Car won't turn-over when cold - Syvecs S7i

[JamesArup]

Hey folks,

Recently had a Syvecs S7i + a whole bunch of other work done! The car runs great, makes good power etc etc.

However, there seems to be a cold-start issue. At first I thought it was my alarm/immobiliser, as the car literally doesn't turn over at all. Fuel pumps all start, lights all come on, but nothing else. After anything from 1 to 15 minutes of pressing alarm buttons and turning the key, the car will finally start. Once started, the car will usually start first time, every time, for the rest of the day. That part makes me think it's not alarm/immobiliser related.

I've been sent a couple of updated maps to try, and yesterday it started first time with one of them, so I thought the problem was solved. However, today (where it is especially cold), the car won't start again. I tried for about 10 mins, and then gave up... my hands were getting cold!

Rather than wasting the tuner's time, I would like to be able to troubleshoot this myself. I have all of the Syvecs software, and I consider myself to be very computer-literate (it's my job), but I really have NO IDEA what I am looking at when it comes to all of the settings in the Syvecs. Can anyone suggest what I should be looking at in the Syvecs map, and what I should be adjusting? As I said, the car literally doesn't turn over at all when it's cold...it doesn't even try!

I can probably get logs etc if needed,

Thanks for any help,
Cheers, James

Edited December 24, 2020 by JamesArup (see edit history)

[Mike2JZ]

Assume you mean the engine cranks but it does not fire? If it dosen't crank then could be unrelated to following. Heres a random list of things you can try. 

Make sure your battery and charging system is in good nick. If voltage to ECU drops below 9v whilst cranking then you will have issues as ECU will turn off. 

Assuming that's all good then the next thing to check is to see if your ECU is able to Sync the cam and crank signals whilst cranking. Depending on how this has been calibrated by tuner, the ECU will either be looking for a 360 or 720 degree sync before it allows any fuel/ignition events to take place. 

The way you can monitor this is by using sCal, connect to ECU and in top right of the screen you should see a variable called SyncState. As you crank the engine, you should see this variable changed to something along the lines of 360 > 720 > SYNC. If it's unable to sync then it will not show SYNC in this area and that will be your problem. If you can get your head around using Sview & Scfg to setup a logging profile and view the log after then you can also log this start up event and track what your syncstate is through there. 

If you suspect that you have a sync issue, in Scal you can check the triggerscope of your crank/cam signals by finding "view sync log" under Device menu. As the engine is cranking you want to see green lines indicated that your Crank & Cam signal are synced. If they are red, then that will again be the issue. 

If the tuner has setup any anti theft settings, make sure they are not kicking in when they shouldn't. In Scal, go to Gauge > Add > EngineEnable. Track this variable whilst cranking, make sure its says YES. 

Also check under Device -> Errors and make sure you don't have any sensor failures etc, as depending on the sensor and how its been calibrated it could disable the engine from starting. 

Failing all of the above, I'd go a bit oldschool on this. Manually check that you are getting spark & fuel then work backwards from there. 

Syvecs have a number of help files on their youtube channel that will go over the many aspects of how to use their software. Takes a while to get a grasp of it but will be a good winter project if you have nothing else to do. 

 

[JamesArup]

Hey Mike,

Thanks very much for the detailed reply! Really appreciate it. I will go through and check all of these things.

However, unfortunately the engine doesn't crank at all. When I turn the key, I hear the fuel pumps kick in, all the dash lights come on, but there is nothing else! It's as if the immobiliser is on, but it's not. 

Once it finally starts, it will then start first time for the rest of the day. That's what makes me think it's an ECU issue rather than an alarm/immobiliser issue (otherwise the same thing would happen every time I try to start it). If I leave it overnight, especially with current temps, I'll have the same 10+ minute battle the next day to get it to crank/start.

Thanks again,
Cheers, James

[Mike2JZ]

If the engine does not crank. IE start motor does not spin when you command it to, then you can rule out anything controlled by Syvecs. The syvecs has no interaction with the starter motor. So dont waste your time checking any of the things I mentioned above. 

The starter signal is sent from your key barrel, down to an orange plug in passenger footwell, then goes to starter relay in the engine bay fusebox. 

You can do some very quick diagnostics on this. 

1) Go to engine bay fusebox and remove the starter relay. 

2) Get a piece of wire and BRIEFLY bridge the relay connections and see if starter motor kicks in. If it works, check that it works everytime you make the bridge connection. 

3) If it works everytime then you now know that you have no problems between your starter motor and your fusebox, but you might have a problem with the signal from barrel or the relay itself. If bridging the wires doesn't work, then you could have faulty wiring or damaged starter. 

Supra's have a bad tendancy to have their starter motor relays die over time. A quick way of testing this is to turn the key to crank in quick successions one after another until the starter kicks. If this works, then replace starter relay and enjoy it starting on the button like it should. 

Otherwise, could be an immobilizer causing havoc. 

[JamesArup]

Hey Mike,

Thanks very much for that. I'll give it a look and see what I can find. There's definitely something going on!

What I don't understand is, if it's a problem with the starter motor, relay or immobiliser, why does it only happen when the car is cold? Is there something that could cause it to only happen from cold, but then be fine for the rest of the day?

Thanks again,
Cheers, James

[JamesArup]

Ooh! Interesting! The bridging trick works, and the starter motor kicks in every time. 

So, as you said, I guess if the issue lies in that system, then it's either the relay or the barrel signal I guess. Where does one find a new starter relay to try? 

[Mike2JZ]

On a new healthy system, there shouldn't be any reason why there is a problem with the cold conditions seen in the UK. On a 25 year old car that's had its electronics modified, its more probable that temperatures could have an affect on the electronics. 

With cold conditions, most electrical systems on a car, specifically the battery and starter circuit will experience more resistance until circuits are warmed up. Though rare on a Supra, this could have a knock on effect with something you are seeing. I doubt it, but its possible. 

Hard for me to take a stab in dark as to what it could be specifically at this stage, but if you can report back what you find from diagnostics on starter circuit then could elude what area needs investigation. 

As a side note, from my own experience I tend to see issues on Supra's with starters relating to starter relays and immobilizers/alarms fairly regularly. Starter motor's rarely die all together, but can exhibit weird behaviors as they start to die. 

 

[Mike2JZ]

5 minutes ago, JamesArup said:

Ooh! Interesting! The bridging trick works, and the starter motor kicks in every time. 

So, as you said, I guess if the issue lies in that system, then it's either the relay or the barrel signal I guess. Where does one find a new starter relay to try? 

Your next test is to do the following when you next cold start the car:

1) Turn key to ignition on, but dont crank. 

2) Go to engine bay fusebox and bridge starter relay until engine starts. 

3) If engine starts no issues then safe to say your issue is related to starter signal from barrel, starter relay and/or immobilizer. 

You can still order new starter relays from Toyota, or if you have a mate with a Supra just borrow his for some testing. 

If relay is not the problem, then you will need to investigate starter signal wiring and immobilizer. Does the immobilizer/alarm have some sort of cold start remote feature or something?

[JamesArup]

Thanks Mike,

I followed your steps above, and the engine started with no issues, so I guess that narrows it down!

I don't know anyone local to me with a Supra, and the problem is that I'm only in the country for a few days!! I've been looking online for somewhere to source a new relay, but I just seem to dig up second hand ones on Ebay. And I'm not 100% sure they are the correct one!

The relay itself looks pretty clean. Had a look inside, and looks clean there too, but there's quite a lot of circuitry, so clean doesn't necessarily mean working! I'll keep digging around!

Thanks again,
Cheers, James

[Mike2JZ]

53 minutes ago, JamesArup said:

Thanks Mike,

I followed your steps above, and the engine started with no issues, so I guess that narrows it down!

I don't know anyone local to me with a Supra, and the problem is that I'm only in the country for a few days!! I've been looking online for somewhere to source a new relay, but I just seem to dig up second hand ones on Ebay. And I'm not 100% sure they are the correct one!

The relay itself looks pretty clean. Had a look inside, and looks clean there too, but there's quite a lot of circuitry, so clean doesn't necessarily mean working! I'll keep digging around!

Thanks again,
Cheers, James

No worries. 

You can contact @Lee P from SRD. He can supply new starter relays if you need one. 

[JamesArup]

Thanks Mike,

I'll give Lee a shout then. The car wouldn't start again this morning, but I took the relay out and warmed it up inside. After warming it up, I ran 12v across it, and it worked. Stuck it back in the car, and it started first time.

I'm in the process of cooling it down again in the freezer so I can run 12v across it again to see if it still works! If it doesn't then we know what the problem is... the relay doesn't like being cold 

Thanks again, and Happy Christmas!
Cheers, James