Thought I would ask if anyone knew what the relays are for on the drivers side fire wall. I have a 91 z and a relay has started to make a loud ticking sound. At first I thought it was under the dash but found out that it was the relay that is closest to the passenger side and is the lowest of the three. If anyone can give me a hand I would be grateful. Thank, b-man.

 

That group of relays for my car, which uses a MAF system, are MAF burn-off, fuel pump, and MAF power(in that order, middle toward the outside, and they all look the same). So for me, that would be the MAF burn-off relay.

You have a MAP system. I've never seen a MAP, but I'd guess your set-up is probably similar with MAP and fuel pump relays. Have you noticed having any air or fuel problems lately?

I've read that if the fuel pump relay is getting weak, you might notice a sluggish feel like the car isn't getting enough fuel. But that doesn't make much sense to me. Relays either work, or they don't. I wouldn't really think one would "weaken."

The electronic spark control module is right in that area, too. Notice any pinging lately?

 

Write down the part number, which is right on top of the relay. Go to www.acdelco.com, you can find the relays and check which one it is by the part number. Then get a new one. They're only like $15 each.

 

I got the numbers off the relay but they did not cross with anything acdelco had. I found an old relay that had a different part number but the wiring diagram on the top was the same, so I put it in. Problem solved? NO. I thought it was, but when I pulled back into my drive the damn thing started ticking again and it does feal like i'm losing power when it ticks. I don't know if it works the fans because they don't work right anyway (sensor on passenger side not connected). I do know that one only comes on when the ac is turned on but the other doesn't. Strang thing though it was working a little when i pulled into the drive while it was ticking but soon shut off. It also stalled on me four times while idling, temp might have something to do with that. Could something else make the relay act up or is that spare probably bad. I think the one in the middle is the fuel pump. If I knew what they all were I'd just change them. Thanks for the help so far. b-man.

ps: has felt sluggish but had more power when I first changed the relay (may have been wishfull thinking though)

 

About the ecm... I can rule that out because I can place my hand on the relay and feel it ticking. Now that I have searched about a thousand posts I can say that I don't have a MAP relay and I'm thinking I have two fan relays there and the fuel pump relay. If this is the case all are actually the same part number according to gmpartsdirect.com. Anyone know for sure on a 91 sd. Thanks, b-man.

 

Well, after consulting my trusty repair manual, which is supposed to cover through 1991, the only diagram of the TPI engine is for 1987(but says others similar), which works for me, but not for you.

But since Delco shows pictures of the relays, I thought that even if you weren't sure of the part number, you'd at least be able to see if it looks like the same relay, which your spare must've been or it wouldn't have fit. So since it fit, but didn't work right, I'd guess it's bad, and that's probably why it was laying around instead of being used. I sometimes won't toss out old parts either. But just knowing that I have it laying around tells me it's old, lol. An auto parts store should be able to cross-reference whatever that number is on the relay, I'd think.

But if that was your fan relay, it wouldn't have caused anything to happen to the engine like that. You'd just overheat in traffic or if idling too long. Ask me how I know, lol! And I'm pretty sure the fan relay is in the same place for all of our years, and that would be on the passenger's side next to the radiator and not up at the firewall where your problem is.

But I'll let you know if I findout anything. It would be nice if someone with an SD would read your problem, lol. Where the heck are they?

 

Yes, two of the three(fuel pump and burn-off for mine) are the same part number. The number for the third(MAF power, for mine) is almost the same, and the relay looks exactly the same, too. So they're all from the same series of relays, and each is probably interchangeable.

And if all three of your relays are also the same, then those relays probably relate to your SD. Just because it's not MAF, it's still gotta have a power supply to link it to the ECM's control, right?

 

From passenger side to driver side is Fuel pump relay, Cooling fan relay, Air condtitioning compressor relay. You are talking about the relays under the hood (drivers side) under the lip of the firewall right? Your map sensor is on the other side of the engine bay. You say it's the lowest one? That's the fuel pump relay. Get it replaced and hope that's all it is.

 

Hello fellas. guess what? The damn fuel pump relay kicked the bucket on the way to the frickin parts store. Here I am in the middle of the road, first one at the red light and bluhhhh. The damn thing dies. After repeated efforts to bring it back to life it still refused to go. About five minutes go by and MR. POLICEMAN pulls up and says I can't leave it in the road. So what does he do? He pulls up to my bumper and pushes me out of the road, then the *** leaves me there!!!!!!!!!!! No damage was done but I still had to walk about four miles round trip to the auto zone to get the relay. Luckily I still had the tools in my car from when I tried the old relay. Put it on and bingo, the pump sounds like a choir of angels singing in my ears. My ac is colder too for some damn reason . Wish one of you were around when my *** had to beat it down the road. The worst part of it all is that I sprained my ankle at the gym last tuesday, so walking in the aircast is a b1tch. Thanks for the help guys, I need to chill out for awhile, upgrading the entire suspension in the morning . Later and thanks again. b-man .

 

YAY! Let's hear it for our wonderful public servants, lol. At least he didn't write you a ticket after he pushed you. It's probably best that he didn't hang around, lol.

Glad to hear you got it worked-out. Sorry to hear about the ankle, though.

I better get a new repair manual. This one is supposed to cover thru '91, but it's obviously of no use to anyone with a car later than '87!

 

You pointed me in the right direction . How's everything out in Cali. I'm from San Diego, but was dragged out here kicking and screaming. Sure do miss it there .

 

Get yourself a helms 1991 camaro service manual. I got mine on ebay for 35 dollars and it was well worth it. If I would have seen this thread earlier I might have been able to save you a breakdown in the middle of the road. The service manual is what GM uses when they work on your car. 200 times better than any chiltons or haynes. Glad to hear you got it fixed!

 

You have another problem whether you know it or not. The car will run even if you pull out the fuel pump relay. The fuel pump gets power from 2 sources, the relay and the oil sender switch. Any TG will continue to run with a bad or missing relay. Once 4 psi oil pressure is reached the switch in the oil sender closes and sends 12 volt to the pump in a parallel path with the relay. Typical indication with a bad relay is hard starting when it has sit for a while. You have to crank the engine until 4 psi is reached. If your car shut off because of the relay you need a new sender as well. Just though I would mention it so you won't get stuck again.

 

Thanks for the info Danno. I'll pick up a new sender today and replace it while I'm playing with the car anyway. Later, b-man.