engled

1998 EX 4cyl. automatic I have read most of the threads on the switch and main relay issues so I have already replaced both but the symptoms continue.

The car will stumble quit and restart when the car is going slow (less than 5mph) and you apply throttle. At cruise it only seems to do it when the load increases like when you start up a grade, then it usually just skips. Here is the real kicker, if there is a code stored before this happens it will disappear. The car has had a check engine light on since I bought it, (gas cap and some other emissions BS) The only way I can think of this happening is to loose power to the ECU to clear the code. Which means if the problem is tripping a code it also clears it!

Maybe this is a problem other than the some what common switch/main relay that I'm not searching for correctly.

Thanks for you help.

Darryl

Nicefeet

egr ports

engled

Can you point me to some documentation on this? All I can find doesn't have the 98.

http://home.comcast.net/~em-engineering/T2T013.pdf

sgraham01

give us all the trouble codes and we may be able to help you better.

engled

"Here is the real kicker, if there is a code stored before this happens it will disappear"

I wish I could. The car hasn't ran long enough without the problem to trip the codes again.

sgraham01

you didn't record them when you first had it scanned? should still be in history i would think. do you have a scan tool?
also, if it is having problems, the codes should not disappear or clear themselves unless the problem has been gone for a given # of drive cycles.

engled

I don't remember, it's been months. I do have a code reader and there are none stored. Maybe I didn't make myself clear. If the car does trip a code and if it dies/stumbles before I can get the code reader on it (which so far has been every time) the code will be gone. It's like the ECU is resetting it's self when the car stumbles. I had the reader on it while driving watching the sensors, when it stumbled the reader lost sync with the car.

sgraham01

you may want to try another ECU. if the codes are lost, then that leads me to believe the ecu is losing power intermittently, which may be the whole problem with the stalling. if you were stalling out and the ECU wasn't losing power, then it should still have a code. I'd check the connections at the ECU, then maybe try a used one. ECU's aren't usually the problem, but it happens.

engled

I did reset all the plugs going to the ecu.

I think I'm going to run a fused hot wire straight from the battery to the 12+ on the ECU and see if it still does it.

This makes me wish it had a Megasquirt like my race car, so much easier to fool with.

sgraham01

that sounds like a good thing to try. if it still happens, i'd try the new ECU

engled

I'm having a little trouble finding which wire is the constant +12, none of the ECU pinouts I have found has it listed.

sgraham01

Maybe this will help.

I see 2 switched powers and a constant backup power. B21
sorry it's small

engled

Thanks!

engled

I finally got the codes, I'm pretty sure these are the same codes that have been in the car for the past 40,000 miles but maybe I an wrong.

P0401
P1457

I'm going to try and test/clear the EGR.

I drove the car about 12 miles with no issue and check engine light came on, I managed to drive the car another 30 miles or so without the problem. I guess this is something I should have mentioned in my first post, the car will run fine for 40-60 miles before it start dying so I guess it could be heat related.

engled

UPDATE
The ECU is not loosening power. I tried the three +12v on the car and none even flicker when the car dies. The last time the codes cleared them selves it was during start up, it just about has to be the ECU...

sgraham01

most of the time it's the ECU when you are having problems and no codes are stored. since you got codes, it appears that they are being stored, but then lost by the ECU when it loses power and memory.

how did you check the three power wires to the ECU? test light while driving or did you run it off the battery directly to the ECU?

engled

I have an analog volt meter just for occasions like this, I hooked it up to the three locations and drove the car around while watching the gauge, it never moved during the hiccups. Every one should have a analog gauge to work on cars with, you can see things happen on one that you can't see on a digital gauge.

GhostAccord

Check your EVAP canister and see what shape it is in. If it is full of fuel or a solenoid has failed it could cause these types of problems. This is not a common issue but it could happen. Just looking at this because you posted the P1457 DTC (EVAP leak detected).

engled

I just picked a another ECU only to discover the immobilizer must be in the ECU so now my keys won't start the car. Any way around this or am I stuck paying the dealer to reset my keys?

sgraham01

i have not dealt with this on a Honda before, only GM. if you can't crank it with the replacement ECU, then you will probably have to take it to the dealer for programming. Call them and see what they say, then search the web to try to verify. I think you will probably need to take it in to the dealer for this unless there is a relearn procedure like the GM passlock system.

engled

$50 and 15 minutes at a local Dealership has me up and running. I'll hope for the best.

sgraham01

Good to hear. i am interested to see if it was the ECU afterall. keep us posted.

engled

A swing and a miss...

No change with swapping the ECU but I did notice something that hadn't before. Before I swapped in the new switch and main relay when the car would quit all the lights on the dash would come on and the tach would go to zero. Now when this happens the tach drops to zero and the gear indicator light goes out briefly, none of the lights come on. It does not act like you cut the switch off as it did before. I'm beginning to think I have had two problems and I fixed one but not the other.

A new description of the problem:

The car cranks and idles normally on cold start. Once warm it idles a little low whether in gear or not (~650). On takeoff it will sometimes stumble with just a slight miss around 1800-2200rpms (EGR?), go on and drive fine. Sometimes it will miss several times during this rpm on take off and actually quit. When it quits the engine stops, the tach drops to 0 and the shift indicator light goes out, if the check engine light was on it goes out and the codes are cleared from the ecu. The car only shuts off for an instant.

Any more ideas?
Thanks.

sgraham01

if the engine is stopping, you are losing fuel and/or ignition. this still should not clear the ECU though.

maybe you have a bad ground to the ECU.

if disconnecting the battery will erase codes on your car (on some makes it won't), this would erase the codes as soon as it lost ground and also kill the car since the ECU is now "disconnected". that's about all i can think of. maybe you can hard ground the ECU ground pins and try driving like that.

engled

Thanks, I'll try a ground.