Have I fried my ECU?

WARNING, THIS IS LONG-WINDED!!

Please could someone help me out, or point me in the right direction?

I'll start from the beginning: on Saturday I fitted an AEM boost controller, no issues.

On Sunday I fitted a Walbro fuel pump, again no issues

Yesterday morning I decided to fit a HKS FCD (brand new), and connect the speed signal (de-restritor) wire for my Thor TSD/DSC... this is where the problems started

In haste, I thought I would splice into the ECU harness with the ECU in-situ, rather than removing the three plugs to have a clearer look.

The problems started when, initially I spliced into the sub-throttle position sensor wire (pin 63), rather than the turbo pressure sensor wire (pin 62). Then, I also fluffed the grounding of the FCD by splicing the ground wire into the sensor ground (pin 65)

I reconnected the battery, and fired the engine up (with the above wiring mistakes). When it started the needle on the rev counter span up to about 4.5k then flickered, although in reality the revs were around the 2k mark. Then the counter needle dropped to 2k then the engine and needle pulsed between 1.5k and 2.3k. I left it running for a while to see if it would rectify itself, but it didnt.

I switched the ignition off then fired it up again, and the revs flew upto 2k, then dropped down to about 700 and idled smoothly. Great I thought, so I decided to go for a test drive, I put it in reverse, pulled of the driveway, stuck it in drive, let my foot off of the brake, and it stalled. I turned it over again, put it in drive and managed to get it back on the driveway.

I thought that it would be an issue with the FCD, so I checked all of the wiring properly with the harness disconnected. I found my "boo boo's" and rectified.

Fired the car up and the same thing was happening; revs pulsing between 1.5k and 2.3k. I decided to disconnect the TSD wire and hook it up as stock, as it was the easiest place to start - no joy. I then double checked all of the wiring, i'm getting continuity through everything, including the repaired c*ck-ups, and have double checked the pin locations - all fine.

I then decided to disconnected the FCD and reconnected all of the original wires. When I started the car, it was exactly the same.

My questions are:

Could I have fecked the ECU by wiring the FCD up incorrectly?

Is there anything worth checking under the bonnect TPS etc?

Could I have killed some sort of relay or fuse?

Could it be that my car is running purely on the ICV, hence the stall when trying to pull away?

Sorry about the essay chaps, but i'm bamboozled

Cheers,

Andy

Did you try reseting the ECU since you put it back the way it was?

I know nothing about this stuff so its just an idea.

Did you try reseting the ECU since you put it back the way it was?

 

I know nothing about this stuff so its just an idea.

I disconnected the neg on the battery everytime I touched the ECU so that should have done the job

Thanks for the input anyway

In summary:

I fitted a HKS FCD incorrectly, splicing into the sub-throttle position sensor wire, and using the wrong wire for the ground.

I rectified all of the mistakes and started the car, but it the revs pulse between 1.5k and 2.3k when idling, and it sometimes stalls when you pull away

Any advice please technical guys - have the car booked in to be resprayed on the 5th of July, so I really need to sort this out

Cheers

Put the wiring back to stock and disconnect the battery for 5 minutes or so.

With the wiring stock reconnect the battery and test the car. It will prob run rough whilst the ecu learns.

Take it for a test drive, if it's fine then ground the fcd to a good ground point on the chassis don't ground to a wire from the ecu and then interface the one wire for fuel cut. Fcd should have an in and out.

I was going to try and take it for a test drive last night, but I was worried about doing damage if it wasnt quite right... think i'll just bite the bullet and give it a whirl tonight

I'm sure my car is'nt as fragile as I imagine it to be

Right, I've tried little bits and bobs to sort this over the week.

Firstly, I removed the FCD and connected everything back up as it should be. When I fired the car up, it idled smoothly and it revved smoothly up to 4.5-5k.

When I took it for a test run, it ran like a bag of sh!t; it was jerky, it was missing occassionally, and it did'nt fuel correctly on change up (its an auto)

I assumed that this was the ECU "learning", and thought whats the point in it learning without the FCD fitted. I refitted the FCD, checked everything twice, and attached the ground to the ECU casing - which is supposed to be the done thing.

I went for a test drive, and the same as above kept happening. I battled on though (having to left-foot brake to keep the revs up ), managed to get off of the estate onto a quiet stretch of service road.

The car seemed to drive fine a very low speeds in "L", it was a little shakey in "2", and completely undriveable in "D". When in "D", it struggled like mad, it kept missing, and it would almost stall on change up/down.

In reverse it strangely ran quite smoothly, even at speed.

When the car felt like it was stalling, there was a lot of relay clicking - would I be right in thinking this would be the EFI relay?

Best bet mate, Id say take it to an expert...

 

When the car felt like it was stalling, there was a lot of relay clicking - would I be right in thinking this would be the EFI relay?

I'm using the EFI power feed from the ECU to power the FCD, as per instruction. When I was stripping the insulation from the wire, the pin popped out of the connector block.

I reinserted the pin the correct way around, and all the way in - could this have caused an issue?

Sorry to ask, but i'm reeeeeally stuck

Best bet mate, Id say take it to an expert...

Yeah I know, cant bloody get it there though.

Would'nt feel comfortable taking it to a local auto sparky, and closest people to me who know anything about Supra's are Thor -and they're 30 odd miles away

Where in Oxon are you? Ive got an Aristo which (I assume) is the same ECU as yours, I could bring it and you could try that, see if its the problem?

Always the easiest thing to do in my opinion. If you suspect a part is broken, try and borrow it from a local to see if it is the case. If it is, buy a new one... if it's not.... then it's time to seek proper help

Lincolnshire! Thats not very local mate, would you seriously want to drive all the way doen here?

Im in the RAF mate, Im based near Wallingford, between Reading and Oxford Im down there during the week

Likewise, where are you in Oxon? If Swampy is not about i maybe able to help you out.

Check for fault codes.

Check all the earths, make sure a bare wire isn't earthing in the wrong place.

I'm in Banbury

I'm going to c0ck around around with it a bit more tomorrow, I dont want to let it beat me!

If either of you would be able to help out if needed, that would be pretty cool. I can offer my mrs in payment :eyebrows:

If either of you would be able to help out if needed, that would be pretty cool. I can offer my mrs in payment :eyebrows:

You should probably post pics first so the lads know what they're letting themselves in for.

Do we have to share?

Pm me if you get stuck i'm sure we can sort someting out. I live just outside Witney.

You should probably post pics first so the lads know what they're letting themselves in for.

Check for fault codes.

Check all the earths, make sure a bare wire isn't earthing in the wrong place.

Thanks Alex, I'll be checking all of these things tomorrow.

I whipped the ECU out earlier to check the connection between pin31 on connector block 1, and the board. This is the pin location which I cut into to power the FCD, just happens to be the power for the EFI relay. Just seems suspect

It was this pin which came free from the connector block, I pushed it all the way back into the block but maybe its that thats causing the problem??

We'll see

Thanks to all of you for your help

It was this pin which came free from the connector block, I pushed it all the way back into the block but maybe its that thats causing the problem??

 

Can you use a meter to check the resistance between the wire you pushed back it and its contact on the plug?

Can you use a meter to check the resistance between the wire you pushed back it and its contact on the plug?

What i think i'll do is just check the voltage from the efi power wire. I'm guessing it should be a 12v constant. Just seems strange that it only really plays up under load. I'm hoping uts nit going to be an issue withthe walbro pump, that collar was an absolute PITA to get on/off.

Anyone able tp shed any light on this?

What I have done this week:

-removed boost controller

- removed HKS FCD

- cleaned out ICV

- removed and cleaned down throttle body

- tested and adjusted both throttle sensors

- checked continuity between ECU pins and severed wires

- checked resitances on engine temp sensor

- replaced ECU

I'm still getting the same fault, but no fault code are being logged

When I fire the car up; it revs around to 2k, pops, then drops down to a steady 1k then 900/800 when warm. I can rev the engine smoothly all through the rev range when its in park

As soon as I apply load, it coughs and splutters. I'm having to use the brake as a clutch so that I can keep the revs up, but the car is more or less undriveable

Should I suspect the fuel pump?

Just incase anyone stumbles on this in the future; I had my car delivered to thor racing yesterday. They were able to diagnose and rectify the problem within an hour..

Basically the 12v feed into the ECU which controls the main EFI relay (pin 31 on the single multi-plug), had a bad connection. Someone ([OOPS][/OOPS]) must have been a bit rough with the wire, and caused it a bit of a mischief. One of their engineers was able to source a replacement section of wire with a decent crimp on it; he fitted that into the multi-plug, soldered it in to loom, and the car was running fine.

I'd like to add that although i'm a "hav-a-go-er", somethings are best left to the professionals. I was tearing my hair out trying to figure out what had caused this problem, and they sorted it in an hour....

....Oh, and since visiting there today; i'm very much interested in the v8 supercharged conversion I spoke to them about :eyebrows: