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Maybe that hesitation might go away with the eprom recal.

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Ok - just read the coolant bypass thread in entirety...

Jury still out?

My lines are painted, so bypass or not, the lines will stay.

Fuel line ok for a by pass?

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Great Photos and a very colorful LT5 for sure :thumbsup:

I am not sure why you did not just block off TB coolant with a 1/8 inch Allen Head Pipe plug (same with IH housing and Plenum TB coolant path). That would eliminate having to draw down coolant every time you remove the Plenum which I just know will be whenever you get the urge :D

I defined a great Coolant Filling technique which has eliminated the fear of Water Pump Air Locking after a Coolant Refill.

Are you uncertain of TB Icing? Just am interested in your opinion leading to your modifications.

Thanks,
Cliff

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What's up Cliff...

If [when] I pull the plenum again, I don't relish the idea of coolant getting all over cleaned parts. Mike100 said it gets dirty under there, but I do more cleaning / tuning, than driving (they called my '94 a 'garage queen' on CF before banning. Not QUITE so...).

anyway

Marc's page says 20' w/ 90% RH, can cause ice-up, and we DO get that here on RARE occasion. But I think even ONLY with sustained hammer down, under those conditions, will you get ice. And I got an extra 'radiator' up front, for the automatic, and the fans stay on most of the time, with the extra heat.

And thanks to Marc for gettin' the re-coded Memory / Calibration module back in short order here http://www.zr1.net/forum/images/icons/icon14.gif (I sure wish someone ELSE could get somethin' in the mail to me as fast as he did, for my tranny http://www.zr1.net/forum/images/icons/icon13.gif ).

Where's the info on bleeding air from coolant lines? Doesn't the air push through after a couple of Closed Loop outings?

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And as far as the TB coolant ports, they are kind of ugly as they are (the caps on now are just temporary).

Only thing I can think of to reduce their 'profile', is spot 'em with the Satin Black.

You got a snappic of the 1/8 inch Allen Head Pipe plugs, that you have installed?

What did the rest of you do? I'd like to keep it 're-configure-able', to OEM, just in case...

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Getting The Air Out of the Coolant System

See Details here of how to get the Air Out of the Air Locked Water Pump Filling With Coolant and the Air Locked Water Pump

See Item #4 LT5 Eliminated Systems You can get the 1/8 inch Allen Head Pipe Plugs at Summit Racing as referenced in the LT5 Eliminated Systems post ;)

There is also a 1/8 inch Allen Head Pipe Plug inserted in the top of each Injector Housing that makes sure you do not have coolant issues when removing the Plenum. That is the Pipe Plug that actually stops the coolant flow. The other (two each side) only plug the holes in the Plenum and TB.

http://i287.photobucket.com/albums/l...enumblockN.jpg

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She spun right up, second try, DESPITE:

I forgot to plug in the TPS.
Forgot to CALIBRATE the TPS.
Had the A/C head unit un-plugged.
Forgot to plug in the rear vacuum connector of the 2 at the plenum, behind the TB.
AND the vacuum connector under the TB extension!!!

I know there's air in it still - it went to about 245 pretty quick - I didn't fill with one of the coolant manifold elbows turned up...

And she's idling at about 1,250.

Anyway, still lots to do, and she'll have to wait til after Thanksgiving.

YouTube (uploading now):

http://www.youtube.com/watch?v=OqjZd...ature=youtu.be

or here

https://www.youtube.com/watch?v=OqjZd_GOaWg

Getting the Air Out of the Coolant System
 

Getting the Air Out of the Coolant System

The two coolant manifolds attached to the injector housings should get warm within 30 seconds with engine running if the water pump is pumping coolant. If not......you have to get that air out of the water pump area (Air Locked Water Pump). See LT5 Air Locked Water Pump Simplified



See LT5 Radiator and Initial Coolant Fill Tricks

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Yeah what Dyno says but don't drink the coolant:) Motor looks good and it seemed to run/sound good albeit the high idle etc. Are you going to run Datamaster again?

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Yeah - I'll plug in DataMaster as soon as I re-calibrate TPS.

No SES for high idle tho', and it DID come on right away FIRST time (idled @ 3k then), when TPS was unplugged. After shut-off, battery dis-connect, and plugging in TPS, it dropped to 1,250. I think it's the last vacuum connector UNDER TB extension - can't remember where that one went...

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Schrade Awesome thread especially with all the pics. I wish I could contribute but I haven't pulled my plenum off yet. I plan to and Ill be eliminating the coolant in the plenum and tb as well as the secondaries when I do mine. Your pics and all the little steps you've gone through are a huge help :) =D>

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Thank you Sir! The thread hits were plenty encouraging, so you helped I'm sure. And
if I can get it done, anyone can (of course, it ain't done yet [NEVER is], but nothing got broken, and no 'problems')...

I could not get the 90' plenum fitting tight in the correct position, for the TB / coolant by-pass. The fabbed by-pass line is still in place, not obstructing anything (see in the video), so I won't have to yank the top to re-reroute it at a later date.

I tried Teflon tape on the fitting threads, and then thread sealant, without the tape, but didn't feel comfy with that. So for now, it's still running through the TB.

First post edited for Cliff's links info...
DEFINITELY read Cliff's links when he posts them. They're not always directly to the pertinent information - you'll have to read it ALL to get to the info, but it's ALL there, and you HAVE to go through it. (Thanks a ton for that stuff Cliff). Use your bookmarks tool in your browser for it, and note that sometimes you'll run across info that's IMPORTANT at a later point...

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Is it running yet? If so how well?

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Sounds good have you had it on the street yet? Curious how the auto will do in the car?

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What's it idling at?

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Still idling at 1k, with TPS calibrated.

And, it's not steady - about a 75 RPM swing, so I can't tell if it's a vacuum leak lope, or what...

To boot, I don't know about the hesitation gig.

New DataMaster uploading now; called Jon B / FIC, for new injectors, which I think are indicated by the DM vid...

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Have you set the Min Air adjustment? When you get DM connected, what is IAC doing at "idle"? How many IAC counts? What does "TPS calibrated"mean? What is the coolant temp as it's idling? Why do you think you need new injectors?

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All you need to do is make sure your TPS is set to the indicated voltage at zero percent opening (about .54v if i recall). The IAC counts are probably 0 if it can't make it run slower than 1k rpm.

you either had a line pop off during reinstallation (or a mistake in tube routing), or your throttle body blade redo got messed up a little. Just seems like too much air. maybe you should double check the throttle angle and not the electrics.

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Minimum air adjustment? You mean the throttle stop screw? Haven't played with that just yet...

TPS calibration - set TPS at .54V with adjustment screws.

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Mike,

Yes I know about setting the TPS v, but that is affected by the Min Air adjustment. You need to get the throttle blade opening correct before you can set the idle TPS voltage properly. It's an iterative process.
Turn the key ON, then pull the IAC CONNECTOR. This should block the IAC port to the throttle body. Then start the motor. Does it idle, and if so at what RPM?
If it's too high, you need to close the throttle blades till you reach the desired idle speed. You actually set it a bit lower so you get some IAC control over the idle. Whenever you adjust the throttle blade, need to re-check TPS voltage and adjust if necessary so it is below the idle voltage threshold. Otherwise, ECM won't use the correct Spark Timing and you end up w an idle hunt.

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Got it there Dominic; will start there in the AM. I was tentative about playing with that, to be able to reverse any adjustment.

Y/T - best I could do this time... I need to change DM window font...
http://www.youtube.com/watch?v=J_9VApesl_o


Auto runs fine Z06, although I can by no means rule out EMI interefence in this hesitation diagnostic issue. SOME circuit 'sings', in sync with TPS range of motion - best I can describe THAT. I can catch that in a vid too, but if anyone can make anything of it, I'll be HAPPILY surprised...


Understood Mike; DM does indicate 0% TB opening, but again, Min Idle adjustment might come before TO % confirmation.

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If you didn't break the adjustment on the throttle stop, that's probably not your issue. I would do what you have to to read the IAC count value on your data stream. (or pull the IAC plug as suggested above).

Lets not make it complicated beyond that. There seems to be a fundamental air leak. it is often suggested to take a stiff binder book cover or similar and block off the air horn (accordion duct removed) while the engine is idling to try to stall it. if it still runs, you can often hear the point of the air leak under the plenum.

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Schrade, did you clean the slimy stuff out of the throttle body,around the plates, nice and clean now?

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R U saying you did re-install the throttle blades? The stock throttle stop stud uses an Allen wrench for adjusting. As Mike pointed out, GM didn't mean for this to be adjusted, but hey this is 20+ years later and things wear and go out of adjustment. These motors are being modified including the throttle body. The point is to check that all the basic mechanical components are working properly before chasing a vacuum leak. It's A PITA which is why several of us have replaced it w an 8mm hex head bolt. One thing to do is take a .002" feeler gauge and see if it drags w the throttle blades closed. A strip of paper will work also. It's a close approximation of where the blades should be with a stock motor. Make sure the motor is up to operating temps before you check on IAC counts and/ or decide to adjust the Min Air.

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Hi Dom,

Touched on something there...as I have idle hunting when the engine is real cold; at/near freezing or below. It goes away as the motor temp gets over around 60º - there abouts.

...and adjust if necessary so it is below the idle voltage threshold.

I'm with you until the term idle voltage threshold. I'm not sure exactly what you're referring to. Do you mean the TPS at idle; a la the 0.54V?? Not sure where I got confused...

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Paul,

Most likely the motor is surging when cold because the Open Loop AFR may be too lean as the motor warms up. On modified motors, the warm up routine may need a higher rpm setting also. The IAC wants to close as CTS increases but it will open up to prevent stalling. So you end up w a seesaw effect. Then it will go into Closed Loop and stabilize. A while back, I posted a vid of my car going through the warm-up routine. If done right, the motor should go into C/L without much discernible difference than O/L.
As for the TPS, the calibration uses a value of >1% for TPS Position to indicate that the motor is no longer at idle. Mine is set at 1.17%. When you adjust the throttle stop, it changes the % TPS as a consequence. So as you make the Min Air adjustment, it's important to check that the TPS V is at or below the voltage the ECM considers to be idle. The calibration has an Idle Spark Advance that overrides the SA in the tables. That's so you get a consistent SA and it doesn't change as the MAP fluctuates. Especially an issue w cammed motors. On any motor, if the TPS V is above the idle setting, the ECM will use the SA in the tables and you could get a hunting idle which may be interpreted as a vacuum leak. Make sense?

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Cold motor; idling STEADY @ 900.

DM IAC says 150.

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Do I pull the IAC BEFORE, or AFTER adjusting Min Idle stop screw?

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The linkage bracket cage, bolted to the side of the throttle body, COULD be bolted back on to the TB, such that it's in a slightly different position, which COULD necessitate the Min Idle adjustment.

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Key ON, pulled IAC, cranked it, and it went to 3k rpm.

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Throttle bores are spotless. Butterflies let no light through when the TB was re-assembled.

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??? Guys? I'm no expert, but they told me not to clean the DAG out of there?

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Don't pull the IAC valve, only the electrical connector to the IAC valve. With the IAC valve removed, you have opened a large bypass around the throttle body.

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The shiny sealing film is intact - I saw that posted many pages ago.

(I had a feeling that's what you were getting at there Steve ;) )


I should have said that I pulled the IAC CONNECTOR...

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OK, seems like that would be an easy mistake to make. I thought about rereading the whole thread, figured it must have already been mentioned, but it's a loooong thread.

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I can't afford to not go back - too much good stuff I miss if I don't....

I cannot get an Allen head in that Min Adj stud either... I did get a 5/16" on the nut, and got it backing out ATM.

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Put a phone book over the TB extension - a hiss started, then got LOUD...

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Found it. Right [near] the FPR vacuum connection to the plenum.

(turned out to be the plenum-to-PCV cap connector. It had a zip tie, and I hadn't replaced it)

Can't hear it too well in the vid; I tried to get the hose near the mike in the cam, but when I held the hose to my ear, it almost pulled out my brain cells. All 2 of 'em :mrgreen:

http://www.youtube.com/watch?v=Hw0mfEs8bLk

So now, it's still idling with a 150rpm swing, 775 - 925... An IRREGULAR lope.

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Ok. Is IAC disconnected? If not, what does DM tell you for IAC counts and what is TPS V at idle? If it's not .57v > TPS > .53v, then adjust TPS with motor OFF.
START motor, then let it idle down. What happens? Still surging? Also, if you unplugged IAC, you should have done an IAC reset after plugging it back in.