oh-yeahcrx

Ok so I recently got a multipoint swap done. Used a 1991 si harness, (I have a 1989 DX) and I have a high idle (3k) and its running rich. I believe it has a high idle because i have a vacuum leak somewhere. I have a 1990 si that is my daily driver and Ive used that as a guide to tell me where all the vacuum lines go. The vacuum hose that runs from the throttle body to the bottom of the map sensor might be the cause of it. Because when I unplug that it seems that my idle returns to normal. So right where that line meets the map sensor I put a T joint there (its what the si has. with it blocked off it had a high idle. but left open...) it idled normal...then shot back up. So now that trick dosent work.
But ive read that the brake booster can cause a vacuum leak too. and I just recently changed the seal that goes between the booster and master cylinder. so could that play a part?
And I have not the slightest idea why its running rich. hah

Sorry it might be a little confusing. I just dont know what to do next.

oh-yeahcrx

Anyone have any ideas at all?

D16SiHatch

ok so let me get this straight. your car is a dx. you swapped over a mpfi intake manifold, then used the complete Si harness on your engine. If thats correct then i am to assume you still are using the stock dx interior cabin harness. If thats the case, what you did although sounds like it should work, unfortunately will not. the dx cabin harness that goes into the engine bay for the engine harness to connect to does not have the proper wires within it to support mpfi. you have to convert your stock dx harness to accept the new mpfi manifold, which includes running a few wires back into the cabin and splicing them into the ecu. you will also need to wire in an injector resistor box, you'll need an Si pm6 ecu, and an Si distributor.

http://hondaswap.com/swap-arti...49557/


Modified by D16SiHatch at 10:52 PM 11/8/2008

oh-yeahcrx

Right. Though I am not sure about the cabin harness, everything else is si. resistor box, dizzy, pm6 ecu, are all swaped over. I think it might have something to do with the cabin harness, because my gauges don't work as well. The lights work fine and the speedo too.(cause thats mechanical.) but the tach, temp, or gas gauges don't work. Maybe some kind of connection there?

D16SiHatch

possibly. although i believe the temp and gas gauge are independant of the ecu wiring. the tach though could be related though i imagine.

i can guarantee you though that if you still have the stock cabin harness you will never get it to work properly as is. your options at this point are to either take off the si harness and reinstall the dx harness, and then convert it to mpfi. or you can swap out your entire cabin harness for the Si harness. either way it's gonna be a pain in the *** lol

nikitad

I don't see how an SI engine harness could have plugged into a DX chassis harness without modification.

Driverside plug is different. On the passenger side, an SI harness has an extra 6-pin connector that can't be plugged into anything on the DX body harness.
??? ??? ???

What codes does it throw anyway?

oh-yeahcrx

Its not throwing any codes. But the check engine light is on aswell

D16SiHatch

having a cel on means its throwin codes lol.

oh-yeahcrx

Haha really? well ya learn something new everyday, but the ecu light isnt blinking at all.

-Trinitron-

Not to insult your intelligence, but are you checking for codes with the sevice plug shorted? If so, and you are getting no code, that is sometimes a sign that the ECU is not functioning properly. That may be your culprit.

oh-yeahcrx

I have never had anyone really teach me, ha so I try another ecu and see if it runs any better.

nikitad

EDIT: below i gave bullshit advice......................

just look up how to pull codes on your car.

service connector (yellow or blue) should be under your glovebox, closer to the right.

pull it out, take the cap off (it may be capped) and stick a paper clip in it so short both wires together. After that your check engine light will start blinking hte trouble codes.

But just look up in the manual for your car, in the troubleshooting section, how to do it.


Modified by nikitad at 2:49 AM 11/11/2008

oh-yeahcrx

Ahhh yes I know what your talking about. I thought the little red light in the ecu told you the code.

I will hopefully check that tomorrow.

nikitad

You know what. I gave you bad advice above.
OBD1 and OBD 2 cars do that.

In OBD0 cars, the little red light is there for a reason - you're so right - and it shouldn't require no shorting of a jumper. My bad, man, i forgot my roots, lol.

Is that little LED not blinking anything? Hmm... dunno what to tell. If it's solid red, then it's a bad ECU though.

oh-yeahcrx

Ok so it decided to throw a code. Code 5, which is the MAP sensor. So i found this lovely bit of information about code 5.

https://honda-tech.com/zerothread/2409044

So I replaced #21 hose, nothing. Switched out the MAP sensor with the one on my DD that I know works, nothing. So the only other option as it says is to replace the throttlebody...

nikitad

it can be much simplier - it can be wire going to the MAP sensor, having a break in it. Or MAP plug unplugged (althouhg in this case the car most likely wouldnt run at all.

When i get map/tps/iacv codes, first thing i do is check wiring going to them. most of the time the problem is there.

I still don't know how you used the SI harness on a DX car. Did you swap all the wires around? Did you have an extra plug on SI harness , not plugged anywhere?

oh-yeahcrx

Yes! I do! but my friend has the same plug that isnt plugged in aswell and his hatch runs fine.

oh-yeahcrx

How would I check if a wire is the issue? Make sure its plugged into the connector?

nikitad

man, i'm not sure what to tell you.

I still can't imagine how one can use an SI engine harness to MPFI a DX car, without reworking half the harness. And i've done plenty of the conversions.
So, dont even know where to start.

Your driverside shock tower plug, by the resistor box - how did you get it to plug in? DX one and SI one have different plugs.

oh-yeahcrx

Its plugged in. Everything wiring wise is si. but i guess when the people did the swap it wasnt starting. So they wired some wires that run from wires in the main relay plug to the fuel pump plug wires.

Would that have anything to do with anything?

nikitad

not sure about that.

other places where you may have a vacuum leak is the place where throttle body connects to intake manifold, bad gasket/no gasket....
intake manifold gasket - was the old one scraped off completely?

Also just for profilactics sake i'd take off your IACV and spray the two air openings in it with lots of brake cleaner to was out all the gunk and stuff from inside the valve.

nikitad

First o fcourse, make sure it's plugged in.
Then take a multimeter and shoot the 2 wires from the plug to the corresponding locations on the ecu, make sure there is continuity.

oh-yeahcrx

Yeah even if i ask the shop who did the swap of course they're gonna say they scrapped off the old intake gasket. So i might check that. And the tb/intake mani gasket is there cause i can see it. Does it need any kind of sealer? Cause it looks like a paper gasket.

Yeah ive cleaned the IACV and it didn't do much.

Alright hopefully sometime ill be able to test the wires. Do i just stick the multimeter in each of the plugs? Then how do i know what they are suppost to be at?

nikitad

no sealer on TB gasket.


you need to goodle up ways to check continuity. One could be using a test light, another - using ohmmeter.

You don't stick probes into the plug.
You need to trace each of the plugs wires and touch both ends of it - one at the ecu and the other one at the plug. If the circuit getscompleted by doing it, your test light will go off or your ohmmeter will beep or show zero resistance.

oh-yeahcrx

Ok so I taped up the IACV hole in the throttlebody, and that seemed to fix my high idle. But im not sure if that should be a permant fix....but we'll see. So now the only problem I have to fix now is the richness. When I rev it up a plume of black smokes come out of the tail pipe. Oh and its still throwing a MAP sensor code and the MAP sensor is good.