sOLLEx

Engine: stock 97 b20b, b18b1 wiring harness/ecu/intake manifold/injectors

Car: 93 del Sol S

The car is throwing 2 CEL's
3 - map sensor
41- o2 sensor

It seems to run fine when you rev it up in neutral but as soon as i back it out and just try and pull forward, it starts to stutter and misfire.

It actually ran a few days ago, it just had a high idle at 1100. The only thing we did was unplug the o2 sensor and replace the one from the d15 and it lost the CEL. Then we decided to plug up not just the b18b1 map sensor but the d15 map sensor as well. We lost the CEL but of course it just ran like ****. It was trying to idle at like 500 but it would not rev up without popping and missing.

Any ideas?

EE_Chris

Do you currently have both MAP sensors hooked up? You should only be using one of them.

Is your O2 still unhooked? Obviously this will cause a Code 41....plug it back in. I'm unsure if its still unhooked because you say "replace the one from the d15 and it lost the CEL".

sOLLEx

No, I unplugged the d15 map sensor and i changed the o2 sensor back to the b20 one because that was what i was using when the motor actually ran ok. I need to get a voltmeter and check the voltage on the b18 map sensor. It just is weird that it ran pretty good the other day, then when we started trying to get the CELs to go away, and started moving the distributor around it just won't keep form misfiring under load.

CHEETAH

iTrader: (2)

on th del sol, you need to use the mapsensor wire on the firewall not on the ls engine harness. connect any manifold vaccum to where the stock map sensor is mounted on the firewall. Don't bother about the stock map and harness plug ont he thr body that is not connected to the ecu.

greg

Blaze45

Once you get those things fixed, it should run like a champ, untill then....

Good luck

Blaze

VTECVillain

In order to get the misfiring fixed, you will definitely need to fix both CEL's, especially the MAP as it is most important. Code 41 is for the heater element of the O2, this could be from a faulty O2 or faulty connection/wiring. Check to make sure it's plugged in properly.
For the MAP, you can use either the stock firewall mounted one or the throttle body mounted one on the LS. Just make sure to have the proper vacuum connections for which one you decide to use. If you use the stock MAP, you need to take the LS MAP off the throttle body and run the vacuum line to where it mounted on the throttle body.

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by VTECVillain &raquo;</TD></TR><TR><TD CLASS="quote">Code 41 is for the heater element of the O2, this could be from a faulty O2 or faulty connection/wiring. Check to make sure it's plugged in properly.</TD></TR></TABLE>

It is also possible that if the heater wiring was shorted, it could have fried something in the ECU.

If you've got a multi-meter, you can check the resistance of the heater section: Disconnect the O2 from the main engine harness and measure across the two black leads - should be ~17-40ohms.

sOLLEx

I used a multimeter tonight and measured the map sensor plug on the wiring harness. It measured absolutely dick, 0.00. I looked in the helms manual and it said to try using a test harness to check and see if the ECU has a short. Has anyone used a test harness before? I'm sure they are expensive as hell.

Basically, where do i go from here, now that i know the map sensor plug is shorted of fucked?

EE_Chris

What exactly was it that you were trying to measure; the MAP output voltage? If you turn the key to 'on', the ECU will power up, feeding voltage to the MAP sensor. At this point, measure the output voltage - should be ~2.85v (engine still not running).

sOLLEx

I measured both the map sensor and it's plug on the wiring harness and both were 0.00. I'm gonna try switching in my friend's gsr ecu to see if it can supply power to the map sensor.
I'm still confused on which map sensor i should be using. If i use the stock d15 one, where do i shove the vacuum hose? I would rather keep the b18b one and get rid of the stock one? What are you guys doing with these map sensors from b18 and b20 swaps

VTECVillain

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sOLLEx &raquo;</TD></TR><TR><TD CLASS="quote">I'm still confused on which map sensor i should be using. If i use the stock d15 one, where do i shove the vacuum hose? I would rather keep the b18b one and get rid of the stock one? What are you guys doing with these map sensors from b18 and b20 swaps</TD></TR></TABLE>

I already answered this a few posts up. I'm using the throttle body MAP on the B18B1 in my 91 CRX.

sOLLEx

are you using the crx half from the ecu to the actual map sensor? I am still using my d15 wiring from the ecu to the firewall and this guy on another board told me to try swapping the map plug from my old d15 map sensor to the b18b one on my throttle body. It got rid of the CEL but the engine runs worse, vilolently shaking back and forth and after about a minute will barely idle at all. I am missing something concerning the wiring between the b18b ECU, the d15 wiring half from the computer to the firewall and the b18b wiring harness. WTF is it?

VTECVillain

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sOLLEx &raquo;</TD></TR><TR><TD CLASS="quote">are you using the crx half from the ecu to the actual map sensor?</TD></TR></TABLE>

I am using the factory MAP plug and wiring from the CRX and have it plugged into the B18B1 MAP sensor on the throttle body.

sOLLEx

Villain, I understand you are using the crx ecu to firewall wiring but are you also using your crx engine harness or a b18b one?
thx
sOLLEx

VTECVillain

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sOLLEx &raquo;</TD></TR><TR><TD CLASS="quote">Villain, I understand you are using the crx ecu to firewall wiring but are you also using your crx engine harness or a b18b one?</TD></TR></TABLE>

There's a difference between my setup and yours, but yes I'm using my stock engine harness because you can't use OBD1/OBD2 harness in an 88-91. In your case, if you are using the stock harness then of course you will need to use the stock MAP plug, this would also apply if you are using the LS engine harness. The reason for this is that the stock MAP wiring goes directly from the MAP plug to the ECU.
If you plug in the LS harness MAP plug then the MAP won't get a signal because the wiring is going to the stock MAP plug. The only way you can make the LS MAP plug work is if you unpin the stock MAP plug wires and repin them into their proper locations on the shock tower harness plugs. That way the wires will match up with the LS engine harness plugs and send the signal to the MAP.

Maintenance

sOLLEx, did you figure out what the problem was? almost the same problem i had when i dropped in a obd 1 b18b into my cousin's 97 civic hx. found out my wirings were loose. but if its throwing a map sensor switch it out with another. hth

ditch diver

If your not suposed to use both map sensors witch one should be pluged in.