I've done a ton of research on this (after I bought the car ). Bought a '91 Accord LX. About half way home the S light started blinking and wouldn't shift into all gears. Researched and found the bad TCM threads. Found a 'fix' by replacing some resistors and capacitors, cutting two traces and adding a bridge and a jumper. Did not work. Bought a new TCM, shifted better sometimes but still having shifting problems when the S light stays on. Took it to a transmission guy who called the next day to say he couldn't get the car to start. I went over and pulled the ECU fuse and it started that time but still intermittent. He checked the transmission and said he didn't see a mechanical problem said it was electrical. More research and found that the PGM FI main relay can cause intermettent starting problems AND sometimes the S light to come on. Removed the relay and resoldered all connections on the board. It starts all the time now but the S light is staying on again most of the time and it doesn't shift correctly while it is. If the S light does go off it shifts great. No TCM codes with the jumper. It's very hot here in Georgia right now, near 100 degees. Could this be a bad main relay and the resoldering can't fix it? Any other suggestions would be appreciated. I really got ripped on this car and I'm trying to redeem myself somewhat with my daughter (who I bought it for). The guy said no problems except the AC needed recharging. Recharged the AC this weekend, yep, doesn't work.

Thanks,

Don

 

OK, I bought a better soldering gun (pencil) and resoldered the relay. Seems to be working fine now. I guess my old gun wasn't getting hot enough.

 

I've never heard that Main Fuel Relay can cause a transmission fault, but perhaps so. Has S light gone off now?

Whats the problem w/ AC? These are good systems, but w/ this much age they need an overhaul to fix evaporator fitting leaks, connection leaks, perhaps compressor shaft seal leak.

I drove a 90 Accord to 265K miles and hated to see it go.

good luck

 

Yeah, it's weird. During the research I did I found two references to problems with the fuel injection system causing an S light to stay on. It does what it's supposed to now. When I start the car the light stays on for a second or two, like the check engine light, and then goes of everything is fine. The AC seems to be a problem with the clutch. I get power at the one wire connector when the AC is on but no clutch lockup. I tested it today by connecting the battery directly to the clutch power wire and got nothing. I don't understand how the clutch is grounded though so it may just be that. I can see two wires coming from the top of the clutch area but I can't see where they go. I guess I'll have to remove the alternator to get a better look. Is it possible to remove the clutch without removing the compressor? The pulley is very close to the frame.

Don

 

I think that the clutch is grounded at a screw on the compressor housing. You can test to see if the wire going to the compressor is grounded.

It will be pretty tight to remove the clutch while bolted in there. You may be able to do it, but I have never tried.

The clutch gap may be too large. You can try to remove the clutch plate and remove a couple of the shims under it.

 

I'll have to see if I can get in there and see where the ground wire is attached to the compressor. Is there a spec on what the gap should be? My Haynes manual does not have much info on the compressor and clutch. Thanks for the help guys.

Don

 

I think the compressor clutch is grounded through it's mounting bolts to the engine.

Look in the DIY section for on-line manuals. The Helm books for my Hondas have had clutch gap specs. I've just never had a 91.

 

I had already downloaded the manual but had not sorted through all the pdf files yet. After I posted the question I dove in and found the gap spec. I haven't had a chance to work on it any more. Maybe in the next day or two. Thanks for the info.

Don

 

I finally had time to look into the AC problem today. After removing the compressor I noticed there was a tab that was holding the power and ground wires to the compressor that looked like it had been hit with something and was pinching the wires. After bending the tab back and sliding the insulation back on the wires I discovered that the ground wire had been pinched in two. The power wire was OK. After fixing the break I tested it with my jump box and the clutch is now working! Now I have to figure out how much oil I should put in the compressor before reinstalling it.

 

I found out how much oil I needed from my Haynes manual. Put the correct amount in and reinstalled the compressor, alternator and PS pump and fired her up. Added two cans of R134a. The system works now but doesn't get very cool. It may need more refrigerant, I'll check the sight glass on the receiver-drier tomorrow. Does anyone know how many 12 oz cans it typically takes to completely charge the system on a '91?