B18 Swap issue - really weird

4G4D Store · #1 06-07-2008, 07:27 PM

Guys - I got my b18 in and everything is running great except for one weird issue. Everything starts up great, but after driving for 10-15 minutes my throttle is practically non responsive. All of the sudden the car either loses spark or fuel and slows down like I just took my foot off the gas but I can hold it at about 80% throttle and nothing. If I floor it everything will kick in and haul ass, but as soon as I let off the gas to 80% it turns off again. If I let off the gas all the way and slowly go back into the throttle it'll get may 30% and then start cutting out. The motor does not sputter or anything - think of it like you just turned the key off - no miss fires, nothing. If I play with the throttle for a while sometimes the ecu will compensate I guess and start working fine again, sometimes it doesn't. I have swapped out the TPS sensor with my old d16a6 one and swapped out the distributor - no change with either one of those. I am not getting any CEL's. I did get one once after I let it bog for a while it through a 43 (I'm running obd1 PR4 ecu). I believe 43 is fuel system but I only got it once. Also, just so you know when I floor it, it kicks in instantly. I was first suspecting fuel pressure, but the way it kicks in just seems to quick. I have found out that if I unplug the TPS sensor and throw a CEL it never does it. Any ideas would be greatly appreciated, this is very annoying.

FrodoGT · #2 06-07-2008, 10:00 PM

Its most likely the tps. sounds dead on. Check your wires! just cause its a new sensor doesnt mean you didnt break a wire. I put a huge hks mushroom filter on my new y8 and the bastard broke one of my tps wires..did this same thing practically. Only threw the code every now and then. And would also kick the car into hardl imp mode with like 3k rev limiter and no power. Then would just reset (freaking cel literally blinked off then came back on) and would go back to before...and repeat.

4G4D Store · #3 06-08-2008, 12:53 AM

I metered the TPS at the ecu and it's metering fine - etc idle is .45 volts. I've never gotten a code for the tps - only that one for the fuel system, but that was after I let it bog for like a minute. I find it kinda weird that both TPS are doing the exact same thing. I talked with a friend and he is thinking either map sensor or o2 sensor. I'm going to swap the map sensor and try that first. Any other ideas??

FrodoGT · #4 06-08-2008, 01:43 AM

Yes, it may read right at idle. But have someone slowly crack the throttle open and make sure that there are no jumps or spikes or dead spots in the tps. it may read idle and full throttle ok but freaks out and reads other voltages elsewhere.

4G4D Store · #5 06-10-2008, 04:09 PM

Does anybody know the pinouts for the tps and what voltages it should be at wot??

FrodoGT · #6 06-10-2008, 05:34 PM

I began to write out the ways of troubleshooting it etc..but then I though it better to just post up the pages from the helms. Im pretty sure this is for the mpfi, as the manual barely makes any mention of dpfi in it. Either way it should work, the mpfi just has the outer wires switched on the plug which Im sure you know if you are the one who did the mpfi swap.

http://i48.photobucket.com/albums/f2.../flowchart.jpg

http://i48.photobucket.com/albums/f2...flowchart2.jpg

FrodoGT · #7 06-10-2008, 05:35 PM

Remember to also connect the plug and have someone slowly work the throttle back and forth, making sure that you have a smooth increase in voltage.

4G4D Store · #8 06-10-2008, 06:16 PM

Cool, I'll check it out. And actually, I am one of the lucky ones that got an EX with the full mpfi already on the car - woohoo. But I've done a few mpfi swaps. I let you know what I find out. Thanks for the pics.

Christ · #9 06-13-2008, 05:52 PM

just for kicks, check the ignitor, and the injectors while you're testing stuff... either of those could be working intermittently.

Christ · #10 06-13-2008, 05:53 PM

and change your fuel filter, just for gits and shiggles.

4G4D Store · #11 06-13-2008, 07:47 PM

Well, I've been running the car for a week with the tps unplugged cause I haven't had time to sit and test it (I've had two other cars in my garage getting work done on them). But I haven't had a single glitch with it unplugged. I'm starting to think it's the tps wiring - got a bad/broken wire somewhere. We'll see if I have time this weekend to fiddle with it. thanks for all the suggestions.

4G4D Store · #12 09-03-2008, 03:38 AM

well, i thought i'd give you guys an update. i solved the problem. i cam across a o2 that a friend swapped out and it didnt fix his issue, but it fixed mine. so far no issues and my air to fuel gauge is working again. thanks for the help.

FrodoGT · #13 09-03-2008, 05:55 PM

Awesome. Very odd and unlikely solution, but if it works it works :P

Christ · #14 09-03-2008, 06:25 PM

Hrm... okie.. whatever fixes it for you lol.

pbrizzle86 · #15 09-09-2008, 08:12 PM

i had an issue similar to this and turned out to be a broken wire for the o2, it would stumble all over itself at low rpm but if i gave it the beans it would go like normal, seems that honda 02 sensors really dont do much over 4500 ish, also seems i am a bit late in posting this but i did it anyway so there.

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