Miss fires when wet - Toyota Nation Forum : Toyota Car and Truck Forums

MR-Deuce · 02-01-2009, 03:57 PM

hello,
I have a 91 mr2 with a 5sfe. my car us very dependable, but when it rains or I go to a car wash I have trouble starting it. I know its a spark problem, but I'm not sure what to do about it. I havn't determined for sure what causes it. I think its the coil pack. It's the only thing as far as I can see that gets wet that would cause this. as far as I can tell this part had no shelter even from the factory since water can just run through the seem of the engine lid and run right down to the coil pack. My question is, is the coil pack supposed to be sealed water tight or is this a common problem? Any help would be appriciated.
Thanks

MR2 Guru · 02-02-2009, 11:28 AM

This is a common problem, mostly with the 5SFE and 4AG. Water gets down into the distributor cap, causing this problem. I never suggest using high pressure or automatic car washes for this reason. Sometimes a new distributor seal set will help with this, but its easier just to wash the car by hand and possibly cover the distributor with a plastic shopping bag for an extra precaution.

Hope this helps!

Ghostyman · 02-02-2009, 04:37 PM

Ditto on it being a common problem. I hear that the spark plug wells are common culprits as well. The usual recommendation is to pull the plug wires and let the wells and the wires dry.

***MR2Jedi*** · 02-02-2009, 04:52 PM

I've heard both those as common complaints.
Maybe time for some new plug wires. They should seal the top of spark plug opening to keep out water. I had a '92 N/A but never experienced that problem and I put 145K miles on it before I traded it in on my Tacoma 4x4.

***toyomoho*** · 02-02-2009, 05:08 PM

Might be a cracked coil.

willtotheumm · 02-03-2009, 10:37 PM

Might had that problem until I got my hands on the spark plug valley cover and seal. no more problems

MR-Deuce · 02-05-2009, 08:58 PM

Well I don't think my little problem really matters anymore!!!!! Yesterday I was on a business trip and somewhere around niles, MI My mr2 threw a rod!!!!!!

If anyone knows of a 5sfe in pretty good shape I'm desperate!! mabee even a 3sgte If its a good price

. I need to get my car back on the road quick. any help would be appriciated. Thanx

***MR2Jedi*** · 02-05-2009, 10:25 PM

ModifierMR2 has got a 3sgte for sale thats in great running condition. Only wants $700.00
PM him if you're interested. Tell him I sent you.
Here's a link to his sale.:
2nd Gen 3SGTE For sale