Runnerfan

I unplugged my spliced plug(plug D on mine) from the ECU to reset my codes. Then I went to go for a test drive to see if any of my other work helped. I forgot to plug it back in before I started it, but it started fine and ran great except for a high idle(2200 RPM). I decided to go for the test drive like this and it ran perfect, the best it has since being swapped. So now I have a couple questions: Could there be any problems caused by driving it like this? And where should I start to look for the cause in the plug?http://images.ibsrv.net/ibsrv/res/sr...ies/rockin.gif

vital22re

iTrader: (2)

the computer runs in default if some of the sensors aren't sending an input. I believe plug d is for the guages and 4wd.

Runnerfan

My Plug D contains the following wires:

+B
BATT
BK(stop switch)
4wd
STA(pwr from Starter Relay)
Check Engine Light
SP1 (Speedometer)
SDL(OBD II) (Which Doesn't Work)
ACT(AC AMP)
AC1(AC AMP)

So how does the computer even work at all with no power wires plugged in?
How does the igniter even know when to fire without signal from the ECU?

RobD

I believe my D plug carries those same wires. I'd go unplug it and see if it runs, but with my luck, I'd set the truck and house on fire.

vital22re

iTrader: (2)

if thats the case.. i'd say you fubar'd your wiring! jk.. maybe the power back feeds somewhere... not sure..

yodathespian87

According to my 2001 Tacoma 4x4 manual EWD the Connector D (E8) goes to the igniter, camshaft position sensor, data link connector 1 and injectors, so I find it hard to have it run at all due to the fact its not sending a signal to the ignition control module on when to fire or the ignitors. ???

Runnerfan

I think that the plug labels and wires they contain changed over the years. My plug D has all the body splices in it. But like you said how does it run? Even though all my sensors are plugged in still, there is no power going in. How does it know what to set timing at, or when to have injectors open? My only thought is that the power going through the sensors somehow powers it enough.

I would really like to know if it is bad to drive it like this. I am worried maybe it will run to lean and hurt something. Any thoughts?

yodathespian87

I don't think there would be any damage. The high rev. So you burn more gas. But I would try to get that rev down but if everything else is good. Are you throwing any codes?

Runnerfan

When I have the D plug plugged in the engine light is on, but I have tried two different scanners and they both come up with a error saying they can't communicate. I almost think that my ECU is haywire, but I don't want to get a new one on a thought.

If you look at the wires my D plug contains(above) there is not much to screw up. And I have checked a rechecked my wiring about 20 times.

yodathespian87

The wires that you have above-
+B
BATT
BK(stop switch)
4wd
STA(pwr from Starter Relay)
Check Engine Light
SP1 (Speedometer)
SDL(OBD II) (Which Doesn't Work)
ACT(AC AMP)
AC1(AC AMP)

Are all in my E5 (A) plug. Those are some pretty striaght forward wires and I don't see how those could get mixed up. Hmm. I have to splice those ones at well and the only one I haven't done yet is hook up the battery wire to power. It just shouldn't work and thats the confusing part.

Runnerfan

So I finaly found my problem. Because I swaped my a/t for the m/t I had the start switches by passed with a constant hot. Which then went to my ECU, so my ECU thought that I was constantly trying to start the truck.

Runnerfan

Now if I can just get my OBD II to work! And hook up my 4wd, then I will be set.

vital22re

iTrader: (2)

you need power to the ob2 port.. thats why you cant communicate.

hamish_18

What do you mean by having them switched to a constant hot? What wires are you talking about.

Thanks,

Runnerfan

When you turn the key to start the motor there is a wire that goes through your trannsmission(auto) or your clutch petal(manual) with 12 v. But there is only 12v when the key is in the start position. So I had mine by-passed wich alowed me to start it, but the ECM thought that I constantly had the key turned to start, which I would guess changes timing etc. (not normal operating settings)

tirogers

I know, its a yr old thread, but I am experiencing the same problem and do not fully understand his answer about the fix. Does it make sense to any one else? If you does It would be awesome an chime in! I can start my swap w/ out the Plug D plugged in. I have a 87 auto engine, repined for a 98 5speed ECU. I've driven it about 80miles and seems to runs great.....but now I'm confused!

Runnerfan

My problem was: because I went from auto to manual trany I had to get a start signal to the STA wire in plug D. What I did wrong was run a wire to STA from the ignition switch that was hot in the run position. What I guess is that when the ECM sees a 12v signal from the STA wire it changes settings for a easier start. For some reason they will run with out the ECM powered, at least mine still does. I'm still not sure if it is a problem or normal for it to run without it.