Service Engine Light Flashing at 100km/h........

ANYTHING TO DO WITH MAKING YOUR VAN MOVE EXCEPT FOR THE ENGINE ITSELF.

pbgbottle
I am merely driving my van
I am merely driving my van
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Joined: Sat Jul 06, 2013 6:56 pm

Re: Service Engine Light Flashing at 100km/h........

Post by pbgbottle »

bump did this get solved
2004 astro AWD
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doyoulikeithere
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Re: Service Engine Light Flashing at 100km/h........

Post by doyoulikeithere »

Since 2008 ? I would hope so !!
As so often is the case, it appears the person is happy to ask for lots of help, and then once its finally fixed, they go away and never post the end of their story.
2021 Yamaha Tenere 700 - Blue.
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pbgbottle
I am merely driving my van
I am merely driving my van
Posts: 13
Joined: Sat Jul 06, 2013 6:56 pm

Re: Service Engine Light Flashing at 100km/h........

Post by pbgbottle »

i was hoping they may jump back on here with an update
my 2004 AWD astro is doing the exact same thing . flashing light mild load heading up hill around 100 KPH
but only once in awhile throws a code P0306
scan tool shows readiness monitor evap not complete .
i may have to drive farther for it to finish the cycle

it has only thrown the code 3 times .306
i have also just for testing purposes removed both cats and once only has it still throw the 306 code after removal
and this was after new plugs wires cap and rotor
pre cat was plugged 6 psi back pressure .should be no more than 2psi i think the mechanic said .
weird thing is it doesn't throw a 420 code for the missing cats (second cat was a bit plugged also but with in the top end of the spec)
and no check engine light either ,which i think it should for the missing cats

maybe someone else will decide to read this thread or i may have to start a new one of my own

PS i know it is illegal to remove cats , i will put one back on , no emission testing here where i am anymore



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2004 astro AWD

pbgbottle
I am merely driving my van
I am merely driving my van
Posts: 13
Joined: Sat Jul 06, 2013 6:56 pm

Re: Service Engine Light Flashing at 100km/h........

Post by pbgbottle »

i thought i would update this for anybody who stumbles onto this problem .
i solved it for my situation . first did a crank relearn that seemed to fix it but while the snap-on scanner was plugged in my buddy noticed my
Camshaft Retard Offset was way off like -9 degrees , should be zero . he figures this is what was really causing the code 0306 misfire.
we modified the distributor mounting bolt and turned the distributor until we got a zero degree reading and tightened her down
van runs great .better than it ever did i guess as these engines where out or get old things go out of spec .

for the tune up i am using after market cap ,not delco only because i didn't read about after market being no good
ngk wires and plugs all aftermarket stuff from the local auto parts store .i would suspect most misfire issues could also be related to worn out distributors.
and Camshaft Retard Offset being out of spec . sort of like the timing on the older cars when you used to get the dwell meter out and the timing light

here is some info about the Camshaft Retard Offset adjustment
Perform the Camshaft Retard Offset adjustment procedure as follows:

With the engine OFF slightly loosen the distributor hold down bolt.
Start the engine and raise the engine speed to 1000 RPM.
Using the scan tool monitor the camshaft retard offset.
Rotate the distributor as follows:
To compensate for a negative reading rotate the distributor in the counterclockwise direction.
To compensate for a positive reading rotate the distributor in the clockwise direction.
Repeat step 4 until 0 degrees offset is obtained.
When 0 degrees has been obtained turn OFF the ignition and tighten the distributor hold down bolt.

and more of how it works

there are two sensors used to calculate “Camshaft Retard Offset”: Crankshaft Position Sensor (CPK) and Camshaft Position Sensor (CMP). The CMP is integrated with the distributor and lined up perfectly with the plug for Cylinder #1. Its only job is to tell the ECU when cylinder #1 is mechanically at Top Dead Center (TDC) of its power stroke. The ECU uses this signal as the timing reference for calculating when to fire the injectors and plugs for the next rotation of the engine. The camshaft sensor and crankshaft TDCs must be lined up within a couple of degrees. If they are not, the distributor’s rotor may not be close enough to the cap contacts when the ECU decides to fire each spark plug. The distance between the crankshaft TDC and camshaft sensor TDC is called “Camshaft Retard Offset” which is measured in degrees


i hope this may help others out before they throw a ton of cash at parts they may or may not need,the sentence in bold above most likely is the cause of the misfire cap and rotor not synced properly

..PS i also got a hold of scanXL professional and can check the cam retard using my laptop also, u don't need the snap on tool u will have to make a separate purchase to get the unlock of the OBDII specific GM codes though

cheers i sure learned a lot



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2004 astro AWD

LiftedAWDAstro
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Re: Service Engine Light Flashing at 100km/h........

Post by LiftedAWDAstro »

Some great information. Thanks.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy

pbgbottle
I am merely driving my van
I am merely driving my van
Posts: 13
Joined: Sat Jul 06, 2013 6:56 pm

Re: Service Engine Light Flashing at 100km/h........

Post by pbgbottle »

bump more info ,a bit late but found out this info last year also which seemed to work ,but it has come back again
.light still flashes occasionally .,van does not miss a beat
but anyways i was talking to a GM master mechanic about a flashing check engine light i have and he said let me guess a v6 vortec ,i said yes and 04 astro van .
he went on to tell me about the V6 being famous for getting sticky valve guides causing the computer to throw the light (im assuming cause's like valve float )
also some of the V8's will do it also ,
the GM dealer magic fix after replacing junk and trying to fix it correctly was to was to pour this stuff into the oil .i have done it and it works .reason for bumping this thread was to mention it and to say my light is back flashing under heavy towing loads the odd time . so i will be changing the oil and trying another bottle ,to see what i get .,and to test this magic fix .lol to see if it cures it again . cheers .

P.S. i know this stuff isn't meant to fix this problem but it seems to work ..

seems fishy to me only 170,000 KM and sticky valve guide. ??? ,i'm not pulling the head .DoH!
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2004 astro AWD

pbgbottle
I am merely driving my van
I am merely driving my van
Posts: 13
Joined: Sat Jul 06, 2013 6:56 pm

Re: Service Engine Light Flashing at 100km/h........

Post by pbgbottle »

Bump. One more update. I still messed around not much happening the odd flashing light under heavy uphill load ie. pulling boat. Still flashed but no real misfire.
Well. Finally tranny went at 202,000 KM. Replaced transmission and haven’t had a flashing light since. Will be doing some super heavy towing in a few weeks big hill climbs so we will see if she throws up the flashing light. Now new trany and vehicle at 212,000 KM. So will see if she flashes. Again.
2004 astro AWD
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