24 lb injection (mite not have been a good idea)

I would look hard at the plug wires,timing, and the timing chain. also take a look at the push rods,rockers,and valve springs. Make sure all are right on. Backfire tells me Spark timing and cam timing are off.
 
Markus2 said:
Update:

New ignition module has solved the idle issue-ALMOST-its 80 percent smoother.
still a slight roll-but not nearly as violent and almost not noticeable.

Car still has flat spots and will even backfire sometimes-it feels like under WOT there is a balloon inflating that does not pull hard- I KNOW THAT SOUNDS WEIRD-BUT THATS WHAT IT FEELS LIKE. LIKE THERE IS A BALLOON NEARLY FULL THAT WILL NOT TAKE AIR AS FAST AS IT DOES WHEN THE BALLOON STARTS TO INFLATE FROM NOTHING>
THATS WHAT MY ACCELERATION BAND FEELS LIKE.
AND SOMETIMES IT WILL EVEN BACKFIRE.

About to sell it im fed up.
power steering is now pissing all over-but thats a whole nother story
Click to expand...

Markus2

My 90 LSC had a bunch of skipping problems at about 165K -- sometimes backfireing. It finally quit - no spark at all. Thought it was a bad igntion module but NO! It was actually a partial disintigration of the physical parts of the distributor down under the plate that's inside. Plastic began disintigrating and tore things up pretty bad. Been running fine since replacement of the entire distributor. Worth having a look in there.
 
Distributor could definately be worn out if mileage is high. Just curious, how much vacuum is the engine pulling at an idle? I would put a vac gauge on it if you haven't already.
 
I will examine the distributor when I bump up timing later in week.

I really think that my timing was fine when i bumped it up a while back and had to run the 91 -93. Than after the ignition module my mech. set it back to zero and wanted me to drive it like that-That day it ran smoother no doubt but the backfiring started...
so.....the NEW ignition module did not make it backfire, I dont think....

i think the timing at base is too far back for my vehicles shape, age, mileage bla bla bla...
i think that once i bump it up it should be fine as far as getting rid of the backfiring.

All the other issues could very well pertain to the DISTRIBUTOR LIKE stated above by you guys-thanks.
LOTS TO DO LOTS TO DO

Waiting on Power Steering crap to arrive and than tackle this SOB.
 
Definitely don't run the timing at zero. 10 degrees before top dead center is the stock setting IIRC. Let us know the vacuum at idle too. You should have approx 16" of vacuum (maybe more) at idle with a 150K+ mileage engine.
 
Timing is most definately at 0 will bump it up-and report back.
Like I have said but still not done....

vacuum @ idle is 17-close to dead steady- AS STEADY AS I HAVE SEEN IT.

You really think the distributor could be the issue if it has the flat spots, like hickups, when im driving along at cruising speeds and also during acceleration.


So odd- because as I understand, correct me if I am wrong, when a car is turned on with cold engine-it runs rich- or at least richer than under normal operation temps-

So....interesting...
...my car pulls harder responds better with less throttle-and the Feels as if all power is there....
but after it warms up....
thats when it becomes REALLY noticeable.
 
update.

Checked timing again...
like you guys said...



It had been reset by mechanic when ignition module was installed..
so idle became STEADIER after install but backfiring underhood was occuring...

So i show up unannounced at mech. shop and told him the timing was off.
He reminded me that it is where it is supposed to be.

I told him my car has been backfiring since you supposedly reset base...with ignition module was installed...

MAKE A LONG STORY SHORT..

it was set at close to 4 or 5 BTDC...
As opposed to factory setting of 10 degrees BTDC-it even says it on the sticker under the hood near the fan-10 degrees before top dead cent i think were the exact words.


So my mech bumps it up...
I go for a ride and find the steepest hill...
Still backfires.
I go back to mech immeadiately and told him give be 3-4 more degrees.
AT THIS POINT THE IS SET TO 13-14 BTDC

I went back to same hill-climbed it faster and no backfire.

I was running 87 octane and noticed the detonation occuring at high rpms under WOT on the highway immeadiately.

So like I did in the past-I ran some 89... it still was snap cracklin and a poppin' under hood.

So I just put in 93 octane....I am gonna beat on it when games end tonite at work.

I think the 93 mite be the trick.

Let me say this...
with my car at 14 degrees-it feels like it got a new engine.
I can not beleive how smooth and hard it pulls.
Off the line it so so quick
I feel like i have gear again (i got 355s out back and can finnally feel em)
It mite be all in my head.
But i am very very excited.

Still sluggish after warming up though....and it still runs better cold while everything is running rich.

IDK.
its a work in progress...
but finnally progress is made...


GETTING THERE.. pita...but getting there.


THANKS SO MUCH GUYS.
ITS FRIGGIN GREAT when progress is made and this forum helps.

Thanks SO MUCH EVERYONE.
gettin there...
we are getting there...
 
Intake manifold gasket leaking

Have you checked if the intake manifold is leaking this will cause a lot of the issues you are experincing. Get a can of ether and when the car is running spray where the gasket is and see if the engine speeds up if it does than the gasket is leaking. Just be careful with the ether it very flammable.
 
manifold gasket was replaced at same time of headgasket.
I will check never the less.
Thanks for insight
Its just so odd how smooth is runs for the first few minutes...
 
update.

had to add a quart of oil today-very dark and around one quart low.
oil change is due- its around 2500 since last...
oil is very very dark.

more clues to the mess that is a mark vii
 
You must log in or register to reply here.

Members online

No members online now.
Total: 176 (members: 0, guests: 176)
Back
Top