sort of stumble at idle

[Toms007]

Too wet, cold and nasty to go work on the Vette tonight. Tomorrow is supposed to be a much nicer day, so I'll get those injectors changed then.

 

[gmjunkie]

Too wet, cold and nasty to go work on the Vette tonight. Tomorrow is supposed to be a much nicer day, so I'll get those injectors changed then.

Yeah well Tom,stay in the house,must be a full moon!!For some Freaking Reason,My 94 has started acting up Big Time!!Has thrown no codes,Won't Idle below 1100 and fluctuates to 1675,Shows 24.8 V sometimes Ignition voltage on the scanner,TPS voltage fluctuates from 0.92-1.26 back and forth at times!! Went and got a new TPS at Chevrolet,still does the same thing!!I guess it's time to start checking all the grounds,either it's developed a bad ground somewhere,I've popped a diode or my ECM has took a Crap!!! Alls I did was decide to clean it up a little bit and change the spark plugs!! :bash

 

[John Robinson]

Yeah well Tom,stay in the house,must be a full moon!!For some Freaking Reason,My 94 has started acting up Big Time!!Has thrown no codes,Won't Idle below 1100 and fluctuates to 1675,Shows 24.8 V sometimes Ignition voltage on the scanner,TPS voltage fluctuates from 0.92-1.26 back and forth at times!! Went and got a new TPS at Chevrolet,still does the same thing!!I guess it's time to start checking all the grounds,either it's developed a bad ground somewhere,I've popped a diode or my ECM has took a Crap!!! Alls I did was decide to clean it up a little bit and change the spark plugs!! :bash

Junk don't you remember. If it ain't broke don't work on it.

Guys I have not read all the threads on this post but it crosses my mind that you are changing out the plug to see if it is suspect and the same with the injector has anybody done an ohms check of the plug wire and wiggled the wire at the connectors to see if you have an intermittent short.

 

[Toms007]

Yeah well Tom,stay in the house,must be a full moon!!For some Freaking Reason,My 94 has started acting up Big Time!!Has thrown no codes,Won't Idle below 1100 and fluctuates to 1675,Shows 24.8 V sometimes Ignition voltage on the scanner,TPS voltage fluctuates from 0.92-1.26 back and forth at times!! Went and got a new TPS at Chevrolet,still does the same thing!!I guess it's time to start checking all the grounds,either it's developed a bad ground somewhere,I've popped a diode or my ECM has took a Crap!!! Alls I did was decide to clean it up a little bit and change the spark plugs!! :bash

Junk, isn't that the way things go? If you need a new ECM, I have one (a new reman'd unit) for a 6 speed.

Junk don't you remember. If it ain't broke don't work on it.

Guys I have not read all the threads on this post but it crosses my mind that you are changing out the plug to see if it is suspect and the same with the injector has anybody done an ohms check of the plug wire and wiggled the wire at the connectors to see if you have an intermittent short.

John, I think you may have hit part of the nail on the head. After swapping the #8 and #1 injectors I have improvement. So I think I must have had a questionable connection. I am going to check Ohm readings on, at least, #8 plug wire. I guess I am too hard headed, because I kept thinking they are less than a year old and not that many miles. :eyerole But I need to check.

 

[John Robinson]

Junk, isn't that the way things go? If you need a new ECM, I have one (a new reman'd unit) for a 6 speed.



John, I think you may have hit part of the nail on the head. After swapping the #8 and #1 injectors I have improvement. So I think I must have had a questionable connection. I am going to check Ohm readings on, at least, #8 plug wire. I guess I am too hard headed, because I kept thinking they are less than a year old and not that many miles. :eyerole But I need to check.

I put new wires and plugs in my car about two weeks ago and when I started it up I had a 7 cylinder engine and the miss moved around to the different plugs. I was checking thiings out with the engine running and suddenly I saw a spark jump from where the molded plug was attached to the wire on the hot wire to the opti. Naturally I did not find this out until I had reinstalled the water pump and had everything buttoned up so I could start the car. Another case of thinking I have new wires so I don't need to check them

 

[Toms007]

OK, I didn't get the injectors changed again today....too many things to do and not anywhere near enough time..... I'll keep you posted.

 

[Toms007]

Here's what I got done today.

I took her out for a little test drive.....bad news really no different than before, so I let her cool down a bit and swapped Bosch injectors for the OE, no change. So I let it cool down again and run a compression test. All cylinders(hu hem except #6 which I couldn't get the tester started in) between 150 and 160.

So I have got a trailer and I will be hauling it to the mechanic who is going to look at it this week. I'm tired and frustrated and I just want to drive my car, I guess this one beat me....I just hope that the mechanic will figure it out in a timely manner.

 

[gmjunkie]

Here's what I got done today.

I took her out for a little test drive.....bad news really no different than before, so I let her cool down a bit and swapped Bosch injectors for the OE, no change. So I let it cool down again and run a compression test. All cylinders(hu hem except #6 which I couldn't get the tester started in) between 150 and 160.

So I have got a trailer and I will be hauling it to the mechanic who is going to look at it this week. I'm tired and frustrated and I just want to drive my car, I guess this one beat me....I just hope that the mechanic will figure it out in a timely manner.

Have checked the resistance on the plug wires???:confusedI know what your talking about though!!I've been driving my 94 for about 6 months and 5,000 miles just because no body has been looking at it on the lot!!Now I get someone interested and she decides to be like my wife,CanTankerous!!~!!

PS Call Gregory,I can't get mine to screw up since I called him today and left a message that I was in the Joliet Jail and needed bail $$$

 

[Toms007]

No, I forgot to do that. I can check them in the morning before I load it up. Oh I got the ECM to the local ups place yesterday...I'll get a tracking number for you.

 

[vette079]

High RPM? Not well at any RPM. Quote from tom94.

Check the TB gasket again. Just a thought.

 

[Kjelle]

I think you have problem with Optispark even if you have change it resently.
A pinging noise happen when wrong cylinder is fired.

I have a oscilloscope to diagnose my Optispark when my 94 also have
problem with pinging, misfire and bad idle.

This is a screenshot at the low resolution signal(cylinder identification).
Number 1, 2, 3 shows missing pulses.
PCM loose counting and starts firing wrong cylinder.
DTC code vill not be set.

http://web.telia.com/~u33227289/Optispark_missing_pulses_2.jpg

Connection:
http://web.telia.com/~u33227289/opti_connect_1.jpg
http://web.telia.com/~u33227289/opti_connect_2.jpg

So if you have a friend with oscilloscope, let him take a look at it before
you take the car to mechanic.

Kjelle

 

[Toms007]

Thanks for your replies, but the car is at the mechanics shop. Hopefully he'll figure out what's wrong....I guess it could be the optispark.

 

[Toms007]

WEll just got off the phone with my mechanic....My Opti is dead on 1 1/2 cylinders and sometimes 2 1/2. One cylinder is missfiring and half the time, #6 is dead all the time and one other will die on a half regular basis.

Why wouldn't this thing set a code? So where is the best place to buy a new opti...my Genuine GM didn't last 6,000 miles. Thinking seriously about an MSD. I don't know. I need to do something tonight.

 

[gmjunkie]

WEll just got off the phone with my mechanic....My Opti is dead on 1 1/2 cylinders and sometimes 2 1/2. One cylinder is missfiring and half the time, #6 is dead all the time and one other will die on a half regular basis.

Why wouldn't this thing set a code? So where is the best place to buy a new opti...my Genuine GM didn't last 6,000 miles. Thinking seriously about an MSD. I don't know. I need to do something tonight.

Tom,call the place that you bought it!!I think it has a 12 month 12,000 mile warranty! I know that my Chevrolet parts man would take care of it if I had a problem!!But I do buy allot of parts from him,but he also buys parts from me too,and I rebuild headlamp assembly's and motors for him!!

 

[Toms007]

Bit the bullet and ordered a new MSD. $526 .....ouch, but hopefully I won't have to deal with this again too soon.

I tried to call the place where I bought the other one and they were closed already for the day...I'll try again tomorrow and see if I can get a replacement. If I do I'll turn around and sell it, hopefully recoup some of the cost of the MSD.

 

[LT4man]

I have heard some good things about the MSD unit. Too bad the beautiful red color of the cap is virtually hidden once the unit is installed.

Keep us posted!

SAVE THE

 

[Toms007]

I have heard some good things about the MSD unit. Too bad the beautiful red color of the cap is virtually hidden once the unit is installed.

Keep us posted!

SAVE THE

You bet I'll keep everyone posted as to the status. The new MSD unit should be here no later than Friday.

 

[Toms007]

Well I got the MSD opti today....wow, this baby is well made. It also comes with the hoses to make it like the GM engineers should have made it, vacuum hoses to tie into the intake and out of the air intake hose in front of the TB. These things are really well made.....I guess they ought to for $515.

 

[gmjunkie]

Well I got the MSD opti today....wow, this baby is well made. It also comes with the hoses to make it like the GM engineers should have made it, vacuum hoses to tie into the intake and out of the air intake hose in front of the TB. These things are really well made.....I guess they ought to for $515.

Well Tom,I'm glad your luck is going better than mine! ECM came yesterday put it in and it ran great for about 45 minutes and then started the same thing mine was doing and then set a code different than mine ever did!!(26 Quad driver #1 fault!) Checked all the grounds and plug connections again and started it up as soon as it went to closed loop it set 26 again!!Disconnected the battery put my ECM back in it ran great for about 45 minutes and started the same thing and then it set code 26!! I've went back over the wiring and grounds at least 10-12 times,I finely quit at 2:30 this morning after it set 18 and 26!!:W:W:WFirst thing this morning I fire it up,runs great for about 20-30 minutes and then set a Bunch of codes and dies!(16,18,26,35,36,41,42,43,46,53) Theres something I'm miss'n somewhere!!:bash:bash:bash:bash

 

[Toms007]

Man, sorry for all your troubles.....I was really hoping that the new ECM would fix you up. At least you have codes to chase.........I guess that's a good things. I know how you feel. I am pretty sure that you will figure it out.