Strange TPS voltage issue, car barely starts/runs

jadkar · Post by **jadkar** » Sat Dec 24, 2005 2:37 pm

For the past 3 weeks I've been having a major issue trying to get my B18C-r 1990 CRX Si engine started. Some basic info, the engine has TODA Spec C cams, RC 370cc injectors, S200, there's obviously more stuff but this is the basics. My first issue was my S200 didn't have any fuel map on the ROM chip so it was blinking and couldn't communicate with my P28. The car obviously wouldn't start because the "limp mode" couldn't handle the 370cc injectors. That problem has been fixed and currently the ROM has a standard base map for my setup, but it still doesn't start. Correction, it starts, barely runs and then stalls with any sort of throttle input. It seems to be incredibly rich, the plugs are fouled bad and the intake manifold stinks of fuel. I have spent about 3 weeks going over everything imaginable, out of desperation I even thought I had bent valves so I pulled the head. The swap consists of a HASPORT re-wired harness & a LoCash ECU adapter. I finally started checking the wiring thinking HASPORT or LoCash screwed something up.

This is where it's a little strange. On the Datalogger I'm getting 1.5 volts (26%) throttle all the time!! The sensor isn't responsive. I can even unplug it all together and it's still 1.5 volts (26%). Now if I check it at the sensor itself I have it set to .45 volts and it responds to throttle, meaning when I open the throttle I get an increase in voltage. So I said fine, someone screwed up the pinning of the harness. So I decided to start tracing it back to the ECU. When I did this however, I got an accurate reading at the stock OBD0 connector, and at the LoCash ECU adapter. So the harness and the ECU adapter are pinned correctly. For good measure I opened up my P28 and I measured the voltage right at the connector inside the P28, that voltage is accurate there as well, .45 volts and it responds to opening the throttle. So why is it possible that I have a correct reading all the way inside the P28 at the connector, but the Datalogging software shows 1.5 volts (26%) throttle all the time, even when the sensor is unplugged?? I'm thinking this could definitely be why the engine isn't starting and when it is it's running way to rich. The ECU thinks I'm 26% open and is adjusting the mixture accordingly. Do you think the ECU has a short somewhere??

If anyone has any suggestions, please let me know.

Thanks,
John

jdmspecdc5 · Post by **jdmspecdc5** » Sun Dec 25, 2005 12:29 am

from my experience, it shows 26% when the car is in the on position. once the car is started it should read 0%.

Post by **Spunkster** » Tue Dec 27, 2005 10:34 am

Have you tried startign the car with a different ecu, or try cutting J1 on the ecu and run it as a stock ecu.. IT should still start. 370 is not that much bigger.

jadkar · Post by **jadkar** » Tue Dec 27, 2005 12:23 pm

I haven't tried starting the car with a stock ECU, I don't have one. Please elaborate on "cutting J1". If this allows the ECU to function as a stock P28 I will be thrilled because I still have my old injectors. I made some temporary connector jumpers to hook them back up. If you can explain how to run the P28 without the S200 I will hook up my injectors and try that tonight.

Right now I'm stumped. I had a friend of mine drive up from Philly on X-Mas eve to try and help me get this thing going. He also has a Rex with a B18Cr and we tried swapping distributors, checking timing, changing plugs all with no luck. It's really strange the car is throwing no codes and everything looks great. It should fire right up, but instead it starts after multiple cranks, runs like dog and then dies out. It stinks like way too much fuel and the plugs are very fouled. I even check my FPR for a torn diaphragm but that wasn't the case.

Any help or suggestions you can offer would be much appreciated.

-John

Post by **Spunkster** » Tue Dec 27, 2005 12:38 pm

Cutting J1 will return the ECU to stock form

jadkar · Post by **jadkar** » Tue Dec 27, 2005 12:52 pm

Spunkster wrote:Cutting J1 will return the ECU to stock form

OK I gathered that, but when you say "cut" do you mean cut a wire, desolder a connection, pull a jumper? I'm not familiar with J1 or it's location and I don't have a schematic of a P28. Is J1 printed on the board?

Please elaborate

Thanks:)

jadkar · Post by **jadkar** » Tue Dec 27, 2005 6:42 pm

So I looked in the S200 installation documentation and I saw where J1 was. I desoldered the jumper that was in place and I reconnected my OBDII stock Type R injectors. Cranked it and still the same thing. She starts but barely idles. If I crack the throttle it stalls, the car stinks of fuel and the plugs are severely fouled. I'm trying to get a hold of a P28 that I can toss in the car now just to rule out the ECU all together. This is what I can gather from today's troubleshooting.

One of 3 things (or combination)

1) My P28 ECU is bad

2) Either my HASPORT harness or LoCash ECU adapter is wired incorrectly.

3) Something in the distributor is dead

What's killing me though is I have no ECU codes other than #22 VTEC pressure (obviously that's not gonna keep the car from starting)

As for the mechanicals, the valve timing has been rechecked about a dozen times, I even took the head back off completely last week. The car is getting 180psi of compression across the board. I ran a leak down test and had 2-3% leakage on all 4 cylinders. I swapped in my friend's distributor (we're 95% sure about it's health) I checked the exhaust for blockage. I checked my FPR for a broken diaphragm. I changed the plugs 3 times, my wires are installed correctly, and I have spark on all four cylinders. My ignition timing is spot on. I reinstalled my OBDII injectors, and took the S200 out of the picture.

If anyone has any suggestions please let me know.

Thanks,
John

jadkar · Post by **jadkar** » Fri Dec 30, 2005 6:51 am

I don't like to let threads die without posting my resolution so here ya go. I finally got it started last night this was the issue......

Text taken directly out of my post on SuperHonda.com.....

OK this can get way friggn' confusing really quickly so I'm going to try and recap what I found last night in as little words as possible.

My CKP & CYP sensors appear to be backwards; I went down to the garage again this morning after reading Sonics post to double check. According to the 1990 CRX Si service manual this is how the car is wired from the factory...

CKP - Orange
CKP(g) - White

TDC - Org/Blu
TDC(g) - Wht/Blu

CYP - Blu/Grn
CYP(g) - Blu/Ylw

----------------------------------------------

Now with that said, presently in my car HASPORT has the harness wired as the following.....

CKP - Blu/Grn
CKP(g) - Blu/Ylw

TDC - Org/Blu
TDC(g) - Wht/Blu

CYP - Orange
CYP(g) - White

----------------------------------------------

If I test for continuity down at the ECU, actually inside the ECU at the connector to the PC board (so we know there's nothing else) I get the following.....

CKP has continuity on B11 (which is CYP)

TDC has continuity on B13 (which is TDC)

CYP has continuity on B15 (which is CKP)

To clarify the way I run this test. I unplug the distributor and with the battery disconnected I ground out the CKP, TDC, and CYP pins on the "chassis side" of the distributor connector. I check each one inside the ECU for continuity. Basically it's a simple way to check which wire leads where.

-------------------------------------

So there you have it....a summary of what I have found. If anyone had anything to add PLEASE do so. Also, with these 2 sensors backwards do you think I would exhibit the problems I have? I think yes, but I want someone else?s opinion.