[Diy_efi] Hesitation, backfiring, jumpy blues :-(

Fri Aug 18 06:01:25 UTC 2006

I got to see an optispark for the first time last weekend.  A friend of mine 
was working on a Camaro with an LT-1.  I was told there is a conversion kit 
that uses individual coil packs per cylinder and uses the optispark to 
trigger those.  That takes all the "juice" out of the optispark and 
lengthens its life.

Arby

----- Original Message ----- 
From: "Lee M. Lemoine" <llemoine at gmail.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, August 17, 2006 1:35 AM
Subject: Re: [Diy_efi] Hesitation, backfiring, jumpy blues :-(

> Yessss!  i remember my friend with a Pontiac Formula having the same
> issue...   damn opti-spark ignition, and yes, that could very well be what
> your seeing as we couldn't tell by the codes or the running conditions. 
> he
> actually rebuilt his whole motor expecting to find something only to fire 
> it
> up and have to take it apart to replace the opti-spark system...
>
> -- LL
>
> On 8/16/06, Brendan Patten <bpatten at centurytel.net> wrote:
>>
>> Ohh yeah I remember the second time my friend had to replace his
>> distributor, one of the pins on the 4 wire connector was badly corroded.
>> We noticed after he had already got it replaced (under warranty) so not
>> sure if it was the pin or the 2nd distributor.  Any ways
>>
>> Good luck.
>>
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]
>> On Behalf Of Brendan Patten
>> Sent: Wednesday, August 16, 2006 6:20 PM
>> To: diy_efi at diy-efi.org
>> Subject: RE: [Diy_efi] Hesitation, backfiring, jumpy blues :-(
>>
>> Sounds like the case of a bad opti-spark distributor.  I had a 93 LT1 I
>> swapped into my truck, then sold to a friend.  Not too much later it
>> started exact symptoms you are describing.  Sometimes it would hardly
>> start.  He replace the distruibtor on it and it ran like a charm, at
>> least for about a year.  Then same thing.  Again, replaced distributor
>> and it fixed it.
>>
>> The 93 was a non vented distributor.  Later models have a line that
>> draws intake air through the distributor and into the intake. Any
>> moisture build up can cause them to go bad.  Sometimes pulling the cap
>> and drying it out will help a lot, but not always.
>>
>> Anyways, good luck, they are expensive, but most likely the cause.
>>
>> Brendan Patten
>> www.lt1swap.com
>>
>> -----Original Message-----
>> From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]
>> On Behalf Of 93 Formula
>> Sent: Tuesday, August 15, 2006 7:48 PM
>> To: fourth-gen at lists.f-body.org
>> Cc: diy_efi at diy-efi.org
>> Subject: [Diy_efi] Hesitation, backfiring, jumpy blues :-(
>>
>> Anyone out there care to offer any other ideas of where to look for my
>> problematic car?
>> Its been years and I haven't been able to drive it.
>> I have both diacom runs and datamaster runs.
>> If anyone wants to take a look, let me know and I'd be glad to email
>> them.
>> I have run VE-MAster 4 times on datamaster data with not enough change
>> to
>> make it go away yet.
>> I see some things I don't like in the data but don't what to make of all
>> of
>> it.
>> Also - could the egr effect anything?  I don't have one hooked up
>> anymore.
>> Should I turn something off or change the on/off values in the ecm?
>> (I've
>> put this back to stock now)
>>
>> Here are the symptoms -
>> 1. Doesn't want to keep a "running" idle -aka wants to die when you put
>> in
>> gear or turn on the A/C...
>>
>> 2. When driving it - open or closed loop - from a stop to anywhere in
>> the
>> part throttle range, there is always like a jerk of the car like it
>> wants to
>> die (I thought it was going lean) and then it surges forward
>>
>> 3. the rpm's seem to have the jitters looking at the data, the  LTs seem
>>
>> wrong - not near 128 usually.
>>
>> 4. the only time it seems to run ok is when I mash it but even then
>> something doesnt sound right.
>>   I also noticed that one LT was stuck at 130 instead of 128 - seemed
>> weird
>> if using WOT
>> I also noticed LT counts hanging around 108-114 range for a 9 second
>> period
>> when I let my foot off the gas after a 10% TPS yikes.
>>
>> 5. popping in the exhaust - especially when letting of the throttle but
>> even
>> at part throttle driving this happens.
>>
>> 6. still starts hard - long crank and then wants to die for the first 10
>>
>> seconds unless I keep in the gas - reminds me more of my 73 Charger
>> before I
>> upgraded the ignition.
>>
>> What I've done... (besides aging 30 years in 3)
>> -------------------------
>> changed programming like no tomorrow, went back to stock programming and
>>
>> started over, tried VE master 4 times - Is this something you should
>> have to
>> run a lot before it gets right?
>> chk'd or changed coil, coil wires, spark plugs - although that was a
>> year a
>> go and they may be "fouled from too rich tests"  Would these really need
>>
>> changing or would just a good hot romp burn em off? (which I've doe a
>> few
>> times)
>>
>> 1. I've helped the idle problem by adjusting the throttle stop out some
>> to
>> raise the idle speed.
>>     I tried raising #s in the ecm but it didn't help.
>>
>> 2. usually the only way to keep it moving when it does this is to
>> feather
>> the throttle until it finally gets going.
>>
>> 3-4. it does better to touch it at say 20% rather than a 5-10% throttle.
>> I noticed in the data that the tps changes even when I don't have my
>> foot on
>> the throttle ???
>>
>> I know there is some exhaust leak in the driverside Collector pipe since
>> it
>> never was a perfect fit
>> I don't know if that is enough to cause all of these problems though.
>> I did have problems with it starting and had to replace the battery -
>> thought the pcm was dead, but apparently it was just my proms so I went
>> back
>> to my DOS program to make sure and it works but it
>> I run 30# f*rd injectors in it now and they are programmed according to
>> the
>> formula someone posted here a while back - I think its is like 31.xx as
>> the
>> constant.
>>
>> Jeff  http://FindFastCars.com 93 Formula
>> Mods: 355 forged for NOS, LT4 HotTop, 58TB, SLP Cnvrtr, 3.73s,
>> Mufflex/Spintech 4" exhaust, Hooker LTs, 300+ Ign, Injctrs, MSD Adj Win
>> Sw &
>> 3 Ign Ret, K&N CAI, Diacom, CATSTuner...
>>
>>
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>
>
>
> -- 
> Sincerely,
> Lee M. Lemoine
> KB1NQI  - Amateur Radio
> http://www.turbochargedsoul.com/
> '06 Subaru Legacy GT Limited - 250/250 AWD 5EAT
> '93 Chevy Cavalier Z24 Convertible - 300/330 FWD 5MT (Mclaren Turbo!)
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