Hey folks.. I've got a b18c 1996 GSR swap in my 1992 hatch. I've got about 600 miles on the swap and even at easy running im getting about 18mph. I've got new plugs, wires, its the original intake manifold, about 99% sure i have the ODB1 p72 ecu. I believe that 600rpm is where idle should be at, but i really have trouble sitting at that low rpm. I've had hesitation at low rpm's when creeping 2000-2500 pretty much all gears. I've had the car stall at stop signs three times, when i push the clutch in and rpms drop when idle was set at 600/700 it would drop next to zero and bounce back up. i now have idle around 1000 and its just ok. I went as far as 1500 idle and the car ran like a dream shifting smooth and all but i know thats not right so i backed it down. I also blow gas smelling smoke at times so thats why i suspect that ive got too much gas flowing. If anyone can give me a little insight that'd be great, I've got an awesome motor it's got got this hiccup. Thanks

 

I can also smell a gas smell on the dipstick when I checked that today. But i've read several posts that alot of people have that smell.

 

Check you fuel injectors to make sure one isn't partially stuck open that would be a good start to a running rich issue. Might also try to find someone in your area with a GSR that would be willing to let you swap ecu's for 5 minutes and see if your car acts appropriately.

 

I just checked the injectors.. I held a screwdriver to each injector and listened to other end.. all seems to be a nice even ticking from each, doesnt seem off at all to me.. My mechanic is looking at getting a ECU to let me try.. should I consider that the MAP sensor is faulty too??

 

That is also a possibility, if the MAP sensor is reading poorly it could be selecting fuel values from parts of the map that its not in. That could make it rich in some areas and lean in others.

 

check engine light on??

intake air temp sensor is the only sensor that could have that great an affect on afr's. that or a bad ecu.

check the resistance of the iat sensor and compare it with honda's spec. (get a multimeter, get a shop manual off the internet)

 

I have no CEL on since we completed install... Will get with my mechanic and check these couple possibilities out

 

Really? How about the ECT. It has correction factors that vary much more greatly than IAT in fact in the stock honda rom there are more tables related to ECT fuel correction than there are any other sensor. MAP sensor as stated previously would also have a large effect on fuel as that is the primary fuel table reference. TPS has correction tables and factors. Hell a sluggish O2 can have a small effect on fuel trim as well. Or here's a wild idea a bad cylinder position sensor (one of the 3 in the dizzy) could cause the injector phase timing to be off and have the injectors firing at the wrong times which in effect give an in-efficient fueling characteristic that can make it "run rich". A failed PA sensor internally in the ECU can also cause this as its the reference to the MAP sensor for it to base atmospheric pressure off of. Point is there is a lot more going on to calculate fuel adjustment then just one sensor.

 

Any luck? I have a 93 gsr swap thats doing the same ****. Blue smoke after shifting no matter the shift point. when the engine gets hot it seems to be a bit worse so i was thinking either the IAT or the MAP or ECU. Tried the IAT and MAP. No luck yet so far and a new ECU is about 300 easy anymore. Would like to know it was going to work before i went and blew 300 dollars on it.

 

Havent yet got another ecu to try it, will definitely repost when i do tho..

 

you have, in the least, bad valve seals.

blue smoke = oil

blue smoke under heavy vacuum (closed throttle, above idle rpm) = oil coming from top end.

i could appreciate you trying to bring more angles into the thread, but your attack on my post is unsubstantiated.

when have you ever seen a bad ect? broken from abuse, maybe. but they don't go bad and you'll probably break a lot of other **** before a baseball bat could ever touch a ect.

tps? nearly irrelevant on speed/density.

sluggish o2? no, just no. did you really think that could be possible?

bad cylinder position sensor? lol wat? no. driveability issues? hell yeah, but in no way could it possibly run that significantly rich.

a failed or out of spec barometric pressure sensor or map sensor? no, because either getting too far from the other would make the computer trip *****. think vafc tuning.

 

Have you tested or tried to troubleshoot anything?

 

Alright Im going to break this up for you. First I have no real need to qualify myself to you. I know that there is a good chance that I have tuned more cars than you have owned but weather or not I have is relatively irrelevant.

So as for the ECT, did it occur to you that i never said it would have to be the sensor I merely mentioned that that circuit has many correction factors. I have seen bad ECT sensors btw, and I have also seen many cases of bad wiring especially with swaps (even more so on what people think is a clean tuck job)

While TPS is mostly irrelevant for speed/density mapping as you had mentioned (look at that we agree) I was more or less stating that it can and does affect fuel values, I never stated the severity of the effect though.

The sluggish o2 was similar in concept of stating as the TPS. It has correction factors and especially overtime will make the car run rich or lean. Again though only slightly but still it affects it.

A bad CYP actually is very common in swaps from poor conversion harnesses and also in aftermarket dizzy's. Typically it will set a code 9 but sometimes it does not. Either way the ca will actually tend to run relatively normal, but most of the time it will be a little richer as the phase timing is off.

The PA sensor has a very small effect on fueling as it is used to trim down the MAP reading however as stated above I was merely stating it as a factor that could affect fueling.

Now to the MAP sensor, this has everything to do with a speed/density tuned car. On a honda there are really no checks and balances for this sensor as far as its readings unless it goes way outside of normal range at a known target reading (2psi at 750rpm idle TPS closed for example). Most MAP errors don't occur at idle though even a bad MAP sensor will usually idle somewhere in the range where the signal sent is tolerable to the ECU. However when the throttle is depressed the change can be quite great and also undetected. Take for example your cruising along the road at 15in/hg but the sensor reads at 5in/hg the computer is not going to flag that because as you pointed out yourself it doesn't really put to much weight into what the TPS is saying so if TPS is at 30% and 5in/hg it thinks its fine when in reality its over fueling the engine with no CEL.

As a matter of fact our race car just had a MAP issue the other day as we were on our way home from IFO at throttle above 50% where it should have been reading 1 to 0 in/hg it would see over 30psi which is where I have boost cut on the car and would kill the injector pulse width, so it would go super rich then cut and stall the car. CEL never set though.

Next time don't be so quick to jump down someones neck when they try and educate, that's a good way to keep yourself in the dark.

Cheers.

 

I have done the following and still running rich, with stutter at low RPMs (slight)
Fuel Filter
Timing
TPS adj.
I replaced the JDM ecu (ODB1 P72) with an USDM ecu (same)... Instantly I noticed that the stuttering was "gone", but I still had a smell of fuel out of the exhaust I still haven't been through a full tank yet after all of these changes. I also put a can of Sea-foam for whatever that's worth. I also finally got a CEL with the new ecu, good!, well.. I ran the code and I got a 43.. O2 sensor, or fuel suppy system.. I replaced the O2 sensor and my old one was shitty bad, black and caked closest area near threads if that makes sense. I've never had to replace an O2 sensor on any other car so I don't know what they can look like. So yea, replaced all of these things and I've got 25 miles on it since the O2 sensor yesterday, but I still smell gas, and see some smoke. It's a rather new swap, no more than 1000 miles on it. Quality motor/trans, all new everything pretty much.. Am I looking at a sensor next? If you have anymore ideas about whats going on since my last post THANKS.
Beau

 

Any ideas on next step for me?

 

What mods had you done to your swap? I have a gsr swap in my eg as well and I have the idle set at 850-900 rpms. I have intake, intake manifold, header and full 60 mm exhaust. Fortunately I have a mint swap with 80k miles but I do tend to run rich. I usually only notice when idling. I am on a obd1 p 72 and always figured a tune would solve the rich issue but I have no black soot on my bumper.

 

Check fuel pressure and also take the return line off the regulator and put a hose on the reg and run it into a gas can, check for constant flow while idling and also at various RPM points. Basically checking for a bad regulator also check the return hose to see if its clogged, but fuel pressure would usually indicate that if it was elevated.

 

I only have intake, high flow cat, and exhaust as far as mods go. I also have no black soot on my bumper like you. I will check fuel pressure as soon as possible.

 

check spark. if you have fuel smell thats because its not getting burnt. Check timing.

 

I have to agree with surfingsk8r check the ECT sensor., yes they do go bad, maybe not as much as other sensors on the engine but never the less they do go bad or as mentioned, poor connections due to corrosion.

Number 1 symptom of a bad ECT sensor, **** poor fuel mileage, so it is definatly something I would want to check, even if just to eliminate it as the possible problem.

MonkeyMagic Really, an "attack" on your post???

I think surfingsk8r is spot on, didn't sound like an "attack" on your post, just a list of other possibilities that you completely dismissed with, "intake air temp sensor is the only sensor that could have that great an affect on afr's. that or a bad ecu".

As I said, even if it is not the problem, you would want to check it to eliminate it as the problem. 94

 

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Sorry to be a noob but are you telling me to check the proper voltage of this ECT?
Thanks!!

 

Take the connector off and check for 4.5-5.0 volts on one side and ground on the other with the ignition switch on and the car off. If you get both of those put the connector back on.

Then warm the car completely up until the fans come on twice. Then take the connector off and test for 180-400 ohms on the actual sensor across the two prongs. It should be closer to 180 than to 400 if the car is completely warmed up.

It's the two prong sensor underneath the distributor.