surging idle, New engine - S-10 Forum
 
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post #1 of 11 Old 07-19-2015, 09:07 PM Thread Starter
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surging idle, New engine

I have an 88 2.8 that I converted to a 3.4,
I use a 4.3 throttle body on a bored out 2.8 intake manifold, it has a throttle body spacer, standard exhaust manifold, no smog pump, or vacuum ball is installed. On a cold start it idles fine, after a min or two when it warms up, it surges, I can't seem to find any vacuum leak. Any ideas....

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post #2 of 11 Old 07-20-2015, 01:16 AM
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Re: surging idle, New engine

throw the 2.8 injectors in and dont drive it, just see if it does the same then report back

1986 S10 PU "SCLB" 2WD 355 TH400 3.73 8.8"
Dart 215 headed full roller 355, Full manual TH400, Killduff Lightning Rods, 150 shot of spray, homemade traction bars
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post #3 of 11 Old 07-20-2015, 05:17 AM
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Re: surging idle, New engine

Any codes being set?
What ECM are you using?
What is the timing set at and did you disconnect that wire if you did adjust it?
Did you set the TPS to .5 vdc?
Is the EGR valve still hooked up or blocked off?
Are you ready to do some tuning to the eprom in the ECM for that set up to run properly? For example, that system is going to try to run the EGR when the parameters are set for it even if the EGR system is mechanically disabled.

I have the 4.3 throttle body with the 4.3 injectors on top of an Edelbrock manifold on top of the 3.4 also.

I am using the original 2.8 ECM, which is a 1228062 and have a heavily modified VE table as well as a spark table.

I don't care what anyone else may state, that crap isn't just plug and play.

1985 GMC S-15 Gypsy ext cab.
3.4l, Edelbrock intake, a 4.3l throttle body controlled by an '88 TBI ECM. 700R4 with 3.73 rear. Real time tuning using a CF-30 Toughbook with a Moates Ostrich 2 emulator.
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post #4 of 11 Old 07-20-2015, 09:43 AM Thread Starter
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Re: surging idle, New engine

I will check everything that you both suggested today after work, I am using the stock ECM, I don't know the number, will have to check that out. I believe the timing is at 8 degrees adv. not 100% on that, its been a few weeks since I set it, I believe I did pull the connector under the dash. I have not set the TPS by voltage, never really had an issue with that but will look into it. EGR is functional at this time, although I do want it removed. I ordered a cable to read the ECM data to have my chip burned but I assumed I need to get this surging situated before I read any data as to not give false readings, Like i said, I will check all these things as well, not sure if it matters but Im not running a cat either.
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post #5 of 11 Old 07-20-2015, 05:19 PM
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Re: surging idle, New engine

Having the cable is actually better in your case because you can see more of what is going on with the sensors and ECM.

1985 GMC S-15 Gypsy ext cab.
3.4l, Edelbrock intake, a 4.3l throttle body controlled by an '88 TBI ECM. 700R4 with 3.73 rear. Real time tuning using a CF-30 Toughbook with a Moates Ostrich 2 emulator.
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post #6 of 11 Old 07-20-2015, 06:57 PM Thread Starter
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Re: surging idle, New engine

Is there a program I can download to my laptop that is good for obd1
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post #7 of 11 Old 07-20-2015, 07:01 PM
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Re: surging idle, New engine

WinAlDl and TunerProRT

Start with WinAldl. Easier to get familiar with to start.

http://winaldl.joby.se/winaldl_109f.exe

1985 GMC S-15 Gypsy ext cab.
3.4l, Edelbrock intake, a 4.3l throttle body controlled by an '88 TBI ECM. 700R4 with 3.73 rear. Real time tuning using a CF-30 Toughbook with a Moates Ostrich 2 emulator.
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post #8 of 11 Old 07-20-2015, 09:21 PM Thread Starter
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Re: surging idle, New engine

Ok so I connected to the truck using WIN ALDL. Idle set at 12 dgrees adv. Here are some pics of the Win ALDL. Reading and sensor data
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post #9 of 11 Old 07-20-2015, 09:25 PM
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Re: surging idle, New engine

That last pic shows a flag for the EST.

Check your pm's

1985 GMC S-15 Gypsy ext cab.
3.4l, Edelbrock intake, a 4.3l throttle body controlled by an '88 TBI ECM. 700R4 with 3.73 rear. Real time tuning using a CF-30 Toughbook with a Moates Ostrich 2 emulator.
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post #10 of 11 Old 07-20-2015, 10:31 PM
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Re: surging idle, New engine

Did you check your private messages?

1985 GMC S-15 Gypsy ext cab.
3.4l, Edelbrock intake, a 4.3l throttle body controlled by an '88 TBI ECM. 700R4 with 3.73 rear. Real time tuning using a CF-30 Toughbook with a Moates Ostrich 2 emulator.
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post #11 of 11 Old 10-02-2015, 07:32 PM
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Re: surging idle, New engine

were to get a cable to use that program ?
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