I own a business doing ECU modifications for a completely different
platform (DSMs), so I'm intimately familiar with this problems (DSM
ECU are notorious for caps leakage issues). I don't know that this is
definitely my no-start problem, but I do know that if left unchecked,
this would most certainly lead to a dead or at the very least a
malfunctioning ECU. And probably while I'm out camping somewhere at
the most inconvenient time.
Anyway, I'm curious if you guys have noticed this problem before? I
searched around, but didn't see any specific mention of Ford ECUs
dying early deaths. It might be something you'll want to keep an eye
on or even pop that case and take a look at to see if you can catch
the problem before it develops into something bigger.
Looking for some discussion on the topic.
Doubt whether you'll find too many people interested in the subject on this
particular group. Electronic topics here tend to be limited to proper usage
of a DVM to measure battery drain... Trying to troubleshoot a problem with a
shorted sensor input I desperately searched for a schematic of the PCM in
one of my vehicles, coming up with zilch. So it's great to know someone who
deals with those for a living.
As for your leaking caps, those cheap aluminum electrolytics don't last --
usually don't leak, but rather dry up and increase their series resistance a
hundred fold within a few years. How badly that affects performance depends
on what the cap is doing in the circuit. If it's in some sort of a switching
power supply, that would be the worst. The one you showed seems to be pretty
well marked. Why not simply replace?
Yup, that's the plan for tomorrow when I'm back in the office. I will
remove the caps, lift that one resistor, clean up underneath
everything, check for shorts, clean up leakage, etc., etc., then
replace the affected components with new units. I was just posting
here to get some discussion going on the topic.
This also gave me a chance to read up on all the EEC-IV information
out there. Wow. You guys have been busy! :) I love that little J3
test port thingie. DSM ECUs have absolutely nothing of the sort.
Will have to hook up to it with the ol' logic analyzer to see what's
going on. Or just hit Moates.com and buy their inexpensive adapters
and stuff. Moates is on top of that pretty well.
EEC-IV is very old news. Very primitive by today's standards and out of
production for 12 years now. Its main advantage is reading diagnostics with
nothing more than a paper clip and a test light.
Incidentally, what in the world is DSM?
Thanks, but of course I'm aware of its age. There is one other
advantage I can think of to the EEC-IV ECU platform...it's installed
in my van. :) So that's the platform I'm going to focus on, old or
Turbocharged Eagle Talons, Mitsubishi Eclipses, and Plymouth Lasers
produced between 1990-1999. Not exactly a "modern" platform either,
of course. But that doesn't mean everyone is scrapping them either.
I was always "told" that there was something along those lines much
earlier than the incident the Wikipedia article references. I'm
pretty sure a similar thing was going on back in the late '80s/ealier
'90s. The caps in question on this particular van ECU have a date
code of about mid '89, FWIW.
Who said anything about re-inventing the ECU? It just needs to be
That leakage residue is acidic and will eat everything around it. In
fact, it's already doing a pretty good job of that on my ECU as you
can see from the pictures. It can also become conductive and
introduce shorts that can cause all KINDS of other problems, some of
which are catastrophic to the ECU.
So it must be cleaned up or else it will cause problems. There's
absolutely no ifs ands or buts about it. We've seen it for years on
the DSMs. Although the caps on the DSMs are typically much worse that
these it seems.
Anyway, to answer your question, yes I did try to scan it for codes.
But the code reader (an AutoXray 6000) just kept saying "No
communication". After that, I decided it was time to pull the ECU
because I had no other way at the time to confirm whether the ECU was
working at all or not.
I thought I'd follow up on this. I replaced the caps and did some
slight rework on that one poor resistor. One lead was *just* about to
fall off. The whole thing looks much better, but the van still
refuses to start. I didn't expect this to cure the no start problem
anyway. The leakage just didn't look severe enough yet to be causing
it. But it was definitely severe enough to require attention.
I'll keep digging and I guess I'll update this thread with the
Your ECU may or may not be responsible for the no start. As usual, check for
spark and fuel pressure first. If memory serves, there will be spark, at
fixed timing, even if the ECU can't control ignition. If you have spark and
correct fuel pressure, it's time to check whether the injectors are firing.
Incidentally, with EEC-IV you don't need any scanners to read stored codes
or to perform on-demand diagnostics. You put the ECU in diag mode by
grounding the single pin connector. You read the codes with a test light
connected from B+ to the STO pin in the 6-pin diagnostic connector. Plenty
of information about the details all over the web.
Thanks, Happy. But this all started as a standard diagnostic
procedure. Checked for spark, got none so I started to track back to
components that might be involved. It came down to the TFI module and
the ECU. Since the ECU was easier to reach and I had an interest in
it anyway, it came out first. The TFI modfule is next. I just gotta
figure out how to get to that one bolt holding the distributor in
place so I can rotate it out before I can even attempt to get the
module off. I've never dealt with a distrubtor before, so this has
been a bit of a learning curve for me.
But the whole point of this thread was simply to discuss the potential
issue with the ECU. I was first curious whether others had seen this
and then I interested in making people aware of this potential on
these old, forgotten platforms.
Just to finally update this thread. The problem was a malfunctioning
MFI relay (powers the ECU). But the problem wasn't just that the
relay stopped working. I wish it had because then the problem would
have been more obvious.
But nooo. The relay was working *just* enough to keep stuff powered
up, but then not actually function when you crank the engine. It had
just enough voltage drop that it really confused the ECU and
apparently just about everything else too, including me. :)
Oh well. Lesson learned. I enjoyed the exercise anyway. I wanted an
excuse to dig into this van a little deeper and that's what I got.
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