2007 2.7 P0328

Hey everyone, I'm new here but I read a lot of posts regarding P0328 but I think my issue is a little different than the others that I have seen.

Initially I wasn't working on the truck because of a P0328 code. I was working on my truck because it was overheating. Late on a rainy night I drove out to Carl's Jr to get a burger. I was at the drive thru when I realized the my temperature was slowly going up. I started panicking and turned the heater to full blast to try to keep the temperature down. Thankfully I managed to make it home without the engine temperature getting to H. For some reason the temperature would only rise when I was idling and would stabilize when I would drive. I knew there was an issue but because of the rain and it being late I wasn't able to see too well.

The next day the rain let up and I was able to see that the engine had dried coolant in the back of the thermostat housing area, however after looking closely I saw that it wasn't the thermostat housing but it turned out to be a plastic bypass pipe that went through the intake manifold. I replaced it with the new metal bypass pipe. In between here, I got busy with life and let the truck sit for a while. A few months later I put the truck back together and refilled the cooling system. As I was making sure all the air was out of the cooling system and letting the engine get to temperature I noticed the check engine light for the first time.

Since I didn't have an OBDII scanner, I decided to test the truck by driving it to AutoZone so I could use their scanner there. The truck drove fine and didn't overheat and I got it scanned and that's where I first saw that it had a P0328 code. I figured that since the battery had been disconnected for a while that I needed to drive like 50-60 miles so that the computer could complete a drive cycle. So I drove the truck to further test the truck's capabilities which it again drove fine but the check engine light never went away. It was late at this point so I ordered an OBDII scanner before bed.

By the time I was free the next day my scanner had arrived and I verified that it was a P0382 code with my scanner. I erased the code with the scanner and it immediately came back. I looked up the code and saw that most people had the wired chewed or damaged. I also saw that the knock sensor was right above the bypass hose so I figured that since it was leaking coolant it was likely that it got covered in coolant and was probably damaged. So I took off the intake manifold again so I could take a look at the knock sensor and the harness but when I saw them they were fine. They didn't look damaged nor was there any coolant on them. They were just a little dusty. There were a couple of bolts on the intake manifold that I didn't tighten, the ones on the middle so I thought maybe it was running lean but that wouldn't really explain detonation or pre-ignition. Regardless I was extra careful and put everything back together and when I turned the truck on the check engine light came back on and again it was the P0382 code.

That night I read about how to test knock sensors. I didn't have an oscilloscope but I had a digital multimeter so I figured I'd try that the next day. I also ordered an aftermarket knock sensor before bed. The next day, by the time I was free, the knock sensor had arrived so the first thing I did was test it the new one so I could compare it to the new one. It read about 197K ohms of resistance and I used alligator clips to check its DC voltage and it read about 0.1-0.3mV and when I would hit the sensor with a screwdriver handle it would read about 0.8-0.9mv and sometimes as high as 1.2mV. I took the intake manifold off again and took out the knock sensor from the engine. I ohmed it out and it had a resistance of 203k Ohms and read similar voltages.

From what I could gather both of the knock sensors were behaving similarly so I figured both were good but I decided to put the new one in. After I put the truck back together, I fired it up and still had the P0328 code. I didn't change the harness but it looks like its in great condition. I'm more than willing to take the intake manifold off again and check the harness but I really don't think that's the issue.

Last time I changed the engine oil, I accidentally overfilled it. I didn't think that it was too big of a deal but when I let the truck sit for a while I noticed that quite a bit of oil seeped out from the valve cover and oil got on some of the vaccum hoses, the upper radiator hose going into the engine and into some of the vacuum hoses. I also saw that some the oil rose up towards the spark plug coils. The dip stick was initially reading maybe 2 inches above the full indicator on the dipstick. I took off around maybe a quart of oil and it sort of reads around the full indicator but its a little hard to read where its at. I didn't realize that I put that much oil, I'm not sure what I was thinking at the time. I had done so many oil changes on this truck and never had that happen to me before. I'm considering completely emptying out the oil and putting fresh oil and go off the dipstick instead of by the number of quarts like I did last time. I'm not sure exactly what I did last time, it was a while ago but I obviously put too much. I checked all the spark plugs and they looked good to me but I'll take some pictures of them and post them on here tomorrow. I changed the upper radiator hose as it looked swollen from getting in contact with the oil. I'll post some pictures of the hoses along with some other hoses that i didn't change yet.

I know this is a long post and a lot to read but I could really appreciate some help here. I really need to get this truck to pass the smog check so I can get its tags up to date so I can use it for work. Any thoughts, suggestions, or ideas? Any help or advice appreciated. I'll post more information, pictures, and maybe even live scan data tomorrow.

 

Having sat for a few months between the overheating and knock code appearing I'd be suspect of rodent wiring damage somewhere further down the harness.

Also sounds like a valve cover gasket project is in order. Overfilling isn't good, but should not excaberate a leak in that area.

Are you certain the high dipstick reading isn't from coolant in the oil?

 

1. Good pertinent info. Sounds like you're done the basics. Curious where are you located? Is the gas old/cheap brand? I would assume (yes I know) you have a lot of miles on the truck? You mentiond rain but only suggested this makes a noticable difference? Why? A couple things come to mind. First i think you have a fan clutch, right? It could be loose causing idle overhaet/misfire setting p0328. Checking youre wires for onvious cracks/danage (resistance/short) and actual values to and from ecu.Any worn mechanical parts making phantom knock frequency sounds like alternator bearings, water pump and belt idler (even overstretched belt max limit knock. Carbon build up on your pistons?

 

Thanks for the great replies.

As far as I can tell, there wasn't any coolant in the oil but I'll check the radiator cap to see if there's any oil on top there and I'll also check the oil when I drain it just to make sure.

I'm in Los Angeles, Southern California. I'm trying to remember, usually I try to put 76 but I might have put cheap gas which I usually don't do, so it could be the computer reacting to that. I was thinking about putting some seafoam in the gas and oil, not a lot, just a little to loosen some things up. Maybe I should put some chevron in there?

In regards to the rain, I think it was helped in the sense that it was cold and driving through it helped cool the coolant that was still in the cooling system. I think when I was driving there was probably a little better flow and thus better heat displacement and when it was idling there was just less coolant flow? I'm pretty sure that as the coolant leaked out the cooling system struggled to keep the engine temperature down. Yeah my truck has a fan clutch. When you say loose do you mean the nuts that hold it in place? I think those are tight but I'll double check. I just got a copy of the service manual, I'll check pins 28 and 29 for continuity, resistance, and voltage and see if they are within spec there.

I'll check the pulleys and the serpentine belt. When I was running it with the hood open I didn't hear any squeaking/whining pulleys but I wasn't really listening for that either. I'm thinking a little seafoam could help with carbon build up. When I took off the intake it did look dirty in there. I'll post some pictures before I get too dirty. I also really want to clean the engine so I think doing the valve cover gasket will make it easier to clean it.

I really appreciate you taking the time to help troubleshoot. I'll try out your suggestions and report back. Thanks again.

 

Oh and the truck has about 187k miles on it.

 

So much information (yes thats good). The sliightly unstructured feed is a little disoreinting. (At least for dunmmy me) . Could you do a re summery of issues?

Correct me if I'm wrong. My no non sense summery;
This is a fairly "new to me" truck with 187k. Initially looking into overheat @ idle only. Coolant going somewhere but uncertain where Later set po328. Typical code related parts replaced, still setting code po328.

My issue of attack always is do obvious issues first. ALWAYS. Whether suspect or not.

Move to secondary possibilities.

Overheat:
Coolant loss... pressure check for external leaks, thermostat operation, internal loss i.e. headgasket, cracked block.
External Cooling: internal plugged/external blocked radiator.

Weak fan clutch engagement (strong possibility IMO)

Is it flowing? I've seen water pumps with metal fins corroded away. Yes GONE. Thermostat operation

Bad/wet gas, plugged fuel delivery (lines, filter, pump). Tnis can cause preignition and influence engine knock. As can highly carboned pistons. An old but very effective and cheap way to decarbon an engine is to SLOWLY add water to the itake on a RUNNING FULLY WARMED UP engine (2k+ rpms). It basically steam cleans the combustion chambers. Seafoam is awsome maintenance item.

 

Agree with these points.

On the V6 they like to nest in the 'V' and typically chew the wires there. Not sure if the I4 has a similar area prone to rodent damage or not

 

Hey everyone, back with another update.

I was working on the truck the last couple of days and finally got a chance to drive it today but the P0328 showed up again. I had to take some stuff to storage and when I was driving it around town it drove like a dream; even with its ignition retarded. So once I get this code cleared I'm looking forward to it driving even better.

I did the following work on the truck:

• I changed the oil and filter, went with 5w-20 full synthetic,
• I did the valve cover gaskets (inner and outer),
• and I changed the PCV valve (I was hoping this would be it but the old one rattled when I shook it)

I put some seafoam in the gas tank which was 3/4 full and then topped it off with some Chevron. I was only able to put in 8 gallons of gas, so if the gas was bad then there is still roughly 13 gallons of old/bad gas in there. In case old fuel is the problem then maybe I shouldn't have filled up the truck until it was empty?

 

Sorry about the mess, I'll try to be more organized.

Yeah I would say the engine has a lot of life in it. I don't think the overheating is an issue. Before I put in the new metal bypass hose I checked the thermostat by putting it in boiling water and saw it open, then when I took it out it slowly closed. Despite this, I replaced it with a new OEM one as I had already gotten it from Toyota. I am a little worried about the head gasket. I'm going to clean the engine really good to see if there is still oil leaking out from there. Honestly, I wish I would have checked that before I did the valve cover gasket. I'm not seeing any signs of a cracked block and that I didn't see coolant in the oil or oil in the coolant make me feel a little better about the possibility of a cracked head or bad head gasket.

Weak fan clutch engagement is something I haven't explored very well. How would I check for that? With the truck put back together it doesn't appear to have any overheating issues anymore. I am open to doing the water pump if necessary but its not weeping and engine temperatures seem good.

I did put some seafoam in the gas hoping that it helps, will that work in lieu of adding water to the intake?

 

Appreciate the suggestion, I followed through and did the valve cover gaskets inner and outer. What's got me worried is why did the valve cover gasket fail? I was thinking that there was too much pressure due to the engine being overfilled with oil and the crankshaft bubbling up? I'm not sure if that actually happened but I'm trying to make sense of it in my head.

I didn't see any coolant in the oil or any oil in the coolant.

 

I took out the spark plugs and this is what they looked like.

They are ordered the same way they were in the engine. I'm not sure if I should replace them. Number 2 was really dry and hard to get out and number 3 was dirty. I was little worried about the porcelain part on number three. The electrodes looked okay though I think? Do you guys think they need replacing?



I guess I'm running out of ideas here. I'm starting to think that it's either fuel or spark at this point.

 

Age and heat cycles.

187k. When was it last changed?

 

As far as I know, it was never changed.

 

Yep, I have a 2006 I've owned since 09. I've done the valve cover gasket twice.
Op I would change those plugs, run the gas down really low and fill it up with fresh gas and not worry much about it until you get fresh gas.

Also did you reconnect the hose on the back of the intake manifold? I forgot to hook that up once and got a ton of codes. It's very easy to miss.

 

A good fan clutch will ROAR when started cold. It'll very loud and get quiter and quiter as the motor idles. Worn/tired clutches slip depending and usually only show up with high idle temps.

In the fuel is good but straight thru is gooder.
Depends on if its a light decarb maintenance or major deep cleaning.

Those spark plugs look like 2xs the wear. Funny Toyota says change every 40k! That's bs. Gaps worn way more worked perfect when i got my 4.0.

 

Buy new oe ignition coils.

 

I'm pretty sure I connected both hoses but I'll double check if I connected the little one by the sensor.

I'm already heavily leaning towards doing this but could you drop some knowledge on me? Why do you think this is the move?

 

Spark is nice.

 

I'd try replacing the plugs before you spend several hundred on factory coils.

 

Yeah, dont just throw (expensive) parts at it and hope you fix something. Besides this is a knock sensor circuit code..