Kidnkorner

The car started started bogging down and bucking if the throttle was given any medium to high input below 2500 rpms, only slight throttle input would get the car going but once it reached 2500 rpms you could stab the throttle and the engine would sing without a hiccup.

I had gotten a CEL, the orginal code came up 43, so I I trouble shooted and the oxygen sensor was bad so I replaced it. The symptoms improved ever so slightly but now I get a CEL for a code 3, MAP sensor. Would a faulty MAP sensor cause this issue and would replacing it clear it up?

I would hate to replace it as I am trying to minimize the cash I dump into this drivetrain as I am doing a K series swap late fall. As it stands I am into this problem for about $95 replacing the stock exhaust manifold (siezed and broken o2) and a new NGK sensor.

Any help or insight would be appreciated!

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Edit: Problem solved - Spark plug gap double of factory spec

Kidnkorner

Well, it isn't the MAP sensor that's causing the issue

shat_head

After you changed the o2 sensor did you pull main fuse for awhile? Had a problem llike this changed the sensor and pulled the main fuse and its all good now. Or could be anothe bad 02 sensor

Kidnkorner

Brand new NGK unit. No CEL are present now, going to replace fuel filter.

Sr420Det

a bad referance to the map sensor will cause all sorts of problems including what uv described. Make sure the referance is good and if it still does it, there r ways to test it (pick up a haynes) or u can just pick up a known good one for dirt cheap. Hell i got like three of them, i could ship u one for 25.

How is ur map sensor picking up on the intake mani pressure? u got a hose? is it on top of the tb?

Kidnkorner

It's not the MAP sensor as I stated, replaced it with a new unit.

The MAP sensor is on the throttle body.

I replaced the fuel filter, still no CEL and the problem remains.

Sr420Det

throttle position sensor

Sr420Det

43 is fuel supply system not o2.

Kidnkorner

I have my bets on TPS as well, would it cause abnormally long cranking time too?

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I replaced the oxygen sensor and it cleared up the code 43.

Chapter 6 section 4
Code 43 Fuel supply system / oxygen sensor
The oxygen sensor regulates fuel supply therefore it may cause a CEL for code 43

Sr420Det

sure can, make sure they r not switched. Think map and tps r the same, did this just start happening out of the blue or did u swap a motor in or something. if the o2 sensor was working properly it would trip the 43 due to it reading low or high oxygen content but i dont c how it would b the cause. If that is what uv found in ur research than i wont deny it....just question it. Generally iv found that o2 sensor dont cause to much trouble. I mean they r only good to tell u if its richer or leaner or spot on stoich, so they r only used for trimming fuel tables at light load

B18C5-EH2

If it's not throwing a code, look elsewhere IMO.

I would not jump to conclusions about a TPS, or any other sensors unless there were codes present for them. For the guy asking about TPS and MAP plugs being swapped I've seen that with swaps, but you'd get codes for each sensor too, not just one.

Can you borrow an ECU for the purpose of swapping it out to rule the ECU itself out as a problem?

Also Fuel Supply code can be caused by an o2 sensor, but it certainly is not limited to simply an o2 sensor issue. I have seen bad fuel injector(s), fuel filter, fuel pump (not exactly common though), fuel pressure regulator, and leaking fuel line(s) cause a code 43 in my time (10 years) at my current Honda/Acura only repair shop.

B18C5-EH2

Sorry to ***** it up too, but a faulty o2 sensor can actually cause some pretty nasty drivability issues such as bogging, surging under acceleration, etc. I've seen o2 codes present on cars that ran 100% perfectly, and then some cars that did not throw an o2 sensor code and they ran like crap until the o2 sensor was replaced.

Now I know it might sound contradictory for me to say an o2 sensor can make a car run like crap and not throw a code, but earlier I also said don't bother with a TPS unless it's coding. I said this because the ECU seems to be less sensitive to o2 sensor problems in terms of when it codes for one. Usually minor issues with a TPS or MAP will result in coding.

Kidnkorner

The problem came on suddenly, the abnormally long crank time has gotten really bad. The car is a daily driver and was bought as a K20 project car slotted for late fall. It's in pristine condition for an 18 year old vehicle all things considered. The drive train is completely factory show room stock 1992 Civic Si - D16Z6

I have swapped out several MAP sensors in the last 2 hours, the problem remains and is tripping code 3 again.

The guy who looked at the vehicle suggested I check timing and mentioned the timing belt jumping a tooth. I do have and was planning on doing the timing belt water pump. He went on to say he saw smoke coming out of the induction tube when the car is shut off. Also when the car does die as a result of this issue it makes a horrible whining noise. I hate to do it but I just may take it somewhere and pay to troubleshoot it, I just don;t want to dump any more money into this drive train.

B18C5-EH2

Try and find any OBD1 Civic/Integra ECU to swap in just to see if the issue goes away. Of course ideally try and find a P28, but those can be hard to come by. A non-VTEC P06 from a 92-95 DX/LX would serve the same function.

Oh and by chance have you looked hard at the wiring at the MAP sensor? also by chance have you seen the pins at the ECU plugs for the MAP? I'll see if I can find those pin-outs...

Click HERE for OBD1 Pin-outs!!!

b18cKoupe

is the problem better,worse or the same on a hot or cold engine?. Is the long crank time the same on a hot and cold engine?

Sr420Det

sounds like good advice to me. Dont pay anyone to trouble shoot it, no one. You can thank me before u pay someone to figure nothing out. Is the mani where the map goes in at clear? Try taking that map out, plugging the hole, and referancing it from somewhere else on the manifold. If u could get ur hands on a good ems with datalogging u could check everything out in one quick glance.

Kidnkorner

I don't understand how the plugs and or pins could have moved on their own, I don't tinker with the vehicle.

I don't have a circle of Honda friends and the ones I was friends with all drive 8th gen civics. I'll ask on the local Honda board if there is someone who can loan me a ECU or an S300 to see.

The issue is the same whether hot or cold. Ive looked at the wiring to everything and it's all secure nothings has moved.

I hooked the MAP sensor up to a different vacuum source and nothing changed.

Kidnkorner

Have a local forum member coming thru with a P28 on chrome with datalogging capability, going to see what's going on. Need my car to deliver my tire sales!

asifbychance

I too have similar issues. I replaced o2 w/ denso unit. I added some ground wires here and there. I also cleaned electrical connectors w/ QD electronic cleaner seems to have gone away. cleaned, iacv, trottle body, tps. lmk what you come up with

Kidnkorner

I am just trying to avoid spending any cash on this drive train as I am going K series this fall.

Kidnkorner

Got someone to hook up a ECU with S300, it isn't anything sensor related. Datalogging showed that it's an ignition problem, spark drop off the chart when the accelerator is @ WOT below 3000 rpms.

Ole chap recommended I hook up with some one who had a working distributor, replace the distributor or trouble shoot the ICM.

Stay tuned

Former User

Regarding code 3, with the key in ON(II), does the original ECU send 5 reference volts to the MAP sensor?

Kidnkorner

Yes, trouble shooted with a multi meter.

Going to replace the ICM with a used unit and see what's up

By the way, pulled all the plug wires and cranked the car with a loose plug in each wire and there is no spark.

Former User

There's no connection between code 3 and the igniter unit.

I think you should focus on code 3. The ECU sends 5V on two separate wires to the MAP sensor. Do both have proper voltage? Have you carefully checked all three MAP sensor wires with a multimeter?

Kidnkorner

WOW, how stupid can someone be? Spark plug gap was bigger than the grand canyon.

With all the CEL codes and the problem coming out of the blue I totally dismissed this.

It didn't help that I relied on the owner telling me he replaced the plugs wires and bought a new distributor. The plug were obviously old too.

The issue is gone, engine runs like before.