Gentlemen,

The engine is starting consistently easily both cold and warm and running fine street and highway both cold and warm. 1990 745T, automatic transmission, 202,000 mi. New plugs, new wires, fresh ATF, transmission screen and pan gasket, fresh motor oil and quality filter, good new front pads and new remanufactured OEM calipers front. A recent fix for the long cranking to start that had worsened to the point of being a no-start was swapping out the electric fan relay for the radio suppression relay, and then also remembering to reconnect the wires to the IAC, which itself had been in a frozen state on top of the radio suppression relay having cracked solder. Details got posted earlier.

Now the engine is starting and running like it used to, except for one aspect. If restarted when warm, then the engine idle is tending, about 90 percent of the time, to hover around 1600 rpm. That is in Neutral or Park. This high idle is about 1400 rpm in gear. This is instead of the normal 700 to 800 or so. This happens only after a restart, not during operation. That is, the engine is warm enough after driving a short distance to restart with the idle almost immediately going to this 1600 rpm, but the engine will not start idling at 1600 rpm during an even longer initial drive of eight or 9 mi. if there is no restart of the engine along the way . The engine has to be shut off and then restarted to induce the high idle, so I guess it is not operating temperature alone that is causing the high idle. Throttle blipping does not bring the idle down. Additionally, if I let the motor run like this in Park or Neutral , then there is a brief periodic let-up in the idle speed every 11 seconds or so, but that recurring letup lasts for one second or less and brings the idle down only temporarily , to about 1300 or 1400 rpm. Then the idle resumes at 1600 rpm until the next temporary one-second-long reduction to 1300 or 1400 rpm about 10 or 11 seconds later.

The IAC valve seems to be the sole source of air for the engine at idle, so I figure the high idle is not due to idle air entering the manifold through both the IAC valve and the throttle body at the same time. When I shut off air that the IAC valve is feeding into the intake when the engine is running at its high 1600 rpm idle, then the engine slows way down right away to what sounds like about 500 rpm or less, runs at that speed for about two seconds and then stalls out. The engine seems to have only one source of air at idle and that seems to be the idle air control valve. I shut off the air supply through the IAC valve by clamping the 1 in. rubber inlet hose that leads from the big three-inch manifold hose down to the IAC valve inlet with a big pair of slip-joint pliers with padded jaws per the FAQ. I figure if clamping down on the IAC hose stalls the engine at idle, then that the throttle body butterfly is closed at idle, because I have seen how important it is to get the pliers positioned right on the inlet hose to shut off the IAC air. if the pliers are not clamping down well enough on the hose and the hose stays open very much, then the engine keeps running even with the pliers on the hose, albeit at lower rpm. But if the pliers are clamping down all the way across on the hose, then the idling engine on my car will slow and stop every time.

There is still some remaining crud build-up inside the throttle body on the throttle body ceiling and also on the upper edge of the butterfly. I have been spraying in there with carb cleaner. I will be getting more carb cleaner - ran out - and working it into the built-up crud with an old toothbrush asap. I wish to keep the throttle body on the car while cleaning the throttle body and figure that may have been a consideration for the engineers when they angled the throttle body down on the car. Carb cleaner and dissolved material runs out of the throttle body like that instead of into the manifold. The vacuum inlets, including the one leading to the pinhole that I can see is a pinhole, are also all cleared out, I shot carb cleaner through the spray can's narrow-gauge plastic dispenser tube down all the vacuum inlets on the manifold last couple of days and still have the high warm engine 1600 rpm idle after a restart.

The FAQ had information on running diagnostics. Results on my car this afternoon were 1-1-1 in diagnostic test mode 1 with ignition key position II and read from socket No. 2 , that is, there were no fault codes stored. Pressing once returned three long flashes, then nothing. Repeating got the same result. Then pressing the button twice returned quick flashes, and slight gas pedal pressure brought 3-3-2 in short flashes then quick flashes resumed, then I took my foot off the gas and the light turned off than resumed its quick flashing. Flooring the gas pedal returned the same code as above, that is, 3-3-2 in short flashes. I expected 3-3-3 in short flashes here after reading the FAQ.

Now I pressed the launch button three times while still in socket No. 2. I got confused here so I held the button down for a long time and it seemed to clear everything up. Then I pushed the button down three times and the injectors opened and closed for about 10 seconds then there was a brief pause and the IAC shutter opened and closed for about 10 seconds then there was a brief pause then what I assume is the cold start valve open and shut for about 10 seconds -- that sounded like a big clock ticking. By the way, I have run diagnostic test mode 3 from socket 2 several times and still cannot pinpoint the location of that cold start valve. I also expected the fuel injection relay and the fuel pumps to run during this test but they never did. But the fuel injection relay and the fuel pumps to work. I have been driving the car around now again for a good week or so and also had the car on the section of local freeway briefly yesterday. The fuel injection relay and the fuel pumps work on the car. Now I pressed the start button four times and this returned three long single flashes and then the light went off.

In socket 6, first thing I noticed when running the diagnostic tests again this evening after nightfall was that the readout diode was glowing dimly right off the bat. There was / is no such dim glowing when I plug the probe into socket 2. I put the probe back into socket 6 , noted the dim glowing and proceeded. Pressing one time brought three long flashes. Pressing two times brought quick flashing, then slight gas pedal pressure returned 3-3-4, all short flashes, then the diode resumed quick flashing. I floored the gas pedal and this returned 3-3-4 again, again all of them short flashes. Now I pressed the button three times with the probe in socket No. 6 and that produced 10 short flashes that repeated themselves over and over again. I stopped that when they had run about 10 repetitions. Pressing the launch button with the probe in socket 6 four times returned the same result as just before.

I also ran the crank sensor part of the test twice this afternoon and got the expected result, I think it was 1-4-1. That did not get repeated this evening because it was dark and I do not want it keep taking the wire off the center post of the coil.

Could someone please tell me if these codes suggest a special reason for the high idle after restart when the engine is warm about 90 percent of the time ? I will be looking more extensively for more code info on the site tomorrow. My dashboard temperature gauge has been fluky for months now, but that is a circuit different from the block temperature sensor for motor management, I understand (?).

Here is the small floodlight idea, it sure works for me: one of those modern small twist fluorescent lights at about 14 watts makes a lot of light and only a little heat. Screwed into a bare light bulb socket, the aggregate fits well in a 12 oz paper cup from any fast foods restaurant or maybe from the kitchen cupboard. A lamp cord is fitted to the back of the light bulb socket such that the lamp cord passes through a hole made in the floor of the 12 oz paper cup. Multiple paper cups can be stacked together for this for added structure. The fluorescent light bulb is taped into the light bulb socket with electrician's tape to keep the bulb seated and add insulation while recessed in the cup, and I taped the socket with its push button switch on. I turn the light on by plugging it into a switched extension cord or power strip. Those 12 oz paper cups are waxed and resist oil for a little while and also are white on the inside so that they reflect the light forward. This all happens without much glare to the side. The shell / 12 oz cup is soft enough to fit into the nooks and crannies in the engine compartment. It does get beat up doing this but replacement is inexpensive and easy. I will be swapping out the current 12 oz paper cup shell soon.

I used my light to get visual confirmation of IAC valve operation this afternoon. The IAC valve was sounding good, and one could also feel it clicking by putting a finger onto it in diagnostic test mode 3, but to make sure, I took the hoses off, pointed the light through the inlet, set up a mirror to look through the outlet, and ran diagnostic test 3. Sure enough, the IAC shutter was opening and closing big-time during that test.

Thank you all, everybody. Sorry that this post was so long.

Paul 740 T