jowo9

iTrader: (1)

Questions:

1. My car isn't throwing any codes, but I've noticed that it's really peppy when it's cold out, and a dog when it gets warmer... I know this is normal to an extent, but could an intermittently failing KS cause ignition retardation only when it's warmer out?

2. Where is the best place to buy a knock sensor? Are the cheap eBay ones garbage? It's just hard for me to justify $150 from courtesyparts for something that I don't even know is bad or the problem.

3. Is there anything else that could be making my car abnormally slow when it gets warm outside? (like 40+ degrees, so not even THAT warm)


Like for example, would it be unwise to try something like this?

http://cgi.ebay.com/ebaymotors/Brand...#ht_581wt_1167

NmexMAX

iTrader: (22)

I would make sure you actually have a problem. I would try and stick with the courtesy piece. If you have access to an OBDII reader /logger like the Cipher, then log your WOT timing with respect to the outside temperature or, if it's a logger, against the IAT's or even ECT's and see if there is a difference.

mahanddeem

I have the same issue like the OP....

Child_uv_KoRn

iTrader: (7)

Welcome to the world of ****ty stock ECUs (perhaps).

It's the KS when it's related to engine temp. I never could fix the problem with crap performance in the summer. I had the KS simmed and it didn't matter.
And I know it's the ECUs b/c I also had a brand new 05 engine swapped in and the problem still persisted.

But your issue is even more bizarre considering it's still cool out. You can try simming the KS and see what happens.

jowo9

iTrader: (1)

How?

getflushed

I thought I had a ks issue, I went to radio shack and picked up a 470 risistor and threw it in to see if it made a difference, it didn't but I had no issues with putting a resistor in the sub harness

Benifits- if your unsure your ks is the problem its better to try a resitor in the ks sub harness because you won't have to remove the intake or cut your hands up Trying to remove it for nothing.
- you are wasting .50 cents as opposed to 150 dollars

Some people disagree with permemently using a risistor because if your engine does knock there is a chance of some damage. I personally would grab a resistor and drive it around for a day and see if you notice a difference, if there is none you just pull it out and plug the harness back in and all you losr out on is a 50 cent purchase. Let me know if you want to know the color code for the resistor they have little color bands to tell you the different resistors, I picked mine up from radio shack and left it in my car for a week with no issues at all! Trust me try this first
-

Gizm0

iTrader: (1)

I have the same problem with my '03 Max. Works great in cold weather, but when it warms up, I feel like I'm hauling a 4000 lbs trailer...

I replaced the MAF with a 2k1 MAF, replaced the KS with an eBay one (around $25), replaced a leaky rear valve cover, cleaned the TB, and no improvement...

Question, there is only one wire on the harness that plugs directly into the KS. is that normal or should there be 2 wires?

jowo9

iTrader: (1)

There's 2 on mine

jowo9

iTrader: (1)

I actually just tried this last night with a 470k ohm resistor... But I got a P0327 code as soon as I did it. I dunno, maybe the resistor wasn't making contact where I stuck it in... But I think it was.
I dunno.

Gizm0

iTrader: (1)

Could it be a bad catalytic converter? I read all over the internet that a bad cat converter will make your car loose power when warmed up...

TunerMaxima3000

iTrader: (4)

I have the same problem jowo. I need to do this test. Here it is for you though, same for a 97 as it is for the 2001, I can't verify if it's the same for the 5.5 but I'd ASSUME so.

EDIT: THERE ARE 2 WIRES

it's just essentially a resistor to ground, the ECM senses VDC needed to make the 'jump' across the KS to ground. This is based on the resistance of the KS. IIRC when it 'knocks' resistance goes down? Thus increasing VDC at the ECM.

FYI you can also test KS as follows:

1. ECU terminal #93 (wire colour W) Engine running at idle, should be about 2.5 VDC

2. ECU connector #93 (harness side, ECU unplugged) Resistance from KS to ground should be about 500-620 OHMS at operating temperature.

3. Similar to above test just easier, disconnect harness in engine bay, install Ohm meter on KS side wire terminal 1, to ground, same OHM reading should apply.

4. If these tests give you Ohm readings outside of the range specified, there are further tests, but it's likely that the KS is the issue, this is the point that I would install a resistor - a 550 OHM resistor.

TunerMaxima3000

iTrader: (4)

Easy way to test that is run the car until HOT on the highway, long highway run, if you lose power substantially the hotter it gets, it's probably a cat. This is a gradual loss of power, as temperature of the exhaust increases, not the temp of the engine.

If his symptoms are the same as mine, power is lost as soon as the engine starts warming up, and power loss is not better/worse depending on specific temperature, just hot/cold.

TunerMaxima3000

iTrader: (4)

So there are 2 wires my bad... one for ECM return, one feed?

If that's the case there should be referance voltage @ the harness. Ill post back need to investigate.

Gizm0

iTrader: (1)

Is it possible that there are 2 wires on the VQ30 and only one on the VQ35?

TunerMaxima3000

iTrader: (4)

Possible.. yes. I can't imagine they'd change the setup though.
Someone with the VQ35 needs to verify.

These were my readings.

Reference Voltage at harness, unplugged - 4.86VDC

Cold Resistance (OHMS) @ KS - 455

Operating Temp Resistance (OHMS) @ KS - 630


These readings are to spec. Strange thing happened though, after I checked the cold resistance I plugged it back in, went for a drive, and the car performed amazing, like it usually does when cold, the entire time I was driving.

I don't know why this is, I very much doubt it was a bad connection in the harness I unplugged (although that would make sense).
I can only suspect that something occured in the ECM when I unplugged it, I did have the engine running when I unplugged it and plugged it back in.

Just thought I'd share.

pkrainert

Sorry to steal your thread but I can't post yet lol. But will the check engine light go off if your sensor is bad? I just bought a 2000 Max, I used to have a 96 and my sensor was bad but I dont ever remeber it causing the CEL to go on.