Where is Main Relay?

Where is my main relay located in the 89 SE-i. I've been having some problems starting the car but only after turning it off when it's been running for a while or when it get's really hot out. From what I've read I'm going to assume it's the main relay. I want to know where it is and if I can use the Main Relay from my 86 LX-i till I can get a new one or if the main relay can be repaird. I thought I read somthing about just reflowing the soldier in it.

Edit:
Just thought I'd add, the car will start but it turns over really slow 2 or 3 times and then fires up. It's kinda embarrassing to pull into the gas station or somthing with music blairing and all and then fill up and have the car start like that :(

Check your air filter first. A clogged one will certainly make it difficult to start.
Do a search and you'll find a pic of the main relay.
Sounds like you'll need new main relay and ect sensor also.

Look by your fuse box (may have to take out the change compartment and lay down to see it). It's a black box with a reddish-brown bottom where you plug it in. It's secured w/ a bolt that is pure hell to get off.

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Originally posted by anchovies
Check your air filter first. A clogged one will certainly make it difficult to start.
Do a search and you'll find a pic of the main relay.
Sounds like you'll need new main relay and ect sensor also.

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I don't think it's the air filter if it only does it when it's warm. What does the ECT sensor do? I did do a search and couldn't find a pic or a description of where to find it.

Sounds like ECT sensor too. I had a similar problem as well and the ECU said it was the ECT sensor (Coolant Temperature). It sends information back to the computer and helps in regulating the amount of fuel that is dumped in the cylinder based in the temperature of the engine coolant. When it's not working, it affects idle, starting and other fuel related issues. It is the sensor located on top of the thermostat housing. Do you get a strong gas smell when you have trouble starting it? Also, after you get it started, does the car want to stall when you come to a stop?

Car doesn't stall, and I don't smell any gas at least not that I can recall. How much does this sensor normally cost? If it's cheap I'll go pick it up and throw it in.

it's like $35-40 at Autozone. I just yanked a couple off some 3gs at the local pick a part for like $2 each and the first one worked fine.

Do you happen to have a pic of the ECT sensor? Or maybe a better description of where it is? My car has trouble starting sometimes, and I already got the main relay replaced.

It's on top of the thermostat housing. Here's a link.

http://www.hondaautomotiveparts.com/...P+%28PGM-FI%29

#10 is the thermostat housing. The sensor is located to the left of the bleed bolt when you're facing the engine. It's right on top, can't miss.

To replace it does the sensor just unscrew or am I going to have to take the housing off?

Yup, unscrews. I used a deep-well socket for mine (17mm i think). Came off in a jiff.

So just wait till the engine cools unscrew and replace?

Ok, I just looked in the engine bay, which sensor is it? The Yellow or the Green?

Mine is white,it's an '88 tho, but yellow one, smaller, closer to the head.

Cool, thanx man.

Does anyone know what this would be under in the service manual? I'm trying to find a diagram just to be sure, and I can't seem to find it in the Cooling section.

If your talking about Paul's 86 manual, :super: it's in the Fuel and Emissions control FI chapter 12. 12-2 gives you a full front shot of the engine. If you have some sort of pipe thread sealant handy, it wouldn't hurt to put a teeny bit on threads of the new one. Here's the little pic from my 88 manual with the torque spec, 20 ft-lbs:

Thanx again.

Hey Hostile.. I had a similar problem with my car. Sometimes it would start and sometimes it would not. It turned out to be a fuel problem. So next time it happens, check ur fuel pressure.

It's not that it doesn't start, it will eventually start but not until it turns over real slow a couple times.

Thanks Dibbie. Next time I get some money maybe I'll take a look at that!

Matt...I had/have (less now) the same problem. How does one check the fuel pressure? Sorry if it's been answered already...it's 4:21am, so I'm out of it :)

Thanks!