Tampa 928s

john S

I am not sure what I .learned so you saying a limp home mode is on an 86/86 I thought that only related to the newer S-4 with the limp home relay?
I disconnect the ox sensor and still surging with the 42 lbs injectors. Per someone to remain unnamed said to set the presser to 30 Lbs and the car does stay running.
Does anyone have this set up on an 85 stage 3 with my computers?

Fabio421

Shane ( posted above ) does but he's running the true stage 3 with higher boost and an intercooler.

Tampa 928s

I am working on it with Murf.

dr bob

"limp home" feature allows the car to run at low load, with some default values, when the MAF fails or a connector comes loose.

The "ignition protection relay" on '89+ cars protects you from cat fire due to failure of one side of the ignition system. Thermocouples in the exhaust detect when only one system is working.

Two completely different functions.

Tampa 928s

Thanks for the limp mode description seems now I am limping but not getting far from my home.
I hope to get this issue straighten out this is the second time I installed this with the same results. I am getting good at tearing everything down so I guess that's a plus! At this point I am leaving this up to the Murf crew I have done everything I know to figure this out.

Tim Murphy

Right now I am thinking something is up with the LH. Mark has the version with a 28 pin EPROM socket whereas the 86 US cars have a 24 pin EPROM. I have never seen the 28 pin version and have no idea what might be different between the two, other than a whole bunch of different surface mounted components.

Here is a picture of Mark's LH and a couple links to discussions on the differences.

https://rennlist.com/forums/928-foru...1812304-a.html

https://rennlist.com/forums/928-foru...rs-beware.html

Tampa 928s

Murphy wants me to try another LH with 24 pin eprom to see if my LH is causing my issues with this stage 3 kit.
My stage 1 works ok except with the light throttle surge that I have never been able to correct. This is the reason I went to the stage 3 and he feels this maybe the issue.
I am looking for a loaner to see if this corrects the problem.

Fabio421

Is the 85 Euro LH the same as the one you're looking for?

Tampa 928s

I don't believe so from what I have read.

John Speake

The Euro LH2.2's don't have the components fitted for idle controller or the O2 loop, so no use for this test.

Tampa 928s

Thanks John!
My info on the 24 vs the 28 pin is that the 24 pin coding is on the eprom and controller sharing the 8K data. The 28 pin has all the coding on the chip do you see this as a possible problem for my issues I am having?
I tried everything to get this to work, with the stage 1 I have never been able to get the light throttle surge out this is the reason a I went to the stage 3. The only test I have available is to try a substantiate and and see what happens unless you can enlighten me.

Tim Murphy

Mark,
How easy is it to rest a stock air box with filter in it on the MAF? This would eliminate any weird turbulence affecting the MAF signal.

Also, make sure the o2 sensor wire on the computer side of the connector has not been compromised. For example, if the signal wire is grounded, even to the shielding in the cord, will cause problems.

John Speake

Not to my knowledge... not on the 928. But the LH2.2 was also used on certain Saab (turbos ?) and Volvos, so that may be where you are hearing about shared data.

Tampa 928s

I have a spare Lh to check it out should be here tomorrow. I data logged it and the injector duty cycle spiked then car stalled.

Tampa 928s

The LH is for an auto would that be an issue just for testing?