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Oh Goody... Electrical Problems

06/21/2004, updated 06/23/2004 Is this going to be a saga???, 06/24/2004 - Maybe not!, 8/10/04

I have some sort of electrical "bad mojo" going on, and it's definitely related to rainfall. Here's the scenario:

There are really three apparent symptoms, the first of which is a very rare stalling problem. It seems to happen only after the car has been sitting (shut off) in a rainstorm. Say for example, I'm at work, and it pours rain for a while, and then clears up before my trip home. On the ride home, everything is fine for a while. After about ten or fifteen minutes, the car stalls when I'm sitting at a red light, or when I'm pulling into my driveway (in other words, no throttle.) If I'm driving and it starts pouring rain, I don't have any problems. Weird, huh?

The second symptom happens in conjunction with the first problem, but also when it is very humid (early morning dew) and I'm pretty sure it has something to do with the SAI pump. Normally, the SAI sounds like a normal fan... a monotone humming upon startup that cuts off after a minute or so. However, when it's icky out, or raining, the SAI sounds like a metallic "whirring" noise--perhaps a dry bearing or something? Also, sometimes it will come back on after the engine is already warmed up. I'll hear that whirring noise for a second or two and the engine will rev up 100rpms or so, but it settles back down after a few seconds.

The other symptom is a barely noticeable rough idle, only when it's raining or very humid. I don't think it's a coil pack--I had 4 new coils put in the back row back in September, about 10K ago, and I don't have any problems when the weather is nice.

So, is there any wiring that I should check first? It seems like this stuff only happens when the car is sitting in rain, so I'm trying to figure out what areas would get when under those conditions, but not when driving through rain. Hmm...

Dan Carman
'97 PG

Could be as simple as a poor boot on a plug getting water in it. Also, check under the hood to make sure everything is plugged in fully, and nothing has shook loose.

Matt Ponke

I have checked all the plugs visible/accessible from the top of the engine compartment. I also poked around underneath with the splash guard removed and I didn't notice anything unusual. The stalling problem happened back in January, and has occurred about three times since (fairly infrequent considering all the rain we've had since then.)

The thing that gets me is that it never happens unless the car sits in the rain. I'm at a loss as to which areas would get wet when the car is sitting still, but not when driving through torrential downpours. Perhaps water is pooling somewhere, but doesn't get the chance to collect when the car is moving? If that's the case, why does the problem not manifest itself until I've been driving for a bit and come to a stop?


I think that you answered that question yourself with the "second symptom". It sounds like all of your problems are based on relative under hood humidity, not actual soaking.

If it's rained a lot, then you drive, you'll start vaporizing any water under the hood. While you're moving, the air coming through the engine compartment will keep the air drier by keeping it moving. Once you stop, all of that steam and humidity starts to affect {insert whatever's wrong} and causes the stalling problems.

I wouldn't be looking for "pooling spots", I would be looking for exposed wiring or harnesses.

Might be a good idea to unplug all of your harnesses and re-assemble them with dielectric grease to help keep the humidity from affecting them. After that, I would look for bad grounds and/or battery cables.

-John Breen III

Sounds like a reasonable diagnosis. I would start with the connector to the IAB.

Paul L Fisher

I know there is one ground strap on the back of the engine (surge tank) going to the firewall, and one on the starter (PITA.) Are there any other grounds I need to check/upgrade?

Regarding the SAI pump, are my symptoms (the intermittent metallic whirring noise) typical of a pump that's about to 5#!+ the bed?


big plug to check is above the transmission under the throttle body tubing. Transmission shops by the way have a nasty habit of not getting this one all the way tightened after they R & R the tranny. Water will cause more trouble with the ECU plug on the firewall though.

Carter Fuji

IIRC, even if the SAI pump goes, you're not losing much. Quite a few people have theirs disconnected from when it died. I'd say it's not that big of a concern.

-John Breen III

Probably not the rain but the high humidity and a cool surface which causes the water to condense inside and out of objects.

When driving in the rain and then shutting the car down there is enough heat to keep the moisture from condensing.

Paul Nimz

I would think the wiring may be grounding out to the relay or a faulty PCM. The SAI should not be running once the HO2S are hot.

Paul Nimz



Yeah but look who is jackin up Paul's car......

Uncl Lar


Figures... Larry asks me about this Monday, and I tell him yesterday I haven't had any symptoms. Then the car stalls out on me while sitting at a red light this morning!

The conditions were the same as the other times this has happened. The car sat overnight, and it rained at some point before I woke up. There were a few droplets left on the car when I got to it this morning, and the air was humid (as usual... this is June, and I live in Philly.) Anywho, the stall-out happened about 3-4 miles from my home. I was pissed.

Then, I had a stroke of luck on my lunch break. The car stalled again while sitting at a light, and this time it triggered the Check Engine lamp. Without delay, I reached into the console and grabbed my handy-dandy $30 Harbor Freight code scanner, and pulled code 1309. I literally did this as I was driving down the road--don't worry, traffic was light, and I'm a good multi-tasker ;)

So I stop and get some lunch, and when I return to the car and start it up, the Check Engine lamp is still on. However, it turns itself off 1/4 mile down the road. Good thing I had already scanned the code.

Now back at work, I just pulled the info off the world's greatest web resource for V8SHOs, and it looks like a camshaft position sensor may be triggering these symptoms. http://www.v8sho.com/SHO/Update38.gif

It could also be a bad connection at the PCM, or a problem with the Engine Coolant Temp sensor. I think I've ruled out the MAF, as the connections are clean and dry, and the sensor wires get a soaking with contact cleaner every 5K or so. I also need to clean up all those ground connections.

Stay tuned for an update, hopefully before the weekend.

Dan Carman
'97 PG


F3LY-2C013-A - This is the Ford part number for the SAI Relay. It's a pricey puppy!!


Well, I started looking around in my engine bay for loose, wet, or dirty connections. The valve cover to firewall ground was tight and free of dirt and corrosion. The CMP sensor connection was pretty gritty and greasy on the outside, but the contacts looked clean when I disconnected it. I sprayed both parts with Wire Dryer and reconnected it. I did the same for the MAF sensor connection and the white "D" shaped plug underneath the TB (goes straight down into the trans, I believe) and the larger rectangular plug right behind that (closer to the firewall, that is.)

The white "D" shaped plug had a dead spider in it, complete with cobwebs and dirt. I sprayed it out and cleaned it up pretty well. Maybe tomorrow I'll go after it with a long-bristle nylon brush and some contact cleaner, just to be sure. Any chance that connector would have had anything to do with my symptoms?

I'll check out the PCM connection again when the engine is cool enough to work on. I have cleaned it out a few times before, but I want to be absolutely certain there is no dirt, moisture, or corrosion in there.



There is no definitive conclusion just yet. Here's an update though:

I cleaned up just about all of the connections on the intake side of the engine. I disconnected the connectors, sprayed the contacts with electrical contact cleaner, and then with STP Wire Dryer to protect them from moisture and corrosion. Wire Dryer supposedly works similar to WD-40 -- it diplaces moisture and protects against corrosion. So far there have been no problems, but it hasn't rained much, and the problem was pretty scarce and intermittent anyway. Only time will tell.

Eventually, I'll get around to cleaning up and/or replacing the engine ground straps, and cleaning up the electrical connections that I haven't gotten to yet (for example, between the engine and firewall, and underneath the engine/trans.)


After spraying with contact cleaner spray with some WD 40 and let it set wet, drying on it's own.

Paul Nimz

The ATF is at the FULL mark, smells normal, and looks bright red. AutoZone pulled a code 1409, which appears to be something to do with the EGR. The O/D light is still flashing, and I can't tell if the TC is slipping--it feels normal when I drive it. I don't understand why I'd get a flashing O/D, and not a CEL, and then have a code for the EGR system. Just my luck.

I was supposed to drive out to Columbus, OH on Monday, but now I'm not sure that I should risk it. On the other hand, I could go the extra 100 miles to Cincinnati and have Brad Hogue take a look at my slushbox. Hmm...

I'm going home in an hour. If the engine cools down enough before it gets too dark to see, I'll dig into the electrical mayhem once again. I'm really hoping to find a bad connection or bare wire shorting out. I don't have the $$$$ for a new ATX right now. :(


The 1409 points to the EGR solenoid wiring.

Don't know about the flashing O/D light. Mine did it when the TC died, but
there was no wondering about the cause of the light.

Paul Nimz

Sorry to be a party pooper, but I fixed the problem(s) and the car is running better than ever. Hopefully this will be the final chapter of this EPIC.

I'm not sure what fixed it, but here's the stuff I did:

1) Cleaned up all those connections on the intake side of the engine with Lectra-motive (electrical parts cleaner), blasted them with compressed air, then sprayed them with Wire Dryer and reconnected them.

2) Checked all the EGR/DPFE hoses. No problems there. (I think it was a bogus code)

3) Removed the PCM and cleaned the main connection thoroughly. There were some fine specks of brass on that blue silicone insulator thingie, so I removed it and cleaned it thoroughly with rubbing alcohol. I sprayed all those contacts with Lectra-motive, then blew them dry with compressed air, then a light coating of Wire Dryer. I replaced the blue silicone gasket/insulator. I pulled the Apten chip and gave that socket the same treatment as the rest of the connections. I replaced the chip and taped it in place with electrical tape. Over that, I used about 3 strips of duct tape to thoroughly seal off the opening (to prevent moisture from getting in there.) Then I used about 4 layers of aluminum tape to completely shroud the chip-end of the PCM. SO that whole half of the PCM has a layer of aluminum about 1/8" thick covering everything. I was hoping this would get rid of my occasional idle surge, which had always been an intermittent problem with the Apten chip. I remember many people suggesting that a random few of the 96-97 PCMs may be subject to some strange electromagnetic interference. I know many people just can't get a chip to work right on these cars.

4) When I was reinstalling the PCM, I double-checked the ground strap on the surge tank. It was snug, but not tight on the surge tank. I could spin the ring terminal with moderate force. I removed it, and relocated it to the next bolt up from that, which is still connected to the same aluminum bracket, but much easier to reach and tighten. I tightened it down pretty darn tight and made sure to sand the firewall surface to bare metal around the bolt where the other end was connected. Once in place, both ends of the strap got a liberal coating of Wire Dryer.

5) I buttoned everything back up, collected my tools, and fired up the engine. After about 2 minutes of re-educating the PCM, I let it idle for about 5-10 minutes while I returned all my tools to their homes. 

I proceeded to flog the crap out of my SHO for about 40 minutes. First I ventured to the highway and did a brief 90mph rip through very light traffic for about 1/2 mile. I then exited and did about 2 miles of stop and go traffic through the city. This is where I would usually get that funky idle surge while stopped at a red light. Not so this time! I continued on to a scenic route through the park, where I usually get a few good opportunities to test my cornering abilities in the 30-50mph range. No problems there. Then I took it up through some nice cobblestone street neighborhoods, rarely getting above 25mph, but definitely allowing underhood temps to soar. After about ten minutes of that, without any problems, I returned to the park to make the short trip home.

NOT ONE PROBLEM TO REPORT! The car is performing better than it ever has! I think I finally solved the chip mystery too. Now let's see how she fares through the next few rainstorms.

THE END... ?

Hey Uncle Lar -

I've been off list for some time now, but I ran across a problem that I thought you might like to share with the list, at your discretion.

My car was having the exact same symptoms as Dan's on


though I wasn't sure about the rain / humidity thingee.

Here's the short version.

Stalled 18 months ago - blamed a "quickee" oil change place that I was leaving at the time (though how I thought they made it stall is beyond me!). Stalled two or three times about 9 months ago. Stalled again about 6 months ago. Stalled about three months ago LOTS OF TIMES. this time I worried - after reading around the site I had decided it was coils and was going to start changing them out . . . I decided to change out the fuel filter (didn't have much hope there, but it couldn't hurt). Going through the procedure I ran the car with the fuel pump fuse pulled - PRESTO - the EXACT stalling symptoms. I E-mailed back & forth with FPS (Doug Lewis) who was convinced that since I threw NO codes it had to be mechanical (i.e. fuel pump) instead of in the electrical system, so I put off repairs until I could get the car to him.

NOW IT WAS STALLING A LOT. and, just to spite me since I'd worked it out with Doug, it threw a code. Pay attention here, because this seems like an unrelated code. P4011(I think was the number), SAI problems. Now it seems unrelated, but I'm curious about it since when I went back and read about Dan's "Oh Goody Electrical Problems" he also stated SAI problems . . . Not sure if there is any relationship here, but maybe someone more knowledgeable can shed light on this. So I decided to take one more self-fix-it crack at the car . . .

I went through the same procedures with the contact cleaner and wire dryer as Dan did, but what I hope was my problem was a little more obvious . . . When I pulled the second coil from the right on the front of the engine, the "boot" to the top electrical connector was broken, and moisture was literally BUBBLING OUT OF THE BREAK IN THE PLASTIC, with no insulation between the two conductors. I finished the front of engine connections, have now replaced the "ugly bubbling coil", and am waiting to see if there are any more problems.

By the way, the idle smoothed out noticeably after the electrical wash up (even before changing the coil), it might be something folks just want to do every once in a while to keep the cars in top notch form.

Thanks once again to all who contribute and maintain this list. It is an unbelievable resource, and from time to time, a psychological support group . . .

Chris Crawford

'97 TR, 157K, FPS welds, SARC switch, Tranny Cooler, K&N, Magnetic oil plug, magnefine ps filter, ALL THANKS TO THIS SITE.

PS - Please try to keep my e-mail on this thread (if it takes flight), I don't have time to read the mass of the list, but I'd like to follow this one . . .

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