ive been chasing a little problem. maybe you could help. bone stock 91 civic hatch. it seems like its not quite making full power when floored and struggles a bit at upper rpms. it idles very smooth and runs very well if not pushed wide open. how well can this thing run if its off a tooth? every once in a while it will throw a light (once a week) and if i restart it its gone so i cant theck the code. every so often i get a backfire through the intake and a little hesitation just off idle when i hit the gas. (2x3 times a week) this is my daily and i want to keep it tip top. any help would be much appreciated.

 

you should definitely check out that code. by "restart" do you mean you reset the computer or you turn your car back on and it's gone... before you reset your computer you should check your cel and then reset your computer to see if some of the cels are still there.

if your check engine light comes on and then off with out you resetting the computer the cel should still be stored on the computer.

 

im just restarting the car.

 

then your cel should still be stored in the computer... pull back the carpet on the passenger footwell and count the number of times the red light flashes. you might have multiple codes so keep counting the different codes until you see that they are repeating, then go and search what the codes are.

 

You will probably have a ECU code 1 for your O2 sensor if you are off 1 tooth on your cam gear. Get the cam timing right, then set your ignition timing.

 

he's not OBD-2 so the code will go away when the key is turned off. if you were off on your t belt the pistons would be hitting the valves because its an interferance engine. now from what you told us it seems like the ignition is to far advanced but you need to get the CEL read. when it comes back on, dont turn the car off and jump the 2 pin harness by the ecu and count how many times the CEL flashes. note how many long and short blinks there are

 

Your belt would have to be off FAR MORE then one tooth to be hitting valves. Also the code IS stored in the ECU, what makes you think it's far too advanced? If anything it sounds as if it's really retarded.

If you haven't cleared the ECU just turn the key to IGN-2 and check what code it's flashing. Sounds like it may be the o2 sensor, which can be caused by a few things, but check that to see whether it's a code 1 or not first.

 

The motor is OBD-0, the CEL will go off when the engine is turned off, but the code will remain on the ECU, and he can read the code when he turns the key to the on position, and counts the blinking LED. One tooth off will not cause piston to valve contact. You do not have to jump the the ECU pins for this. Count the LED flashes not the CEL flashes, this is a '91 stock motor not OBD-1 or 2.


~sp33~ types faster than me.

 

not on hondas. you do know that they are a zero tolerance motor correct?
if the motor isnt running but you still didnt turn off the acc, then the code will be there untill you turn everything off. then it wont come back on untill it trips again because its OBD-0, 1 works the same way. OBD-2 is diff pending on the code

 

There is a point where you will have piston to valve contact, but it is more than 1 tooth. The code is not cleared when the car is turned off, it is only cleared when you reset the ECU.

 

So well that it is a little hard to detect by just listening and feeling the car when it is running. I think the easiest way to check for being off one tooth is to try to adjust the timing. One tooth off is around 16 or so degrees of crank timing on a Honda Civic. The three marks etched into the crank pulley for setting the timing cover 16 to 20 degrees BTDC. So if you are off a tooth, it is going to show by not being able to rotate the distributor so as to line up that middle etch mark. Or, ya know, you will throw the timing light on there and the marks will be so far from lining up that it will be obvious you're off a tooth.

 

ok, i am throwing a code 1. i guess ill check the timing (cam+ignition)before i go throw money into an o2 sensor. sound like a good plan?

 

Yes. It costs nothing to check the timing, assuming you have your own timing light, the shop manual instructions (see the free online shop manual for your Civic at autozone.com), and the time to let it warm up the 40 minutes or so this time of year until the rad fan comes on 2x.

Well before you go buy a new O2 sensor, check your wiring on it. A shop manual can help. An oxygen sensor code is generally not going to be thrown unless the wiring is fouled up somehow. IOW, the sensor might be fine. If you do need a new sensor, you can get an OEM manufacturer (Denso) O2 sensor for about $30 total at Amazon for your Civic right now. Put your car's info in at densoproducts.com, and it will give you the right part number, then go to Amazon yada.

 

I've run my engine 4 teeth off with no contact. I wasn't debating whether they were interference engines or not, i was telling you that there will be no contact if the timing belt is off 1 tooth.

Your still incorrect as far as codes go too. You can take your keys out of the ignition walk away, come back put your keys back in and flip it to IGN-2 like i previously stated and the ECU will flash it's code.

Feel free to continue making a fool of yourself though.

Often a new sensor will prevent the code from coming back for a while, though the problem (if there is one) will eventually foul the new sensor too. This if often caused by your car running rich. If it's not your cam timing, or your ignition timing then check for vacuum leaks around the map sensor.

 

i loosened the alt belt to pull it out of the way. i cant find the timing marks on the crank. i know im close to tdc using a screwdriver but im struggling now. any hints?

 

i think i've the same problem with my H22, code 1, i'll verify my belt!

pimpwagon, find your position with the piston

 

There is a arrow on the engine block by the crankshaft gear. There is also a etch in the gear for the crankshaft timing belt gear. The etch is very hard to see, but it is on the edge of one of the teeth. If you line those up together, you will be at top dead center. This is all behind the crankshaft pulley. I had to put my crankshaft gear a little clockwise, then put the timing belt on, as when the belt would tension it would move the crankshaft gear counterclockwise a little bit and then it was lined up perfect.

 

ok i found the damn marks. timing is proper. i put an o2 sensor in and it instantly made a small difference. after a tank it picked up a few mpg too. from 21-24 with slightly added power. still dosent want to scream up top. put new fuel filter in. pump is new too. its still off though. how do you properly hook up a timing gun to this thing? is there anything to jump out? its better but not perfect. i thank everyone for help so far.
i know dpfi isnt known to be a screamer, but my last dpfi 91 sedan had lower compression but made more power. it screamed and got 25 around town stop sign to stop sign driving like a maniac. i should be able to duplicate this if it is running exactly as it should.

 

X2

The memory for the PGM-FI warning light on the dashboard may be erased when the ignition switch is turned OFF; However, the memory for the LED display will not be canceled. Thus, the warning light may not come ON when the ignition switch is again turned ON unless the trouble is once more detected. Troubleshooting should be done according to the LED display even if the warning light is OFF.

To clear the ECU/ECM trouble code memory remove the ECU/ECM memory power fuse for at least 10 seconds. The correct fuse to remove is the HAZARD fuse at the main fuse box for the 1988-91 models, and the BACK UP fuse (7.5 A) in the under-hood fuse/relay box.

 

Timing gun is simple, put the + and - on battery and connect the volt clip right on the number 1 spark plug closest to the plug on the valve cover. If ur 90-91 jump the blue connector next to the heater/ac fan the cel should come on, also make sure the car is 100% fully warm. If your 88-89 the jumper is in the engine bay standing in front of car on right side wiring harness yellow plug, jump that also cel should come on. Aim gun at the marks on the crank from top they should be around the marking on the timing belt cover, there is an arrow you line the crank pulley marks up with the arrow on the t belt cover. There is 3 lines right next to each other and there is 1 by it self a few inches away from the others. The 1 by itself is TDC and the other 3 are 14* 16* 18* it goes like this.

TDC | ||| 14* 16* 18*

if ur gun has the adjustable * **** on it turn it to zero and aim light at the crank line the 16* or 18* degree with the arrow up by turning the distributar while the car is running. 18* is a little more power but leaner but its okay to run at 18*. also 18* is by the rad side and 14* is firewall side so 16* is in the middle. Also TDC is farthest to the firewall.

 

we've look for the timming belt...
it look like incorect when adjusting camgear and the mark on the flywheel (no mark on the crank pulley???) like one tooth
i've see the tension on the timming belt is very low... i think i've a problem with the automatic tentioner... i'll change this to a manual tentioner soon...
thanks for the help ! (i was very lost with my poor idle and the o2 sensor light)

 

​​​​​​With it being an older civic I'd say that the compression has just depleted from the rings and sleeves just getting worn out. But I'm not a professional just a shade tree mechanic with a few Honda motor rebuild/swaps under my belt.

 

He posted that 13 years ago and hasn't logged into Honda-Tech in over 7 years. Come on man...don't wake the dead!