Same car, Different issue. i need some pointers!

TeggyB18 · 10-01-2011, 05:37 PM

ok, well, my daily is messing up (again). some info on the car:

its a 1993 civic Ex body
it has a D15B7 with matching ecu (cant remember the number)
its an automatic.
car has no check engine lights on. (it does work, its just not throwing codes)

now, the issue is intermittent. it happens once really bad, then it will go a day without missing a beat, then it will give me two days of this, then maybe wont again for a few hours, and so on and so fourth.

now, what its doing (mostly going up moderate/steep hills) it will fall on its face terribly. i have to do WOT just to try to make it up the hill, something is cutting out. i belive its fuel. then whenever you make it up the hill, it will keep hesitating really bad, until you pull over. and turn the car off. wait a few seconds, turn the car back on, then drive it and its just fine.

the problem is usually occuring when the car is warmed up, when its cold its not really an issue.

the only diag i have had time to do, was i took a timing light, hooked it up to cyl 1, then cyl 2, ect. and kept it in the car, to see if spark was cutting out. but id didnt on any cyl. it kept firing, which is why im leaning torwards fuel.

i would imagine if it was a sensor messing up, giving false readings, like a map, or tps, that it would throw a code. but im probably wrong. ive taken a look at the harness, and its ok, no bare wires, corrosion, all plugs secure..

and a side note. when the car has been hesitating, and you manage to make it to where im going, i can put it in park, and revv it up, and you can hear/notice the hesitaion really bad. but when you turn the car off and back on, its back to running fine.

i have an idea on my next step, which would be to hook a fuel pressure gauge, and see if fuel pressure is dropping off. but before i go cracking lines, and renting a gauge, i figured id post and see if anyone has ever messed with an issue like this.

Thanks!
-nate

Mista Bone · 10-01-2011, 07:19 PM

Gas mileage really crappy?

O2 sensor is my guess.

I have a spare or two OEM B7 exhaust manifold with good O2, the O2 welds itself in over time. If you want one of them to swap, get it out of my way!!!!

TeggyB18 · 10-01-2011, 09:05 PM

Well, I'm still getting over 280 to a tank, so I think that's normal. But I've had bad o2's before, and it was never that bad. I mean it will idle perfect. But as soon as it gets about 1500 it misses like crazy. I just wish it would give me a code so it could st least point me in the right direction

ej1bmx · 10-01-2011, 09:07 PM

You're only getting 28mpgs? When I had my 93ex, I was getting 35+ every tank.

Mista Bone · 10-02-2011, 01:57 AM

Quote:

Originally Posted by ej1bmx

You're only getting 28mpgs? When I had my 93ex, I was getting 35+ every tank.

he has a slushbox....

TeggyB18 · 10-02-2011, 03:07 PM

Well, that's 28 in the city. But that's what this car has always gotten. Maybe its from the issue I'm having, or the fact that its an auto. I dunno. But thanks bone

Mista Bone · 10-02-2011, 06:44 PM

My 4 door would get 32 mpg mixed with AC on. The D15B7 with a slushbox is just SLOW and stressed, when OD kicks in on the highway.....weak isn't then word.

TeggyB18 · 10-02-2011, 06:57 PM

Yeah, it sucks. So what bone, you think the 02 is telling the ecu its rich on certian conditions and telling it to cut fuel or something? Then when the car is restarted, the condition is cleared then back to normal? U think it could be a ecu problem? I'll look and see what's in there. The 02 does not look original, it doesn't mean its not bad though I guess

Mista Bone · 10-02-2011, 10:58 PM

I had a NGK O2 burn up in 5 weeks on the Accord this summer. Its gas mileage went from 29 mpg to 22 mpg.

It was giving low voltage reading to the ECU as if it was lean and the ECU added more fuel and pulled timing.

I love OBD2 cars simply because I can hook up a scanner easy and watch the sensors while driving.

TeggyB18 · 10-03-2011, 06:06 AM

That makes sense. You said you had a few good manis with 02's in them? How much do you want. I could come get them Friday or Saturday from ya

Mista Bone · 10-03-2011, 11:09 AM

I think I have one at the house and one in storage, come get one out of my way.....

TeggyB18 · 12-12-2011, 06:06 PM

Well, ill bring this back to the dead since its still going on lol
I have since installed a new 02 sensor. It didn't help the problem, and I've inspected the ecu, wiring, and various sensors and plugs for corrosion, and everything looked good. The plugs have a rusty brownish tint to them, when they were brand new 6k ago. Wires look good, and so does the cap.
The timing is good. Now, every time I take this car on the highway, it does it. I'll be steady at about 75 mph for roughly 15-20 mins then it starts, complete loss of power, sputtering, and missing. So I put the car in neutral, turn it off, then back on, and back in drive. All while moving lol.

delsoldon · 12-20-2011, 02:35 PM

have you happened to check your plugs at the MAP, TPS, and IACV? i can't remember which of the 2 share the same type of plug, but it's pretty easy to get them reversed. i've done it before when doing a swap and i was having pretty similar issues. no CEL, very bad hesitation, seemed like a timing issue, but ended up being the plugs were backwards.

VtecFreePrelude · 12-20-2011, 03:24 PM

my prelude would overheat a few years back and i couldnt figure it out until i actually checked the rear hose and it wasnt as hot as the computer was saying, ended up being the ground from the trans to the chassis was rough looking. might as well eliminate an easy option

Kisor · 12-20-2011, 03:38 PM

Look at the plugs for carbon tracking,

This will cause misfires and you will still have spark through the wire to light the timing light.

Your symptoms describe an ignition issue.

If there is any do wires too, once the boot is subjected to this they are done... if you put them back in on new plugs it will eventually burn them too.

TeggyB18 · 12-20-2011, 04:52 PM

I'll check that, thank you.

And kisor, ill check it tomorrow, thank you, and I was assuming it was either fuel or ignition. I just don't want to throw parts and crossing my finger ya know. But ill post my findings tomorrow.

Kisor · 12-20-2011, 07:16 PM

No prob. That and coil issues are all I really see that's common with those. And by the description of symptoms I think the carbon tracking is a real possibility.

killer025 · 12-20-2011, 07:44 PM

I don't know hondas at all, but my brother had a 90 accord that did the same kind of thing, and it ended up being the fuel pump. It was a few years ago, but I seem to remember the harness at the pump wad corroded and shorting out the pump intermitently. Either way we put a new one in it and it is still running/driving today.

TeggyB18 · 12-20-2011, 08:10 PM

The thing that don't make sense to me, is how under the same conditions, it does it sometimes, then others it don't. And when it does do it, as soon as you shut the car off and right back on it quits. Maybe something is putting the car in some type of "limp mode" until its reset. I dunno.