Annihilate

iTrader: (1)

Hello again,

So I have made two steps forward one step back many times over the past year.

As the year comes to an end I am desperately trying to get my car to run as it did when it was stock.

My current issue is thus,

It turns out I was running the wrong firing order for probably around a year, Id rather not talk about it.

Solving this issue provided great joy.

However things were still not well in my world.

I've replaced the coil and module with an upgraded performance component. Ignition feels strong. I bought some summit racing plug wires last year, while playing around with timing and such, I found that I am able to be shocked with through at least 2 boots on the dizzy.

No visible arcing in the dark, have not tried spray bottle test.

Believe it or not, my idle is relatively smooth, but things weren't right. I got into tuning, mainly due to having the Bosch injectors and needing to tune around them.

Things seemed alright with a tune I had. However the car shakes far more than it should from the engine across the board. Fifth gear especially seemed to struggle accelerating with more of a shuddering acceleration vs a smooth one.

Earlier tonight, while playing with some tunes to try and get better cold start cranking, amongst other fine points of the tune (really over my head about to blow), I find that my rear two passenger side injectors apparently have no effect on the engine, under any condition.

All my injectors ohm out at 17, and theyve been installed for less than 5,000 miles.

So I can unplug any other injector and get a noticeable rpm change, except for the rear two on the passenger side.

They both are getting power as well.

I have not had a chance to undo the plugs yet.

I would like to hear any theories.

Is this strictly an injector issue? Are either of those cylinders firing at all? Is it a spark plug issue or related to the wires? Is it in the tune? Did I screw something up by driving it with the wrong firing order for a season? Or am I just a little crazy?

More questions than answers my friends.

I'll say I've gotten to know this car more intimately than any other car I've owned, and she is almost running like she should. But frustrations mount.

Two main issues
Heavy vibration at highway speed (multiple driveshafts, joints, pinion angle, road force balance, newish axles)
Going to see if the extension house bushing resolves this issue.

General Engine vibration... Now I know this is a "performance" engine, however I feel the engine isn't running optimally. I've hears reports of the car running so smooth, people can place a bucket of water in the passenger compartment and not get any ripples... Fantasy? Perhaps, but a dream worth shooting for.

She's only got 46k, but she's had a bit of a rough few years.
I've replaced the harmonic balancer and all vacuum lines. New fuel pump/filter. New Catback exhaust. Have motor mounts for when I get the guts, but they look okay. Plugs and wires done last year with new cap and rotor.

Thinking this injector issue may be my golden goose. But we will see what yall think.

Any input would be appreciated!
Help my people!
Thanks!

vinny R

My buddy had a similar issue with his when he installed the Bosch 3's. The car would shudder really bad (he said it would huck and buck) at certain rpms and just at certain times when shifting. His was in the tune and when finally right all that went away. He used Tuned Performance on this board to get his tune right.
For the injectors I would get a Noid Light and hook it to the injector plug and make sure it is firing. Firing and having power are 2 different things. All 4 on that bank fire at the same time so maybe you have a bad connection where those two connect to the harness.
If you find it to be the injectors themselves I would recommend switching to the Delphi's. They are a direct replacement and require little if any tuning. They are also twice the cost but from the tuning issues with those Bosch 3's IMHO I feel they are worth the extra cost.

Komet

If you're returning your car to stock, put the stock tune in it with stock injectors (Delphi).

Tuned Performance

iTrader: (92)

You might double check spark to those cylinders as well as a compression test on the cylinders to check engine health.

SlowAndSteady

I had almost same Problems as you, may be slightly severe but basically identtical

You have also the HEI Ignition right ?
I was also searching for long time , changes coil cap and rotor.....old problem still there

one day i completely dissasembled the distributor and changed also the following:

- Ignition controll module (ICM)
-Distributor reluctor (ACDELCO D4155)
-Distributor Pick up coil
- Radio Capacitor ( also build in distributor)

after that everything was runing perfectely again

i found ot after that the icm was faulty and pickupcoil had a high resistance

Annihilate

iTrader: (1)

Interesting. I have replaced the ICM but I was unaware of these other components as potential culprits..

I'll look into this, thanks!