will do the trick.

Now if I can just figure out how to open the gas door with the dash completely out of the car...

[MikeFleming]

I have Sta-Bil, B-12 Injector Cleaner, and Iso-Heet standing by (to be joined with 5gal of fresh gas). I'm hoping that will do the trick.

Drain/pump out as much of the fuel it in the tank as you can. Once it gets past 12 months without having StaBil in it before, it's no longer petrol.

Then add fresh petrol wit a *small* amunt of cleaner adn run it thg=rough. Then add more fresh petrol and StaBil.

Now if I can just figure out how to open the gas door with the dash completely out of the car...

Open the hatch and feel around in the right rear for the back-up release cable. Under the carpet.

[Desert Patina]

Many thanks, I found the gas fill release cable.

I drained the tank as best we could at the fuel filter, about 10gal came out. Not sure if anything more would come out if we engaged the pump or not.

The gas from the tank was yellowish, but otherwise fine. The gas from the filter was cloudy and dirty. The filter was replaced, and I'll get some fresh gas in there with a little bit of cleaner.

[Desert Patina]

It took a bit of revving through sputters and jolts, but its running right now on the new gasoline. It idles just fine too (maybe just a tiny bit rough still).

I'm going to let the cleaner + gas work its magic on the lines by running it 5-10 minutes a day for the next week.

Just one point to clarify, the gas from one side of the filter was dirty, the gas from the other side was just cloudy.

Thanks again for all your help, everybody, I think the worst is behind me now and I will have it put back together soon.

[TheSVOTrust]

Filter media breaks down under the additives of today's fuels. Combine sitting , stale gas and gunk at the pintiles and you get this. Glad you got it.

After years of looking at SVO's over a computer screen WE SHOULD ALL be better at getting the "rest of the story" as P Harvey would say! Mike has said it before " it is easy to confuse problems of spark and fuel" When I read you first post to went down the rabbit hole of wiring. That is really bad of me - as I've always been an advocate of dropping tanks and putting plug wires on cars. (seems I do 1 car a year)

Mark

[svono50]

Glad to hear you got it running again! I run at least 1-2 total bottles a year of cleaner through my SVO's system as well as a bottle in each of my DD at each oil change to keep things 'clean' from a fuel system standpoint.

Best one I ever used, back in the day, was the Chevron intake valve cleaner...unfortunately that isn't offered any more. 3 bottles of that on a road trip down/back to Atlanta from Chicago brought my highway mileage up from 21 to 29 mpg. I had bad valve stem seals and had some hefty buildup on the tops of my intake valves...which was all but gone after the trip. Now I generally run Chevron ProGard Injector Cleaner, but will also use Chevron Techron Concentrate...if on sale. YMMV, of course.

[Desert Patina]

So it looks like the EGR Control Solenoid for the Turbocoupes are nonexistent. If I found any 81-85 2.3L LTD (etc) I could use it, but its all old plastic.

I might try my hand at impedance matching, does anyone have the specs on how to adapt a typical late '80s Ford solenoid to the LA3? Or is that just a fruitless effort?

Thanks again,