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[snm95ls]

I am cheap, and I was bored so I decided to build my own conversion harness.  I am pretty sure that I have the connections correct, but the car disagrees.

It will prime the fuel pump and start up just fine when I adjust the map for the Y7 fail injectors.  About 10 seconds or so later, whether I start the car or not, the ECU will go into limp ode and kill the car.  I assume this is because of the shear lack of fuel with the Y7 fail injectors.  The biggest issue is that I cannot pull any codes from the ECU when I ground D4.

I decided to try to bypass the 3 wire fail IACV by just temporarily tapping into the conversion harness and plugging a spare one in.  That didn't seem to cure my issues.

I hooked the ECU up to a datalogging cable and checked to see that IAT, ECT, TPS, and MAP values were doing what they should, and all seemed to be good.  I had to add TONS of fuel to get it to stay running at all while in limp mode with the CEL on.

All equipment used is in know working condition except for my DIY fail conversion harness, and I can plug the stock P2E back in and drive the car around with no issues..

What all will revert the ECU back to limp mode?

Is there some little trick that I overlooked when building the harness that isn't obvious when you compare the schematics for the two cars?

I hate D16Y7s.

 

[chris]

arent conversion harness like 40 bucks shipped now

[snm95ls]

arent conversion harness like 40 bucks shipped now

For the pile of fuck ones off eBay, yes.

I have like 3 dollars into this one.

[chris]

I can do them for 99 cents

[clwtwizted]

Can we see a pic of fail harness?

[snm95ls]

Can we see a pic of fail harness?

Sure.  Give me a few minutes to find the camera and host the pics.  lol.

[snm95ls]

Full resolution pics below:

[Joseph Davis]

What pinout did you follow?

Are you sure your ECU is good?  Also, adding fuel/etc into your maps while in limp mode doesn't do anything, limp mode on those ECUs is a triple redundant hardware setup - basically the ROM isn't used.

[snm95ls]

What pinout did you follow?

Are you sure your ECU is good?  Also, adding fuel/etc into your maps while in limp mode doesn't do anything, limp mode on those ECUs is a triple redundant hardware setup - basically the ROM isn't used.

I made a spreadsheet off of the pinouts on ffstech.net.  Then I checked it over via Alldata.  Some of the wire colors for the OBD1 plugs were wrong, but pin assignments seemed to be correct.  The OBD1 plugs came form a 94-95 Integra LS with a 5 speed.  I pulled out all of the pins that I knew were unnecessary on the OBD2A plug.  There are a few still sticking out for VTAK in case I get ambitious and modify the Y7 engine harness.

That is what I thought about limp mode, so there must have been something else going on when I did that.

With a P30 base in Crome rescaled to 180 cc/minute injectors, it starts up and idles just fine until the CEL comes on.

EDIT:  Yes I am sure the ECU is good.  I have been using it for the past 4 or so years.  I'll put it back in mhy CRX to double check though.

[Joseph Davis]

Go to pgmfi.org forums and search for "icecream thread" by RPT.  He and I authored the first openly published OBD2A/B to OBD1 conversion harness pinout, it is the one I use to this day if I have to troubleshoot one.

[snm95ls]

Go to pgmfi.org forums and search for "icecream thread" by RPT.  He and I authored the first openly published OBD2A/B to OBD1 conversion harness pinout, it is the one I use to this day if I have to troubleshoot one.

Thank you sir.  Will do.

[snm95ls]

Go to pgmfi.org forums and search for "icecream thread" by RPT.  He and I authored the first openly published OBD2A/B to OBD1 conversion harness pinout, it is the one I use to this day if I have to troubleshoot one.

Thank you sir.  Will do.

Found the chart in the second post in that thread.  Looks like I switched IGP1 and IGP2, but I don't see how that would matter much.  I will double check pins tomorrow.

[Joseph Davis]

Yeah, double check the pinout.  Also examine the pins going into the ECU, etc.

[bigwig]

http://wikitest.pgmfi.org/twiki/bin/view.pl/Library/WireHarness

I figured I'd post it if you haven't seen it already.

Have you confirmed continuity between the pins?

[d112crzy]

lol thats the first thing I would have checked.

[snm95ls]

Yeah, double check the pinout.  Also examine the pins going into the ECU, etc.

Will do when time allows.

http://wikitest.pgmfi.org/twiki/bin/view.pl/Library/WireHarness

I figured I'd post it if you haven't seen it already.

Didn't even think to check the Wiki.  I did not see that particular page, but it tells me nothing new really.

Have you confirmed continuity between the pins?

No I have not.  I really don't see there being an issue as every connection was soldered by hand, And I did a visual check after soldering each pin.  Anything is possible though since I am a blind bastard.  lol

lol thats the first thing I would have checked.

I honestly do not get onto PGMFI very often, so I really didn't even think about it.  I figured maybe I missed something that isn't obvious, and maybe there are others on here who have built one of these.

thanks for the input and feedback so far all.

[snm95ls]

It works.  It turns out that I had a bad image on the Ostrich.  I haven't ever run across that problem before.

I even have the 3 wire IACV working too.

[Joseph Davis]

It works.  It turns out that I had a bad image on the Ostrich.  I haven't ever run across that problem before.

I even have the 3 wire IACV working too.

How?   I'm pretty sure you just have it wired so that you don't pop IACV codes, you shouldn't be able to control the idle speed with one of those.

[snm95ls]

It works.  It turns out that I had a bad image on the Ostrich.  I haven't ever run across that problem before.

I even have the 3 wire IACV working too.

How?   I'm pretty sure you just have it wired so that you don't pop IACV codes, you shouldn't be able to control the idle speed with one of those.

You are probably right, but it seems to work.

D14 and D12(for future 2 wire IACV use) to D9 on the OBD1 connector and D13 to PG1.

I had to up the IACV duty cycle to +30% for it to idle above minimum air idle when fully warm.  Cold idle seems to work as well, but I will verify that one in the morning when I head out for work.

Having the stock ECU still mounted for backup FTW.  lol