Mrmerlin

John thanks for the info , I also ran the car after fitting the new O2 sensor with the bad LH at first it was showing .50 volts after about a min of warmup, then the ICV control was lost at the test port.

The new used LH that was fitted worked as it should from startup to fully warm,
the ICV circuit was able to switched on and off at the test port,
also the engine could be restarted after it was shut off from cold to hot .

The other LH would not restart the engine after the engine got warm,
the temp 2 sender was also replaced and checked for function and appeared to working

What can you tell from this info?

John Speake

It's the usual hybrid failure in the LH ECU, both O2 loop and ISV loop circuits are on there....

Lizard928

But I thought the LH2.2 didnt have a hybrid circuit.?????

Mrmerlin

John, what causes this Hybrid failure??

John Speake

Doh ! Sorry, my mistake, didn't read the thread title correctly. Very unusual for an LH2.2 to fail. No hybrid as Colin says.....

Mrmerlin

John any idea what the failure might be here?

John Speake

I would have to test on my test jig to really find out, otherwise I'd just be guessing.... as I said, these inits are very troublefree, faults are rare.

Soundslike that one has been trouble before.

Mrmerlin

well in addition to the failed LH
I also removed a Viper 5000 alarm, not withstanding the car alsready had a factory alarm that was still connected and functioning.
Plus i disconnected 2 huge amplifiers that were attached to the rear carpet in the hatch area lots of sparks when the battery is connected. Anyhow my thinking was to get rid of all the extras electrically speaking as there were jumper wires going everywhere.
Thanks for your time, Stan

Mrmerlin

thanks i got one and the car is running fine,

the old LH was bad ,
the LH wouldnt continue to operate in the test mode ( bridge C and B at test port) and began to run rich after about 2 mins of running from cold . Lots of parts replaced but funny they were all bad ICV, MAF, T fittings ,Vacuum lines, O2 sensor, LH,
87 FPR

Plus I got Porken chips in it and the engine runs stronger


Note this LH was verified bad in another 86.5 and the same thing happened.
Thanks again

Mrmerlin

Hi all I am looking for a good used set of LH and EZF computers for an 86,
this is showing similar issues as the last car.
Runs fine when cold but after warmup it runs rough ,
test port operation is intermittent to disable the idle circuit.

NOTE the LH appears to have been rebuilt as it had stickers on the tabs ,
though the rough running issues were still happening prior to and after the LH had been replaced,
so the LH may have been bad all along even though it was rebuilt?

again this is quite similar to the other car i did where the LH had been replaced,
the rough running issues continued till another good LH was installed

Parts replaced,
fuel lines
all the dampers
and the 87 FPR
new CPS
new ICV
New Porken S300s chipset
MAF was way out of adjustment reading was .034.
after turning the adjuster pot it took about 7 turns to get back to baseline of 380

Will be installing new caps and rotors and spark plugs,
the old plugs were NGK platinums,
the caps and rotors are worn, will update as things progress,
These computers are forr Markmandudes car
Thanks for your assistance, Stan

Mike Frye

Stan,

PM your address and I can have them in the mail by this afternoon. I'm working from home and have a spare set.