How should the throttle body blades be adusted? Mine has almost not space around them when closed.

 

that should be good as you want the idle circut to do its job. I measured one once and it was .003. So if your car is running good and the BLM's look good don't mess with it Ask me how i know

 

I agree, you don't want much more than .002-.004 per side clearance between the blades and bore. As long as the blades do not bind they are fine.

 

I have a related thread about high idle and bad engine performance, with the tps being at 3% open during idle. My throttle blades have almost no gap (less than a paper thickness) after cleaning the throttle body. Would opening the gap a bit help the the tps position problem?

 

The TB blades being almost closed and the TPS reading 3% at idle seem like two opposite indications. Your TPS might read high if the blades were open too much-not closed.

When you turn the key to ON, the computer looks at the TPS voltage value and normally sets that to be 0% for the ignition cycle. Maybe you have a TPS problem.

 

True, that was my first line of reasoning. I'm on the 3rd new delco tps. During cold startup, everything reads fine, but after reaching 160deg temp I keep getting tps failures. It may well be somethingother than the tps that I can't find. Put in newiac, cleaned TB,replaced fuek filter and removed gas from tank.

Will be cleaning the maf next.

My main question was about slotting the tps to move it so that the tps position reads 0% at idle.

I did find about 10cc's of water in my fuel line just before the filter. I wlill be taking this to Amaco to see if badgas could have created a problem. The Amaco premiumgas taken from the tank is greenish in color. Is this normal?

Anyone have experience with waster in the fuel?

 

GREEN? Hell no thats not normal.

 

I let a 60 cc sample of the gas set out. It separated into two portion, a thinker water like portion on the bottom and a lighter greenish/yellow portion at top.

But I don't see how bad gas explaines the tps issue.

Cleaned maf and determined that throttle body plates are closed.

Started car this morning and new tps reads 15% at idle.

Put original tps back in and reads and tps reads 0%.

Drive car at light throttle for several miles and warm it up. It runs great.

Start to accelerate at half throttle and hear slight metallic pinging out of exhaust. Do this a few times, just short of pinging and car starts to buck a little and ses light comes on with a tps low voltage code.

At idle, the tps is changing from 0 to 8% open, with the car idling and TB plates closed and Throttle not touched. I tap the gas twice, idle returns to 800 rpm’s and tps is reading 0% position.

Is a set voltage supposed to be fed into the tps at all times?

 

I swapped the oringinal tps and new tps several times.

The new tps shows a 15% throttle opening and the old tps shows a 5% throttle opening.

The original owner mentioned that he had ported the Throttle body, but this was 25K miles ago and the car ran great up until this last gas fill-up.

I will be exchanging this tps for a third time, I suppose it's possible that they are all bad.

 

To set the throttle plate correctly you need to cut off the IAC air. Usually what I do is take a small piece of rag and stuff it into the opening in front of the throttle plate. Then the only air getting to the engine is from around the plates. You want the "minimum air rate" to be about 550 (in drive for auto's). This is the minimum RPM that the computer can lower the engine to. After that the IAC motor controls idle RPM. This would be the TPS setting... Not adjustable. The computer needs to see a little percentage for idle. As for the difference in TPS's, I don't know without being there. You may need to drive the car to reset the idle, you may have a high idle after removing the rag. Check the specs on minimum air rate.

 

Is 800 rpm right for the M6?

 

800 rpm is factory setting at idle, coolant fully warmed up. I disagree with the above "throttle setting procedure". You want to adjust the throttle stop screw until you get the correct rpm, AND the IAC counts are in the range of 20-40. Then check the TPS voltage to insure it is within the factory spec of 0.20-0.90V.

You should see 5V constant across the black and grey wires. The signal, across the blue and black wires, should be in the range of 0.20-0.90V with the blades fully closed, approx 4V above the "closed" value at the WOT position, and the voltage should change smoothly as you slowly rotate the throttle blades from closed to full open.

Your confusing things by continuing to run with water in the fuel. Get the tank drained immediately, put in a tank of good gas, and then attack the TPP problem

 

I drained the gas and it ran 95% better, so I'm mainly back to the high idle issue. Since there is still some exhaust pinging, and a lack of any type ehaust popping during deceleration, I think that the old gas is not completely cleared out.

BP took my gas sample and is supposed to check it out. In the mean time, I will add a bottle of gas dry out to the tank and get a fill up at exxon.

 

The computer controls the idle RPM not the throttle plate screw. Unless the computer has been disabled or removed, the throttle plate screw DOES NOT
control idle RPM. The IAC motor contols the idle depending on how much air is going around the throttle plate. With the idle air control motor fully closed, that's called "Minimum Air Rate." Look up the adjustment procedure for that. Once the Min Air Rate is adjusted the throttle plate is adjusted and the tamper plug is reinstalled so it won't be messed by some one who thinks that's how you adjust the idle RPM. I have had to do that on many a GM when they come to our shop and the car either dies coming to a stop, because the throttle plate is caked with carbon. Or some one has messed with the screw and didn't look to see it was dirty.

 

Well, it is running better. I had to adjust the idle screw to close the TB plates. Turned it in 1 turn. at first I opened the TB bades, but that raised the idle. This makes sense to me since I cleaned a lot of build-up off of the TB and blades.

I was able to drive it to the closest gas station, about 7 miles. It bucked and wasn't happy. Filled it up with premium and it is running smooth and quiet now.

I put the original tps back on, and it threw a failure code after about 10 miles test driving and kept the idle up. When I got home and checked,the TB position was scanning at 15% and idle was at 1500 rpm. Turned car off, cleared the code and restarted it w/o touching the gas. No code and it idled at 800rpms.

It still doesn't start as well as normal either.

I'm thinking of closing the TB blades down another turn. Before anybody says anything, I don't know how to do ais counts.

Big note, the TB blades opened too far can create tons of idle and tps reading problems.

Also talked with BP about the gas being bad. BP gas is green, that's normal. They agreed that the gas sample I brought was very bad, but are researching the matter. According to them, no other problems or complaints have arisin.