Rich idle / ignition advance backwards??

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SR85DET
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Rich idle / ignition advance backwards??

Postby SR85DET » Thu Dec 29, 2016 1:47 pm

Ok now that I hope the title got your attention.
I just finished my 20v swap
Setup:
1985 AE86 GTS
Silvertop engine
Blacktop Automatic harness/ECU
SQ Engineering distributor cap relocation kit (read below for issue 2)
ITB trumpets with individual pods
3SGTE O2 sensor (it's possible my heater 12v/gnd are backwards as they are both black (would this affect my AFR that much?)

Issue:
1) Car runs rich at idle (10.0:1 (gauge maxes rich at that reading)) When I start the car up it runs at normal AFR for a few seconds and then slowly drops to 10.0:1 after a few seconds.
2) When i short my diagnostic plug connector the idle goes to say 10 BTDC but not shorting the connector is at 0. I tried setting idle at 16 BTDC without the diag connector shorted and then shorting it the connector idle was around 21 BTDC. Isn't this backwards?? The SQE kit has the CAS on the back of the engine and the distributor cap and rotor button in the front (spinning backwards from normal) so wouldn't advance be actually retarding the ignition and vice versa? I can't find anyone else who has brought this up before.

What I have done for running rich issue:
I adjusted the TPS and checked water temp sensor, swapped a MAP and all seems normal (except the TPS being off)
Also checked the FPR and none of these things being idle to a leaner condition.

I'm just confused at this point.
Last edited by SR85DET on Fri Dec 30, 2016 3:15 am, edited 1 time in total.

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jondee86
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Re: Rich idle / ignition advance backwards??

Postby jondee86 » Thu Dec 29, 2016 2:34 pm

From where are you taking the MAP sensor signal ?

Cheers... jondee86
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SR85DET
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Re: Rich idle / ignition advance backwards??

Postby SR85DET » Thu Dec 29, 2016 4:45 pm

The "T" off that goes to all 4 cylinders

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SR85DET
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Re: Rich idle / ignition advance backwards??

Postby SR85DET » Thu Dec 29, 2016 4:47 pm

Can someone give me a MAP sensor part number if they have it handy? I have a few of them. I bought a supposed ST (AE101) sensor but it's not the same part number as any I have that look identical from the junk yard. I'm using all ST sensors also.

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jondee86
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Re: Rich idle / ignition advance backwards??

Postby jondee86 » Thu Dec 29, 2016 5:21 pm

SR85DET wrote:The "T" off that goes to all 4 cylinders

Have a read here.... http://forums.club4ag.com/zerothread?id=44759

Then tee your MAP sensor vacuum line into the line (if there is one) attached to the
spigot marked C in this pic....

Image

Engine will be running rich because the ECU will be reading atmospheric pressure at idle.
Can't say if that is what is screwing your timing, but wait and see what changes after
you fix the MAP sensor reading. ST(AE101) never had a MAP sensor... if you have one
off a BT(AE111) that should be fine.

Cheers... jondee86
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SR85DET
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Re: Rich idle / ignition advance backwards??

Postby SR85DET » Fri Dec 30, 2016 3:30 am

thanks Jondee, i just had a read and I will try this morning when I get my lazy butt out of bed. I did notice that there is supposed to be a pulsation dampener running to the map sensor but my engine did not come with one (or a map sensor). Are these sourceable from other vehicles in the U.S.? I'll try hooking it up without in the mean time.

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SR85DET
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Re: Rich idle / ignition advance backwards??

Postby SR85DET » Fri Dec 30, 2016 8:58 am

Update, relocated vacuum to point "C" and car won't start at all, relocated back, still won't start... idk what is going on now. All I did was put my blower motor back in as it was never installed since swap. I visually checked connections but saw nothing wrong. Time to retest everything as something may be loose??

Car does attempt to fire so it's getting fuel and spark, have tried several positions on the CAS and it helps but at certain positions but won't actually run. Man this is aggravating

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SR85DET
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Re: Rich idle / ignition advance backwards??

Postby SR85DET » Fri Dec 30, 2016 9:33 am

Also still no codes from ECU. For a car I started and drove around, it's so odd to me that it won't start at all. It's only a little colder outside than yesterday but nothing has really changed. If a major ECU wire got interrupted then wouldn't it throw a code?

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Re: Rich idle / ignition advance backwards??

Postby jondee86 » Fri Dec 30, 2016 12:04 pm

Maybe it needs more air ? Have you tried starting it with your foot on the
gas pedal ? Plugs might be fouled. If you have a spare set put them in and try.

EDIT: The ignition retarding istead of advancing problem has come up before,
but I don't remember the exact cause. I think it was because something was
wired back to front. If you spliced wires to connect the MAP sensor, it might
be worth swapping them around to see if that makes any difference.

Cheers... jondee86
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SR85DET
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Re: Rich idle / ignition advance backwards??

Postby SR85DET » Fri Dec 30, 2016 1:22 pm

Plugs were fouled... coincidentally happening after last shut off yesterday. Put another set in and fired right up. Also car ran around 12.8 to 13.1:1 at idle. Car runs well, thanks for your help!

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Re: Rich idle / ignition advance backwards??

Postby jondee86 » Fri Dec 30, 2016 2:19 pm

Has the ignition advance/retard returned to normal ?

Your MAP sensor is now connected to the common vacuum rail which serves much
the same purpose as connecting into the individual throttle bodies and averaging the
vacuum signal. Pulsation dampers are found in the MAP sensor hoses on many cars.
You should be able to pocket one at you local Pick and Pull ;)

Cheers... jondee86
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