Posted: Sat May 12, 2012 10:26 am
I just quit smoking (tobacco) this week... AGAIN!
Wedgy is correct about certain things being unlikely, or not involved, in the starting issue.
A step-through approach is required... EG - is it cranking, is it sparking, is the ECU lit, is there fuel...?
But, a non-quick and un-short comment (ramble) on electrics & manuals in general....
IMO, factory manuals are the best you can get, at least for Jap cars (Isuzu etc).
Others may be bad despite "looking" good.
And I still reckon Gregory's have the WORST electrical diagrams I have ever seen ANYWHERE for ANYTHING. (That's based on box or circle outlines or all devices - you have to look to the legend for what each box is. And with the "simple" TX-Gemini having over 80 such labels...).
The Jap manuals often provide "a course" on the particular subject item.
I have a copy of Mr P's PiazzaManual CD (as available from this site).
IMO such sources are essential for modern vehicles - the electrics and interaction are simply too complex otherwise.
Older "1-page" electrics on Geminis and earlier could be ok without schematics.
Initially I HATED the multi-page wiring diagrams for ANY car. I wanted it all on one big page.
However, a 1-pager is not practical. Hence splitting is required.
And whilst I still hate many other electrical schematics (typically non-Jap), I now appreciate the PiazzaManual.pdf's schematics.
Each fold-out page is a reasonably self-contained sub-system or collection of systems.
The relevant power source is present on all pages (on the LHS) for understanding & troubleshooting ease.
Normally I hate duplication, but it is well worth it in this case!
And "functional" or "circuit diagram" type symbols are used. IOW, relays and components or modules are shown electrically rather than physically - the latter IMO being useless when trying to understand or troubleshoot.
Despite that, once the circuit labeling is understood, it is easy to convert the diagram to physical connectors and pins etc.
Translating the above into reality....
Despite not "knowing" my Geminis or Piazzas etc, from their quality electrical diagrams I can often understand and predict behaviour...
VIZ - last year's episode with someone that insisted on shorting out their Piazza's air-con idling or starter relay etc.
For the Piazza, I can even suggest what incorrect "re-plugging" might occur, and the likely impact.
Compare that to other electrical diagrams - whether Gregory's or other vehicles that IMO are difficult to decipher...
Some pages are merely "bridges" between actual components.
A system's functionality might be spread over several pages (with cryptic connection labels)!
Back to the Piazza...
IMO, at first the Piazza engine-bay was an electrical plumbing nightmare!
Now I see it as a collection of reasonably stand-alone subsystems.
Some are merely "add on luxuries" that are not essential. EG - the turbo "not cold" coolant system; remove that and you substitute a single hose for a hose with a valve and an additional solenoid.
The bulk of the wiring is not helped by the Piazza's innovative features. Few cars had CPUs at the time, and the Piazza was quoted as having 3 CPUs (or 4 if automatic transmission).
Plus the technology. What I thought was some crazy ignition or power system is merely the front windscreen wiper's variable-speed controller.
The wiper's low shoebox sized control could now be matchbox sized.
Similarly with the digi-dash. That could now be reduced to a single board even if using the same display technology.
Anyhow, the above is my opinion for what it's worth.
It is well worthwhile getting the appropriate wiring diagrams and spending a bit of time trying to understand their madness.
Not that any of the above effects the most common fix for ANY electrical problem (ie, over 90% for vehicles; probably over 96% for piazzas) which is to break and remake all connections and ROTATE all fuses (else exchange or at least break and remake if the only fuse of that type or value).
[ By rotate I mean "leap frog"... Remove the first fuse. Replace it with the next same-rated fuse until all done; the first removed fuse it fitted into the last fuse's position. Spare fuses should only be used for single fuses in which case a new fuse should be bought as spare if that circuit's behaviour changes. ]
Note that fuses can have intermittent contact. Typically such fuses break (or open) when warm.
As to Mr Dikhed mechanic that after 2 weeks merely succeeded in blowing up a mate's Piazza's ECU (and costing me hours on the phone and under my Piazzas removing my fuel pumps etc - all to no avail)...
My mate found the problem. It was a "likely problem" I alerted him to months before - namely that his battery flinks were likely to cause problems in the near future.
Sure enough, damp weather was all that was needed.
Two weeks, many hours, and an ECU could have been saved if (1) the break & remake rule was used, & (2), my predictive advice had have been followed. (He was lucky - I prevent things; I don't do repairs nor assists for subsequent passive damage.)
Wedgy is correct about certain things being unlikely, or not involved, in the starting issue.
A step-through approach is required... EG - is it cranking, is it sparking, is the ECU lit, is there fuel...?
But, a non-quick and un-short comment (ramble) on electrics & manuals in general....
IMO, factory manuals are the best you can get, at least for Jap cars (Isuzu etc).
Others may be bad despite "looking" good.
And I still reckon Gregory's have the WORST electrical diagrams I have ever seen ANYWHERE for ANYTHING. (That's based on box or circle outlines or all devices - you have to look to the legend for what each box is. And with the "simple" TX-Gemini having over 80 such labels...).
The Jap manuals often provide "a course" on the particular subject item.
I have a copy of Mr P's PiazzaManual CD (as available from this site).
IMO such sources are essential for modern vehicles - the electrics and interaction are simply too complex otherwise.
Older "1-page" electrics on Geminis and earlier could be ok without schematics.
Initially I HATED the multi-page wiring diagrams for ANY car. I wanted it all on one big page.
However, a 1-pager is not practical. Hence splitting is required.
And whilst I still hate many other electrical schematics (typically non-Jap), I now appreciate the PiazzaManual.pdf's schematics.
Each fold-out page is a reasonably self-contained sub-system or collection of systems.
The relevant power source is present on all pages (on the LHS) for understanding & troubleshooting ease.
Normally I hate duplication, but it is well worth it in this case!
And "functional" or "circuit diagram" type symbols are used. IOW, relays and components or modules are shown electrically rather than physically - the latter IMO being useless when trying to understand or troubleshoot.
Despite that, once the circuit labeling is understood, it is easy to convert the diagram to physical connectors and pins etc.
Translating the above into reality....
Despite not "knowing" my Geminis or Piazzas etc, from their quality electrical diagrams I can often understand and predict behaviour...
VIZ - last year's episode with someone that insisted on shorting out their Piazza's air-con idling or starter relay etc.
For the Piazza, I can even suggest what incorrect "re-plugging" might occur, and the likely impact.
Compare that to other electrical diagrams - whether Gregory's or other vehicles that IMO are difficult to decipher...
Some pages are merely "bridges" between actual components.
A system's functionality might be spread over several pages (with cryptic connection labels)!
Back to the Piazza...
IMO, at first the Piazza engine-bay was an electrical plumbing nightmare!
Now I see it as a collection of reasonably stand-alone subsystems.
Some are merely "add on luxuries" that are not essential. EG - the turbo "not cold" coolant system; remove that and you substitute a single hose for a hose with a valve and an additional solenoid.
The bulk of the wiring is not helped by the Piazza's innovative features. Few cars had CPUs at the time, and the Piazza was quoted as having 3 CPUs (or 4 if automatic transmission).
Plus the technology. What I thought was some crazy ignition or power system is merely the front windscreen wiper's variable-speed controller.
The wiper's low shoebox sized control could now be matchbox sized.
Similarly with the digi-dash. That could now be reduced to a single board even if using the same display technology.
Anyhow, the above is my opinion for what it's worth.
It is well worthwhile getting the appropriate wiring diagrams and spending a bit of time trying to understand their madness.
Not that any of the above effects the most common fix for ANY electrical problem (ie, over 90% for vehicles; probably over 96% for piazzas) which is to break and remake all connections and ROTATE all fuses (else exchange or at least break and remake if the only fuse of that type or value).
[ By rotate I mean "leap frog"... Remove the first fuse. Replace it with the next same-rated fuse until all done; the first removed fuse it fitted into the last fuse's position. Spare fuses should only be used for single fuses in which case a new fuse should be bought as spare if that circuit's behaviour changes. ]
Note that fuses can have intermittent contact. Typically such fuses break (or open) when warm.
As to Mr Dikhed mechanic that after 2 weeks merely succeeded in blowing up a mate's Piazza's ECU (and costing me hours on the phone and under my Piazzas removing my fuel pumps etc - all to no avail)...
My mate found the problem. It was a "likely problem" I alerted him to months before - namely that his battery flinks were likely to cause problems in the near future.
Sure enough, damp weather was all that was needed.
Two weeks, many hours, and an ECU could have been saved if (1) the break & remake rule was used, & (2), my predictive advice had have been followed. (He was lucky - I prevent things; I don't do repairs nor assists for subsequent passive damage.)