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Discussion Starter · #1 ·
Hi all, I have a 2002 Astro with 166k that is new to me and came with a misfire issue in all cylinders P0300. Also throwing code P0341 "Camshaft position sensor 'A' circuit" . From doing research on these forums it appears most likely culprits are either worn distributor gear or chafed main wiring harness. Any insights into which I should chase? Something else? DTC report attached

Screenshot_20210619-145133_FasLinkM2.jpg


Thanks!
 

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I have a 2002 Astro. I replaced my distributor that had same problem (around the same mileage). Remove distributor cap. if there is any at all side to side movement in the distributor ,replace it. Easy to do once dog house is off. I have 310,00 plus on my odometer now. runs great Just need to address some oil leaks and maybe replace timing chain, PS make sure to mark old distributor before removing. No need to do all that getting engine to number 1 cylinder ect. I also would recommend replacing intake gasket or you will have to pull it out again later to do it. It's tricky because of space but I accomplished it with no issues.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Note two distributor "rotor positions":

1) Where it swivels to once lifted
2) Resting place when seated

I'd make two marks.

You'll want to pre-align new distro to same "swivel to" location, then drop it in.
Doing this makes the job go quickly and smoothly.

Note: If the new distributor won't fully seat, you have two options:

1) You can reach in with long flat-blade screwdriver and align oil pump shaft (preferred)
2) If you're certain you dropped it in correctly, you can bump the starter, and it will drop into place.
If you're wrong however, you will need to go though process of lining up TDC on cylinder #1 to align new distro.
 

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Common Sense + Critical Thinking
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You are on the correct track IMO. I would definitely start at the distributor, they are not expensive to buy and are quite easy to install if you follow instructions.

Mmusicman said:
1) You can reach in with long flat-blade screwdriver and align oil pump shaft (preferred)
This is what I do, because the slotted drive for the oil pump almost ALWAYS moves just a hair out of place.
 

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Discussion Starter · #5 · (Edited)
Update nearly a year later (wow! been busy with other things and have another vehicle I use). Replaced distributor. Part was indeed cheap and indeed quite easy to replace (hardest part was that damn dog house!!)

Noticed a big improvement in performance and now feels good except after warming to operating temp, idles rough. Unfortunately also, still throwing codes P0300 random misfire and P0102 MAF low input (but takes about 5-10 min into drive before light comes on)

I cleaned the MAF with MAF cleaner, no luck. I fed about 1/3 container of Sea Foam into air intake, let sit hot, then drove hard. Further improvement in performance but mild and same codes

Replace MAF? Air filter is clean. Maybe the connector? Already replaced the speed sensor connector because wire broke. May be same type of issue
Bad fuel could be contributing as well, gas is probably 6 months old, half tank

Also noticed old codes about coolant temp being low. Temp gauge never gets to middle (210), typically around 180. Maybe wrong tstat was installed?
 

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all those sensors are bad or there are some bads wires, chunks of wiring harness or bad grounds. older vehicles often do not suffer from a new trifecta grounding system. batt to engine, engine to frame, frame to batt. bad grounds can look good.

hell i found a bad ground on my car after the windshield washer stopped spraying. traced it down with a power probe. the washer motor was getting power but, not ground! i Ted off the ground wire adding a left straight ot frame not only did the washer spray but, the blinkers were no longer blinking fast. granted that was a new beetle.

might not be your problem but never hurts to service and add grounds. infact i should do the same on mine
 

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Discussion Starter · #7 · (Edited)
all those sensors are bad or there are some bads wires, chunks of wiring harness or bad grounds. older vehicles often do not suffer from a new trifecta grounding system. batt to engine, engine to frame, frame to batt. bad grounds can look good.

hell i found a bad ground on my car after the windshield washer stopped spraying. traced it down with a power probe. the washer motor was getting power but, not ground! i Ted off the ground wire adding a left straight ot frame not only did the washer spray but, the blinkers were no longer blinking fast. granted that was a new beetle.

might not be your problem but never hurts to service and add grounds. infact i should do the same on mine
Appreciate the advice, thank you. Will start checking the grounds and see what resistance Im getting (if any). Also going to change the fuel filter and run Redline cleaner cause I figure I may as well do that


Edit: Today gave it a check. MAF ground reads 20-50Ω (depending on where I check, frame, battery post). Intake air temp sensor ground reads 250Ω though which seems high. Any ideas where this ground is attached? O2 sensor ground reads near 0Ω

Also checked voltages. MAF is getting 12v and 5v. IAT is getting 5v. Manual says to whack MAF with a screwdriver or something with engine running and check for stumble; will have to try that

Edit2: Gave it a drive today, still CEL and running a little rough but also pretty good. Some hesitation though when accelerating from a stop, assuming the misfire condition. Tapped on the MAF with engine running, made no difference, guess its good “¯\(ツ)/¯“
 

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Appreciate the advice, thank you. Will start checking the grounds and see what resistance Im getting (if any). Also going to change the fuel filter and run Redline cleaner cause I figure I may as well do that


Edit: Today gave it a check. MAF ground reads 20-50Ω (depending on where I check, frame, battery post). Intake air temp sensor ground reads 250Ω though which seems high. Any ideas where this ground is attached? O2 sensor ground reads near 0Ω

Also checked voltages. MAF is getting 12v and 5v. IAT is getting 5v. Manual says to whack MAF with a screwdriver or something with engine running and check for stumble; will have to try that
scan the frame and body work for wires bolted to it, if you find any, remove it and sand the eyelet and the body/frame where it attaches, rub it down with some dielectric grease and put in back on, snug it up. the grease will mush out and fill and air pockets and voids with grease to displace moisture. if it's old and work maybe replace the wire or ground strap. maybe even trace it back to see where it goes?

in the case of my bug like mentioned above i could see the washer motor had positive.
 

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Discussion Starter · #9 ·
Went on a longer highway run yesterday and CEL went off and stayed off! 🎉 Not really sure why but happy none the less. Could have just needed more time at sustained RPMs or could have been me fiddling with the O2 sensor (unplugging, replugging). If this issue reappears Ill check the connector to see if its broken the same way the speed sensor was.
Idles much better now but still not perfect, Im sure could use some other tune up help.

Also didn't note earlier but I put 1/3 can of Seafoam into engine oil and just drained it yesterday after the long drive. Noticed oil pressure seems much more consistent now
 

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Discussion Starter · #10 ·
Aw crap, SES light came back. Throwing P0301 (cyl1 misfire) and P0420 (catalytic converter not working properly) on main codes but deeper codes show P0102 (MAF low input) , P0300 (my old friend random misfire) and P0420 (the cat, which might be borked from the persistent misfire condition)

Any advice on which direction to head at this point?
 

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