figured i'd run this through here real quick. she has complained that the last few times she took the car out in the rain/rainy weather, the car idles irratically and often stalls. she has even said it wouldn't rev, or move much.

there is no check engine light on when it happens, except for one time, but went away. that was a few months ago. but in the rainy/wet weather its an issue.

i haven't had a chance to look at it yet, but was thinking MAF.
i did put a SLP cold air kit on it, so not sure if it sucks water in.

outside of this, the car is perfect. runs awesome otherwise.
has been recently tuned, etc.

anyone have an issue like this before with the TPI's?

it's an 88 forumla 350 with 80k
i have washed the car in the past, and drove it afterwards, and didn't notice any problem. i'm going to try to dive it tomorrow after work to see if i can duplicate the problem since it's rainy/wet/damp out now.
she said it happens after a little while in the rainy type of weather.
the last few times she said the CEL did not light up. it does function as normal.

i've been looking for my little code reader just to double check it anyway, just cant find it.

 

what code did it throw.

if you have a cold air intake without a bypass valve you should definately get one. if it sucks in to much water you'll be out alot of money

 

i dont know what code it threw out that time, she just said the light went on that time it was rough.
all the other rough times, no light went on

what's a bypass valve?
i dont recall anything like that being mentioned in the SLP kit

not sure if anyone here has had the same issue with the SLP kit

i want to see if i can drive it now since it's raining to see what she is talking about

plus i gotta find my damm code scanner
it's around this mess somewhere. buggers never around when you need it lol

 

paper clip??

 

yup thats what i'm gonna do since i can that reader

hopefully i'll drive it in the rain later to get it to act up like she said it was, then see what is causing it

it's been sitting all week in the rain now, so i'll see if it starts first
i'm suspecting a MAF going bad or water getting into the air filter etc...
just didn't know if the SLP intake was prone to that.

i wouldn't think so since it's in a higher area behind the fender (wheel inserts are there too)

 

ok just drove it in the rain
started fine
ran it down the road
it wwent erratic
then CEL came on

limped it home
code 12 and code 45

45 says rich 02
why would it do that in the rain?

best thing to fix this is?

 

did u check the filter and make sure it wasn't soaking wet?

 

Usually you have a voltage leak somewhere and when it gets wet it jumps and then runs like crap. Bad or crappy plug wires are notorious for this but in this case it sounds like your wire to your oxygen sensor is getting wet and causing the problem. You need to replace the sensor and or seal the connection to keep moisture out.

 

when i did the tune up in the spring everything was replaced. accel 8.8 wires, bosch plugs, accel cap rotor, msd 6a, msd coil, cleaned throttle body, fuel filter, all the typical BS stuff

the filter looks good, no guck in or on it
air box looks clean too, no signs of water entry

reset timing to 7 degree's from 12 (ran awesome at 12)
seems ok at 7 now
disconnected negative terminal, reset ecm
only code 12
took it for a little ride
it's ok now but again, not raining

reconnected some wires (took wires of coil assy. etc.)

pulled #1 plug, clean, one black strreak on the side of the white porcilan, other wise nice

i dont have the fuel pressure gauge here, but turned the screw down about a 1/2 turn, when i was at the shop i checked it and it was 50

after these changes, idle settled down and doesn't smell as bad
since it's 85k on the car i want to replace the 02 anyway. i'll go to autozone to get a bosch replacement anyway, the o2 wire is one wire into a connector, reseated that anyway. looked good
took the air hoses off the throttle body, looks on inside
MAF looks ok too

i will put her stock air box back on for the hell of it
i dont have the charcoal canister stuff hooked up. but the car has ran great with no CEL on.

will have her use it tonight to see how it rides

that timing out i can feel at initial take off

what size wrench can i use to take the 02 off with?
i dont have my 02 socket here, it's in my tool box in the shop.

 

well, i changed the 02 with a new bosch one, original one was still in there

i also put some tubbing over the connector just incase

i put the stock air box back on
if i get time i'll take it to the shop to get a fuel pressure gauge on it.
i also put the charcoal canister back on as well

she ran it last night and it was perfect, but again it wasn't raining either.

not supposed to rain until friday
i also reset the MAF and checked codes, only came up with a 12, the fans turn on and all

we will have to see what happens.

 

I know this is old but this has started happening to me also. Only when it rains andd I have wipers/lights on and only once in a while.

Maybe plug leads?

 

A similar thing happened to me about a year ago. The idle would go from 500 RPM to 800 then to 500 over and over again and almost stall (only when it rained) then set a code 33. The solution to my problem was to thoroughly clean the MAF electrical connector pins with 800 grit sand paper then alcohol. If you have a code 33, I would look here first.
Randy

 

Thank you Randy. do you mean the connector underneath the MAF? Should I do the relay too? Where is the relay?

Bought some electrical cleaner today and have done the 1st connector but may as well do the relay too whilst I'm at it ?

Cheers

 

Yes, that's the connector I'm talking about (the one attached to and directly under the MAF). Unfortunately the location of the relays vary from year to year and car to car so I can only show you where they are on my 1987 Iroc 5.7L (see photo).

RelayLocation.jpg?t=1286479632

 

Thnak you- will give it a try. Mine is an 88 but I know now where the relays are (and they are different) Cheers for your help

 

Good luck. I hope it works.

 

Hi there,

Well used electrical contact spray on MAF sensor plug and both burnoff and MAF relays. Definitely better now! I've ordered 2 new relays just to completely sort it (they are the originals so no harm in changing right?)

Thanks- recommended and easy solution!! Hope this helps others.

 

not enough air gettin through your filter being wet, got it .

 

I don't think there would be any harm in changing your relays. When I had the problem with my car, the contact cleaner/ electrical sprays did not completely remove the tarnish off the contacts which is why I used the 800 grit sand paper then cleaned off the residue with alcohol.