Multiple issues, need help diagnosing 4.7 V8 (2 Viewers)

[gthoman]

Hello All,

I have a 2003 GX470(245,000 miles) V8 4.7L and last weekend all my problems started. I was towing the boat home when all of a sudden the CEL/VSC lights came on and smoke pouring out under the hood. Pulled over, opened the hood and the top radiator hose had come off! I had some water in the car and was only about 8 miles from home so filled it up, clamped the hose back on and started again. Only made it about a mile and smoke out of the hood again. Both times I was looking at the temp gauge and it was sitting between hot/cold(normal). I had the car towed to my house and checked the codes, it had a P0117. Someone suggested that it might be the thermostat, so I replaced the thermostat and while pouring the new coolant in I noticed dripping coming from under the top radiator hose, the radiator had a crack in it. So, I then ordered a new radiator and replaced it, hoping that was the problem. Filled the car with fluid/cleared the codes and started it up. It seemed to have a hard time starting(turning over several times before starting), but it did start. I had the radiator cap open and the car to fill with coolant. I was filling up the coolant as it ran, but seemed to start boiling and overflow from the overflow. The idle was rough(not really rough, but lack of power), tried to put it in gear and it turned off. I checked the codes and this time it had P0300, P0302, P0303, P0305 and P0306(bunch of misfires). I've read it could be timing belt, head gasket, water pump?? Any help would be GREATLY appreciated.

 

[GXO]

Sounds like the timing belt could have let go. That would explain the multiple misfires. The coolant issue...the TB is RIGHT behind the water pump, so you could have a lot going on. 2003 is good news. Non-interference motor. You can tear into it, replace the timing belt, water pump, hoses, and refresh the coil packs and plugs and catch up on maintenance.

 

[gthoman]

Thanks Dan, I was thinking this might be the case, but thought this was an interference motor. Good to know that its not. Thanks Again!!

 

[GXO]

05+ are. The subtle difference of 03-04 and 05+ are the timing and vvti. It causes all sorts of confusion. Hence why you can SC an 03-04 but can't in the 05+.

 

[HomersCanyonero]

That’s great advice from Dan. I had a independent mechanic replace all my cooling parts on my 2003 including radiator, big hoses, cap, thermostat, water pump, and timing belt.

I got all the parts/coolant myself and only cost about $550 including tax and shipping. All were done together at the same time. Labor was $500.

The 2003 GX470 4.7 V8 seems to run quieter than the V8 on my 2008 LS460. Not sure why but my GX470 engine is super quiet.

By the way, how hard is it to get to the coil packs? That’s one thing I haven’t done

 

[GXO]

Coil packs are simple. They are RIGHT there in the open. Plug and play.

 

[LaserNomad]

I dont want to think about how much a supercharger would kill the mileage. You could take it to a pro and have them figure it out and then fix it your self... I would only do this if it was a fun car and not a DD.

 

[half k cruiser]

Hmm, so it built up enough pressure to blow the hose off ( not blow a hole in the actual hose ) ? Then you develop a bad radiator. Sounds like a significant overpressure on your cooling system. That can be caused by either a bad radiator cap, or exhaust gasses entering the cooling system.

 

[gthoman]

So, since this has been an extra car for the time being, daughter is away at college and its "her" car, I've been working on it when I can get to it, and finally have most things done. Once the timing belt and water pump were replaced(timing belt was still intact and water pump seemed ok, but the tensioner pulley was very hard to move. So..
-changed timing belt
-changed water pump and pulleys that came with the kit
-changed upper/lower radiator hoses
-changed the coolant temperature sensor
Once this was done, tried to start the car....the car did start after a few tries, but had to push on the gas to keep it from cutting off. I did this a few times and checked the codes, it had a P0354
Since this code seems to deal with a misfire on cylinder 4 and I needed to change the plugs anyways. I....
-changed the spark plugs
-moved the ignition coil from cylinder 4 to cylinder 1.
Got the car started again, had to keep on the gas to keep it running
It would not stay on long and I have not got it to start again. Checked the codes Since I had disconnected the battery, it had wiped out the P0354 and not showing any codes now. Could this be the ignition coils? Any ideas to narrow down would be greatly appreciated.
Here is a link to it trying to start:
20180903_182347.mp4

 

[gthoman]

Just went out and cleaned the MAF, the car was able to start again, took time to start and didn't stay on long before it cut off(basically like before) Could it be that its not getting enough gas? I have the bluetooth reader and the torque app, but have only used it to read codes, I know it has other logging, just haven't used it

 

[Kelevra]

I am not a mechanic, I do have an opinion though. Is it possible that the coolant got into the coils? If so, I would think it would be hard to "dry them out" with the antifreeze in the connections. Second guess, did you do a compression test? Third, it might be possible that a pulley is sticky and hard to turn? I think that is all I have.

Good luck, I hope it gets sorted out,

B

 

[gthoman]

Thanks for the response Kelevra, when I changed the plugs I didn't see any fluid on the coils or plugs. I don't have a compression tester, I guess that might be next on the list. Pulleys should be good since I spun each one before I put on the belt, but could try to get someone else to try to start the car, so I can see if I can see anything while its trying to start

 

[Kelevra]

Thanks for the response Kelevra, when I changed the plugs I didn't see any fluid on the coils or plugs. I don't have a compression tester, I guess that might be next on the list. Pulleys should be good since I spun each one before I put on the belt, but could try to get someone else to try to start the car, so I can see if I can see anything while its trying to start

OK, I was just thinking if the antifreeze got inside the electrical connection it might have caused it to misfire. My P car had a bad coil, stopped the car from running, unless gas was given. I wish I could help more, I am just not very mechanical. I would say the compression test should rule out a bad cylinder. From there should be gas or spark. When it does start, does it backfire like timing is off, or just a rough idle?

 

[gthoman]

Thanks for the replies, no worries, your giving me ideas. When it started, I was able to hold it at about 2K rpm's and it seemed fine, as soon as I let go of the gas it cut off. The last time is started seemed a little more rough idle and then cut off, but no backfires

 

[Kelevra]

Thanks for the replies, no worries, your giving me ideas. When it started, I was able to hold it at about 2K rpm's and it seemed fine, as soon as I let go of the gas it cut off. The last time is started seemed a little more rough idle and then cut off, but no backfires

So, it sounds like timing is correct. If off, I would think popping and backfire? Well, I got nothing else at the moment. Did you post up over on GXOR? They have sharp mechanical guys there.

 

[ArBrnSnpr]

I've had similar symptoms from cars in the past. On one occasion I had a badly clogged fuel filter. I don't think the GX has a serviceable fuel filter so I would check other fuel system components, ie injectors, pressure regulator, etc.

The other time I had these types of issues was on a BMW that the MAF had failed on.

On the BMW I was able to unplug the MAF and start the car and get an improved idle, but not enough to drive without the sensor. What it told me was the sensor was part of my problem though. On the lexus, that won't work as it's much more sophisticated than a 93' BMW. Do you know anyone with a GX you could swap and check sensors with?

As far as the fuel system, I'd look into getting my injectors flow tested (or just upgrade to 12 hole densos). You can make an injector test device with a 9v battery, door bell button, some wiring and a measuring cup but that's a lot of trouble when our injectors aren't that expensive. You might also want to check your fuel filter pick up screen isn't clogged. At 245k miles it's a possibility.

Good luck!

 

[GXO]

Did you do the coilpacks? Are the codes cleared? Misfire is almost always coilpacks first. Rough idle is almost always O2 sensors or MAF.

 

[gthoman]

Unfortunately I don't know anyone with that same year/model so can't swap the MAF, also I believe the fuel filter is inside the tank, so like you said not serviceable.

I have the coil packs on order, so they are next to be put on.

The last code was a P0354, but when I changed the plugs I disconnected the battery and now there are no codes and I guess the car hasn't been able to stay on long enough to throw any codes. But hoping its the coil packs, just wanted to see if there is a way to determine whether I'm throwing money away and the engine is toast....It doesn't seem to be since I can get it started and seemed to be running ok and noone has really gone there, but thats why I'm here, looking for help. I really appreciate all the responses.

 

[gthoman]

Also, I ordered the coil packs from 1Aauto, seemed to have really good reviews for their coil packs and were 1/5 of the price of the name brand ones. Anyone else use these?

 

[GXO]

That code is a coilpack error. It should have had text to tell you which one was bad (usually a letter). The letter is the alpha-numeric to tell you which cylinder (a=1, b=2, etc). I wager your issues will be resolved when you do the coilpacks. I only use aisin/oem coilpacks as the bosch seem to be slightly different than OEM, and I have no experience with other brands. If they suck, you will see more codes soon enough!