We have a Megasquirt in wife's 1979 Cadillac Seville running an Olds 350ci , which seems to be going really good now, but I want to ensure that all is OK. When cruising down the highway my DIY-WB O2 kit LEDs hover around Stoich, so I'm guessing I have it pretty close.
I have it somewhat richer at idle, which seems to suit this motor. When cruising, however, the RPM readout on the tuning software is not as stable as it should be, 'bouncing' from 2000 -> 3500 but mostly sitting around the correct RPM. This must be having an effect, but the motor seems smooth enough. Could this be a loose connection somewhere, or should there be a dampening component on the input from the HEI distributor?
Regards, Terry Griffin from downunder in Oz
RPM readout question
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Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
-
Bernard Fife
- Super Squirter
- Posts: 1009
- Joined: Mon Feb 16, 2004 3:15 pm
RPM readout question
--- In megasquirt@yahoogroups.com, "Terry Griffin" <terry@g...>
wrote:
>
> We have a Megasquirt in wife's 1979 Cadillac Seville running an
Olds 350ci , which seems to be going really good now, but I want to
ensure that all is OK. When cruising down the highway my DIY-WB O2
kit LEDs hover around Stoich, so I'm guessing I have it pretty close.
>
> I have it somewhat richer at idle, which seems to suit this
motor. When cruising, however, the RPM readout on the tuning
software is not as stable as it should be, 'bouncing' from 2000 ->
3500 but mostly sitting around the correct RPM. This must be having
an effect, but the motor seems smooth enough. Could this be a loose
connection somewhere, or should there be a dampening component on
the input from the HEI distributor?
Terry,
Do you have the Dave cap in place? This solved my false triggering
problems on a HEI 350 Chev. You can find info on the Dave cap here:
http://www.megasquirt.info/manual/mwire.htm#ignition
Also, if you have the large cap HEI, make sure the screws that hold
the coil in place are snug, the ignition is grounded through these.
Lance.
wrote:
>
> We have a Megasquirt in wife's 1979 Cadillac Seville running an
Olds 350ci , which seems to be going really good now, but I want to
ensure that all is OK. When cruising down the highway my DIY-WB O2
kit LEDs hover around Stoich, so I'm guessing I have it pretty close.
>
> I have it somewhat richer at idle, which seems to suit this
motor. When cruising, however, the RPM readout on the tuning
software is not as stable as it should be, 'bouncing' from 2000 ->
3500 but mostly sitting around the correct RPM. This must be having
an effect, but the motor seems smooth enough. Could this be a loose
connection somewhere, or should there be a dampening component on
the input from the HEI distributor?
Terry,
Do you have the Dave cap in place? This solved my false triggering
problems on a HEI 350 Chev. You can find info on the Dave cap here:
http://www.megasquirt.info/manual/mwire.htm#ignition
Also, if you have the large cap HEI, make sure the screws that hold
the coil in place are snug, the ignition is grounded through these.
Lance.
RPM readout question
Thanks, Lance. I'll check on that. The dizzy has the 'rotate the clip' type lock instead of screws. I'll see how it goes next weekend.
regards, Terry
regards, Terry
-
Bernard Fife
- Super Squirter
- Posts: 1009
- Joined: Mon Feb 16, 2004 3:15 pm
RPM readout question
--- In megasquirt@yahoogroups.com, "Terry Griffin" <terry@g...>
wrote:
>
> Thanks, Lance. I'll check on that. The dizzy has the 'rotate the
clip' type lock instead of screws. I'll see how it goes next
weekend.
Terry,
Yeah, that's how mine is too, 'rotate the clip' type locks to hold
the cap in place.
But if the coil is in the cap, the coil is held in place by 4 small
screws that may need to be 'snugged up'. Usually there's a cover
over the coil, held in place with two small hex screws. Remove that,
and you'll see the coil, which is held in place by four screws, one
of which should have a sheet metal 'grounding band'.
If this is even a bit loose, it creates all sorts of noise in the
ignition. However, the 4 screws only grab the plastic distributor
housing, so be careful not to overtighten them!
Lance.
wrote:
>
> Thanks, Lance. I'll check on that. The dizzy has the 'rotate the
clip' type lock instead of screws. I'll see how it goes next
weekend.
Terry,
Yeah, that's how mine is too, 'rotate the clip' type locks to hold
the cap in place.
But if the coil is in the cap, the coil is held in place by 4 small
screws that may need to be 'snugged up'. Usually there's a cover
over the coil, held in place with two small hex screws. Remove that,
and you'll see the coil, which is held in place by four screws, one
of which should have a sheet metal 'grounding band'.
If this is even a bit loose, it creates all sorts of noise in the
ignition. However, the 4 screws only grab the plastic distributor
housing, so be careful not to overtighten them!
Lance.
-
bob.holman
RPM readout question
If you are putting an HEI together from junkyard scraps, that metal ground
strap is not obvious and it will run (for a while) without it. That was a
few years back on carbs and I don't know what that would do to tthe
trigger circuit for any EFI. Make sure it's there.
strap is not obvious and it will run (for a while) without it. That was a
few years back on carbs and I don't know what that would do to tthe
trigger circuit for any EFI. Make sure it's there.
RE: Re: RPM readout question
The HEI and injectors etc are original equipment, Bob. I'll check that ground strap, though. Thanks for your help.
regards, Terry
regards, Terry
RE: Re: RPM readout question
Thanks, Lance. I've got a spare cap (the original one), so I'll check that out & maybe swap caps after tightening. We have to hold a lot of spares down here.....Until we went the Megasquirt way, I had swapped out the original analogue computer six times, and never did get the motor running right. Now though, Robyn has a heap of fun with it.
regards, Terry
regards, Terry
-
Ipex100 at hotmail.com
Re: RPM readout question
--- In megasquirt@yahoogroups.com, "Terry Griffin" <terry@g...>
wrote:
>
> Thanks, Lance. I've got a spare cap (the original one), so I'll
check that out & maybe swap caps after tightening. We have to hold
a lot of spares down here.....Until we went the Megasquirt way, I
had swapped out the original analogue computer six times, and never
did get the motor running right. Now though, Robyn has a heap of
fun with it.
>
> regards, Terry
Hi Terry....I may be wrong here but I get the impression that your
missing what the Dave Cap is, it is short for "Dave Capacitor" and
is added to the ignition input side to help eliminate rpm
spikes.Make sure you check the link that Lance posted for more info.
Brad J.
wrote:
>
> Thanks, Lance. I've got a spare cap (the original one), so I'll
check that out & maybe swap caps after tightening. We have to hold
a lot of spares down here.....Until we went the Megasquirt way, I
had swapped out the original analogue computer six times, and never
did get the motor running right. Now though, Robyn has a heap of
fun with it.
>
> regards, Terry
Hi Terry....I may be wrong here but I get the impression that your
missing what the Dave Cap is, it is short for "Dave Capacitor" and
is added to the ignition input side to help eliminate rpm
spikes.Make sure you check the link that Lance posted for more info.
Brad J.