vrracing

iTrader: (1)

yes, I searched and will even refer to some of the results of that effort.

Background:

• 90 S5 vert with newly rebuilt and installed JDM Tii. Ported using Pineapple templates. Performed Tii tranny swap last year and it's worked fine.
• Using as-yet-unmodified NA harness with all NA auxiliary components (AFM, APM, etc)
• All vacuum lines replaced and all gaskets on intake side siliconed. We did not disconnect the throttle body from the UIM during the rebuild.
• Car started right up on first try

Symptoms:

• Surges at idle from about 500 to 1200
• Accelerates nice (at a stop, we haven't driven it)
• Surges if you try to hold it at 2500 rpm

Diagnostics performed so far:

1. Used a torch to find vacuum leaks and air intake leaks. Removed fan to minimize air disruption. Didn't find any signs at all of leaks.
2. Did a visual inspection of the air filter to turbo lines looking for cracks and/or loose or missing clamps.
3. Have not checked timing, replaced plugs (used the working NA ones) or the plug wires (again using NA ones)
4. Grounded the ISC to the battery and there was no change
5. Put in my LED TPS checker (we'd used it on the NA with success) and both lights are on

Next steps:
Thanks!

Jim

Icemark

Jpsec engines do not have AWS, but do have cold start. The engine must be warm and at operating temps to set a TPS.

One of the two TPS's is out of adjustment (figuring that you are using a S5 engine and harness). You probably checked the wrong one.

or your timing is off.

vrracing

iTrader: (1)

Ah, glad I asked then as I'd assumed the cold start was the same as the AWS. All I did was stick the LED tester in the green port near the airbox and both lights were on. So I know the TPS is wrong. I guess will let it run until it's fully warmed (doesn't take long when it is 102 outside) and then go thru this procedure.

Can you reasonably check the timing with the idle surging?

Icemark

AWS = Accelerated Warm up System (heats the engine and cat converters faster).
Cold start= idle at 1500 rpm and drops to 700 rpm as the car warms when started with a cold engine.

and follow the factory service manual for timing.

vrracing

iTrader: (1)

Thanks, Icemark. She's purring like a kitten!

RETed's TPS instructions appear specific to the S4 since the S5 TPS has 6 wires, not 3. But the FSM was uncharacteristically clear and we checked the TPS ohm readings and they were all well within range. Then we used the LED light method and had to crank it a lot counter-clockwise to get just one light lit. Then we worked the throttle and got inconsistent results - sometimes one light, sometimes two - so we used a little spray lube on the tps and associated moving parts until letting off the throttle consistently left one light on.

Then we put the TMIC back on and attacked the CAS. We had to pull and restab it three times before we got it right. The idle isnt Lexus smooth but it sits at 750. I expect it will smooth out as the engine breaks in. The oil pressure is sitting at 40 psi at idle and moves above 60 when verped. Temp also sits right below halfway.

Thanks again,

Jim