Throttle pedal help needed

Throttle pedal help needed

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V8 Vum

Original Poster:

3,206 posts

227 months

Tuesday 14th September 2010
quotequote all
Guys, I REALLY need your help...

I have a 'special' LS7, 'special' because I believe it was a non-production version with forged pistons etc straight from the factory as a 'left-over' (2007) from a run for motorsport.

The ECU supplied seems to have a very small stamp between the vanes with the letter E98. I thought most were supplied with something liake an E40?

I cannot find any reference to the E98 if that what it is on the net. This ECU came with the fuse box, and two relays (1 x pump + 1 x A/C)

Why am I asking? Good question... The engine is up and running now - it starts and idles but totally ignores the FBW throttle-pedal!

The Throttle-body has a silver throttle plate. (I believe some used for motor-sport have gold ones), and reacts to me gently pushing the plate open to returnb to closed.

I have checked all the connectors for bent, pushed in or broken pins, and none of the fuses has blown.

SO... is this the right ECU/Throttle-body/Throttle pedal combination? I have no idea...

Please help!!!!!

vetteheadracer

8,271 posts

259 months

Wednesday 15th September 2010
quotequote all
I've got a Motec M800 ECU and that can "talk" to both the throttle body and accelerator pedal and see the parameters that are set.
From memory one counts from about 10% up to 90% and the other down from 90% to 10% outside the limits (which I can't remember off the top of my head) the pedal stops working as the ECU shuts down and the engine goes into a fast idle setting.
Basically if the ECU can't "see" the throttle body / pedal within it's pre-defined limits it protects the engine by going to this default setting.
You will need to get a ECU tuning tool and plug it into the OBDII port to see that is going on as you press the throttle pedal down, but my bet is either the pedal position sensor or throttle body sensor is either not sending or is not being seen or as I said earlier one of them is outside its limits.

V8 Vum

Original Poster:

3,206 posts

227 months

Wednesday 15th September 2010
quotequote all
Needs two people then! ...or a huge mirror! ...or a very long stick!

Thanks I will have to persuade the missus to venture into the garage then!

cheers

7YEL

66 posts

170 months

Monday 20th September 2010
quotequote all
E85 marked on the ECU may mean it is programed for E85 fuel, here
is a link. The corvette race team also run E85 fuel

http://green.autoblog.com/2007/12/27/2008-indy-500...

V8 Vum

Original Poster:

3,206 posts

227 months

Monday 20th September 2010
quotequote all
Update Guys - Found that the 'Alternator'...Yes! Alternator plug when plugged in was dragging down the reference voltage from +5v to 1.4v, causing the throttle not to operate!!!!!!

Why the heck this is happening I don't know!

The Alternator plug is two wire, Orange and Grey, and the pins appear to be in the right place (ie not swapped accidentally), although I cannot prove it. If looking down onto the top of the alternator the GREY wire occupies the second pin out from the engine side, the Orange the third. Is that right? This is a brand new alternator and harness. As soon as I reconnect the plug - then the ref voltage get leaked.

Any ideas?

vetteheadracer

8,271 posts

259 months

Thursday 23rd September 2010
quotequote all
If it is a "racing" ECU the racing alternator would be a lot smaller than the standard road one, so it is possible that the ECU is programmed to expect a different voltage.

Could of course be a dodgy alternator.......