[Bubash]

Hello, i have a 97 astro van with 155,000 miles but only 7000 on new jasper motor( supposedly).
i love this thing but when idleing it has a shake, it usually only happens in gear but sometimes will do it in park. if i rev it up slightly it goes right away. im throwin a 420 code, i heard its for a bad catalytic converter, but its been doing it before the code got thrown. id really appreciate any advice.

-Brian

 

[Bubash]

i hate to be needy but my fuel guage doesnt work, its always way over full. i put a new sending unit and pigtail but still is messed up.

 

[Big_kid]

Check the ground on the sending unit, and the body ground to the battery. Not sure about the 420 code, I'm sure someone will have one before too long.
My first thought when I saw 420 had nothing to do with Astro van trouble codes!

 

[Bubash]

Check the ground on the sending unit, and the body ground to the battery. Not sure about the 420 code, I'm sure someone will have one before too long.
My first thought when I saw 420 had nothing to do with Astro van trouble codes! [ http://astrosafari.com/images/smilies/obscene/smokingred.gif ]

lol my vans always throwin that code, i checked the sending unit with a volt meter and it shows on there it works when i move the arm, but the guage doesnt move.

 

[Matrixx]

Hi Bubash

With the extreme sensitivity of current North American emissions controls, and the extremely low emissions limits that have been imposed, certain errors now crop up that didn't happen before. One of those is the P0420 error, which is supposed to mean that the catalytic converter is not working as well as it should. Unfortunately, it just means the downstream O2 sensor thinks too much oxygen is sneaking past the cat and tattles to the ECM.

A catalytic converter is an oxygen storage device. The only way it can function is if it can take up and release oxygen in the quantities required to convert engine emission gases to water and carbon dioxide. OBD-II specifications require that the catalytic converter be regularly tested by the ECM. Test failures tell the computer that the cat has lost some of its oxygen storage capability, which is what's meant by "below threshold".
Your car's computer is allowed to adjust the fuel/air mixture within a very narrow range in order to help keep the P0420 error from happening. If the needed adjustment exceeds that range, the error code will be set.

"Three-way catalytic converter (TWC) efficiency is measured by how well it can store oxygen.

"The ECM monitors converter efficiency by comparing the voltage values of the heated oxygen sensor 1 (HO2S-1) and heated oxygen sensor 2 (HO2S-2). Under normal operating conditions, the HO2S-1 should vary between 10 mV and 1065 mV and the HO2S-2 should remain relatively steady between 500 mV and 800 mV. This steady reading of the HO2S-2 indicates a correctly functioning catalytic converter.

"When all parameters have been met, the ECM will run a 5 second DTC P0420 diagnostic at idle. The ECM will command rich and monitor the time it takes the HO2S-2 to go rich. It will then command lean and monitor the time it takes the HO2S-2 to go lean. The longer it takes the HO2S-2 to change rich/lean means the converter is storing oxygen and is functioning properly. If the five second test fails, the ECM may take several tests during several ignition cycles to set the DTC. DTC P0420 sets when the ECM has determined that the catalytic converter is no longer efficient."

Causes

A code P0420 may mean that one or more of the following has happened:

* Leaded fuel was used where unleaded was called for
* An oxygen sensor is not reading (functioning) properly
* The engine coolant temperature sensor is not working properly
* Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
* Retarded spark timing
* The oxygen sensors in front and behind the converter are reporting too similar of readings

Possible Solutions

Some suggested steps for troubleshooting a P0420 code include:

* Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required.
* Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has
a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
* Inspect the downstream heated oxygen sensor (HO2), replace if necessary
* Replace the catalytic converter

Hope this helps.

 

[Matrixx]

Hi Bubash
Could you explain this vibration a bit more Bubash. Does it come and go or is it Consistent? What frequency is the vibration? Did it just start or was it always their since the motor change? Thanks.

As for the fuel gauge, their is a Fuel Gauge Module located on a bracket just above the Data Link Connector inside the vehicle that has that Purple Wire (for your year) running directly from the sending unit to that Module. The wire "maybe" purple and white as it seems to change colors along the way with a plug-in just before that, that's in between the sending unit and module.

The wire you want will be in port C or the purple or purple/white wire at one end or the other (Corner wire) of that module plug-in. This is the link between the fuel gauge in the cluster and the sending unit in the tank. I'm sure you can follow it out from their. This particular wire (sending unit) does not hook into the VCM, it goes staright from the unit to that module.

Hope this helps. Please keep us updated, Thanks.

 

[Bubash]

Thanks matrix, my buddy said it needs a cat, but its always my luck to change the expensive part 1st and then learn its something dumb so i wastrying to avoid that. the van runs good and was getting around 20 mpg, but now its like 14-16 anywhere. the rough idle is a deep slower shake that causes anything loose in van to rattle, its about the same consistency as the idle. but it usually only does it in drive, when i shift to nuetral it usually stops. its almost like the idle is too low but when i give it a lil gas it stops but if i let off the brake the van moves so i think the idle is right. ill check that wire for the guage thanks

 

[Matrixx]

Hi Bubash
Hmm, interesting with the vibration you have (comes and goes with Park and Drive). Yes, if the idle is to low these engines vibrate some what (nature of the beast). The idle should be consistent at around the 600 rpm mark in Park or Drive, if it drops in rpms and stays their when Drive is selected then your idle air control, idle speed control or throttle position sensor isn't functioning they way it should to compensate for the change in engine load.

Also bad motor mounts and exhaust mounts can vibrations as well if the rubber is worn out on either.

Please keep us updated Bubash,Thanks.

 

[Bubash]

Ok so i decided to give the van some love with a new cat/y pipe,shocks, wheel cylinders, all new rear brakes, air filter, and some 150 psi Train horns, so it runs great, really great. So I went to florida and get 21 mpg with two streetbikes in the back, half way back the check engine light goes on, when i get home I have it checked, mafs is not working so i replace it and the fuse that it popped(ecm 20amp) it works for three days and then pops the fuse again so i probaly wasted my money on the mafs, but either way now everytime i replace the fuse it last for 20 minutes the pops. when it does pop the van isles funny, stalls when you try to take off from a dead stop, and bucks when driving.
So now my gas guage dont work, speedo is choppy, randomly the (check guages) light comes on and the water temp goes to like 400, but then goes rght back, vibrates while idling, and now this lol AGGHHHHH!!!!

 

[Matrixx]

Have you tried disconnecting different sensors to see if the fuse stops blowing? It's strange this all happened when you replaced the MAF. My rule of thumb is to go back what was last done (replaced) and work out from their. Please keep us updated and I'm sure others will chime in if they can.

 

[Bubash]

Have you tried disconnecting different sensors to see if the fuse stops blowing? It's strange this all happened when you replaced the MAF. My rule of thumb is to go back what was last done (replaced) and work out from their. Please keep us updated and I'm sure others will chime in if they can.

I was thinking the mafs was never bad and theres an exposed wire that popped the fuse originally making me think it was bad and replace it. if that makes sense. But I will be finding the answer soonn oro else it will be in the classifides

 

[Matrixx]

Hi Bubash

Back probe the power side of the wire leading to the fuse that keeps blowing and work out from their would be my suggestion. Their isn't any easy answers or solutions, just good old fashion trouble shooting will be the cure to this problem. We will do our best to help.

 

[Bubash]

Hello again,
So after weeks of being annoyed and hours searching.... I thought i heard a noise while driving, kinda like a small plant caught underneath or a broken wire flopping so I crawled under my van and seen the plug for one of the o2 sensors laying on the driveshaft eatin through... so i instantly remember when i put the new cat on atwo months ago one of the sensors was 2 inches further down the pipe and the plug wouldnt reach its correct mount on the van body so I zip tied it up pretty well but i guess not good enough..

so all in all the mafs was never bad and i wasted $180... plus $50 to my Friend/mechanic for replacing it and then to help look for wires... Still no fuel guage or ac but she's gettin 22mpg with 2 street bikes in the back again.

 

[Matrixx]

Wow, now how bizarre is that? Learn something new everyday. I'm glad you got it sorted out.

 

[Bubash]

Wow, now how bizarre is that? Learn something new everyday. I'm glad you got it sorted out.

I know, its my luck though. As soon as the fuse blew the first time i had a bad feeling it was never bad and it was a waste. suspicion confirmed lol

 

[Matrixx]

Indeed it was. Great job finding that one Bubash.