2000 Safari has a bad miss...

PLACE ANY ISSUES RELATED TO HOW YOUR VAN RUNS. IF IT BOGS, HESITATES, BACKFIRES OR JUST PLAIN RUNS LIKE CRAP...THIS IS THE PLACE FOR IT!
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Topic author
Dungeness
I am merely driving my van
I am merely driving my van
Posts: 12
Joined: Thu Apr 05, 2012 8:26 pm

2000 Safari has a bad miss...

Post by Dungeness »

Boy am I stumped! Here is a list of the things I have replaced on my AWD 2000 Safari 4.3 with 234Km while trying to get rid of a low speed hesitation which turned into a miss:

fuel filter
air cleaner
spark plugs
plug leads
coil
distributor (new, complete with cap, sensor, rotor)
mass airflow meter
fuel injection spider (inside plenum)
It still has a miss barely detectable at idle and high revs but pronounced off idle in neutral or drive.
compression test at 165 or better all cylinders
spark plugs look fine
It throws up a PO135 code sometimes after driving on the highway (O2 sensor)
Before FI replacement, fuel pressure would drop 1 psi per minute, after new spider, maybe 1/3 psi drop over 2 minutes
Since FI replacement, is putting up PO303 code (misfire cyl 3) (spider not crossed up, I checked)
tried new plug and wire in cyl #3 to no difference
all cylinders seem to act the same when removing individual leads at distributor cap while running
fuel pressure at 58 lbs (within 55 to 60 limit)
no detectable sparks at night
is cam rounding off?
is new FI faulty?
is some other sensor faulty?
is wiring harness faulty?
is engine computer going bad?
????
My best guess is new FI is faulty since the PO303 code started then, but maybe disturbing the wiring?

Any suggestions would certainly be welcome. Thanks everyone!
2000 Safari AWD full load
'87 Astro full load of rust

Captn. Crunch
I sleep in my van
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Location: southeastern ct
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Re: 2000 Safari has a bad miss...

Post by Captn. Crunch »

Dungeness
I see nobody has come to your aid on this and I think I know why. It looks like you've already done everything anyone could think of doing. Electicity is funny stuff and ive only got a couple of left field ideas. Did you use a spray bottle to mist water over the wiring? Also find and clean any ground straps
Last edited by Captn. Crunch on Mon Oct 05, 2015 4:07 am, edited 1 time in total.
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

AstroWill
I finally get the smurf thing
Posts: 163
Joined: Sun Nov 14, 2010 12:09 pm

Re: 2000 Safari has a bad miss...

Post by AstroWill »

I would start with a compression check.

Topic author
Dungeness
I am merely driving my van
I am merely driving my van
Posts: 12
Joined: Thu Apr 05, 2012 8:26 pm

Fixed the miss!

Post by Dungeness »

Hi everyone,

Thanks for your suggestions, as it turns out, the injection unit I installed was faulty and replacement made the codes go away and it ran the same as before, with a noticeable miss. I misted the coil to no avail and then replaced the plastic protectors on the plug leads for the left bank where they come out of the distributor. Looks like the new leads were touching the metallic cowl lining. Low and behold, when I reinstalled the engine cover the miss was all but gone! There is still an occasional miss when cold but it appears that was the problem. I've replaced a lot of parts chasing this issue, I recommend a making sure all the plastic protectors on the plug leads are in place when first trying to find a miss on an Astro or Safari.
2000 Safari AWD full load
'87 Astro full load of rust

Captn. Crunch
I sleep in my van
Posts: 557
Joined: Wed Feb 01, 2012 12:10 pm
Location: southeastern ct
Has thanked: 1 time
Been thanked: 1 time

Re: 2000 Safari has a bad miss...

Post by Captn. Crunch »

Hey
Good job sticking with it and tracking it down. So that was a faulty injector spider rite out of the box? That's some frustrating stuff right there. Your trying to diagnose and your thinking " can't be that-its brand new". But we're seeing more and more of it as more and more parts are garbage made elsewhere.
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Topic author
Dungeness
I am merely driving my van
I am merely driving my van
Posts: 12
Joined: Thu Apr 05, 2012 8:26 pm

Re: 2000 Safari has a bad miss...

Post by Dungeness »

That was one tricky miss to sort out! Despite all my replacements the miss just kept coming back so finally I gave up and brought it to a shop. Guess what? Even though it has only 250K the timing is worn enough that the computer can't compensate so we oblonged the distributor hold-down bolt hole enough to get the timing right and it has completely cured the miss.

Sure appreciate everyone's help and hope sharing my fix pays it forward to someone else in the same fix.
2000 Safari AWD full load
'87 Astro full load of rust
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