> 97 vic 4.6L w code engine. does this have 2 ect on it? intake has 2
> sensors in front on same water passage. 1 on drivers side and 1 on pass side
> next to gauge sending unit. which one is the ect?
> getting a lot of spark knock with no codes stored/visible. dealer suggested
> checking ect,act,egr systems. haven't yet checked egr ports and act values
> within specs I have.
Thanks for the link.
I was going to check out the ports in the next few days just to rule
them out, this link will help!
The dealer and I discussed the ports extensively and we think its not
the reason for the spark knock, but as a last resort we figured to try
it.
I,and dealer agreed, think it's a bad ECT that's causing a too lean
condition. It really looks like 2 ect sensors there on the one water
passage, separated by about 3 inches. This morning before running the
vehicle I ohmed the sensors.at an ambient temp of about 80 deg F 1
read 25 ohms, which is what it should be for that temp. the other
ohmed out to 5 ohms which correlates to about 175 deg F. after running
vehicle the first one ohmed to 5, which is within tolerances. The
second read 1 ohm, which correlates to 240 deg F. I think that's
causing a lean out at operating temp which is causing the spark knock.
I'll find out as soon as I verify they are both ect sensors.
dmac
> Sounds like the EGR passage is dirty, I've heard of that happening on a lot
> of 4.6L's. See this for more info.
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> > checking ect,act,egr systems. haven't yet checked egr ports and act values
> > within specs I have.
Stan Kasperski - 15 Aug 2004 18:17 GMT
> Thanks for the link.
> I was going to check out the ports in the next few days just to rule
[quoted text clipped - 12 lines]
> causing a lean out at operating temp which is causing the spark knock.
> I'll find out as soon as I verify they are both ect sensors.
The following information is for my '92 but it should probably hold true
for your '97:
The sensor near the #1 fuel injector on the passenger side is a coolant
temperature sensor that feeds the instrument cluster only.
The sensor closer to the thermostat housing on the driver side is the
Engine Coolant Temperature (ECT) sensor that feeds the computer.
The resistance of it should be 24,270 ohms at 86 degrees F and 2800 ohms
at 194 degrees F.
My money is on the MAF. Clean it quickly... takes only a few minutes of
time.
Stan K.
dmac - 15 Aug 2004 23:47 GMT
I'll give that a shot tomorrow. whats best way to clean it?
the sensor near thermostat ohmed ok but the other was way off from the
ect specs I had. but if that other is just the gauge sender its
probably correct.
egr ports were checked today and were ok. not squeaky clean but no
blockage either. fuel pressure and flow were ok too.
I have to check the act and clean maf now I guess. its odd because it
only knocks when engine is hot and ambient air temp affects it too.
5 brands of gas (all three grades) didn't help either.
> > Thanks for the link.
> > I was going to check out the ports in the next few days just to rule
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> time.
> Stan K.
Scott M - 16 Aug 2004 19:50 GMT
> I'll give that a shot tomorrow. whats best way to clean it?
> the sensor near thermostat ohmed ok but the other was way off from the
[quoted text clipped - 7 lines]
> 5 brands of gas (all three grades) didn't help either.
>==============
yes, that is the way it happens. pings when hot. clean the MAF and put a
fuel filter on it if its been a while.
dmac - 17 Aug 2004 22:45 GMT
ok, cleaning mAF and ect/act contacts has helped a lot. no knock for
last 2 days under full throttle now. am putting new fuel filter on
both my vehicles saturday anyways so that works out well too.
Thanks everyone.
Dmac
> > I'll give that a shot tomorrow. whats best way to clean it?
> > the sensor near thermostat ohmed ok but the other was way off from the
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dmac - 17 Aug 2004 22:45 GMT
ok, cleaning mAF and ect/act contacts has helped a lot. no knock for
last 2 days under full throttle now. am putting new fuel filter on
both my vehicles saturday anyways so that works out well too.
Thanks everyone.
Dmac
> > I'll give that a shot tomorrow. whats best way to clean it?
> > the sensor near thermostat ohmed ok but the other was way off from the
[quoted text clipped - 14 lines]
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.735 / Virus Database: 489 - Release Date: 8/6/2004