riofrio

I finally tested all the voltages in the ECU as per the Haynes manual. Everything checked ok, except for 2 of them:

- Terminal 'h' (vent solenoid valve). Should be < 1.5 V; was 11.00 V.

- Terminal 'e' (pressure regulator control valve). Should be <1.5 V; was 12.00 V.

so... should I replace these?


I also tried testing the ACV. I unhooked the air silencer hose at the ACV... the haynes manual says that you should only feel air blowing out of the ACV when rmps are between 1500 and 2500 or above, but mine was blowing air at 800 rpm. Will this be enough to suspect that the ACV needs replacing? I wasn't able to test the port by the split air hose.

Is the ACV in the SE supposed to pump air to the cats all the time, or just at high(er) rpms?

the overall problem: running rich, not passing emissions.

gsl-se addict

iTrader: (3)

So the engine was warm when the test was performed, right? Unfortunately, if the voltage is incorrect, you cannot just replace the device that it is connected to. The ECU is the one outputting the voltage. If it is incorrect, the ECU is the one that should be replaced. After all of the voltages are okay, then you need to check the individual solenoids, etc. to see that they are actually operating correctly.

For the voltage at terminal 'e': The ECU output 12v to this terminal during hot starts (during cranking and approximately 60 seconds after the engine has started. What this does is increase fuel pressure by directing the reference port of the fuel pressure to atmosphere instead of manifold pressure. This will increase the fuel pressure from 28 psi to 37 psi at idle. So if your ECU is putting out 12v to this terminal all of the time then you have the higher fuel pressure all of the time causing a rich condition (about 15% additional fuel). The easiest fix is to just unplug the orange solenoid plug. This will disable that solenoid. I have ran my car several times without the plug connected and I haven't had any problems during hot starts. Do you have a fuel pressure tester to verify pressure?

For the voltage at terminal 'h': Probably the cause of this one is a misadjusted TPS. When you do the adjustment with the two light setup, you are actually measuring the voltages at the vent and the vacuum solenoid pins on the ECU (one should be in the high state (12 v) and the other should be in the low state (less than 1.5v)). I would double check the TPS adjustment to verify. I don't think this one will affect the conditions that you have. If it is wrong you would likely get surging during idle as you do with a misadjusted TPS.

I am not sure about the ACV. I would try to complete the tests to see if the other aspects check out. This is probably the culprit in not passing emissions. If I remember correctly, you have a fairly new catalytic converter, right?

Anyway, I hope this helps. Feel free to pm me anytime if you have questions. I am sure we will get this figured out.

Kent

riofrio

Thanks for your reply... I think I'm getting closer to the problem.

Yes, the engine was warm and all, and I double checked the voltages. I'm gonna replace the ECU, then. In the meantime, I'll unhook the orange solenoid connector.

About the 'e' terminal. You're suggesting that this is related to the TPS, and I'm glad this came up, because my TPS adjustment has been quite peculiar, I'll explain you how: With the two light tester, I can see both lights off if TPS far enough out (screw counterclockwise); If I turn the screw clockwise, eventually one of the lights will turn on... BUT, from that point, no matter how much I keep turning the screw, I will never see both lights on. Even if I manually push the TPS rod all the way in, I will only see one light on. I think this is a bit misleading, and it sounds by your explanation that this might be somehow related to the ECU output voltage. So, would you think this is more reason to replace the ECU? I'd really like to hear your opinion on this one.

Yes, my catalytic converter is *fairly* new. It's a Bonez high flow, and it's been run hard and rich. Once I pass emissions I think I'm gonna strip the exhaust system.


Thanks a million,

rio

gsl-se addict

iTrader: (3)

It seems strange about the TPS. Did your test indicate ~12v on the 'n' terminal (vacuum control valve)? Because this would indicate that both of the TPS lights should be on in this case, so it doesn't make sense that you can't get both test lights to come on unless it is a ground problem, wiring problem, or one of your lights does not work. Try checking continuity between the mouth of the TPS conector and ground. This should be less than an ohm or so. The other two wires on the TPS connector connect to the two upper wires on the vent and vacuum solenoid connector (WB and WG wires). You could check for continuity between the TPS connector and the vent and vacuum connector (WB to WB and WG to WG). Again, this should be less than about an ohm or so. This should be done with the key off because these wires are powered from the ECU.

If you can get another ECU fairly cheap, I would try it. The combination of the TPS problem and the pressure regulator problem leads me to believe that there is something wrong with the ECU, but check continuity as mentioned and double check the voltages at terminal 'e' and 'n'.

You should also look at testing fuel pressure with both the orange connector on and with it off. You may be able to borrow one from someone. It needs to be for EFI of course. If you have a hard time finding one, I can ship you mine and then you could ship it back after you are done. I bought mine because I too was having a rich condition, but it turned out that my fuel pressure regulator was keeping pressure high (about 37 psi instead of 28 psi with no power to the orange connector and about 45 psi instead of 37 psi with power to that solenoid) during idle. I replaced the fuel pressure regulator and solved that problem.

Kent

riofrio

Kent,

I made a typo on my last response... I was refering to the 'h' terminal (vent solenoid valve), NOT the 'e'. So the 'h' terminal read ~12V, and I wanted to know if this is somewhat consistent with why the TPS result is so weird. The 'n' terminal actually read correctly. Both my lights work for sure, and I've even performed the test with a multimeter. Thanks for explaining where the signals to the TPS connector come from, I've always been curious about that. I will check for continuity (hopefully today) and let you know if it reads ok.


I'm not sure I know what you mean.... borrow *what* exactly?

Thanks again.

gsl-se addict

iTrader: (3)

Yes, I understand that you were refering to the 'h' terminal (vent solenoid). What I am saying is that you tested the 'h' terminal at about 12v instead of less than 1.5 volts and if the 'n' terminal tested okay (about 12v), this means that both test lights on your TPS tester should be on in this case unless there is a wiring problem or something. It should be like this:

terminal TPS tester condition
'n' 'h'
H H 'Both lights on'
H L 'One light on' **
L H 'One light on'
L L 'Both lights off'

H - means approximatly 12v
L - means less than 1.5v
**- This is the proper setting

What I was refering to *borrow* is a fuel pressure tester. I guess that I should have been more clear. You can borrow mine if you can't find one locally. This will tell you if your fuel pressure is too high like the case that I had. Hope this makes sense.

riofrio

Oh, oh.... I see what you mean now. I will check for all continuities tonight, and let you know if something's fishy. I guess the most obvious explanation would be that the signal from the vaccuum solenoid valve to the TPS tester might not be good (assuming that the one light that does come on corresponds to the 12V signal from the vent solenoid valve). But oh well, I'm on it!

After I swap the ECU I will let you know if I need that pressure tester. Thanks for the offer!

rio

riofrio

Ok, I checked for continuity and it all tested ok. Now I'm really baffled by this. I was thinking about what you said, that if the 'n' terminal tested at 12.0 V, then I should have been able to see both lights on. Maybe there's a wiring problem between the ECU and the solenoid valves. Does the signal go through the valves before going to the TPS tester? If so, could it be that the valve(s) need replacing?

gsl-se addict

iTrader: (3)

No, I am pretty sure that the wire harness goes from ECU to the TPS connector and then over to the solenoids. You could unplug the solenoids while doing the test to see if it changes anything or you could also unplug the solenoids and test the voltages there. It should be the same as at the TPS test connector. Did you check continuity between the solenoid connector and the TPS connector? Did you try unplugging the orange connector to see if that helps your rich condition at all?

If you get the same resluts at the solenoids and you have continuity between the TPS connector and the solenoids, then I would suspect the wiring between the ECU and the TPS. This assumes that teminal 'h' and 'n' are at 12v but you are only getting power to one wire at the TPS connector. Do you remember which side of the TPS connector lights up (WG or WB)? This will at least tell us know which terminal we are getting power from.

Good luck. Let me know how it goes.

Kent

riofrio

I checked continuity between the solenoid connector and the TPS connector and they were all good. I didn't do any signal testing, though. I'll do all that later this week (maybe tomorrow). How big of a pain in the *** would it be to re-wire the ECU terminal to the TPS tester?
I unhooked the orange connector and the car ran fine, but I can't tell if it's leaner or not... i guess I'll know for sure after a full tank of gas. I only drove it for about 20 miles.
This weekend I should get in the new(er) ECU, and I'll get a fuel filter, cap and rotor. I'll put those in and figure out this wiring problem, then I'll clean the plugs and run a can of one of those 'guarantee to pass emissions' things. I'll go take the test and and tweak things here and there based on the outcome (it's a $10 test, and if you fail you get a second one for free).
Thanks, I'll let you know what I find out this weekend.
rio

riofrio

Ok. This is the new deal...

After swapping ECUs, the TPS tester now works the way it should (for the first time ever I'm able to see 2 lights on if TPS is in too far). I'm a little confused as to why this solved the issue, but I'm not gonna hurt myself thinking about it.
Anyway, while on the TPS issue... between getting only one light, and two lights on, there was barely 3/4 of a turn of the screw. Is this normal, or should there be some more play?

I checked voltages at the orange connector (pressure regulator control valve) and it was still 12V... so I guess this wasn't an ECU screw up. I still have it disconnected for now... but I guess a pressure sensor might be faulty somewhere?

Finally, my idle is pretty good and steady, but it has always had a tendency to 'miss' (not sure if i'm using the right word). It's like real subtle sputtering, that makes the engine shake just a tiny bit, nothing scary or anything.

rio

gsl-se addict

iTrader: (3)

It sounds like you are making good progress. The amount of TPS adjustment that you mention sounds about right. I am not sure why the new ECU fixed that problem, unless there was something wrong with the old ECU to where it provided 12V to that pin but maybe could not provide the current needed to light the tester. But, at least that problem is now fixed.

I am not sure what is up with the fuel pressure solenoid, unless that wire has a short to 12V. I guess you should just leave the orange connector unpluged until you figure out the cause of the problem.

I think that I also have that "miss" that you are talking about. Maybe DLIDFIS would help to cure that problem. It could also be from one rotor face being a bit low on compression either from age or from a stuck seal. You could verify with a compression test, but I think you should check/upgrade the ignition system first if the "miss" bothers you. The "miss" will also cause higher emissions if when it misses, the fuel is not burned completely.

Kent