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Old 03-17-2014, 08:10 AM
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Default Engine stalls

I need to find out why the motor dies when hot? It starts right back up but will stall again after driving a short distance it will again start right up and if I hold the gas pedal when stopping with one foot on the brake pedal it seams to run?

It stalls using either systems Gasoline TPI or LPG injection. All sensors are new including the injectors and 02 sensor. The dizzy is used the coil is new.
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Old 03-17-2014, 11:07 AM
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minimum air set correctly? cold the idle speed is bumped up, keeping it from stalling. Timing set correctly? Must be set hot (cold has more spark advance so wait for it to go into closed loop) Depending on what prom you have, base timing will vary a little. I find it's easiest to just simply set it with the hei bypass disconnected and then double check with the engine running and a scanner hooked up to red total commanded advance and verify with a dial back
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Old 03-17-2014, 12:15 PM
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Originally Posted by Twin_Turbo View Post
minimum air set correctly? cold the idle speed is bumped up, keeping it from stalling. Timing set correctly? Must be set hot (cold has more spark advance so wait for it to go into closed loop) Depending on what prom you have, base timing will vary a little. I find it's easiest to just simply set it with the hei bypass disconnected and then double check with the engine running and a scanner hooked up to red total commanded advance and verify with a dial back
The hot idle is around 800rpm. How do you set the minimum air? Timing was set cold 6* with bypass wire disconnected. No one has a scanner over here.
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Old 03-17-2014, 01:29 PM
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OH, you didn't say about holding the brakes and giving gas....in the email, so most of my ideas are best kept for the future.....

what you maybe try doing is to get a torx bit into that idle adjustment screw on the TB, and open it up a tad,

have you wiped the throttle blades and passages out with solvent?? I use brake cleaner it tends to gather crap on it and not enough air for the IAC motor to overcome.....maybe pull it apart also, and clean the passages....

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Old 03-18-2014, 04:13 AM
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Originally Posted by mrvette View Post
OH, you didn't say about holding the brakes and giving gas....in the email, so most of my ideas are best kept for the future.....

what you maybe try doing is to get a torx bit into that idle adjustment screw on the TB, and open it up a tad,

have you wiped the throttle blades and passages out with solvent?? I use brake cleaner it tends to gather crap on it and not enough air for the IAC motor to overcome.....maybe pull it apart also, and clean the passages....

Gene
Actually I am not sure holding the gas and breaks actually worked. Driving in Bangkok is difficult with the traffic. I have been hesitant in driving the truck due to it stalling when hot and never knowing when it will stall. The distributor is probably the only part that is old and I would buy a new one if I knew where to buy it? It is not a typical HEI but computer controlled, do you know where I can order one, see picture.
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There is no break cleaner available here but maybe lacquer thinner will do?

"try doing is to get a torx bit into that idle adjustment screw on the TB, and open it up a tad"

OK what is this and where is it located? Also TT recommended "minimum air set correctly?" How do you set this? It now idles 800 rpm hot.

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Last edited by BangkokDean; 03-18-2014 at 04:18 AM..
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Old 03-18-2014, 07:15 AM
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That's a normal EST small cap HEI, nothing spectacular and yours looks very clean. Run it, it'll be just fine.

On the TB there's a 90 deg bent tang on the throttle linkage that sits against a screw @ idle. The TB casting has a rounded wider casting that you can see in the pic, the back side is open and has a torx screw inside, that's used to adjust the screw against the linkage tang. In the pic it's right above where your TV cable attaches.

To set minimum air you have to cycle the IAC closed but since you are having stall issues, just adjust the screw so the throttle blades open a little further and see what it doe.

You DO have the correct prom in it right? For an automatic and not a manual? IAC steps, stall saver etc. are different for a manual.

you can actually see the adjustment screw in this pic, right next to the cable



OH WAIT!!! You are using a speed density system right? Well, is your upper plenum a speed density one where the map sensor bolts to the back side of the manifold? If so your plenum may not have the IAC triangular hole between the throttle bores. You re using an older style throttle body that does have the opening. Please double check that!!

LEFT plenum is a SD unit...notice how it lacks that hole!!

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Old 03-18-2014, 09:00 AM
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Yes there is a screw to set the idle and it idles at 800 RPM hot.

I will have to remove the front section to see what type of Pentium I have.

I am not sure what a map sensor looks like. See pictures with the Pentium removed.
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Old 03-18-2014, 11:19 AM
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OK I just took the front off the TBI and this is what it looks like.

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[url=http://smg.photobucket.com/user/deanscorvettecoupe/media/56%20truck%20build/IMG_5988_zps7b2231d1.jpg.html]

Last edited by BangkokDean; 03-18-2014 at 11:28 AM..
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Old 03-18-2014, 11:21 AM
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Idle screw, I turned it in a little, but what should it idle at hot in neutral?
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This tube (A) has nothing connected?
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Last edited by BangkokDean; 03-18-2014 at 11:31 AM..
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Old 03-18-2014, 12:04 PM
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Tube a is a timed vacuum source, cap it off. Also, make sure you set your tps in an acceptable range. The speed density systems simply check 0% tps on key on engine off but it will help to set it to about .54V

You have a non SD specific upper plenum, your map sensor must be located elsewhere. It's a black square sensor with a green colored metripack connector going into it and a vac hose.
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