[xj-s] 3 ECUs and a car that doesn't run-electronics pundits?

XJ-S
1

Fuel pressure was about 44 with the car not running and 37 after I started
it. I don’t know about full throttle.
I changed the oil.

After installing the old ECU (forgot to ground it), only 1/2 the injectors
were firing. It was running this way for a little bit and then (randomly)
started to run normal-then bad again.

I am now rebuilding the wiring harness-just to make sure that isn’t the
problem.

ECU PINS:1,3,18,17,`16,15
34,35,23,25 are grounded (key off)

Most of these are supposed to be grounded, but I’m not sure about pins
3,18,and 15. Are they supposed ot be grounded? Can anyone confirm so?

The problem went from bad to worse. Seems to only be running off the right
bank-I measured this with a stethoscope. Maybe when I forgot to ground the
ECU, I fried the transistors? I think I might be able to rebuild my ECU
(from 2 of them) if it weren’t for the fact that I can’t find the part
numbers in the ECU.

There are 6 heat sinked-transistor-looking chips inside the 6CU. They all
say “RCA 510” and something like 17434A. I’ve looked everywhere-even
outdated chip catalogues: 1973,1976,1979,1984, 1993. Seems that most things
close to those data numbers are transisitors. Does anyone know where to
find them? I am desperate.

I would even reverse engineer the characateristics of the chips, but…

  1. I don’t know for certain they are a transisitor.
  2. I can’t interpret any definitive characteristics on the curve tracer-
    something turns on, but there doesn’t seem to be anything else interesting
    happening-couldn measure a collector current.

Kirby mentions fried transistos in his book, but I still don’t see whih ones
he was refering to.

Any help would be greatly appreciated.

Rob

 I think an IAT is an Intake Air Transducer. The little gizmo

on the port side air intake trumpet with a couple of wires on it.
Oil wise?. I think its time for an oil/filter change. Don’t think
you will have caused any damage by fuel/oil contamination unless a
fountain of gas came out when you removed the dipstick. Just call
what’s in it flushing oil. If this runs lean have you had plug
problems what’s the plug colour after a thrash also give us an idea
of how lean is it like is there a big flat spot or something.
What’s the exhaust colour inside the tail pipes. How much fuel
pressure are we at in the rail at wide open throttle.
Regards Mark–
Bassmec, XJS V12 1977 Coupe
Ipswich, Suffolk., United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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2
]There are 6 heat sinked-transistor-looking chips inside the 6CU. They all say "RCA 510" and something like 17434A. I've looked everywhere-even outdated chip catalogues: 1973,1976,1979,1984, 1993. Seems that most things close to those data numbers are transisitors. Does anyone know where to mfind them? I am desperate.

I would even reverse engineer the characateristics of the chips, but…

  1. I don’t know for certain they are a transisitor.
  2. I can’t interpret any definitive characteristics on the curve
    tracer-something turns on, but there doesn’t seem to be anything else
    interesting happening-couldn measure a collector current.

Kirby mentions fried transistos in his book, but I still don’t see whih ones
he was refering to.

Any help would be greatly appreciated.

Rob, I can’t help a lot, but I did want to note that the components you
mention do appear to be PNP transistors that happen to have the same
physical appearance as the TIP42 transistors used in MegaSquirt.
http://www.digikey.com/scripts/us/dksus.dll?KeywordSearch “TIP42”
Certainly a substitute exist. I wonder if you can unsolder one & put it
into a multimeter transistor tester & deduce it’s properties. You note that
all your 6CU “transistors” say RCA 510 & 17434A.

On one of my 6CUs three of them say “17343A H RCA 423,” one of them says
“17344A H RCA 423,” & two of them say " “17343A H RCA 419.” Each is at
a component location T### presumably for transistor, component location ###.
(6 total transistors)

Interestingly, the 16CU I have has 5 total transistors in the same general
location as the 6CU. (I can’t read the #s because they’re held upright to
their respective heat sinks by metal clips rather than by screw & nut.

You might call Walt at Corsairo electronics as he might be willing to
suggest some substitutes. He’s also got some nice diagrams, a little
diagnosis & a trick ECU mod to improve idle at his site
http://www.corsaro.com/wiring_diagrams/diagram_index.htm

When I get a chance I’ll update my website with pictures of the guts of 16CU
as well as release your TPS mod.

Paul Kobres
85’ XJS
95’ Miata
Columbia SC

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3

In reply to a message from Hill Robert J 1stLt AFRL/DELS sent Sun 27 Jul 2003:

Christ, I just got a new 16cu ECU from EBay for 20 quid, why bother
looking for chips, you’ll pay a hell of a lot more for the
component parts than you will for a working ECU!–
The original message included these comments:

There are 6 heat sinked-transistor-looking chips inside the 6CU. They all
say ‘‘RCA 510’’ and something like 17434A. I’ve looked everywhere-even
outdated chip catalogues: 1973,1976,1979,1984, 1993. Seems that most things

–
durbs
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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4

In reply to a message from Paul Kobres sent Tue 29 Jul 2003:

I think that those critters on the 6CU would be NPN power transistors in a ‘TO220’ package, the opposite of
the PNP ‘TIP42’ flyback transistor on the megasquirt. Many different devices can come in TO220 packages.
A ‘TIP41’ is such an NPN device. Its good for 6 or 7 amps of current, the ECU injector output should only be
running around 4 or 5 amps, so I think it would be OK here. TIP41’s cost around a buck or less.

IIRC, the 16CU has 4 power transistors and one voltage regulator, for a total package count of 5 TO220
devices.–
The original message included these comments:

]There are 6 heat sinked-transistor-looking chips inside the 6CU. They all
say ‘‘RCA 510’’ and something like 17434A. I’ve looked everywhere-even
outdated chip catalogues: 1973,1976,1979,1984, 1993. Seems that most things
close to those data numbers are transisitors. Does anyone know where to
mfind them? I am desperate.

  1. I don’t know for certain they are a transisitor.
    Rob, I can’t help a lot, but I did want to note that the components you
    mention do appear to be PNP transistors that happen to have the same
    physical appearance as the TIP42 transistors used in MegaSquirt.

–
Joe Bialy 87 XJ-S
Grosse Ile, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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