More Engine Idle problems

[96blackgt54]

Not saying its the same thing but most of the time its a faulty tps sensor causing a hanging idle with a Ford. Just replace it but be sure its set to the correct voltage.

[TorqueEffect]

Not saying its the same thing but most of the time its a faulty tps sensor causing a hanging idle with a Ford. Just replace it but be sure its set to the correct voltage.

TPS on the B3 and B6 is just position switch, Idle, open throttle, WOT. open throttle being an open circuit.

[96blackgt54]

Wow....entirely to simple! I like it

[rmoltis]

You know, I had a loping idle issue after I installed my header back exhaust.

Been working on dialing in my engine for quite some time now.
I make small incremental changes then drive for a while; days, weeks, months, or just plain not driving at all

I noticed that as more ignition advance was added the better the vehicle would run, just all around.
Setting timing on a fully warmed up engine 195-200* and setting the idle mixture for 7-800rpm idle.

But! On the coldest days when it had to warm up, my idle would jump up to anywhere between 1300-1700rpms.
And they would stay in that range until the point the engine coolant temp hit a certain deg F.
But it also had a strong lope in the idle like you guys are mentioning.
The high idle was normal.
The ecu enriches the fuel mixture and incrementally decreases enrichment as engine temp rises.
And this process happens when the coolant temp is below a certain temp.
So since our cars have a hard time retaining engine heat. It always gets back to the point where the idle kicks back up again.
This part is normal.
But say your coolant temp sensor goes bad or reads lower than it really is.
Your idle might constantly stay higher since the computer would "see" it as not being warmed up yet?

The next culprit of a high idle is when the cat is not getting hot enough to "light off" the chemical reactions.
The ecu can see this and increase idle speed to help get it up to temp..
But this is only on obdII vehicles (like my aspire).


But the part that wasn't normal was,
The loping/hunting/stumbling idle I had. turned out to be from a small lean condition.
But through a combination of adjustments via; adjustable fuel pressure regulator, ignition timing, idle mixture.
The loping/hunting/stumbling idle, has since gone away.

So signs point to lean condition, either caused by the afr, ignition advance, idle mixture.
But since you said the high idle is constant, it may be a sensor based problem causing it like the coolant temp sensor for example.
Or even a bad o2 sensor could be the cause.

There was a point where my non heated stock o2 sensor wouldn't get hot enough to read exhaust gas oxygen content.
So the computer would kick up the idle just until the o2 sensor got warm and started producing values.
But once warmed up the idle would return to normal and the o2 sensor would cool down, then idle would increase again.


One of the simplest answers might be that your ignition timing is off by a tooth or something, just keeping the distributor out of the correct range.

These are just some thoughts related to smoothing out my idle.
Keep in mind I have an obdII aspire so there may be some differences ,
But I'm just trying to put some ideas out there for you to look into.

Good luck!

[TorqueEffect]

Thanks for the reply.

But I was finally able to get the timing marks to actually read on the scale, but when I try to lower the idle the timing mark on the pulley starts jumping around (won't stay on 8* btdc) But if I increase the idle over 1k rpms to about 1100 or 1200, then the timing mark stays rock steady.

I have changed the coolant temp sensor, that really didn't change anything.
I took off and cleaned the IAC, didn't really change much. I even temporarily bypassed it, but that didn't help at all. Just made it to where the car wouldn't idle at all when cold. :p

Adjusting the TPS back into spec helped quite a bit, but still can't get the idle down to where it is supposed to be, and have a nice smooth idle, with the timing marks staying rock steady in place.

[TorqueEffect]

What are the possibilities that maybe the Dizzy was installed incorrectly?

Because I know the tangs could have been flipped, so that while at TDC the rotor wasn't at the #1 plug position, but the #4 position. This is the only other thing I could think of that would cause the timing to be so far off, but I have no idea if the engine would even run like that anyway. So instead of the firing order being 1-3-4-2 like it is supposed to, it would be firing at 4-2-1-3. To me that sounds like it would still run. I guess the only way for to check this is to put the timing light on the 4th cylinder plug wire and see if I can get the timing mark closer to the scale without going to extremes. Or just set it to TDC, and remove the dizzy cap and see what plug wire the rotor is pointing to.

[defprun]

Make sure the 1 plug wire is on the disty hole with the "1" on it and that at 10° tdc the rotor is pointing to that 1 wire as well

[nitrofarm]

What are the possibilities that maybe the Dizzy was installed incorrectly?

Because I know the tangs could have been flipped, so that while at TDC the rotor wasn't at the #1 plug position, but the #4 position. This is the only other thing I could think of that would cause the timing to be so far off, but I have no idea if the engine would even run like that anyway. So instead of the firing order being 1-3-4-2 like it is supposed to, it would be firing at 4-2-1-3. To me that sounds like it would still run. I guess the only way for to check this is to put the timing light on the 4th cylinder plug wire and see if I can get the timing mark closer to the scale without going to extremes. Or just set it to TDC, and remove the dizzy cap and see what plug wire the rotor is pointing to.

No Dude, there is a much easier way,just roll Cyl #1 up to TDC Compression Stroke then pull the cap and mark the outside of the Dizzy with a sharpie exactly dead center of where the rotor is pointing. Loosely reinstall the cap and see what plug terminal its pointing at.Its that simple... and FYI 1-3-4-2 is the same as 4-2-1-3:thumbs_up: