Best Answer

I dealt with this problem on a 1999 Astro for almost a year. I replaced the rotor, cap wires, ignition control module, and the crank shaft sensor. I finally figured out that it was a defective ignition coil (would arc out in wet or humid weather. Pretty easy to change. Only costs about $50.

AnswerI am guessing the car (van) runs fine when it is not raining?

Things that it �Could� be (this is not a complete list):

  • Bad, Cracked, or Cheap distributor cap.
  • Contaminated MAF sensor
  • Bad O2 sensor(s)
  • Bad or Cheap spark plugs
  • Bad or Cheap plug wires

Explanation: A bad or cracked distributor cap would allow moisture to get into the cap, normally this causes backfiring � but not always. It also interferes with the rest of the spark circuit � the wires and plugs are basically the same thing, from the excess water in the air. The OBDII system does not use a BARO sensor to determine air density or humidity, it uses a learned routine from the MAF, MAP, and O2 sensors to determine the figure.

This is the exact problem that I have with my current 1997 van. I have 20 years experience at working on cars, am ASAE certified for computer electronics, and I still do not know �yet.�

In My Situation: There is no backfiring, and there are no trouble codes present. The O2 sensors have been replaced and there is no apparent contamination of the MAF sensor. The distributor cap has been replaced (twice) the second time it was coated with an electrical sealer(outside only), and sealer (electrical RTV) was placed at the base; the Coil and internal components of the distributor have been replaced as well. That does not mean that these things are not bad in your situation, but if they are not you are in for a long diagnostic in finding the trouble.

UpdateThere seems to be a chance that rain can run into the Air Temperature Sender on the air intake hose. If there is no seal or a bad seal on the hood it allows water to run down the inside of the fire wall. The placement of the sensor is right in line with a leak of this nature, and it points up so that it can catch water. This sensor is a simple resistor that reacts to temperature, so any change in resistance (like conductivity of water) changes its readings.

Location: The air intake hose is approximately 4� in diam. And runs from the air intake box (where the air filter is) to the intake manifold, this hose also houses the MAF sensor. On this hose just under the firewall is a small plug with 2 wires (the plug should point up) and this is the ATS.

Solution: I would NOT suggest using any form of sealer on this sensor, or the plug. It could make it impossible to replace or interfere with its function. I would NOT suggest trying to �turn� the hose; First it may crack as it is now formed because of age and heat, Second, it could adversely affect the MAF sensor. We placed a small piece of rubber weather-stripping on the firewall just to the right of the Windshield wiper motor. Purchase a small amount of 3/8 inch automotive weather-stripping and some weather-strip adhesive from your local parts house. Use a green scrubbing pad (that you would use for dishes) and lightly scrub that area with a grease fighting dishwashing soap. Thoroughly dry the area, then cut and glue the weather-strip to deflect water away from this sensor. I have not had this problem since doing this.

New Info from another owner- I own a 2002 GMC Safari and found that my catalytic converters were clogged and this is what was causing it to be very sluggish and I could not go much over 35-45MPH. This may have also contributed to hard starting. I did replace my spark plugs, rotor, wires and caps (what a nightmare) and starting was a little easier (and this was before the catalytic converter replacement.

User Avatar

Wiki User

โˆ™ 2011-09-22 17:48:15
This answer is:
User Avatar

Add your answer:

Earn +5 pts
Q: Why would a 1997 Astro not start when it rains?
Write your answer...

Related Questions

When it rains your 1997 Honda prelude doesnt start?

Needs cap and rotor

Firing order diagram for 1997 4.3 Chevy astro van?

fireing order for 1997 astro van v6

Why does a 1997 Chevy Astro van stall every time it rains?

Take off your distr. cap and spray some wd-40 under it. your getting moisture or water in your engine compartment.

Does a 1995 safari van transmission fit a 1997 astro van?

A 1995 safari van transmission does fit into a 1997 astro van

What did a 1997 Chevy Astro van cost new?

Astro 4WD Base: 29.370$ Astro 4WD LS: 31.895$ Astro 4WD LT: 34.600$

What is wrong when your gauges on dash board stop working on your 1997 Chevy astro van?

what is wrong when your gages on dash board stop working on your 1997 chevy astro van?

How do you change a flywheel on a 1997 astro van?

The Astro does not have a flywheel, it has a flexplate. To remove it you have to remove the transmission so you can unbolt it from the crankshaft.

Why won't my 97 rav4 start after it rains?

My 1997 Rav-4 had this problem too. I had new spark plugs and wiring put in and this cleared up the issue!

Where is the fast idle thermal valve in a 1997 Chevy astro van located?

Is anyone on line to help me with this question? Where is the fast idle thermal valve in a 1997 Chevy astro van located?

OEM tire size for 1997 astro cargo van 4.3L AUTO?

There is a table of Astro Tire Sizes at

Why your 1997 Astro van revs very high?

Vacuum leak?

Will a 1997 astro transmission fit a 1999 suburban both are 2wd?

NO it will not.

Why would a 1997 astro van not start only in the morning no fire on plugs or coil only in the morning?

dear .about a year ago I did a tune up new plug wire and plugs but now am having touble. have replaced coil distributor cap and rotor. my trouble is my 1997 chev astro van will not start when it rains or heavy dew. it runs fine when dry or during a rain storm. It will turn over, there is gas,there is spark from coil but none from distributor to plugs but if i add a wire and plug to ground there is spark or if I turn the distributor (made hole bigger) there is spark, just no ignition and when you shut the key off, it acts like it wants to start. I have had it put on a computer diagnostic, but nothing was found. new distributor cap, and rotor. If you let it sit until the dew is gone, it starts with no problem. Any thoughts on the problem? heavy dew...

How do you remove the ignition lock cylinder on a 1997 astro van?

Remove the retaining ring, from the top of your 1997 Ford Astro ignition lock cylinder. Remove the wiring harness from the back of the ignition lock cylinder.

How do you replace head gasket on a 1997 Chevy Astro awd?

Remove the cylinder had from your 1997 Chevy Astro engine. Remove the head gasket and clean the surface. Put the new head gasket on and reverse the process.

Where is the fuel pump located on a 1997 Chevy Astro van?

in the fuel tank

1997 astro van misses at idle and driving?

inspect the distributor gear.

Where is the door lock remote control receiver for a 1997 Chevy Astro Van?

The door lock remote control receiver for a 1997 Chevy Astro van is located inside the cabin. it is found on the right kick plate.

1997 Chevy blazer won't start after it rains what is the problem?

Ignition control module.. located under the distributor The distributor cap is probably cracked and moisture is getting into it. Replace the cap .

How many mpg on a 1997 Chevy Astro passenger van?

Averaging about 16 MPG.

How do you change the battery in a 1997 Chevy Astro van?

Get a mechanic to help you out. He will know how to change it.

Where in Chevrolet Astro AWD 1997 Crankshaft sensor is located?

its right behind the harmonicbalancer

Where is the voltage regulator on a 1997 Chevy astro minivan?

The voltage regulator is built into the alternator.

Result of El Niรฑo that occurred in 1997-1998?

Sever rains in Brazil.

How many gallons in a 1997 Chevy Astro gas tank?

I haVE A 1999 CHEVY astro and it holds just over 25 gallons. once ran out of gas and then had it filled.