Candela

iTrader: (1)

Just to clear out any confusion this is a 1993 SC300 with the non-VVTi 2JZ-GE with Distributor and Karman Vortex MAF.


Okay so I have been searching for a very long time now, I don't like to open new threads at all, but searching has not led me to a solution. I have not had much time until recently to experiment, so here's the issue:


On a cold start (in the morning / car off for a very long time), the car struggles to start, sputters and shakes.

It'll start, then shut off, repeat this about two times, then finally idle -- yet very roughly with the rpms going up and down -- beneath 1,000 RPMs and almost touching zero.

If I give it a little bit of gas, it'll shut itself off.

It also will not do the cold start idle sequence, after a few seconds I have to manually bring up the rpms to warm the car up.

Once all that starting drama is done, the car idles perfectly fine, drives fine, no hesitations at all, WOT is perfectly fine as well.

--How could it be the starter if it winds up every single time and the car eventually starts when it stops acting up?
--I have already done the 12v fuel pump Mod.
--Knock sensors are fine
--Coolant temp sensors are fine
--Engine grounds are all good
--MAF is good
--Fuel pump is Good
--Fuel filter is brand new from dealer
--Igniter/Coil/distributor/spark plug wires and spark plugs are all good.
--The car has a cold air intake with 3"piping
--The car also has OBX headers
--The car has the Check Engine light on, codes 02 (MAF Signal) and 25 (Air-Fuel Ratio Lean)
>>>>>>>I am very positive this is because of the intake, as well as the headers, and I am currently looking into installing O2 sensor defoulers

**EDIT** Forgot to mention that after driving the car around and the car is all warmed up, the car would start right up with no problems.

Which now leaves me to look at the TPS, as well as the IACV. I am confused as to what exactly each one governs, and what their fault symptoms are.

I just wanna be able to start my car up normally, it's a goddamn Toyota it's supposed to work!!

What the hell is going on? If it drives fine and idles fine, which sensor can be faulty?

Gurus please chime in, I have been dealing with this and searching on this issue for a very long time, only to find loose-ended threads.

2jznosht

It's an sc...things will go out.

Oh and how old is your fuel pump? When its going up and down does it stay running if you shift into gear? Have you actually tested the fuel pressure to say the pump is good?

Candela

iTrader: (1)

I say the pump is good because once the starting drama is done, it idles perfect and drives perfect. It only goes up and down during that initial start-up sequence and thats for about 2-3 seconds until it shuts off, start it back up and then itll be rough and after me manually raising the rpms, it'll struggle a bit then smoothe out and everything goes back to normal.

2jznosht

I'd start by checking your fuel pressure

Candela

iTrader: (1)

I guess I'll give that a shot but, you mean to tell me for a few seconds, the fuel pressure will suck, and then once it smoothes out it'll go back to normal? Forgot to mention car has a fresh fuel filter as well.

2jznosht

Well I thought my fuel pump was good because I could hear it prime and the car ran, but died if shifted outta park or revved the motor. When you say it dies when you give it gas it sounds like the pump may not be delivering enough fuel when you rev the motor. My guess is the fuel pump is on its way out

Candela

iTrader: (1)

Well when i said it dies, it's literally only within about a 2-3 second range that it will do that, my car is manual, when i let off throttle and change gears, motor does not die or bog or anything at all.

2jznosht

I could be wrong and it could be tips or iacv, but it wouldn't hurt to eliminate a fuel issue.

Candela

iTrader: (1)

I think you're onto something about the fuel pump issue, I'll buy one, swap it out and see. I appreciate it man.

Anyone else wanna chime in possibly about anything else like tps or iacv or something else I might be missing.

Candela

iTrader: (1)

bump

msglngth

Candela

iTrader: (1)

Took some videos to demonstrate

SC400slide

iTrader: (11)

You did the fuel ECU 12v mod, but the entire unit could be faulty. Also, I personally think it might be the main ECU. I wouldn't go as far to say that the TPS or IACV would cause that big of a problem...GL

EDIT: looked @ second video, a faulty ECU would be causing way more problems then that, I think. So now, I say it COULD be the IACV.

Candela

iTrader: (1)

So then so far, one vote for fuel pump one for iacv. Thank u sir

Anyone else please watch my videos and share some ideas

Candela

iTrader: (1)

3rd video showing how it easily starts once it's been driven around

Brianmoss

Ever solve this?