2002 Rx300 AWD.

Hi, I had a misfire on number 1 clyinder so, I took the plenum off and replaced number one Coil pack, and plugs on all 6. I put everything back together and made sure I connected the one ground on the back and the two grounds on the side stud. Used Denso plugs and coil.

When it cranks, it just turns over like it has no fuel. When I hooked the obd2 to it, it cranks but runs rough for a while then smoothes out to run perfectly. Unplug the obd2 and it cuts off. It ran fine earlier this morning before the tear down.

It sounds very similar to a bad ground but again, unless there are two behind the plenum, I have the one hooked up. Plus the grounds on the side. Any advice is appreciated, I'll be on standby until solved and will post the solution.

 

Check again for an unconnected ground at the back on the block, hidden from view as it is close to the firewall. Use light and mirror to get a visual in the tight space. From memory there are more than one ground strap. There is another ground near the dog bone torque brace.

Too late now, but removing the plenum was not needed to replace the plugs. I can only suggest that minimum must be touched during DIY.

Salim

 

Grounds going to side of plenum

Two grounds near the bone shaped mount.

I couldn't take a picture of the one ground wire behind plenum, coming out of the harness and onto the back of the plenum. But, its hooked up. Is there supposed to be two in the back, out of sight?

 

There is a ground post between the firewall and the engine at the top. This post is not visible and there are more than 1 wire that needs to be connected. [I am going by memory ... there is more discussion in the knock sensor DIY].

Salim

 

I took it apart and cleaned every ground again, put it back together and it cranked right up. I still don't know what I did different. Im idling at 2krpm even when warm though, I must have a vacumme leak I guess.

 

As you pointed out the idle is high.

Check slack in the throttle cable 1/8-1/4".
Also ensure the cruise cable is fully released.

ECU has to relearn the proper idle (IACV position), so give it some time to adjust. Obviously if they're like vacuum leak .. that has to be fixed.

Salim

 

Thank you, Salim. Youre the man.

I am aware of the cable slack. Odd thing is, when I first cranked it after the job, it idled great (750) and drove like a new car. Then two miles down the road, put it in park and was at 2krpm. I followed the hood diagram and have all vacum hoses correct. Ill just drive it until it hopefully settles. Thanks again.