Need help troubleshooting

[jonncarr]

 

Recently purchased 2000 ls400 with 128k . Will barely idle , disconnected maf and it ran better. Replaced maf with eBay one and it runs worse. Jumped fuel pump circuit with maf disconnected and runs barely better. So I’m lost. Any trouble shooting help will be greatly appreciated. Thanks. 

[paulo57509]

1. Does the Check Engine Light (CEL) come on with the engine off/key on?
2. Is the CEL on with the engine on/key on?

If you have No. 2, have you scanned for trouble codes?

1. What made you decide to disconnect the MAF?
2. What else have you done as far as diagnostics?

 

[jonncarr]

CEL is on with engine off/ key on. It’s on when running since maf is unplugged. Today I had to start it like 10 times to get it to idle. Then I could give it a small amount of throttle up to 3k rpm and it idled. I changed the maf because I had a Camry that had same symptoms and new maf fixed it lol. I know it’s getting air, fuel and fire BUT seems like a sensor problem I guess. What would you do?  Thanks for your help. Btw codes now are p0100 air flow meter circuit  p0101 mass air flow circuit/range performance. P0110 intake air temperature circuit and b2611 telescopic position sensor or motor. First 3 are from maf being disconnected I guess.  Any help would be appreciated. Thanks 

[paulo57509]

15 hours ago, jonncarr said:

CEL is on with engine off/ key on. It’s on when running since maf is unplugged. Today I had to start it like 10 times to get it to idle. Then I could give it a small amount of throttle up to 3k rpm and it idled. I changed the maf because I had a Camry that had same symptoms and new maf fixed it lol. I know it’s getting air, fuel and fire BUT seems like a sensor problem I guess. What would you do?  Thanks for your help. Btw codes now are p0100 air flow meter circuit  p0101 mass air flow circuit/range performance. P0110 intake air temperature circuit and b2611 telescopic position sensor or motor. First 3 are from maf being disconnected I guess.  Any help would be appreciated. Thanks 

For obvious reasons, codes that are set with the MAF disconnected are meaningless.  What are the codes with the MAF connected?

[jonncarr]

There are NO codes with maf connected. It barely idles connected , takes no throttle and dies. With maf disconnected it idles and will go up until 3k rpm. Runs rough. So what are some ideas?  Thanks. 

[Zeus253]

Check ALL vacuum hoses, one tiny air leak caused mine to act severely inconsistent in terms of everything you mentioned.

[paulo57509]

Q:  Was the car acting as described when you purchased it or did it start acting up after a while?

While the '98-'00 models aren't likely to have this issue, they're not immune to it.  Don't ignore this:

https://www.clublexus.com/forums/ls-1st-and-2nd-gen-1990-2000/656360-all-my-crazy-lexus-issues-solved-ecu-leaking-capacitor.html

Take the time to read the link.  Also, you cannot just get another ECU and plug it in.  The engine will never start because of the immobilizer.  The immobilizer is in the specific ECU that shipped with the car.  The only option here is to send the existing ECU out for repair.  Tanin is the go-to for work like this.  Contact them first before shipping off your ECU.

https://taninautoelectronix.com/

 

[Ed Fenwick]

Do you think maybe that the computer needs a few days to recognize the new MAF sensor?