I've read as many posts that I can find and, I think, have tried all the suggestions. So I'm making a pretty lengthy post to try and explain everything I've done. But still no change. So please bare with me.
I want to thank everyone ahead of time for the help. I very much appreciate it.

I have a 92' chevy k1500 with a 5.7 and a 700R4. It runs good, but when idling in gear with foot on the break if I turn toward the left or right it stalls the engine. Engine idles in park around 900 rpm, and in drive with foot on break it idles around 450 - 500 rpm. Check engine light comes on and throws a code 32, EGR circuit error.

These are things I've done and it still stalls idling in gear and turning the steering wheel.

I lifted up on the EGR valve diaphragm with the engine running and it makes the engine run rough. Hooked mity vac to EGR and it lifted diaphragm and held suction. Pulled EGR off and checked for carbon and plugged ports with a wire and small screw driver, and brushed EGR valve, it all looked good. EGR looked fairljy new. Put a gasket on. No change.
Far as I know it is the right EGR. It was on when I bought the pickup.
The numbers on the EGR are: 19209958
091109

Put on a new TPS. No change.

Put on a new ACDelco IAC. No change.

MAP sensor tested good. Vacuum numbers are: 0 - 4.55, 5 - 3.58, 10 - 2.66, 20 - 0.930

Put on a new ACDelco EGR Vacuum Solenoid. No change.

Took off serpentine belt so power steering wasn't turning. It did not stall when in gear, foot on break and turning steering wheel. But, I son't know if that means anything because there is no load being put on the engine either from the A/C, water pump, etc.
When I bought the pickup the previous owner said he put on anew power steering pump. It does look new.

I set the timing to 4 degrees BTDC in this way:
Unplugged the black connector with a single tan with black stripe wire that breaks out of the wiring harness and battery junction block on the firewall. (Timing no longer controlled by the computer)
Lined up timing marks to 4 degrees BTDC with a timing light. Shut engine off. Reconneted the tan with black stripe wire. Waited 10 seconds to restart engine. Run engine for a little while and tkurned it off. Unhooked battery to reset ECM.

I set the Idle as to instructions from AutoZone website.
file:///Users/michael/Documents/92%20Chevy%20pickup%20info./IDLE%20ADJUSTMENT/1992%20Chevrolet%20Truck%20K1500%201:2%20ton%20P:U %204WD%205.7L%20FI%20OHV%208cyl%20Repair%20Guides. webarchive

1992 Chevrolet Truck K1500 1/2 ton P/U 4WD Throttle Body Injection (TBI) Repair Guide

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MINIMUM IDLE SPEED ADJUSTMENT




[img]file:///images/repair_guide/enlarge_icon.gif[/img][img]file:///images/repair_guide/enlarge_tooltip.gif[/img]Fig. Fig. 1 For access to the idle stop screw, pierce the cap with an awl and carefully pry the cap from the side of the throttle body

1992 Chevrolet Truck K1500 1/2 ton P/U 4WD Throttle Body Injection (TBI) Repair Guide

Print
MINIMUM IDLE SPEED ADJUSTMENT




[img]file:///images/repair_guide/enlarge_icon.gif[/img][img]file:///images/repair_guide/enlarge_tooltip.gif[/img]Fig. Fig. 1 For access to the idle stop screw, pierce the cap with an awl and carefully pry the cap from the side of the throttle body



Beginning in 1985, some engines were available with a throttle body fuel injection system. All throttle body injected vehicles are controlled by a computer which regulates idle speeds and supplies the correct amount of fuel during all engine operating conditions. No periodic adjustments are necessary. However, if throttle body is replaced AND a proper idle speed cannot be obtained, there is an adjustment which may be made. An idle stop screw is set at the factory and then covered to discourage tampering. If all other components of the fuel system are working properly and there is still a problem with the idle speed, the screw may be adjusted.

Incorrectly adjusting the minimum idle speed stop screw will result in the IAC valve pintle to constantly bottom on its seat leading to an early valve failure.

1. Set the parking brake and block the drive wheels.
2. Start and run the engine until it reaches normal operating temperature. Make sure all accessories are turned OFF.
3. Stop the engine, then disconnect and plug any vacuum lines, as required.
4. Using an awl, pierce the idle stop screw cap and carefully pry the cap from the throttle body. The cap and screw can be found on the opposite side of the throttle body from the Idle Air Control (IAC) valve and Throttle Position (TP) sensor.
5. Connect a tachometer to the engine.
6. Ground the diagnostic terminal of the Assembly Line Data Link (ALDL) connector by using a jumper wire to connect the terminal to the Electronic Control Module (ECM) system ground terminal. The diagnostic and ground terminals are the 2 top right terminals on the ALDL connector which is found under the dash, near the steering column.
7. Turn the ignition

ON , but DO NOT start the engine. Wait at least 45 seconds for the IAC valve pintle to extend and seat in the throttle body.

1. With the ignition

ON and the ALDL test terminal still grounded, unplug the IAC valve connector. This will keep the pintle extended throughout the procedure and prevent the ECM from adjusting idle speed using the valve.

1. Remove the ground from the ALDL terminal, then disengage the distributor set timing connector in order to prevent the possibility of engine speed changing during the procedure due to timing changes.
2. Place the transmission in Neutral, then start the engine and allow it to idle.

If equipped, double check to make sure that the cruise control cables do not hold the throttle open.

1. For 1985 vehicles, set the idle screw to obtain 500-600 rpm.
2. For 1986 vehicles, have an assistant place the transmission in Drive and apply the brake pedal, then set the idle speed to 400-450 rpm.
3. For 1987-88 vehicles, set the idle screw to obtain 400-450 rpm.
4. For 1989 vehicles, set the idle screw to obtain 400-450 rpm for the 4.3L (VIN Z) engine or to 450-500 rpm for the 5.0L (VIN E) and 5.7L (VIN 7) engines.

1. Wait until the idle stabilizes, then check and adjust the idle speed as necessary:
2. Turn the ignition

OFF , then reconnect the IAC valve and distributor timing wiring.I set Idle at normal temperature to: In park - 900 rpm In drive with foot on break - 500 rpm

It still stalls at idle, in drive with foot on brake and turning steering wheel.

I sorry for the long post, but I wanted to give you as much information as could.
I don't know what to try from here.
Thanks for the help.

 

I would check your fuel pressure. https://www.chevytalk.org/fusionbb/s...php?tid/253427
Guessing it's marginal and when at idle, where ECM attempts to adjust injector pulse to maintain idle speed, there's not high enough pressure to maintain idle when engine is under some load like from power steering pump.
Driving - TPS is probably higher than normal for maintaining speed but you may not notice with a 700R4 as shift points aren't controlled by ECM.

 

Thanks Sabino56 for the help.
I checked the fuel pressure and it is 14 psi. I don't have any problem when driving. Runs good. When I kick it down into passing gear there is no hesitation or missing like it's not getting enough fuel pressure.

 

just curious, how/where did you check fuel pressure? I don't have a lot of experience but it seems most people struggle to get 11-12 psi. I had 9-10psi with an autozone pump and when replacing it with a ACDelco pump I was able to get ~12 psi.

regardless, it seems ECM can't control target idle speed with even a small load on engine. It shouldn't be dropping idle that low. I think, but not positive, that ECM controls rpm @ idle with injector pulse width and IAC. I don't think it messes with timing though if it wasn't set right it would cause problems. Hopefully someone who knows more will correct if I'm off.
Since you replaced IAC I was thinking fuel pressure. It can be possible for ECM to think it's not at idle due to some sensor being off - eg. TPS (also replaced). You could verify if you had datalogging capability (eg. like Tunerpro) to see what cell ECM is in @ idle.
I don't have great ideas.

A couple thoughts/guesses/things to verify - always easy to give someone else ideas to try...
- did you check that throttle adjust screw on throttle cable is not holding blades open? If it were, perhaps IAC can't control properly
- did you check that TPS was ~0.5V (google to check I have that V right) @ no throttle?
- google how to check injector spray pattern - I've never done it but I understand you can see if spray pattern is good. perhaps if an injector is dribbling, maybe not spraying well it won't cause big problem @ speed but it's more sensitive @ idle.
- assuming you checked fuel pressure between filter and TBI and were seeing 14psi (what type pump? how old?) perhaps the fuel pressure control spring in the TBI is messed up? I've read cases where people said it broke and they were getting too low of fuel pressure @ injectors even with measured fuel pressure in range into the TBI. However, if this was the case I'd think you have trouble getting higher than normal 14psi before TBI.
- do you know if, after it's warmed up, you've been driving, if it stays in closed loop @ idle? I had in my head that there was a way to check via OBD if engine was in closed loop without a datalogger but couldn't find it with quick google.

good luck, sorry can't help more

 

Thank you Sabino 56 for all the help.
I bought an adapter that goes in the fuel line where the fuel filter is. You take the fuel filter out and put the adapter in it's place and hook the pressure guage to it. I put a new fuel pump in it last summer and really haven't driven it but about 2500 miles since. It was a Carter pump.
To set the Timing you have to disconnect a tan with black stripe wire on the firewall by the junction block to keep the ECM from controling the timing while your trying to set the timing with a timing light.
I checked all the wires on the TPS for voltage as to instructions on internet and they were all right on.
I've checked the injector spray pattern and had a mechanic check it too and it seams to be fine.
I don't have data logging capability. Throttle adjust screw is not holding blades open.
I don' think it is the pressure control spring, it idles good in park and in gear with foot on break, at recommended rpm, until I turn the steering wheel. I would think that if the spring was broke that it would affect the idle and excelleration. It doesn't hesitate a bit when I rev the motor in park, in gear with foot on brake, going down the road, or when I kick it into passing gear at 55 mph. I would think a broken spring would affect something else somewhere.
I don't know if it is in closed loop at idle. Not sure how to do that.
I'm begining to wonder if it is the ECM it's self.
It's still drivable. Just have to start moving a little before turning the wheel.

Thanks again for all your help and information.

 

I really don't think it's the ECM. People tend to suspect ECM when they've tried everything else they can think of and still stuck. I doubt ECM can fail such you only have problems @ idle under a little load. These early systems aren't very adaptable/smart. They have no feedback on actual fuel pressure or timing - they assume both are correct/in range and use the various sensors input to decide what mapping for fuel and timing. This is why the first two things people say to make sure are correct when debugging problems are fuel pressure and timing. The third fundamental thing to check is that your grounds are good - marginal/bad grounds can affect the signals from sensors to ECM. I forgot to suggest that previously. If you haven't done that I'd go thru grounds for good hygiene. No good reason why that would be problems at idle and not elsewhere but easy to check/fix the grounds. There are about 3 in addition to the battery, I think. One on firewall/power block, I think to back of engine somewhere to firewall and one at thermostat housing.

I once had problem where it wouldn't idle smoothly, would hunt up/down, etc. It seemed to drive OK otherwise except shifting was harsh. I tried everything and eventually found it was marginally low fuel pressure. I think the reason it was a problem @ idle and not apparently @ driving was I was when driving I would just push throttle to get speed I wanted and ECM would read the TPS and Map as I was trying to accelerate and increase fuel mapping. As a result, when just normally driving the only thing I noticed was harsh shifts. The harsh shifts were because I have a 4l60E where PCM controls both engine and transmission and TPS, MAP, speed made PCM think I was trying to accelerate hard when I actually wasn't. A 700r4 shift is controlled by rpm/vacuum so I was thinking you'd not necessarily experience harsh shifts as indication of something off. btw - after fixing fuel pressure, I got back performance I forgot it had. It had slowly degraded over years so I didn't realize it was actually low on power. This experience is why I'm stuck on thought it's a fuel problem.

If you removed filter to check fuel pressure that would explain why you have higher than I'd expect - 14psi. There's a pressure drop across the fuel filter and the ~12psi desired is after fuel filter. I've never seen a note on fuel pressure drop across fuel filter so don't know if what you have is right or no. You might google around to see if 14 with filter out correlates to ~12psi with filter in. Chevytalk may be another board where people have opinions/advice on that.
regardless - just to confirm even though you've been pretty thorough - did you replace the fuel filter?

When I asked about open/closed loop. I didn't mean to suggest that was a cause of your problem. The ECM adjusts injector pulse width up/down to move O2 up/down between limits. If @ idle it can't get into closed loop (after engine hot), it's either because of a bad/lazy O2 sensor or inability to adjust injector pulse to move the O2 readings. If you couldn't get into closed loop @ idle after warmed up/driving I was thinking it could be another possible indication of fuel issues at idle. Not really a good indication either way due to O2 sensor variable - but, btw - the way to check without datalogging is to put ECM into field service mode. google "gm aldl field service mode"
Field Service Mode
On the OBDI ECMs, you can jump 'A' and 'B' terminals on the ALDL while the engine is running.
WARNING! This must be done after the engine is running. This is called "Field Service Mode" and will not harm the ECM.
If the ECM is in Open-Loop mode, the SES light will flash rapidly, about 2½ times per second. If it's in Closed-Loop mode, it will flash about once per second. When in Closed Loop mode, flashing less than once per second indicates the ECM is enriching the mixture above the 128 count base line. Flashing more than once per second indicates the ECM is leaning the mixture below the 128 base line.

So, I don't have a lot of other suggestions. Given what you've said, if you have no better ideas from anyone I'd:
- verify all grounds are clean/good
- figure out if 14psi without filter is actually a good pressure with filter. Either find someone who knows or check after filter with adaptor like in link I posted above. I found it easiest to do just after filter as you can release the fuel line retention there easily - it's a pain by TBI. (good/new fuel filter?)
- get a gasket/rebuilt kit for TBI - get in and check fuel pressure regulator spring, gaskets/orings, etc.
- perhaps get your ICM checked - I understand you can get it checked off vehicle, never done it. I have no idea why it would be OK at load/speed but not at idle so just suggesting as something which can be done - not because I have idea as to why it could be problem.
- if still stuck - I'd invest some time into getting something to datalog before assuming anything is wrong with ECM. With datalogging you can see if ECM thinks you are in an idle cell, you can watch what sensor inputs are doing as idle speed drops when turning steering wheel @ idle, see if injector pulse width is increasing or no, etc. Datalogging is what finally clued me into marginal fuel pressure after I replaced everything I could thing of. I saw that when idle speed dropped, fuel enrichment was kicking in which indicated PCM was attempting to add more fuel for some reason. Check out Tunerpro - its free/donate PC software. You need a laptop and some PC skills + a cable. I used cable from Moates. It was ~$100 all in and time - which you've already spent more of both so far. There are also turn-key dataloggers. If you decide to go down this path google around on boards for opinions. Tunerpro web page and gearhead-efi is source for info though the later is for people really into tuning.
Good luck