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Location:
Victoria
Registered:
December 2002
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3T-GTE Design flaw?
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Sat, 15 January 2005 23:49
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Just wondering if 3T-GTE's have an an inherent design flaw that causes leaning out and thus detonation on cylinder no 4.
I've had this happen on 2 engines, and have heard that other people have had no 4 drop.
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Location:
Sydney
Registered:
June 2004
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 00:02
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what intake are you using? stock or custom made?
with intake the best design is having a centre throttle body which allows even air flow throughout. thats why with custom intakes they usually are smaller towards the end (no 4 cyl) to maintain the air flow rate to be consistent all the way through...
leaning can be caused from many things like injectors not supplying enough fuel, sensors not reading correctly or ECU
where is it leaning? low RPM, mid or high? or is it just in general that it occurs
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Location:
Terrigal
Registered:
May 2002
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 07:28
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I cant add much to what Fade-e said but my tuner always adds a bit more fuel to cylinders 3 & 4 on my 3t-gte. But you of course need an aftermarket ecu to have this kind of tune-ability.
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Location:
Dandenong Ranges, VIC
Registered:
July 2004
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 08:28
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wouldnt insufficient air supply make the cylinder run rich? tapering the plenum would remedy a rich #4 cylinder by increasing air velocity to the rearmost intake runner.
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Location:
Brisbane
Registered:
May 2002
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 10:18
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On most engines the rear of the engine suffers the most heatsoak because of the way the coolant flows through the engine, so it's common for the rearmost cylinder to detonate first.
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Location:
brisbane
Registered:
October 2004
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 11:01
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the stock manifolds on these things are a design
flaw by themselves. it wouldnt surprise me to
hear of problems like you have. i still want one
tho!! forgies, management sys, intercooler, rx7
injectors and a few other bits would go hard 
the dude on here with the saab intercooled one -
what a weapon!
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Location:
Pilbara
Registered:
November 2004
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 12:31
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Bigger injectors (Red Denso?) and wind the adjustment screw in on the afm for stock ECU's. Will give ya more fuel.
Also, this may be a stupid question, but I'm assuming that you are using a swirl pot/ surge tank setup? It'll lean out going round a corner unless you have your tank at least 2/3 full, if you don't have a surge tank or intank swirl pot. Is the Engine in a TA22? I'd be addressing the lean out problem by using bigger pumps and lines as well. Intercooled?
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Location:
Madrid - Spain
Registered:
August 2002
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Re: 3T-GTE Design flaw?
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Sun, 16 January 2005 23:33
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Ha, I thought you were making a generic statement that the 3T-GTE was a design flaw.
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Location:
Victoria
Registered:
December 2002
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Re: 3T-GTE Design flaw?
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Mon, 17 January 2005 08:48
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The motor is in my TA22, I bought the motor in a car from QLD and got is shipped down here to Vic. Aparently it had been rebuilt about 5000kms (with forged pistons and head work). I swapped the motor into my car along with the Microtech and Bosch fuel pump to avoid any changes that may affect the accuracy of the tuning. It was only running standard boost (7 psi). I only drove it into town and back (about 15kms, and it wasn't an overly hot day). So now I have water in the oil and both in the number 4 cylinder. I'm hoping its just the head gasket, i'm in the process of taking the head off now to find out. I hope its not a cracked head or block. There shouldn't have been a fuel supply problem as I had a full tank (optimax) and a 2 litre surge tank and lift pump.
My last 3T-GTE lasted a fair bit longer untill it broke the ring lands on number 4. But they were only standard cast pistons and it was running 12 psi, with wolf 3D computer.
If it's anything more than the head gasket I think I'll give up on these motors and fit a SR20DET or a 1UZFE. I had a S14 for a few years and it seemed really reliable.
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Location:
Victoria
Registered:
December 2002
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Re: 3T-GTE Design flaw?
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Mon, 17 January 2005 08:53
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I hadn't hooked up the intercooler yet as I wanted to make sure the motor ran alright once i'd swapped it into my car and so I could judge any increase in lag with the extra intake tract volume due to the intercooler...
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Location:
Brisbane
Registered:
February 2003
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Re: 3T-GTE Design flaw?
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Mon, 17 January 2005 09:33
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did you get any logging from teh microtech before it died?
maybe it was running hot (air intake temp) due to lack of FMIC? was it surging (lean fueling)?
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Location:
Pilbara
Registered:
November 2004
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Re: 3T-GTE Design flaw?
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Mon, 17 January 2005 09:41
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It really sounds like you had some bad luck with the motor. Feel for ya mate. I think it's a dodgy 'rebuild' and you probly got a thrashed motor. There is no way it should have shat itself if it was rebuilt to the specs you said and you were running stock boost. It definitely is not a lean out problem. With any luck it will be just a gasket. I do wonder about tuning with Microtech's. Timing being too advanced can stuff things up as well. (I know that the Ignition with these is independant of the ECU)
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Location:
Victoria
Registered:
December 2002
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Re: 3T-GTE Design flaw?
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Sun, 23 January 2005 10:20
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Okay I pulled the head off and the gasket had a small "low" section that lead to a water jacket hole so thats hows the water got into the cylinder (Number 4). Although there was also water marks in the intake port of number 4. I don't know if that suggests a crack in the head or if the water could have ran or been pushed into the intake port. The gasket doesn't really explain the water in the oil though, as sealing around the oil galleries was still fine. I dont know if the water could have been pushed past the rings, water doesn't compress so it had to go somewhere when the piston came up and the rod isn't bent.
Also there was evidence of detonation in the fire rings of the head gasket, predominatly on cylinder 1 and 4. (Little dents in the fire rings) And also a score mark on cylinder number 4.
I also discovered that there was no intake airtemp sensor on the engine. I neglected to find this earlier as I just swapped the engine and computer as they were. Having been dyno'd by a reputible tuner I assumed everything was okay and that was why I didn't want to change anything at that point, I even swapped the exhaust from the other car.
Regarding logging from the Microtech, I don't yet have the PC link cable or software. I'm back at work now so only have weekends to work on the car again. So i'm collecting up stuff again so I can take a week or two off in a month or so to try and get the car back on the road again -having presumably wasted a heap of time and money allready. I'm getting the head pressure tested (hot) soon so hopefully it comes back good.
A 1UZ conversion is looking really good right now - the power I want, standard and N/A.
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Location:
Victoria
Registered:
December 2002
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Re: 3T-GTE Design flaw?
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Sun, 23 January 2005 10:21
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Okay I pulled the head off and the gasket had a small "low" section that lead to a water jacket hole so thats hows the water got into the cylinder (Number 4). Although there was also water marks in the intake port of number 4. I don't know if that suggests a crack in the head or if the water could have ran or been pushed into the intake port. The gasket doesn't really explain the water in the oil though, as sealing around the oil galleries was still fine. I dont know if the water could have been pushed past the rings, water doesn't compress so it had to go somewhere when the piston came up and the rod isn't bent.
Also there was evidence of detonation in the fire rings of the head gasket, predominatly on cylinder 1 and 4. (Little dents in the fire rings) And also a score mark on cylinder number 4.
I also discovered that there was no intake airtemp sensor on the engine. I neglected to find this earlier as I just swapped the engine and computer as they were. Having been dyno'd by a reputible tuner I assumed everything was okay and that was why I didn't want to change anything at that point, I even swapped the exhaust from the other car.
Regarding logging from the Microtech, I don't yet have the PC link cable or software. I'm back at work now so only have weekends to work on the car again. So i'm collecting up stuff again so I can take a week or two off in a month or so to try and get the car back on the road again -having presumably wasted a heap of time and money allready. I'm getting the head pressure tested (hot) soon so hopefully it comes back good.
A 1UZ conversion is looking really good right now - the power I want, standard and N/A.
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I Supported Toymods
Location:
Glenmore Park, NSW
Registered:
March 2004
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Location:
Sydney
Registered:
June 2004
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Re: 3T-GTE Design flaw?
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Sun, 23 January 2005 12:39
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| KoinTA22 wrote on Sun, 23 January 2005 21:21 |
Okay I pulled the head off and the gasket had a small "low" section that lead to a water jacket hole so thats hows the water got into the cylinder (Number 4). Although there was also water marks in the intake port of number 4. I don't know if that suggests a crack in the head or if the water could have ran or been pushed into the intake port. The gasket doesn't really explain the water in the oil though, as sealing around the oil galleries was still fine. I dont know if the water could have been pushed past the rings, water doesn't compress so it had to go somewhere when the piston came up and the rod isn't bent.
Also there was evidence of detonation in the fire rings of the head gasket, predominatly on cylinder 1 and 4. (Little dents in the fire rings) And also a score mark on cylinder number 4.
I also discovered that there was no intake airtemp sensor on the engine. I neglected to find this earlier as I just swapped the engine and computer as they were. Having been dyno'd by a reputible tuner I assumed everything was okay and that was why I didn't want to change anything at that point, I even swapped the exhaust from the other car.
Regarding logging from the Microtech, I don't yet have the PC link cable or software. I'm back at work now so only have weekends to work on the car again. So i'm collecting up stuff again so I can take a week or two off in a month or so to try and get the car back on the road again -having presumably wasted a heap of time and money allready. I'm getting the head pressure tested (hot) soon so hopefully it comes back good.
A 1UZ conversion is looking really good right now - the power I want, standard and N/A.
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have you chacked for any visible cracks on the head? i have found that predominantly the crack is usually between the valves
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Location:
Victoria
Registered:
December 2002
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Re: 3T-GTE Design flaw?
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Wed, 26 January 2005 08:31
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Nah I can't see any cracks... Gotta get time to get home to pick up the head and get it tested. I suppose I could just put my other head on, but its only standard...
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Club President
I supported Toymods
Location:
Sydney
Registered:
May 2002
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Re: 3T-GTE Design flaw?
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Wed, 26 January 2005 10:22
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Dude,
If the engine was tuned without an air temp sensor I would be concerned as to the quality of the tune. Get it checked out by someone who knows what they ae doing.
While its appart get your injectors cleaned and tested, A bad spray pattern will give poor atomisation and can also cause pinging.
Let us know how you go.
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Location:
Brisbane
Registered:
February 2003
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Re: 3T-GTE Design flaw?
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Thu, 27 January 2005 02:43
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in regard to lack of air temp sensor - it's one of the key sensors that many ECUs will use to determine and apply any fuel enrichments. If the ECU always thought the engine was always at operating temps, you would have been running lean until you got it to warm-to-hot.
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