Dominik

I just finished my B16A swap into my 89' Si.
The car bogs like crazy under load. If I take it extremely easy, I can get it going. When it bogs, the CEL keeps flashing. I tried searching but nowhere explains how to use a paper clip to read the codes.
I'm using a PR3 ECU. Everything is ODB0.
Although it only bogs when it's really warm, if its cold, it doesn't bog.
I'm thinking it's coolant temp sensor related.
Also, I haven't hooked up the VTEC yet, would this cause this?
Any ideas would be MUCH appreciated. If someone could even swing by and lend a hand, I'd greatly appreciate it.
Thanks,
-Dom

zeeman

iTrader: (1)

where are you located?
Maybe you have the TPS and MAP sensor plugs switched up.
On obd0 ecus a light on the ecu itself should be flashing...u don't need to jump anything.

chris_si98

dominik, thanks for atleast pm'ing me back and telling me you don't want it

Dominik

Chris **** dude, pm coming your way.

HamiltonsIsuzu

Zeeman can help ya out, im smart. I want him to do mpfi swap for me.

Good guy.

CaptHowdy

update (I'm dom's bro)

we're flashing a 21/23 (knock/vtec) when I get home from work I'm gonna ground the knock / wire the vtec proper and go from there.

hopefully it' s just the lack of a knock sensor that's causing the car to go ape-sh...

but now that you've mentioned it I'll check to see if it's actually the tps/map mixed up... all those plugs look the same

CaptHowdy

ok the problem got from weird to absolutely ridiculous.

I grounded the knock sensor so I'm only flashing a 21 (vtec, which I still haven't hooked up)

the car still bogs HARD under any sort of load. while it's bogging the CEL flashes on/off and I can hear a relay firing off somewhere on the drivers side

now this is where it gets ridiculous; the car runs perfectly fine in reverse, I can take it slow, WOT, everything, runs great across the entire rpm range.

forward however bogs like a **** :/

anyone have any idea? the only wire cutting I did was extending the O2 sensor and one of the coolant sensors (the one in the housing).

plugging / unplugging the coolant sensor didnt' change anything so I'm at my wits end...

any experience something similar or have any ideas what's going on?

thanks.

zeeman

iTrader: (1)

well the knock sensor doesn't need to be grounded....seeing as there is only 1 pin on the knock sensor i don't know how you grounded it. Its on the back of the block right where the head mates to the block.


U must be thinking of the vtec oil pressure sensor, it has 2 wires (grey plug in the picture) one goes to the ecu and the other is just grounded. Then the vtec solenoid has 1 wire that goes to the ecu (blue connector in the picture)

zeeman

iTrader: (1)

seems to me like you might have some wiring issues.
Make sure:
vtec solenoid (blue plug) goes to pin A8.
vtec oil pressure switch (grey plug) goes to pin B5
knock sensor goes to pin B19

imported_kIeRaN

nice finger Zee!

zeeman

iTrader: (1)

haha...i totally stole that picture from some else that posted it on here...actually i think it was you.

Prelude Dude

If you extended your coolant temperature sensor maybe the conections are not good enough, I am not saying that they are not but who knows. It would all make sense since the stumbling happens when hot. The coolant temp sensor is a thermistor, it acts like a temperature dependant variable resistor. The resistance of the thermistor decreases when temperature of the coolant increases. So unplugging it won't do anything because the ecu is expecting a certain resistance across the terminals. It will actaully cause code 6. The resistance at normal operating temperature across terminals should be 200-400 ohms. Chek if there is 200-400 ohms at the sensor terminals with the engine at normal operating temp. Check if you are getting 5 volts at red/white and green/white wires. Trace the wires back to the ecu. Check your spark plugs, what color are they ?? The reason why I am writing all this is if your coolant temperature sensor reading is wrong and the engine is all warmed up, the ecu is still running the engine in the 'cold mode' and that would cause stumbling. Don't worry about the other codes, as soon as you connect the vts and ks back to the ecu they should dissapear.

CaptHowdy

zeeman,

I grounded the KS from the ecu and it stopped throwing 23.

the vtec I haven't touched yet (bot the soleniod/pressure sensor)

as for the coolant sensor (the one in the thermo housing) I unplugged it and wasn't getting any errors.

it's gotta be electrical but this reverse business makes absolutely no sense, I mean, the car has no idea if it's in reverse or not? (it's 5spd). the reverse lights work so that sensor is hooked up right (it was a unique plug from what I remember)

I don't know, ti's a nice day today, I just wok eup so I'm gonna spend a few hours on it.

thanks for the input guys, hopefully something will come of it today.

imported_truluder

i duno if any one has said it i didnt read everybodys msgs. but u sure the car doesnt have a miss fire. and if its that bad i would flash the CEL.

Dominik

Well we made huge progress.
We decided to take out the entire harness and trace everything with a volt meter, we found a couple sketchy wires and fixed them up. Upon installing it when hooking up the reverse sensor we noticed the wires were touching. We didn't plug it back in and the car runs nice and smooth now, NO bog no bull****.
Thanks for the help and suggestions.