Update............

[ae102]

well i finally changed the head gasket on me GXi after it had gone brittle from being standing for a while, engines only covered 20k but was stood up for about 2 years.

She fired straight up but was still ticking over a bit high, did the timing and this rose the tickover to 1800rpm???

i've got no warning light on and have changed the vacuum sensor and air intake temp sensor cos i had some spare in me garage and i changed the idle control valve...... all to no avail. not sure what else it could be - only 2 guesses i can think is maybe the water temp sensor or the throttle position sensor but would they really make tickover that high?

Any ideas?

[jay13]

have you bled the coolant through the system properly (all hoses hot, cooling fan working, hot air coming from the vents?), did my head gasket on my gti and as there was no coolant registering on the coolant sensor it went into pulse mode,

[ae102]

have you bled the coolant through the system properly (all hoses hot, cooling fan working, hot air coming from the vents?), did my head gasket on my gti and as there was no coolant registering on the coolant sensor it went into pulse mode,

thanks for the reply. cooling working as it should - i'm presuming/hoping its just a sensor. when your temp sensor failed how high were the revs.

[4afte]

some of the TPS sensors are very fiddly (demand to be spot on) and also the TPS sensor on the 4A-FE/7A-FE changed constantly between models so the impedance between this one and the original may be different

[ae102]

some of the TPS sensors are very fiddly (demand to be spot on) and also the TPS sensor on the 4A-FE/7A-FE changed constantly between models so the impedance between this one and the original may be different

that's kind of an interesting point - got me thinking!! this GXi is a '93 and me previous/donor is a '94 model, the only differences i've seen is the rear seats dont have proper rear headrests and the oil cooler. i noticed on the vacuum sensor the part numbers are different - not sure on the idle control valve but will check. wondering if its as you say there are different specs for the sensors (being different part numbers) and if the ECU is specific to the sensors? i might be a mile off but just an idea.

[4afte]

i belive that the ECU's are tuned to their specific sensors, though thier function and operation is the same i'm pretty sure as i said earlier some of the impedances between the years don't match up.

[ae102]

i belive that the ECU's are tuned to their specific sensors, though thier function and operation is the same i'm pretty sure as i said earlier some of the impedances between the years don't match up.

i'm gonna check the 2 ECU numbers

[ae102]

well the 2 ECU's have different numbers - swapped them over.........same :( changed the coolant temp sensor............same :(

the onlything i havent checked is the lambda sensor but i cant see that causing such high revs at idle? i hope it aint as its in a real arkward place and a bit of a pain to get out.

this ones got me stumped - just cant seem to get anywhere, any suggestions as to what could be causing this?

[4afte]

the lambda sensor can cause hi RPM at idle, used to do it on mine. got a universal replacement and has eased the problem but not resolved it completely

[ae102]

the lambda sensor can cause hi RPM at idle, used to do it on mine. got a universal replacement and has eased the problem but not resolved it completely

dont think its the lambda - car wasnt doing it before i swapped engines.

when i start the car from cold it ticks over at 1200rpm. as the temp raises so do the revs - once the car is fully warm it is revving between 1800 - 2000rpm.

basically i'm gonna have to go through all the sensors again - wondering if i have damaged the loom somehow, but if i had damaged a connector/wiring i would have thought the check light would come on?

[peebee50]

Hi, sorry to hear that you are having some problems with your GXi. Unfortunately I cannot offer any suggestions although it does sound as though the ECU is not getting the right signals from the temp sensor somehow. Good luck though! Was wondering if you found the time to check the front disc diameter of yout T-Sport? Thanks.

[4afte]

hmm thats a curious one. are you aware that the water temperature sensor effectively control's how rich the FE head engine's run?

[ae102]

hmm thats a curious one. are you aware that the water temperature sensor effectively control's how rich the FE head engine's run?

when i looked it to it i was surprised myself at how much influence it has on things - gonna check all sensors and connectors today or monday. i've swapped things over presuming i knew what was causing it and swaping sensors to match ECU but that obviously isnt the problem. got it in my head that i've contaminated a connector or damaged some wiring when i've swapped the engines over - that will soon be obvious with a few checks with the multimeter. could also be a vacuum pipe leak but thats less likely due to the symptoms.

you say your idle isnt perfect - i had similar issues in the past with the 7a - nothing like this though!- and got to the bottom of it with emmissions on the lowest limit. what have you changed already? do you get the slightest, and i mean slightest, hesitation on acceleration?

[peebee50]

Hi, take a look at this link - loads of technical info on Toyota engine management systems including temperature sensors and idle speed control. Hope it helps!

http://www.grubinski.com/grubinski/automot...toyota.manuals/

[ae102]

Hi, take a look at this link - loads of technical info on Toyota engine management systems including temperature sensors and idle speed control. Hope it helps!

http://www.grubinski.com/grubinski/automot...toyota.manuals/

thanks mate - appreciated lots of stuff on threre to confuse me! i've just been reading idle control section, very detailed.

[4afte]

my 4A-FE unit is very tempremental, not in a bad way, it just sometimes performs better and other times not so good. It doesn't like intake temperatures above 24 degrees and optimal is anything below 15. i've changed the lambda sensor, timing, fitted a new head gasket and new piston rings too. runs okay most of the time with spritely preformance. Giving the old 4A-fe a good send off this sunday by taking her round silverstone. she'll be out after that for the 3S to go in.

[ae102]

my 4A-FE unit is very tempremental, not in a bad way, it just sometimes performs better and other times not so good. It doesn't like intake temperatures above 24 degrees and optimal is anything below 15. i've changed the lambda sensor, timing, fitted a new head gasket and new piston rings too. runs okay most of the time with spritely preformance. Giving the old 4A-fe a good send off this sunday by taking her round silverstone. she'll be out after that for the 3S to go in.

dont suppose you fancy taking pictures as you do the job? would like to see what goes into the conversion. if you get a new exhaust i want the b/box

[4afte]

okay mate, will do a progressive step by step starting from next week, hopefully. as for the exhast, if it changes i'll let you know

[ae102]

okay mate, will do a progressive step by step starting from next week, hopefully. as for the exhast, if it changes i'll let you know

that would be spot on with Fensport not selling the GZE anymore could be the way forward with mine next year. been looking at all sorts of things - gotta have a dream - and the 3S conversion seems to be the most cost effective way. if you leave it fairly stock it will run forever..........

i see in Australia they got a limited run of 7a-fte's but with the inherent bottom-end weakness of the 7a you'd be spending a small fortune on forged rods and GZE pistons just to make it reliable. "weejohn" over in N.Ireland is doing a 3S conversion but he's going for the GE head. he does a lot of track days and has found turbo's problamatic in the past - worth considering.

[4afte]

well the engine conversion is only stage one. i'll need a year or so to bed in the engine (i'm rebuilding it too) and then i can begin stage two. but more on that at a later date... :!Removed!:

[ae102]

finally got round to diagnosing the car properly! me old man is a whizz withthe multimeter and i thought i had damaged the loom so i wanted him involved.

Got to take me hat of to you 4afte lambda sensor seems to be at fault. interstingly after i tested the lambda sensor i bridged e1 and te1 and i dot tp fault codes - 22 & 41? cant understand why its throwing up coolant temp sensor as i tested that and the connector and all was as it should both when cold and warm. the check light isnt staying on and these codes where not logged last time a started the car when i checked for fault codes. hopefully get the chance to remove it this weekend - hoping its just contaminated or the connector is faulty but i aint that lucky!

i managed to damage the o2 sensor off me old GXi when i was removing the exhaust. why it aint like most lambda sensors i dont know as they are easy to remove but these......................

[4afte]

i know what you mean, the toyota lambda sensor appear to be designed so they are impossible to maintain. I rounded both nuts trying to get it off, in the end resorted to a large pair of mole grips.

oh and glad to be of assistance.