mikeinatruck wrote: fuel pressure is good has a rising rate regulator, throttle position switch is new, butterfly gap is correct, air flow meter is in spec,, galleries and plenum are not spotless but certainly not gummedup. Oilc changes every 5000?
I am going to look into my ignition system next, I have a new dizzy on it it has the the three pin amp/ecu on the side of it. What is the correct coil for this?
Its good that you are ahead of the game there, Mike. and clearly confident of the work already carried out will not need to be re-scrutinised.
One of the difficulties with any remote diagnosis process is that one is completely unfamiliar with the mods/changes that may have been introduced with the propblem system.
That always leaves me (in my style) simply offering a reasonable route to long term solution that very much depends upon the owner knowing what he has got, knowing what he has done and following the diagnostic route set down.
Thus by implication requiring the owner to re-review the advice variously offered
to see what has not yet been done or to try and understand the fallability of what modifications have been made
that might upset a standard system.
On that latter point, by way of example, a rising rate fuel pressure regulator will vary fuel pressure in a completely different way to the OE fitment. It can also be setup with a different baseline pressure than originally intended and expected.
The question that poses, then, is whether the fuel pressure at idle is matched to the settiings of the AFM and the ECU. Who knows? I dont, and in all probability neither do you.
That means that one is left with the probability that with a RRFPR, the engine may not be capable of being set up as per ORIGINAL.
If the pressure is too high - at idle- therein lies a possible cause of hunting, as you will have already studied and read about.
Moving onto the coil.
Essentially there are two systems, needing different coils.
Ballasted system needing a 9 volt coil and unballasted, needing a 12 volt coil. Your system is almost cetainly unballasted and thus you need a 12 volt coil. If you fitted any old available coil that might result in two similar situations.
A 9 volt coild would become overstressed (and eventually fail) and also produce a HT voltage that is too high for the rest of the sytsem causing a propensity for arcing and/or tracking, thus misfiring.
Or maybe the coil is a high performance 12 volt unit also giving way too much HT voltage for the rest of the system, giving similar problems to those just described.
What would I advise? Well, if you have a normal performance ignition system with original equipment plugs and HT leads, then fit a standard OEM or equivalent 12 volt coil.
Conversely. If you FANCY fitting higher performace coil, then be sure that your HT plug leads, connectors, boots, shrouds and plugs are suitably matched.
Expressed in the simplest of all terms. The OEM equipment was perfectly adequate when these cars left the showroom. It didn't fail, arc, track or leak high tension voltage. Kept clean and bright it would continue to operate thus for many, many years.
HOWEVER.
Lets say, for sake of argument, a PO fitted a high performance coil because "it seemed like a good idea" and the guy down the pub, said it worked for him - what might happen?
Well the extra "5 or 10 thousand volts" intended to give a bigger and fatter spark, now stresses the whole of the HT system from the king lead thro the dissy cap to the plug leads and the various connectors and shrouds.
That, in turn, causes arcing and carbon tracking, often made worse by unresolved damp and dirt. You get the idea?
So the bottom line it this: Whatever coil you fit, make sure it matches the capability of the remainder of the system, which in your case is probably going to be a standard OEM item or its equivalent, unless of couse you have info to the contrary.
Regarding the new dizzy with a 3 pin connector, I am not familiar with the arrangement, so others will be better placed to advise, but whatever the connections, the basic circuit will be very similar to this.
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