1991 Civic DX sever idle surge - 487,000 miles
 

My 1st post.... Hope all u experts can help

Have a 1991 honda civic hatchback DX that’s my son will be driving. My brother gave it to him and it was my father’s commute vehicle years ago.

Its in almost perfect shape and 487,000 miles and burns very little oil. Only thing that the car has had done since new is

1. Clutch 50k ago (original had over 400k)
2. Muffler
3. alternator
4. new distributor
5. Transmission Bearings and 5th gear replaced
6. Basic tune ups and maintenance (4timing belts, adjuster, water pumps)

Issue stared as this. Driving along and car quit. The rotor came off the rotor shaft. Put back on ( lock tight) and fired up, but idle surge. (the we some times before this the idle surge would start, but not consistant. Also, turn AC on and for about 5 seconds its trying to adjust, but goes back to the surge again. The fuel pump has had a intermittent problem that 50% of the time it will not activate when turned to the second click of the ignition, and when it did prior; after warmed up or driven had to wait 10 minutes before it would start again.

Here’s the idle surge….


The fuel pump is original and is going to be replaced, almost 500k on the original fuel pump. Also, fuel filter was replace 4 months ago. Actually the car has never had any problems and runs and drives very good before this.

Now I have possibly narrowed it down to this.

1. IAC valve
2. fuel pump relay
3. main relay
4. (fuel pump) already a given
5. throttle position sensor

I am going to see if can get the codes on the ecm. I anyone can give me any help or advice, I would be so appreciative… Thank you all in advance...:D

fuel pump issue sounds like the common main relay issue. tap on it next time it doesn't start. if it starts by doing that, there's one problem. either re-flow the solder joints in the main relay or convert it to the 92-95 EG Civic version (that's what I did)

Your video sheds some light. Check for vacuum leaks. You're putting a load on it when you turn the AC on, that's why it regulates for a bit. I wouldn't be surprised if it was a vacuum leak... those hoses have to be falling apart by now! :P

Sounds like ticking valves in the video, too. Doing a valve adjust is pretty simple and will quiet down the motor.

487,000 miles... That's like... almost 800,000kms. That's insane. I demand extensive pictures. Rust and all. I'm really curious what a Civic looks like after a life like that. Also I love this chassis.

Please post pictures!

The "won't start-- no fuel-- but only sometimes" is a common problem, it's the relay not the pump. There is only one relay involved, the "main relay". You can tell the main relay is bad if the pump doesn't run and the CEL does not go out when you turn the key on but don't crank. If the relay does click and the CEL cycles on and back off, it could be the pump, but like the other guy said it is almost always the relay.

Unsteady idling is usually a dirty IACV, or the coolant is not completely full -- check in the radiator.

Thanks for the input. Sorry for the delays to respond. Found out a few things.

1. Did a jumper wire to the fuel pump and pump was pumping like crazy. Also I started checking for vaccum leaks and it was the IAC valve. It was sucking like a whale sucking for air. I removed the IAC and cleaned it. I was very clean already, and still the same. I pluged the hole with my finger and it started idling much smoother almost perfectly.

The main relay seems to work ok, except for the fuel pump. Cranks and fires ok.

2. Valves... yes they are over due for adjustment. gonna do that when its dead cold.

3. Going to replace the fuel pump, screen and fuel filter anyways, just because after almost 500k it could go any time.

4. The main relay your speaking about for 92+ does not have the right connections. The one I located according to the hayes manuel is right above the hood latch if I seeing this correctly... please more input if you can.

5. Going to do new wire and plugs anyways...

Also I will upload some photos. Only thing wrong with the body is the hood. Hit a deer and messed up the hood. Other wise then that, interior is perfect and the body and paint is in good condition. I get a photo of the speedo so u can all see the milage. engine is untouched and in 3k burns about a pint of oil in the warmer months. winter it burns a bit less... Thanks....:D

Your right on what you said. IACV is a goner. Coolant it full and no air pockets and coolant has about 10K on it. The relay is bad as you described. Gonna order 2 new ones just to have a spare.

Any further input would be appreciated.. Also someone please confirm the main relay. Is it the one just above the hood latch release? I dont like the hayes manuel.

Thank again... you all are awesome....:D

Yes, bolted to the side of the car above the hood latch release, it is a box about 1.5 x 2 inches labeled "RELAY, MAIN". This relay only controls the fuel pump and injectors, it does not affect cranking or igntion. https://www.hondacivicforum.com/foru...-repair-89522/ (That is a 1992 car, which has a slightly different design of the relay, but the process is basically the same for a 1991.) I suggest a 1/4 inch drive socket wrench with a 10mm deep socket to remove the bolt at the top of the relay, which you will pretty much have to do by feel.

Don't mess with the fuel pump, it sounds like it is fine.

With the wires unplugged from the IACV it should spring to fully closed and flow no air. If it doesn't do that try cleaning again or replace it (expensive though). The CEL will come on when the ECU detects an open circuit from pulling the plug but it should go out again when re-plugged.

Thanks for the advice. The IACV is definately bad. The valve does not move, its stuck open. Found one for $160.00 on rockauto.com .This is the vaccum leak. The valve is clean, but after almost 500K of heat and cold cycles, its a gonner. The fuel pump is fine, but I know it's not going to last longer so going to replace with new screen and fuel filter.

I found the main relay and its a 7 prong as stated. There is for sure 2 soder joints and 1 other questionable joint that needs to be re-sodered, but I going to just replace it. Thanks for the link, it was just above the starter relay, hayes book was wrong.

Going to just go thru everything with plugs, cap, rotor, wires, filters, valve adjustment, trans oil change, oil change, relays, IACV, oxy sensor, (this goes out about every 80K so do it again anyways. My son is going to be driving so I want to make sure everything is running and working ok. It's amazing after almost 500K everything works including a/c, heater, radio, and interior is almost perfect, exterior is almost perfect except the hood and I'm getting a new hood for about $60.00 and shoot it myself.

Having a hard time uploading pictures, so I will upload a video of the car to utube later. Thanks....:D

UPDATE 12/31/2012 - pics and video

Well ordered parts and should have them all by wednesday or thursday.

I ordered more things then what pertained to the problem as preventitive maintainance and peace of mind. My son is going to drive the car.

Ordered, IACV, main relay, ignition relay, oxy sensor, air filter, NGK plugs, new wires, fuel pump, intank filter, fuel filter.

Things to do in the next few months...

Timing belt, idler, water pump (not due for another 20k, but just do it), new tires, new hood ) i'm going to paint it and touch up, should run about $ 250 in hood and materials).

We did a deep clean yesterday and thought I would do a quick video (need to wax the car, paints in pretty good condition all in all). I sound stupid in it.... I said fender instead of hood and this is the 2nd time I've done this on my phone... sorry...


Everything still works on the car (original engine, never been apart) and on the video I ment to say during the warmer months it burns about a 1/2 quart every 3,000 miles not 1/2 pint...

I will post an update this weekend once my son and I install all the parts and adjust the valves... Thank you to everyone who helped and posted.... Hope everyone has a blessed new year....

well replaced everything but the fuel pump and the idle issue was the iac valve and the relay. drove it for a few days and it just died on me. AAA is on its way to tow me. i think new relay went bad... damit