Hi Everyone,

 

My dad is trying to help out a mate who is having some cold starting issues with his 2001 corolla. When the car is cold, it takes a lot of revving and a lot of attempts to get the car started. Once its warmed up, you can turn it off and restart it without issues (at least not until it cools down again).

 

Dad has already replaced the fuel filter and spark plugs, but it hasn't helped. He's now thinking the problem may be with the automatic choke/fuel injection.

 

Has anyone got any ideas, or experienced similar issues as above? If yes, what was the solution?

 

Cheers,

J

The main thing to look at is the cold start injector timing circuit (normally loacted on water outlet on back of head), Also check it for fault codes.

+1 to check the water temp sensor, most likely faulty or unplugged causing the computer not to know the engine is cold and not to inject enough fuel...

 

Could also possibly need a throttle body and idle control valve cleanout as that only happened to mine last week...

The main thing to look at is the cold start injector timing circuit (normally loacted on water outlet on back of head), Also check it for fault codes.

 

7As don't have cold start injectors. That sensor on the water outlet is the coolant temperature sensor.

My bad, I thought the 7afe used the same sorta injection system as the 4afe.

My bad, I thought the 7afe used the same sorta injection system as the 4afe.

 

Old 4AFE had the cold start injector, new 4AFE (and hence the 7AFE) didn't

I think the issue could have something to do with the idle air control valve.

Here's my logic:

The later EFI systems use the regular injectors to richen the mixture, they don't use CSI's anymore.

I think the ECU will still read the lack of temp sensor input as being cold - that way the mixture won't lean out and burn holes in the pistons.

If it is reading the temp sensor (it knows the car is cold) it's going to be pumping extra fuel in anyway.

So, in my estimation, the fuel ecu is trying to provide a rich mixture for starting but the other half of the equation is out-of-kilter - that's the air - hence idle air control.

 

RollaBoy suggested the throttle body be cleaned - this is where I'd start.

Make sure the IAC (Idle Air Control) valve is removed and thoroughly cleaned (carby cleaner is good).

Another point to make is that you need to be sure that if there are any small holes (like vacuum ports) present, you clean them really good and test them to make sure air can flow through them.

 

Hope that helps ...

I had cold start issues on the 7A a while ago, and idle problems as well, seemed like the ISCV wasn't working properly. Took the connector off, checked voltages/resistances (they all seemed normal), so I put it back on (no cleaning of the valve or t/b or anything), and then it worked fine. So it could be something as simple as a loose plug....