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Can a questionable ground kill 7730 ecm?

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Old 09-29-2017, 02:05 PM
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Re: Can a questionable ground kill 7730 ecm?

I don't know how your 02 injectors compare flow wise and battery voltage offsets slope. They might be a plug and play with flow constant change. Or you might have to tune your ve.
I hear the wasted funds , is just get rid of the multecs. Having a known good injector from southbay seems like a logical cheap way to go . Or if your wanting to learn to tune install the 02 injectors set the constant flow and remap the ve. It would be a good learning tool until you go boosted code.
Old 09-29-2017, 02:34 PM
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Re: Can a questionable ground kill 7730 ecm?

So change of plans. I'm going to grab a set of 3 year old replacements out of another car I have tgats currently laid up with a blown rear end. The 02 injectors are a totally different size and shape. The others I have are 17# I think for a 3.4L
Old 09-29-2017, 04:01 PM
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Re: Can a questionable ground kill 7730 ecm?

The somewhat new replacements are #01d110b 17# Accel injectors. I'll try these tonight. I will be getting with southbay soon, to discuss the new injectors my new set up will need
Old 10-02-2017, 12:06 PM
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Re: Can a questionable ground kill 7730 ecm?

So update, the injector replacement solved most of the issues. Now all I have left is the high idle, which has become intermittent. Weirdly enough, if I turn the car off and coast when its got the high idle, then use the momentum to restart the car it goes away until I shut the car off again.
I am trying a new tune because I just noticed how high some of the upper RPM numbers were in the idle VE table. Something like 55 at 1600RPM at 20 Baro pressure

Thank you all for your help!!!
Old 10-02-2017, 12:24 PM
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Re: Can a questionable ground kill 7730 ecm?

Have you tried another ecm to see if that cures the intermittent high idle. I have seen turning the key off and back on temporary fix the issue caused bye a bad ecm.
Old 10-02-2017, 12:29 PM
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Re: Can a questionable ground kill 7730 ecm?

Huh. Ya I put a different ecm in yesterday, and it's still happening. Is it possible the I got a bum IAC? If you watch the logs, it's like it forgets to close. Then usually after I shut the car off for about 30 sec, it closes all the way then reacts fine after I restart.
It's only about 1 in 3 or 4 trips tgat it idles over 1500 and only 2 times since I replaced the injectors has it gone to 2k
Old 10-02-2017, 12:32 PM
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Re: Can a questionable ground kill 7730 ecm?

I’m not sure what to advise, on the ve numbers the lower numbers might not be used like in 20kpa except for decel but you have dfco. I hate to tell you throw parts at it like a iac since it does close it could have a bad winding I’m not positive never experienced that before.
Old 10-02-2017, 12:39 PM
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Re: Can a questionable ground kill 7730 ecm?

Ok, thank you. That was the highest number, the entire table was 10 to 20 higher than the main VE table, so I transferred over the numbers I could and just averaged the others. I then smoothed the entire table out, so I guess we'll see what happens.
I would simply replace the IAC if not for A-I just replaced one that had the same issue, and B- this ones less than a 3 weeks old.
Old 10-02-2017, 02:26 PM
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Re: Can a questionable ground kill 7730 ecm?

Check what the TPS% is when the high idle is present. If high enough the ECM thinks your foot is on the go-pedal and won't close the IAC.

RBob.
Old 10-03-2017, 11:51 AM
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Re: Can a questionable ground kill 7730 ecm?

I just made a quick run to the gas station. Tps read 3% at .41 volts both with the high idle and after I shut it off and restarted to get the idle down.
It does read 225% at 4.7 volts wide open. Is that normal?
Old 10-03-2017, 12:28 PM
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Re: Can a questionable ground kill 7730 ecm?

4.7 off a 5v ref seems ok. I thought the tps on a 730 should start at .76v maybe that’s just for tpi.
Old 10-03-2017, 12:32 PM
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Re: Can a questionable ground kill 7730 ecm?

Ya, I believe it's supposed to be around. 57 closed for the v6. What about the 225% at WOT is tgat normal of the 7730 v6's?
Old 10-03-2017, 12:47 PM
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Re: Can a questionable ground kill 7730 ecm?

I’m not sure why tp shows 225% you would think it should show 100%.
I bet rbob might have a explanation.
Old 10-03-2017, 01:31 PM
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Re: Can a questionable ground kill 7730 ecm?

Originally Posted by broke91firebird
I just made a quick run to the gas station. Tps read 3% at .41 volts both with the high idle and after I shut it off and restarted to get the idle down.
It does read 225% at 4.7 volts wide open. Is that normal?
The scan tool is reporting incorrectly. TPS% goes from 0% - 100%.

At idle with a TPS voltage of .41 V, that is getting on the low side.

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Old 10-03-2017, 01:33 PM
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Re: Can a questionable ground kill 7730 ecm?

Oh ok. I'm using tunerpro. I'll try a different version of the mask
Old 10-03-2017, 01:35 PM
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Re: Can a questionable ground kill 7730 ecm?

I read online a testing for the 3.1l and 3.4 the tps range was .5-.9 .9 seems high though.
Old 10-03-2017, 05:21 PM
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Re: Can a questionable ground kill 7730 ecm?

The TPS on the 3.1l f-body engines is non-adjustable. Although nothing prevents one from elongating the holes.

broke91firebird: I don't recall if this has been mentioned. The $88 mask used with the 3.1l engines when coupled with an automatic trans, needs to have an idle learn done.

This idle learn is required every time the ECM loses power. It is a pain, but it is required. Otherwise all kinds of bad behavior rears its ugly head.

RBob.
Old 10-03-2017, 08:27 PM
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Re: Can a questionable ground kill 7730 ecm?

Originally Posted by RBob
The TPS on the 3.1l f-body engines is non-adjustable. Although nothing prevents one from elongating the holes.

broke91firebird: I don't recall if this has been mentioned. The $88 mask used with the 3.1l engines when coupled with an automatic trans, needs to have an idle learn done.

This idle learn is required every time the ECM loses power. It is a pain, but it is required. Otherwise all kinds of bad behavior rears its ugly head.

RBob.
Is it the same with the $88 mask and a manual? It's weird because when I start it, it jumps to 1500 drops to 900 then when I accelerate it wont come back down below 1500 rpm.
Old 10-03-2017, 10:24 PM
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Re: Can a questionable ground kill 7730 ecm?

Originally Posted by broke91firebird
Is it the same with the $88 mask and a manual? It's weird because when I start it, it jumps to 1500 drops to 900 then when I accelerate it wont come back down below 1500 rpm.
Which BCC did you start with?

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Old 10-03-2017, 11:07 PM
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Re: Can a questionable ground kill 7730 ecm?

BCC? I downloaded a copy of the BAWX_90_3_1MPFI_5_speed bin from gearhead-efi.com. All the stock chips i have are weird. Ones from Canada!
Old 10-04-2017, 07:10 AM
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Re: Can a questionable ground kill 7730 ecm?

OK, that is a 5-speed BIN. For an idle learn just need to let it idle until the fan cycles on/off once. Your mini-sig states a 700R4, so wasn't sure. If that was the trans in the car then the idle learn is very important.

Not so much when running a stick trans.

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Old 10-04-2017, 12:37 PM
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Re: Can a questionable ground kill 7730 ecm?

The minisig is my convertible lol.
So is there a vss portion to idle learn? Because I have yet to figure out how to make the stock 86 vss work with the new ecm.
Old 10-04-2017, 01:10 PM
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Re: Can a questionable ground kill 7730 ecm?

Is the stock vss a 2k ppm from the up to the ecm ? If that’s the case the optical vss signal can goto pin c6 of the 730 . You will need to change the vss flag from magnetic to optical.
Old 10-04-2017, 01:16 PM
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Re: Can a questionable ground kill 7730 ecm?

That sounds right. Is the magnetic to optical flag in the hex code? I read an article about changing the hex code for the v8 but I'm not sure how to change the v6. I couldn't find the area they were talking about in my code.
Old 10-04-2017, 02:04 PM
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Re: Can a questionable ground kill 7730 ecm?

I bet rbob knows the answer. On a v8 it 0x18 changed to 98 I’m sure it’s different in $88 mask.

Last edited by Tuned Performance; 10-04-2017 at 02:07 PM.
Old 10-04-2017, 02:23 PM
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Re: Can a questionable ground kill 7730 ecm?

The alternative would be a dakota digital sgi5e hooked to pin b10 4k ppm input.
Old 10-05-2017, 10:32 AM
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Re: Can a questionable ground kill 7730 ecm?

Originally Posted by Tuned Performance
I bet rbob knows the answer. On a v8 it 0x18 changed to 98 I’m sure it’s different in $88 mask.
ya, in 88 ox18 says F0
Old 10-05-2017, 01:45 PM
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Re: Can a questionable ground kill 7730 ecm?

It might be at the same address but I have no idea what bit is there a $88 hac you can browse ?
Old 10-21-2017, 02:19 AM
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Re: Can a questionable ground kill 7730 ecm?

So some new developments.
1st the injector swap did help things a bit. However the car is still idling too fast. I've been playing with the VE tables and that has been helping some, however I took it to work tonight and after work I put a new tune in where I dropped the entire Main VE table before 2000 down 2 markers. After that it would Idle at the very low Desired Idle Speed(575 RPM at 410*s), but kept kicking code 13. I reset the computer 3 times.
I brought the idle for average operating speed back to 900-1000 RPM and its right back to the High idle again.
Is there a way to test if the ECM is bad?




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