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Discussion Starter · #1 ·
Well as some of you know, I have recently rebuilt the engine, and unfortunately have a few issues with the car, and am not sure where to go with some of them:

1) the car is pulling relatively low vacuum at idle, and needed the idle raised to about 1600rpm in order for it to stay on, during the rebuild 272 cams were installed, and i have heard that you are supposed to lose vacuum with these cams however, on my MAP ECU im idling in the -5 cell row and on my greddy gauge im idling in the middle off 500 and 0 on the gauge, which seems really low as before the motor build and the cams i was idling at 500 vacuum.

2) the car is reading extremely high EGT's under normal driving/cruising, shifting at 3500rpms during motor break in, I am seeing 800-850 C on the greddy EGT gauge, this is very odd as my wideband a/f reads anything from 12-14 which relatively speaking out of boost is safe, however the EGTs shoot up real fast; prior to the motor build under full boost redlining the car I would see 700-750 C after a long night of racing, hence why my concern has arosen.

3) the car is running warmer than it used to, it will read 3/4 - 7/8 of the gauge, whereas prior to the motor build it would be 1/2 of the gauge at all times, the overflow seems to constantly be losing water, and i keep refilling it.

These are the main 3 problems that come to mind, if you have any suggestions or ideas they would be greatly appreciated, thanks.
 

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Sooooooo JDM
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1.) Check for vaccum leaks. If need be, do a boost leak check to isolate.

2.) See #1

3.) Burp the cooling system. Sounds like you have an air pocket. Leave the cap off and let it idle for a bit. Also double check for leaks. If need be, do a pressure test to make sure you are not losing it at the head.


Try that and report back :)

Ryan
 

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Discussion Starter · #3 ·
Ryan23 said:
1.) Check for vaccum leaks. If need be, do a boost leak check to isolate.

2.) See #1

3.) Burp the cooling system. Sounds like you have an air pocket. Leave the cap off and let it idle for a bit. Also double check for leaks. If need be, do a pressure test to make sure you are not losing it at the head.


Try that and report back :)

Ryan
Forgot to mention that i already did a boost leak check, and have already taken care of any minor leaks.

Burped the cooling system until there were no more bubbles, overflow still fluctuates and boils over occasionally.
 

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Sooooooo JDM
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UF2JZ4U said:
Forgot to mention that i already did a boost leak check, and have already taken care of any minor leaks.

Burped the cooling system until there were no more bubbles, overflow still fluctuates and boils over occasionally.
Did you get the head rebuilt/skimmed while it was off the car? Have you done a leakdown test since?

Ryan
 

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Discussion Starter · #5 ·
Ryan23 said:
Did you get the head rebuilt/skimmed while it was off the car? Have you done a leakdown test since?

Ryan
i had 2 thousandths shaved off the head, no leakdown test however
 

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Discussion Starter · #6 ·
bump for more suggestions, I am hearing BHG, but want to get some more opinions before i go tearing the car apart
 

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feeding your habit
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If your af ratio is good, you may want to tell us where you have located the EGT probe. EGT is going to vary quite a bit depending on exactly where the probe is (distance) from the piston face.

-M
 

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Double check you timing marks (Crank, Cams.) If you had everything aligned and then put the tensioner on, you may be off a few degrees. I usually do it like this:

1) Align the cam gears with the alignment marks
2) set the crankpulley's TDC mark a couple of degrees counter-clockwise of the TDC mark on the timing belt cover (or oil pump.)
3) install the tensioner
4) rotate the engine 1 revolution (clockwise)
5) recheck that all marks are aligned -- if not repeat steps 1-5

It usually takes me a couple of tries before I get everything lined up perfectly.

Good Luck,

Shane
 

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Discussion Starter · #9 ·
98mkiv said:
If your af ratio is good, you may want to tell us where you have located the EGT probe. EGT is going to vary quite a bit depending on exactly where the probe is (distance) from the piston face.

-M
EGT is in the collector of the manifold directly below the turbo
 

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UF2JZ4U said:
Well as some of you know, I have recently rebuilt the engine, and unfortunately have a few issues with the car, and am not sure where to go with some of them:

1) the car is pulling relatively low vacuum at idle, and needed the idle raised to about 1600rpm in order for it to stay on, during the rebuild 272 cams were installed, and i have heard that you are supposed to lose vacuum with these cams however, on my MAP ECU im idling in the -5 cell row and on my greddy gauge im idling in the middle off 500 and 0 on the gauge, which seems really low as before the motor build and the cams i was idling at 500 vacuum.

2) the car is reading extremely high EGT's under normal driving/cruising, shifting at 3500rpms during motor break in, I am seeing 800-850 C on the greddy EGT gauge, this is very odd as my wideband a/f reads anything from 12-14 which relatively speaking out of boost is safe, however the EGTs shoot up real fast; prior to the motor build under full boost redlining the car I would see 700-750 C after a long night of racing, hence why my concern has arosen.

3) the car is running warmer than it used to, it will read 3/4 - 7/8 of the gauge, whereas prior to the motor build it would be 1/2 of the gauge at all times, the overflow seems to constantly be losing water, and i keep refilling it.

These are the main 3 problems that come to mind, if you have any suggestions or ideas they would be greatly appreciated, thanks.
I had a motor rebuilt and had the same problem with EGT buildup also. I never figured out what it was. This is why lately I prefer to just use a stock motor, rather than trusting a shop to "rebuild" it.
 

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Discussion Starter · #11 ·
ShaneW said:
Double check you timing marks (Crank, Cams.) If you had everything aligned and then put the tensioner on, you may be off a few degrees. I usually do it like this:

1) Align the cam gears with the alignment marks
2) set the crankpulley's TDC mark a couple of degrees counter-clockwise of the TDC mark on the timing belt cover (or oil pump.)
3) install the tensioner
4) rotate the engine 1 revolution (clockwise)
5) recheck that all marks are aligned -- if not repeat steps 1-5

It usually takes me a couple of tries before I get everything lined up perfectly.

Good Luck,

Shane
Went back and checked valve timing, and it is dead on.

As far as the other issues, the update is, I went back and burped the cooling system, and for about an hour air bubbles would intermittently come out, and I would fill it up as the level would drop in the radiator, drove the car for a day and it stayed at temperature for about 50 miles then after that it would occasionally start to rise from the 1/2 mark on the gauge to about the 2/3 mark on the temp gauge. Went back burped the system again, once again it took about an hour, once again drove the car around and it stayed at temperature for over 50 miles, then would start to run slightly warm, this time only a few ticks above 1/2 maybe 5/8 or so. I did a block test and there is no exhaust combustion present in my coolant. I did pressurize the cooling system, im not sure if the equipment was setup or working properly, but pressurized the cooling system with 15psi and within 2-3 mins it had dropped down to under 14psi within 5mins it was down to under 13psi.

As far as my EGTs go, i richened my map up, and now under boost the EGTs stay around 700C, but under vacuum EGTs rise very rapidly. Someone used a timing light on my car and said that it is very advanced, by like 20 degrees, im not sure how accurate his equipment is though, and if thats true, what would cause that, i ran the only check engine code on my ecu, and it is malfunction of secondary O2 sensor. I'm puzzled, any help would be appreciated, thanks
 

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When I had my EGT buildup problem under boost and vacuum, I started to suspect it was ignition timing. Check your ignition timing and let me know if that solves it.
 

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Discussion Starter · #13 ·
KevinB6876 said:
When I had my EGT buildup problem under boost and vacuum, I started to suspect it was ignition timing. Check your ignition timing and let me know if that solves it.
I have no way to monitor or control my ignition timing, however like I said, I had someone use a timing light, and it was reading 20+ degrees advanced but I am not sure if that was read or done correctly

Still open for any suggestions, if my timing really is that for off, what would cause that ???
 

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Discussion Starter · #14 ·
UP, for any suggestions
 
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