01 accent no power

Since you've got harness damage, first check to see that the wires to the oxygen sensors are the proper wires. You can find schematics at

Once you've selected Web Tech, your vehicle and engine, click on the ETM tab. The schematic you'll need is the MFI schematic in the fuel section. The numbers at the connectors represent the pin location in the connectors.

You should have battery voltage across the heater wires with the key on and the engine running.

The other wires are oxygen sensor output, which will need to be checked for voltage cycling between 0v and 1v while the sensor is plugged in. With the car hot and idling, it should cycle across 0.5v at least once every three seconds.

The first place to check should be in the area of the wire repair. The washing of the car seems to hint that water got somewhere it wasn't supposed to. Also check to make sure bare wiring isn't rubbing on metal, grounding it.

okay .. front 02 sensor (read bad before the wreck) is givin me about 800mV at idle ... i also ran it without the front o2 sensor in just to make sure cat/exhaust wasnt clogged and no change ... i keep thinkin MAF sensor ... it checked out fine except MAF term 1 to ground read at 10k ohms (says it should be open on webtech) so i jumpered from MAF term 1 to ECM

37 (same color wires as a double check .. hard to count under the dash with a flashlight)

did not check voltage drop across o2 heating elements

all wires have been reconnected and have survived another car wash ... however there were numerous pairs of wires that could be crossed wired ... ive solved 3 pairs for certian one blinker .. one for starter relay ... and a 3rd for MAF (org blk line dont remember its term but when mixed i lost proper power to radio and door buzzer)

looking at troubleshootin common items for high idle and engine hesistation include ( i get better gas mileage in the city at around

30mpg keeping the rpm's as low as possible

ECT sensor ( does hyundai use different metals to induce voltage when they are at different tempratures ... if so what should be a normal running voltage betweent the two sensor portion)

injectors

PCM

IAT (normal thermsistor resistance on a cool day? had 5v on MAF term 2 ) TP sensor ( resistance shot off range around last 3rd and not enough hands to change ... assumed it was workin okay, what sort of resistance range should this be at

sorry about being a pain, but its the best way to learn about a new vehicle

hyundaitech wrote:

Your O2 should be fluctuating, not steady. If it's steady, you have a problem and need to find it. Could be the sensor, an exhaust leak, the wiring, or some other problem entirely.

My presumption is that the water temp sensor is bimetal, but I've never attempted to look at one. It is supposed to change resistance depending on temp.

It will be very difficult to check individual items with a voltmeter, especially in the fashion you suggest. Ideally, you'd hook up a scan tool (which I'm sure you don't have) and look at the readings and flag anything which looks suspicious.

One of the difficulties here is that it's difficult to know where to send you. On the one hand, an O2 fault code almost always points to a faulty O2 or leaking exhaust, but on the other hand, your case suggests some issues with the wiring. So I'm reluctant to send you into a painstaking inspection of the components with a voltmeter.

Not seeing the wiring repair work, it's difficult for me to know how the repairs were made and how well they were sealed. This can have a great deal to do with how water intrusion would affect the circuits in question. I guess you need to decide how sure you are that the wiring repairs are in good condition and correct, and let that be your guide as to whether you should start investigating elsewhere.

Hope this helps.

hello, well no scan tool i can just sit and use means im stuck with a multimeter. i found a lovely section on webtech (shop) which tends to have more info i can check myself. MAF sensor seems fine. according to routing diagrams there should be nothing wrong with engine harness since it comes from the middle of the firewall and the one with issues came from the drivers side fender to behind the drivers side headlight (where it got messed up). and all that should be on that harnes are accessory items ie radio power turn signals headlights etc.....

car did spend a few months with a cold air intake and a huge exhaust ( exhaust is still on it )

if temp sensor changes resistence then it is bi-metal

would a faulty o2 sensor cause the engine to not rev past 2-3k (i will tach it when i can find where to attach multimeter for tach input .. has rpm sensor ) I myself have never seen an o2 sensor cause that much performance... the plugs are decent to poor condition .... wires are

2.75K to 1.41K ohms ... the engine will rev up when there is no load on it

current codes set are

P0562 System Voltage Low (my subs drop battery to 10v in about 2 seconds with engine off ... running with subs off does not affect perfomance) .. also i did not find this on WebTech

P0136 Oxygen Sensor Circuit Malfunction (Bank1, Sensor2)

P0134 Oxygen Sensor Circuit Inactive (Bank1, Sensor1)

P0507 Idle PRM Higher Than Expected

none of these items seem as though they would cause this much of a perfomance issue

Lastly i have been making sure to tell everyone about this level of post warranty service with you here at the newsgroup helping people and the WebTech ... again i have to say wow i would never have expected this level of service for free for a 5 year old car with 45K miles that has been totaled 2 times now ( ps last wreck was against a new chevy malibu and it had to get towed away )

sincerely

jerry

hyundaitech wrote:

You're not fully out of the woods with the O2 sensor. The engine harness (the one that was cut) provides some power to some of the control harness (the one coming through the firewall and going to the sensors) items.

I'm not able to check code info right now, but the O2 codes suggest a problem with the front O2 being properly connected. I'd be sure to check this fully like I described earlier.

For the P0507, check to be sure the idle actuator is plugged in and wired correctly. Also check to be sure that the throttle cable is not misadjusted and holding the throttle partially open.

For not going over 2-3k, if the engine is running smoothly, I'd check fuel pressure and cam timing. I did have a really oddball case where the front O2 on an Elantra caused an incredible hesitation on acceleration. The manifold cat had been replaced and the tech who swapped to O2 bent it. Took me a long time to find the problem. But I do suspect your O2 issue isn't the full problem and probably isn't the main problem, based on your description.

yes i doubt the o2 sensor is the main issue ... front o2 sensor heater was receiving 18v (odd that it was a good 5v above battery voltage ) ... couldnt get a good connection to test it plugged in though .... fuel pressure is something im fairly certian i cannot test myself , cam timing i assume to be mark on cam aligned to mark on head with piston #1 at tdc .. hope thats correct for the vehicle ... so i guess its back to the whole game plan of just switching matched pairs of wires around until something works ... also i dont know if i mentioned that on some occaisions (rare) the engine will have proper power for about 1 city block and then returns to its current state.... throttle was fully closed i instected all that while testing the MAF and TPS today .. man why couldnt they have used less identical pairs running through there ... or a current flow diagram with wire coding on it ... thanx again jerry

hyundaitech wrote:

What's your battery voltage with engine running? 18V at O2 is definitely a problem. Do you think it's possible the alternator is overcharging?

battery voltage was right around 12v .... but that voltage was checked only with key on not while engine was running ... know of any voltage supply wires colors that ran through the fender off hand ... im just gonna resume my original plan of slowly swapping connect pairs and see what makes a difference, hopefully single pair will make noticable difference if its multiple pairs that are improperly connected

hyundaitech wrote:

assuming the cam timing uses the trailing mark (second mark) and that mark straight up ( red mark on head pointed straight up) when @ tdc via timing marks on balancer... its spot on ... belt feels good also ... double checked wires and i could not find any mixed ... no signs of head(gasket) failure .. oil is oil and water is water ... nothing out the exhaust ... does this sound like a possible ECM failure? going to fog intake area with starting fluid see if i got a leak around there

LameBMX wrote:

well no change in engine idling so i highly doubt an air leak .... fuel pressure seemed okay maybe a little high (finger pressure test .. not accurate but i know its not like 120psi or like 10 psi either .. so how much would a new ecm be selling for these days?

thanx again for all your help .... jerry

New ECMs are about $600 to $1000 if I remember correctly. ECM failure rate on Hyundai is very rare, and when it happens, it is often caused by another component. You'll want to be absolutely sure it's the PCM prior to replacing it.

Did you manage to check battery voltage with engine running? An alternator charging at 18v will blow up solid state components faster than you can say "holy...

but what im kinda thinking ... you said there are sensor power wires running through the area that took damage ... then friends wife washed the car ... power line from ( iat ... coolant temp ... others?) will have + from the computer through the damaged area ... when area got wet they got shorted from the sensor they was sending power too ... increase current through the pcm for that sensor ... fry pcm ....

now the low failure rate i like ... increases chances of finding a good one at a bone-yard ... but i would also like to have a 3rd party check out the re-wiring (if you cant find something ... someone else normally can)

thanx

LameBMX wrote:

The power wires there aren't actually in the control harness, they're in the "engine" harness (which doesn't actually go to the EFI components). I believe the two harnesses plug together inside the car and power is connected to the control harness there. Another thing to think about is to check the ground points and make sure the wires appear to be intact and that the ground lugs are making good contact with the body.

It will take some poring over the schematics to see which specific wires bring the power into the control harness, and I think it's even more difficult online because the pages don't have links to the other pages. Another set of eyes is always a good idea, however.

87 octane.