Running Rich

[ChrisSiR]

not throwing any 02 codes or anythig of the sort... but the car seems to run way to rich.... sometimes after leaving from a light or stop at 1/4 throttle it boggs down really bad, until i open it up all the way then runs fine... and when i shift from 1st to second, the car likes to pop/backfire

so i guess my question is, could my coolant temp sensor not be sending the right voltage to the ecu telling the puter that the vehicle is warm and to lean out? or could it be something else?

i have a bit of experiance with Domestic Fi , and i know the car does this when cold.... but not sure if the JDM/Honda ecu runs the same way..... this car has been a wireing nightmare since i purchased it... upon purchase i found that 1 of the harnesses wasnt even hooked up to the ecu fully (kinda crooked with half the pins in) and that EVERY connection from the ecu and to the sensors was crimp capped together(still dont know today how the thing still ran)...theres a freaking mess behind the block that i have yet to sort out... any idea's?


Chris

 

[pills_PMD]

i'm thinkin O2 sensor.. mine was doing a similar thing.. and i checked and my ECU was not seeing a voltage from the O2

 

[ChrisSiR]

Originally posted by pills_PMD@Jul 9 2003, 10:14 PM
i'm thinkin O2 sensor.. mine was doing a similar thing.. and i checked and my ECU was not seeing a voltage from the O2

wouldnt it throw a code? it runs PERFECT first thing when i start it up when the motor is cold.... when it heats up is when it boggs down and backfires.... up here to much fuel is my enemy without the air to compensate... im not seeing the HP out of this motor that i should be....


its interesting, i did a fuel injection cleaning (no not just the in tank additive)about a month ago, we have this stuff where i work from heartland (pure power plus) and its induced through the vac line on the back of the intake (that leads to brake booster) it cleans from intake to cat .... anyways, after just a month, after the cleaner was induced you wouldnt believe all the carbon smoke this thing was throwing out, ive seen higher mileage vehicles throw out less smoke...



Chris

 

[steelbuster]

I'm not sure what motor you have ,but if it's a B16 from the JDM SiR I have an idea the problem might be the O2 sensors. Do you have 1 or 2 sensors? If 2 they have to be in the right place.They go in the primary tubes about 6" from the head NOT in the collector. Onegoes in the 1-3 cylinder pair and the other in the 2-4 pair. They also have to be connected up to the proper pins on the ECU. If reversed the computor is regulating the mixture for the two seperate cylinder pairs based on the wrong info. The result is to run very rich and idle poorly and then run perfectly at WFO when the system is in open loop.
More info if we are talking about the correct motor.

 

[steelbuster]

By the way ...no codes as the sensors are operating...just not in the right place

 

[ChrisSiR]

It is the b16a out of an automatic sir , It does infact have the 2 02 sensors.... and both are hooked up, now being hooked up to the right pins is a different story, like i said, this thing has been a wireing nightmare since i baught it..... the idle isnt all that bad... its pretty smooth... everyonce in a while it will drop RPMS(to 100 or so)at idle when warmed up and run a little rough but it usually goes back to normal within a few moments...

i'll have to take a look at the Ecu pinout diag. when i get a free day to look at it and see what i have goin on...



Chris

 

[posol]

it runs ok when it's cold due to the o2 sensor being "heated". all 4 and 5-wire o2's are heated which stimulate the o2 to get it to read correctly before its at optimum temp

 

[pills_PMD]

mine didn't throw a code at all but it was still bad...

 

[ChrisSiR]

02's arnt that expensive(1 wire), so maybe i'll pick another one up (i already have one) and clean up/finish the wireing behind the block while im doing my clutch and hopefully this will fix my problem.....

Thanks for everyones input


Chris

 

[blundar]

Are you running stock headers?

I read in your sig that you have a 88DX w/ B16A.

In all likelyhood, its a B16A1.

B16A1s are very picky about the placement of the O2 sensors when you run them with the stock PW0/PR3 ECUs. The ECU will actually lean out 2 cylinders at a time in closed loop and look for a difference between the two O2 sensors. Its a retarded design because it requires a replacement ECU program to run a 4-1 header...

I bring this up because in many swaps, you'll find that the second O2 sensor (C8) is just jumpered to the primary. This will cost you 2-4mpg on the highway, according to consensus among those who have done it.

Your problem sounds like it could be a bad FPR as much as a bad O2. You often don't notice FPR problems at idle because the pulse width of the injectors is so small, fuel pressure being wack can't affect things quite as much. If the car runs ok while moving until it warms up, you can ignore that.

If you are having problems under wide open throttle, you can eliminate your collant temp sensor because the ECU does not apply coolant temp correction past about 3/4 throttle. Problems under partial throttle may indicate a bad coolant temp, intake air temp sensor or throttle position sensor. Check your TPS voltage - 0.5v idling, 4.5v WOT. Sensors only throw a code when they stray OUTSIDE acceptable range. You could totally have a bad O2, TPS, ECT or IAT and not be throwing a code, although its unlikely.

Good luck.

 

[HardLowrdRanger]

It could be the temp sensor, or the o2 sensor(s), the TPS... man it could be a grip of sensors... Or, it could simply be your fuel pressure or FPR... When you first start up idle is higher so it would eat the fuel more efficiently and not show the hesitation you speak of so clearly... I'd say check everything just to be sure... and yes try checking the voltages from the sensors... good call blundar...

 

[ChrisSiR]

Originally posted by blundar@Jul 15 2003, 10:52 AM
Are you running stock headers?

I read in your sig that you have a 88DX w/ B16A.

In all likelyhood, its a B16A1.

B16A1s are very picky about the placement of the O2 sensors when you run them with the stock PW0/PR3 ECUs. The ECU will actually lean out 2 cylinders at a time in closed loop and look for a difference between the two O2 sensors. Its a retarded design because it requires a replacement ECU program to run a 4-1 header...

I bring this up because in many swaps, you'll find that the second O2 sensor (C8) is just jumpered to the primary. This will cost you 2-4mpg on the highway, according to consensus among those who have done it.

Your problem sounds like it could be a bad FPR as much as a bad O2. You often don't notice FPR problems at idle because the pulse width of the injectors is so small, fuel pressure being wack can't affect things quite as much. If the car runs ok while moving until it warms up, you can ignore that.

If you are having problems under wide open throttle, you can eliminate your collant temp sensor because the ECU does not apply coolant temp correction past about 3/4 throttle. Problems under partial throttle may indicate a bad coolant temp, intake air temp sensor or throttle position sensor. Check your TPS voltage - 0.5v idling, 4.5v WOT. Sensors only throw a code when they stray OUTSIDE acceptable range. You could totally have a bad O2, TPS, ECT or IAT and not be throwing a code, although its unlikely.

Good luck.

ok..... what should happen if i unhook the vac line from the FPR?...... the car runs no different when disconnected then when it is connected... any idea's? or am i just asking a dumb question



Chris

 

[pills_PMD]

when its pulled off the fuel pressure rises

 

[ChrisSiR]

Originally posted by pills_PMD@Jul 18 2003, 07:21 PM
when its pulled off the fuel pressure rises

should the car run any different? :unsure: maybe my problem is a bad FPR thats causing me to run rich....



Chris