spl642

Have a problem . . . looking for suggestions. My 1990 Z runs rough immeadly after a hard rain or i drive thru a puddle . . .
It idles rough to the point of dying and throttle postion that would normally yeild 3000 RPM only get a gargling 1500 . . . if i mash the accelerator it sluggishly responds and the suddenly surges to typical power.

DDSLT5

So - what do you think is the problem?

spl642

Who knows . . . i was thinking something electrical/ignition related . . . just curious if anyone every came across anything similar . . . my local shop couldn't figure it out easily and admitted not LT5 familiar

Hodos

What I would do, is when you start having the problem pull over and open the hood. Check to see what parts are saturated, paying attention to the ECM and other electronics. Then I would take off the bellows to see if there is a build-up of water leading into the throttle body. If it's water causing the short, then just follow the water's trail, IMHO...

DDSLT5

Sounds reasonable. What makes me think is your puddle comment. What could be affected by a puddle that would cause an idle problem? I can't see under your hood - take a close look - something isn't where it should be. What kind of intake do you have? Are your wheel wells intact?

cv67

How are your inner fenderwells, are they intact and have good seals on them? Im not sure if some water would affect the TPS or not if it got splashed.

Polo-1

Check the passenger side 02 sensor. If it has headers, the wire extension for the 02 might not be sealed good. Water gets in the and gives bad 02 readings.

Happened to me.

A26B

He's right on! Disconnect both O2 sensor leads, wash them out by spraying WD40 over both parts, dry off as best you can. Then coat the seal part of the connector with silicon grease & reassemble.

What is happening is the O2 leads are shorted with water, providing bad signal to ECM in closed loop. As soon as you reach open loop, the ECM recalls the settings and it runs fine.........as long as you keep it above 3K rpm.

I know because AC condensation leaked into mine after installing headers. Drove it 175 miles home in open loop. Way better than trying to figure it out at night in Gainsville, TX when you can't even get under the car to try. Put it on the lift the next morning, pulled the connector apart & water poured out.

Good luck

Jerry

spl642

does sound like O2 sensor now that you mention it . . . had my A/C repaired and it ran poorly . . . noticed a bunch of condensation

4DSZR1

Good thread! I mean information.

Blown67427

Sounds like water is making it's way to the air filter. Your car should have a splash shield (made of plastic) right under and in front of the air filter box. It is there to keep water from splashing into your air intake.

flyin ryan

spl642

i'll test the O2 sensor idea next week

Zethco

Don't drive in the rain






(sorry - somebody had to say it)

Rex Ruby

Have you checked for fault codes?

If it was an O2 problem wouldn't there be a fault code?

Rkreigh

had a toyota once that even though it was in a carport wouldn't start whenever it rained. it was the strangest thing. turned out the spark plug wires were bad and the moisture in the air was preventing spark

no kidding. my 93 LPE ran bad in the rain too, the sparc controller and othe ignition parts can get moisture in them and cause a weak spark

also check to make sure you aren't splashing water onto the cam covers, it gets down in the sparc plug wells and the car will miss until they get hot enough to dry out.

the o2 thing is interesting, makes sense.

Goldcylon

Agree we need more like it!!

Zethco

I agree on the O2 thing. But I'm not sure it'd throw codes unless it sensed (or thought) the sensor was bad.

I *think* the only thing that'd happen in this case (wet O2) is the O2 sensor would cause the motor to react to the condition is senses.

... Or am I on crack?

DDSLT5

Sounds about right.

phrogs

Why not?