Idle issue

jkendall86

Member
Apr 10, 2005
155
3
18
69
Salem, Oregon
I just acquired a 1989 NA 7mge....was told the TPS needed replacing. When I first drove it, the idle would bounce from nearly zero to about 2k....when I unplugged the TPS, the engine idle went sky high....thought it was boing to blow before I got to the key. I do have code 51 and I hear the ISCV click when I turn it off. I have tested the tps with an ohm meter and it seems fine. I'm not certain that the cables and screws weren't messed with on the throttle body, but everything looks fine....anyone have an idea what I should check next?
 

jkendall86

Member
Apr 10, 2005
155
3
18
69
Salem, Oregon
Update....Ok, I replaced the TPS, cleaned the IACV...that got rid of all the codes, but it still did not really run right and the idle was really high when warm, about 3000, but would drop if the throttle was punched, but then go back up once driven. I did notice a timing problem. The exhaust cam was one tooth off. Fixed that and it seems that the idle is a bit better....it is times right on at this point....I will check again tomorrow after work.
 

g_smityy

New Member
Feb 16, 2015
1
0
0
Maryland
jkendall86;2041011 said:
I did notice a timing problem. The exhaust cam was one tooth off. Fixed that and it seems that the idle is a bit better....it is times right on at this point....I will check again tomorrow after work.

so it was a timing issue with your supra? the reason i ask is because im having the same problem with mines. when it started going bad it seemed to be stuck at 2000rpm then it went up to 5000rpm now its at 5500rpm and idk what to do
 

jkendall86

Member
Apr 10, 2005
155
3
18
69
Salem, Oregon
After checking a bit further, I found the can shims were not within spec...fixed them all and it runs much better...someone did not pay attention when they dismantled the head...

contact me via text...503-930-7268
 

sup89t

New Member
May 19, 2017
5
0
0
54
AU
plaaya69;2094001 said:
You have any codes? When did your problem occur?

Gday mate thanks for replying it started about a year ago or so there was no codes i know on but the batterys been on and off the car so there wont be any in it any way
So i start the mrk3 1989 7mgte and at the time it wood start ok but other times it wood start and sit on 1500rpm and then as time gos by it went to 2500rpm and this is just on start up and wood not come down and now as soon as it starts it gos to 6000rpm ive tryed every thing i swaped out computers, the hole inlet manifold ive blocked off the brake booster valve and have had 3 idle control valves any help wood be appreciated
 

plaaya69

87T Supra
Nov 18, 2006
947
7
18
Lake County, IL
No problem. Are you sure your throttle linkage is not sticking? On the throttle linkage assembly on the passenger side valve cover, I would check for any play in it as those plastic washers also wear out and can cause a sticky throttle. Also I would use some silicone spray in that area on all those springs.

Usually if you have a intake leak it would make the car sputter and stall out but on your condition it is revving up the motor when its not suppose to sounds like it could the the idle air control valve or the tps sensor. On the ISC valve I have seen those take the motor to about 3k rpms when they go bad. Do you have your circular check valve installed as well with the ISC valve?
 

sup89t

New Member
May 19, 2017
5
0
0
54
AU
And i dont think the throttle butterfly is sticking open coz i can hold it shut on the link and it just drops 500 rpm