Elantra won't start/replacing fuel injector
 

Hey all,

My '97 Elantra GL wagon won't start. A few weeks ago, it was misfiring and I was getting a code on random misfire and misfire in cylinder #4. All the plugs and wires were good, I even swapped out the coil pack (both tested OK). I listened to all of the injectors.. #4 didn't seem to be working. I unplugged it and the car ran the same. Ah-ha! I plugged it back in, and the idle smoothed out and the injector seemed to be working. I drove it about 200 miles with no problem, though one cold night I started it up and it misfired again, but then smoothed out once the car warmed up. Drove it 100 miles that night with no problems. The car then sat for a day or two in 20 degree f weather and now won't start. It sounds like it wants to, but it just won't "catch".

I'm guessing that the #4 injector is not working again, so I have ordered a new one. I just wanted to see if there is anything else I should check. I don't have a fuel pressure gage, but at 247kmi, I'm wondering if I should swap out the pump.

Spray the intake to cylinder head seam with a can of some flammable to make sure you do not have busted intake gasket... See it all the time on the later 2.0 in Elantra.

Good idea, but when this first started happening, I waved some blasts of propane all around the intake gasket and there was no change. This is also a 1.8L engine.

update: replaced #4 injector, and cleaned a lot of chalky tan/white deposit out of the fuel rail. Put it all back together and it still won't start, but its almost like it wants to. I believe its getting fuel and spark.

argh! any help?

you say you 'believe' its getting fuel and spark. check this on every cylinder, don't guess. turn the engine over a few times, pull the plug. should be wet with fuel. next get a spark/ignition test light. they're dirt cheap, light goes off when the plug fires. attaches to the wire. it just senses the voltage pulse.

figure out if we're talking one cylinder or all of them. sounds like all, but leave no stone unturned.

next we're looking at odd electronics problems mostly, or possibly a dead sensor. taking out the crank position or cam position sensor will cause this.

here's why i say check everything and narrow it down: i have a 2004 accent, the odd time had problems where it wouldnt start when cold. it would crank and nothing happens, but always eventually started after a couple minutes. i checked a lot of stuff, and everyone here and on another hyundai forum swore up and down it was the crank position sensor. i didn't accept that for one simple reason: why only on startup? why no misfires later? the solution was something very simple: a main control relay behind the dash. got the clues from the ECU, it was bitching about BOTH o2 sensor heater circuits being dead (which is bloody impossible) and 'low system voltage'. checking the wiring schematics, that relay was the only thing both the ECU and o2 sensors go through together at any time.

moral of the story: check everything, don't jump to conclusions. if i did it would have cost me a new crank sensor that i didn't need. get that info on here so we can narrow it down more. but also do what you're doing and try to work your way through the problem.

Thanks ZG! Latest update, I do have spark going to all plugs. I'm positive its not a problem with the wires. I sprayed a 2 second shot of starting fluid in each cylinder and it ran for about a second or two. I believe now its a fuel problem. Though, I did notice that the #4 plug was wet and the others weren't. Strange. #1 was a little carboned up. Could it be a sensor?

I had a P0300 and a P0304 code showing multiple misfires and a misfire in cylinder 4. I also have an evap leak code, but I have had those in the past. Usually occurs in the the winter. I did replace the flexible portion of return line that attaches to the fuel rail as it was cracked. BTW, I checked compression. Cylinders 1 through 4 were about 180, 210, 220, 200. The engine is definitely showing its age, but it should still start and run.

Question: Should the fuel pump have voltage when the ignition is on, or only when starting? I'd like to supply 12v to the pump directly from a battery to see if it will kick on.
If it doesn't I'll replace the pump.

There are 5 wires going to the pump harness. Top row: black yellow red/white; bottom row: black green/brown. +12vdc goes to the yellow wire when the ignition is on, and I'm getting +12vdc to the red/white wire when I'm trying to start the engine. I'm assuming +12vdc can go to the red/white wire to test the pump?

yes a sensor is very possible at this point. if a sensor isn't reporting the correct crank and/or cam position to the ECU it has no idea when to fire the injectors. sounds like an electronics problem to me big time, there is no way you're going to blow 3 injectors at once here! check your wiring to be sure.

if there's a problem with evap, fix it. i don't care what it did in the past, the thing doesn't work now. eliminate those problems so that you know they are not a cause.

i believe my accent will put power to the pump only during starting and after engine is running. good call on checking the pump with 12v before replacement, dont replace stuff blindly. just be sure to run it VERY briefly. running that pump dry is a sure fire way to kill it.

this i'm not sure on, hyundai is very good at changing the wiring EVERY YEAR for some models. god knows why they do it, but there it is. check www.hmaservice.com for your schematics, connector pinouts and wire colours.

Thanks, ZG! For some reason the forum isn't sending me updates when someone responds even though I'm subscribed.

So here is the latest. I could not get the pump to run with 12v from a battery. So, I replaced the pump. I can now hear the pump kick off after trying to start it, so it should be running while starting. However, it still won't start! At least the gas gauge works now. One thing I really like about this car is the porthole to access the fuel pump. Every vehicle should have one.

OK, back to the problem. I need to get this thing running. Whenever I try starting it, the #4 plug is always a bit wet. Not dripping, just slightly wet. So, something is screwed up. Which sensors should I check, crank angle sensor?

Edit: Terminals on crank position sensor read 476 ohms. Spec is 486 to 594, but at room temperature. Its probably 20 degrees in the garage. I'll try to heat up the sensor a little, but its close to spec.. should it be replaced?

OK, I put a hairdryer to the crank position sensor. I got the resistance to go to 490 ohms, and then with a little more heat to 510 ohms. It was warm to the touch, but not hot. Should I replace it? Its within tolerance.. (486 to 594 ohms).

At the end of my rope here...