wanted To borrow, for a fee. ECU J-Spec TT auto

[Chris Wilson]

Got a nightmare car in, done everything I can think of but still runs so rich it soots the plugs, now thinking the ecu itself is broken. Need to borrow a known good J-Spec auto TT engine and hopefully throttle control ecus for test purposes. Will arrange insured collection and return and pay a loan fee

 

Symptoms. Engine ecu light permanently on, seems to start off in 2nd or third gear, only drives backwards normally, runs MAD CRAZY rich.

 

Thanks.

[Frank Bullitt]

Pm dude Chris, you can borrow mine as it's just sitting there at the moment not being used

[Nodalmighty]

Got a nightmare car in, done everything I can think of but still runs so rich it soots the plugs, now thinking the ecu itself is broken. Need to borrow a known good J-Spec auto TT engine and hopefully throttle control ecus for test purposes. Will arrange insured collection and return and pay a loan fee

 

Symptoms. Engine ecu light permanently on, seems to start off in 2nd or third gear, only drives backwards normally, runs MAD CRAZY rich.

 

Thanks.

 

What Error codes does it report if any?

 

Basically 6 things effect fuelling on a JTT, map, Lambda, water temp, air temp, throttle sensor and fuel pump ecu. Disconnect all but the fuel pump ecu and see if the fuelling changes due to the ecu reverting to known warm settings. Dodgy ecu grounds at the inlet manifold can cause similar symptoms and I've seen plenty of those left hanging after and engine out.

 

Have you had the injectors cleaned and flow tested? Maybe one is stuck open.

 

Does it have a Fuel Cut Defender ?

 

With regard to the auto being a bit weird, I've had something similar with one of those full on HKS speed cut boxes than connects to both the engine and TRC ecu if the earth was left off.

[dude]

Pm dude Chris, you can borrow mine as it's just sitting there at the moment not being used

 

I can't find my one any where Chris, Ben says you can try his, are you pretty sure it will be OK.

[Chris Wilson]

Thanks Ben, very kind of you.

 

Nod: I can't pull codes as the light is permanently on. It's been to several garages, all have drawn a blank. Tried new O2 sensor, known good throttle pot, water temp sender,

MAP and air temp sender. Fuel pressure is normal and references to vac and pressure normally at the FPR port. Injector on times are huge, all injectors are pouring in loads of fuel. Very occasionally the light is known to go out and it seems to be OK. It also has another problem in that number one turbo is partially seized, but it's not an air flow restriction problem as it idles mad rich even with the TB to IC hose off. All coil pack connectors are new and I can't believe it's a crank or cam pickup issue. Cam timing is correct, the TDC line is referenced correctly to TDC, so the damper isn't on the move. I can see no additional gizmos either under the ecu cover area, nor behind the dash or under the car in the transmission tunnel. the ecu is receiving sensible voltages form the MAP sensor. I am 90% sure all engine earths are on, where exactly do the inlet manifold earth tags bolt to the manifold, I can't remember? I did have very weird issues with a customer's used MR2 engine that came with a loom, but without the ground tags connected under the intake. Thanks for the help!

[jagman]

The good news is that the light is on ,so the ECU recognises a failure.

The Ecu can only "see" a limited amount of failures,and it has on occassion all come good and light has extinguished , it is far more likely to be external to the ECU,as an intermittent fault.

Start with the voltage sense I guess , and work across each input to see which is out of range or missing -

That's the logical approach , but sometimes simply grabbing hold of looms and connectors and giving them a "shake check" can give results far quicker than elimination one by one.

[Nodalmighty]

Thanks Ben, very kind of you.

 

Nod: I can't pull codes as the light is permanently on. It's been to several garages, all have drawn a blank. Tried new O2 sensor, known good throttle pot, water temp sender,

MAP and air temp sender. Fuel pressure is normal and references to vac and pressure normally at the FPR port. Injector on times are huge, all injectors are pouring in loads of fuel. Very occasionally the light is known to go out and it seems to be OK. It also has another problem in that number one turbo is partially seized, but it's not an air flow restriction problem as it idles mad rich even with the TB to IC hose off. All coil pack connectors are new and I can't believe it's a crank or cam pickup issue. Cam timing is correct, the TDC line is referenced correctly to TDC, so the damper isn't on the move. I can see no additional gizmos either under the ecu cover area, nor behind the dash or under the car in the transmission tunnel. the ecu is receiving sensible voltages form the MAP sensor. I am 90% sure all engine earths are on, where exactly do the inlet manifold earth tags bolt to the manifold, I can't remember? I did have very weird issues with a customer's used MR2 engine that came with a loom, but without the ground tags connected under the intake. Thanks for the help!

 

That does sound like a comprehensive set of tests. The earth tags are front and rear just before the two inlet manifold parts join head side. I'd try unpluged sensors and see if you can get the light to go out. Does sound like the ecu is having a brain fart though.