Overheating + Misfire... Suggestions?

[jdemara]

Problem #1
The coolant is boiling and spitting out of the overflow canister.

I'll start by saying the car has previously had the head gasket replaced by Toyota.

I have done a compression test as of today:
Cyl #, in PSI
1. 180
2. 175
3. 175
4. 172
5. 175
6. 170

Also, I have replaced my thermostat with both a 192 degree, and now a 160 degree to see if it makes any difference. (don't notice any difference)

No smoke out of the tailpipe, just coolant loss out of the overflow.
Also, I do hear the gurgling sound from the heater core, and have tried to bleed out the air, but doesn't seem to work.

I am looking for some ideas on what this overheating problem could be? What should I be testing/looking for to eliminate this problem?

Problem #2.

The car seems to be misfiring only between 0-5psi when keeping the throttle steady.
Changed the plugs, I *think* it helped a little bit, but is still hesitating. Car pulls hard under full throttle and boost though (8psi). So this makes me confused.


Help would be great guys, in need of some advice/suggestions on what to do.

Thanks everyone.
(sorry if it is not detailed enough, let me know if i have forgotten anything)

 

[IwantMKIII]

fixing problem one should fix problem 2, if you're boiling then things are WAY WAY WAY too hot. Check to make sure you radiator cap is good, next, get a coolant system flush, you're probably blocked up somewhere since your compression test checked ok.

GET RID OF THAT 160* TSTAT! Don't forget the jiggle valve mod or whatever its called.

 

[NewWestSupras]

+1 on the coolant system pressure test. I'd ensure your water pump is good as well. Make sure none of your hoses have pinholes, and the rad is not opening under pressure. Don't overpressurize when testing, either. Any leaks should hopefully be apparent at 12 lbs or so. The top tanks on the rads like to split, hard to see sometimes. Also that hose at the back of the head can get pinholes easily. gl.

 

[fonz87]

seems like i have the same problem with the overheating.

 

[jdemara]

should i go back to the 192* thermostat? or go with a bit lower and get a 180* ? ?

any experience with that? i know this 160 is too low and takes forever for my car to reach operating temp.

 

[Kckazdude]

Have you checked the radiator to make sure it isnt partialy blocked? Also have a leak-down or combustion gas test performed. Will give you more insight into any problems than a simple compression test.

 

[jdub]

should i go back to the 192* thermostat? or go with a bit lower and get a 180* ? ?

any experience with that? i know this 160 is too low and takes forever for my car to reach operating temp.

In Vancouver? Go with a stock temp stat.

Have you checked your timing?

 

[Nick M]

Problem #1
I have done a compression test as of today:
Cyl #, in PSI
1. 180
2. 175
3. 175
4. 172
5. 175
6. 170

You need to pull the EFI fuse.

 

[jdemara]

You need to pull the EFI fuse.

I did pull the efi fuse while doing compression check, always do.

Just put a 180* thermostat in and a new rad cap (other cap was still pretty new, but wanted to try another)
Made no difference>

my timing is 10 degrees BTDC with the wire joining the Te1 and E1 in the diagnostic port.

Thermostat is a failsafe, which means it locks open when the car gets too hot to prevent overheating. But it keeps going into the locked open position which means the car is obviously running too hot. (And taking forever to reach operating temp.)

I am going to hopefully do a pressure test tomorrow after work, possbly leakdown test as well. This shouldn't be too expensive, correct?

If that doesnt show any problems, I am going to flush my radiator and take off my water pump to check it out.

and if THAT doesnt work, im stumped!!!

 

[jdemara]

Also, replaced the plugs and I believe the misfire is gone. The car also pulls much harder with the new plugs. I'm not 100% sure why this would be, considering my other plugs were higher quality and only had about 7,000km on them... Maybe the bigger gap on the new ones gives me a bit more power?
These plugs are gapped at .040 instead of the .028 or .032. (.032 is what i was running before)
Seems ok at 9psi.

 

[jdub]

Couple other things:

For the misfire, check your plug wires and test the coils per the TSRM. Gap at 0.40" is too much for a turbo car...go to 0.30".

For the overheat, Your radiator may be partially clogged and/or the fan clutch is not working properly. Does it overheat in stop/go or highway driving?

Cutting the jiggle valve off the thermostat will help rid the system of air. Like I said, you need to use a 190 deg stat in your climate.

 

[jdemara]

is there anyway to test the fan clutch?

and how do i check to see if my rad is clogged, maybe take it off and flush it for a while?

 

[chevyeater]

What did the plugs you took out look like? Can you post closeup pictures of the end that goes inside the combustion chamber on each plug?

 

[jdemara]

sure, will take pics tomorrow after work!
i believe they were a bit glazed but a more experienced person can maybe tell me otherwise

 

[Nick M]

You are washing your cylinders down. That is why you have the drop in sequence. Well, your tester could be magic or something.

A water pump that doesn't pump won't force coolant out of the radiator. That fluid takes a long time to heat up from conduction without circulation.

 

[Kemosabe]

seems like i have the same problem with the overheating.

Don't rule out the BHG! Remeber, it's a Aluminum head and everything expands and contracts, possibly opening and closing the blowby from your head gasket. Therefore, compression and leakdown tests don't always give you a true picture. Get the Combustion Leak Tester (Block Tester Kit) from napa, mac, or snap on.

http://www.mactools.com/portal/site...toid=7a3152850014d010VgnVCM100000426fa8c0RCRD

It will show if there are exhaust gasses in the coolant. Then you will have that answer, period. As for the OEM gasket being changed by Toyota, so what? I went in the shop to observe their skills on another customer's car. The Toyota dealer here didn't even have the torque wrenches to do the job! Just a few old timers and some kids that said "Don't worry, I got the feel". And they used no book guide for the torqueing sequence! Just a random tightening. Things are not always what they seem. Dealerships are hiring "Techs" and paying them $7-$10 per hr. while they charge you $95 per hr.! A head gasket job is 10 hrs. in their labor book. Plus the parts and machining.

 

[jdemara]

You are washing your cylinders down. That is why you have the drop in sequence. Well, your tester could be magic or something.

what are you talking about? drop in sequence?

the compression test reads 170-180 whether the engine is cold or hot.

dont automatically assume its going to be a BHG either, just because most people have it.

 

[GrimJack]

What he meant is that your cylinder pressures appear to drop as you test - starting at 180 and going to 170. Most common cause for that is forgetting to pull the EFI fuse, which allows the injectors to spray fuel into the cylinders during the test - the later cylinders get more fuel and read lower.

Could be a coincidence, of course, and your pressures really are 180 - 170.

Don't put too much faith in the block tester, either, I've had it pass my engine when it had a BHG. You can test the fan clutch by spinning it by hand with the engine off and cold, it should spin, but not very far - a quarter turn, maybe a half. If it spins freely, it's dead.

Is it spitting coolant after working hard, or when idling hot, or idling cold? Or all of the above?

 

[jdemara]

im not dumb, i always pull the EFI fuse when doing a compression check. stated that before.

fan clutch is fine, doesnt spin more than 1/4 turn.

spits coolant out of the overflow after working hard.. doesnt seem to do it at a hot idle or cold idle.

however, it depends, because sometimes it wont drip out at all, and sometimes it will (after working hard)...
there have been a few times where it was fine