troy12n

Girlfriend's 1998 Civic HX coupe has been doing this thing where it drives down the road, and stalls. No warning, just cuts off. You let it sit 15-20 minutes, it will start, and run for a while before doing the same thing over.

It's not the ignition switch. She took it somewhere, and they did $1800 worth of crap to it, the catalytic converter, DOWNSTREAM O2 sensors and fuel filter. Still does it. They now say the EGR valve needs to be replaced.

This car I don't think is worth much more than what she has already put into it, they are saying like $400 for the EGR valve, but based on their track record, I do not trust it will even work properly afterwards.

Any ideas? it's throwing a P0401 code, which refers to EGR valve, but it's my understanding that a bad or plugged egr will cause rough running, maybe a misfire, but not a straight up stall, no start condition. And the other stuff that's been replaced, I already know that is a joke. All emissions stuff which have no bearing on it running or not. Unless it's a 100% clogged cat, that would not cause it to flat out not start.

Help!

ol Dusty

iTrader: (2)

Not being there to actually diag the car myself the only educated guess I could make would be the main relay. Dig around a local scrap yard and find a couple. Swap yours out, it's one 10mm bolt and a connector. You can search google images and find plenty of info on location of the part as well as how to change it. I'd start there as its a cheap and easy thing to do if you use parts from a scrap yard and do the work yourself.

troy12n

Is the main relay part the same across all civic models for MY1998? or is the HX different. I know the HX and EX were the only ones with the VTEC engine that year.

Also, I called back the shop which did the work on it before, and they are saying carbon is getting loose, lodging itself in the EGR which causes it to shut down, and it can start in 15-20 minutes because vacuum has let up and the carbon unlodges itself, which sounds like complete BS to me.

Would a bad or failing main relay have any sort of engine code? The only code it is throwing is P0401

antrmo

your right when u say no start and engine stall with plugged cat, hit the cat with a hammer and listen,,does it rattle like it has parts in it?

ol Dusty

iTrader: (2)

You probably do have issues with the EGR as far as the code goes but I highly doubt that's the no start cause. The EGR is fairly easy to remove but you will need a new gasket. Pulling it off can give you some idea if it's clogged and either way clean it before putting it back. You will want to try and clean out the passage it goes into as well.

The main relay should be the same for any 96-00 civic, maybe even the same as 92-95 and the 94-01 integra but I'm not 100% on this, partly because there is no Hx up here in Canada.

troy12n

But a clogged, even a FULLY clogged EGR probably should not cause it to completely die at speed, right?

antrmo

EGR is there to introduce exaust gas into the intake, I would think the only way it would kill it is if its stuck open and the air/exhaust mixture was to weak to be enough to fire.to much exhaust ,not enough air/fuel.,oh and missed that you already replaced the cat, sorry for other response. possible a fuel pump plugging up in the tank? so no fuel flow. possible fuel pump quitting? coil wire grounding out ? no spark? if you can catch it doing this while idling, then get a fuel pressure gauge and watch it when it stalls, look for any black burn marks around coil to see if arcing is happening? spray a water mist around wires watch for sparking? just a few ideas. cheers. lol sorry so long.