4L60E (TH700) problems

[meanvrss5.0l]

Hi all,

I have recently completed my VR SS project with a warm rebuilt 5L running crow 282 cam, flat tops, haltech E8 ecu, etc. She's been dyno tuned and makes 170rwkw for all intents and purposes. The transmission is standard apart from the 2500 hi stall converter. Today was the day for rego and whilst on my way to and from Queensland transport, I noticed a problem with transmission. I have not driven far enough to know all symptoms but I believe 3rd gear is the only one available. From a stand still with 'D' selected, when I stand on it, it flashes to 2500rpm as it should but once it reaches 2500rpm it is slow to build up speed. I can then drive to about 130mk/h without a gear change!!! It does not go into over drive and does approx 3000rpm at 110/120. Now, if I select any other gear, 1, 2 or 3 it does the same thing. Whilst travelling at an approx speed of 60km/h it will down change manually from 3rd to 2nd. I have spoken with the guy who did the Haltech install he said no wires have been touched between pcm and transmission. So here I am. All obvious checks have been made, fluid level etc but still no change. Does it hot, cold, and any other way it wants to. Does anybody out there have any idea's or advice speaking from experience or common knowledge? I am good with engines and manual gearboxes but auto's are like women to me. Very hard to understand. Thanks.

[greenacc]

any error codes coming up ?

[clubby_you]

It's in limp home mate i would be looking straight at the haltech

[meanvrss5.0l]

Thanks mate I think your right about the limp home mode. Do you know what can cause the PCM to activate this mode apart from problems in the transmission circuits? I understand the PCM requires signals from various sensors in order to make gear changes which is why I ask. I dont think it is tranmission related due to the fact it was working fine until Haltech install. One wire they disconnected is Pin D16 (Engine Coolant Temp sensor signal) and have that wire connected directly to Haltech ecu. So the PCM has no temp signal at all. Can this cause Limp mode? Cheers.

[clubby_you]

I would say it has more to do with the ecu giving directions to the motor and nothing happening since the haltech is managing the engine now.
I dont think the temp sensor will be related just the factory ecu wiggin out cause the motor is doing things its not telling it to and vice versa

cheers doug
(ps) i assume this is why haltech advertise there ecu is for vr vs manual only..!

[sircruisealotVS]

This is the main reason i hate piggyback units on an auto - they just never work right. Even when you get one that states it's auto compatible and wire it up exactly as shown the auto still never works the same as it did stock.
There's a definate possiblility that the coolant temp sensor not being connected to the pcm could be causing your dramas but im not 100% sure. I'd also be thinking without this connected you'd have an engine light on constantly?
I'd make them connect back everything like it was stock and just have the haltec wires spliced in to the signals they need (which is what they should have done...) and see if the auto works then. If there's no love there, and your wanting to still keep the haltec your probably looking at either a standalone auto controll unit being installed or converting to manual.