Car stalls when warms up (87 turbo)

[chappo123]

Still trying to get to the bottom of this problem, lots of advice and experience picked up from this and other forums. Previous owner has already replaced the CHTS x 2, air regulator, fuel filter, fuel pressure regulator, oil pressure sender, dist cap and rotor.

I have been working around the connectors and all so far look clean. Some vacuum pipes have been removed - those to the carbon cannister - which has also been removed. No EGR - is this just a US spec sensor?

Checked the MAF this morning, disconnected it with no difference noted. Positive in that ECU picked up it wasn't working when disconnected.

The ECU changed between 1986/87 models. Does anyone know if they are interchangeable? Looking at differences in the list of error codes, I suspect I have a 86 in my 87 car? Is there anyway of checking the serial number or are there any physical differences?

One thing for to get a mechanic in to look at is the return fuel pipe - understand that a blockage can cause a pressure build up and a stall result?

Any other advice welcome.

 

[Mr.F]

One area that the previous owner and I discussed was whether the fuel pump relay was allowing the pump to run continuously or switching off after a period. I believe he also replaced the fuel pump control module (located under the battery area). There were also some discussions about replacing the fuel pump itself, but this didn't get done.
I'm familiar with most of the work done and the parts replaced (supplied most of them) and the problem has baffled most who have looked at it!

 

[chappo123]

Thanks Mike - I'll add that to the list of things to check!

 

[morbias]

What errors are you getting from the ECU? Maybe it has an incorrect fuel map.

 

[chappo123]

Currently showing:-
31 air cond (presume as I didnt do a switch on test)
14 speed sensor (again presume as I didnt drive it)
24 neutral switch

ECU is from a 94 Turbo which I don't think is compatible with injectors and o2 sensor, so will be looking to see if I can get the correct one.

Thanks

 

[Mr.F]

Z31 ECU error codes are cancelled by operation of the parameter being "sensed". Speed sensor code 14 would be cancelled by driving forwards at more than 6 mph. Neutral switch code 24 would be cancelled by moving the gear lever into each gear position and back to neutral.
Note - edit posts to show '80s dates as quoting '90s will confuse some readers!
Part code 23710-07P00 is the correct ECU for ALL UK turbo models, 1984 - 1989.

 

[chappo123]

Z31 87 turbo stalling problem

OK so the Zed is up and running now after disconnecting the CHTS. The sensor has been replaced a couple of times this year so suppose I can rule out faulty sensor.

Came across an old posting on the net from a couple of people who had the same stalling problem and problem tracked down as the CHTS.

The solution was to reduce the sensitivity of the sensor with a 500ohm resister place in the circuit.

Anyone had experience of this?

thanks

 

[STEVE BURNS]

Does the car fire up and then once it gets to near normal temperature cut out and will not restart and after then after about 20 minutes it then restarts for a while and then cuts out again

 

[chappo123]

Yes exactly that - when the CHTS is connected.

cheers

 

[STEVE BURNS]

The senile old fool will now make a complete idiot of himself
When I first got my first 280 the exact same thing started to happen to me
went out not long after I bought once and it happened for the first time. called out the AA and after about twenty minutes I tried to start it and it fired up so recalled the AA and cancelled the call out and started to drive home after about 5/6 minutes it stopped again and would not start so had to call up the AA and when they arrived turned the key again and it started again.
Told the AA guy what had happened so far he said start it up and he would follo9w my for a while to see if it was OK and hey presto again after 6/7 minutes it stopped again he then checked it over could not find out anything that was wrong with it so called out the recovery truck and got it brought home

Remember I had only had the car for a couple of weeks and did not have any contact with the Z Club then so took it to local Nissan garage they had it for about a week and although they had it for a bout a week they could get it to start aand then stop and then start again etc but could not seem to fix it
Then heard of Samuri and contacted them and to be fair Spike was really honest with me he Said By all means bring it over to us but you would be far better taking it to Fourways as they know far more about the fuel injection system than us so contacted Fourways and they said there is a club that might be able to give advise and hey the bearded one came to my attention and after a couple of conversations it was decided to replace the Fuel Pump and guess what so impressed getting it sorted Paid my £10 membership fee straight away as no more stopping after the pump was changed

Not being that mechanically minded decided to take the pump apart to see if I could learn why it had caused the problem and found that one of the little rollers in the pump was slightly worn and was not pushing enough petrol continually through the pump and what was happening was as it was turned over a couple of time enough pressure was built up to fire the engine but would not keep the pressure up continually to keep it running

No Doubt I have not explained it 100% correctly and maybe although this worked for my 280 it may be different on a z31

Sorry for long reply but even if it not correct for you it does give something to read

 

[chappo123]

That's really helpful Steve. The fuel pump was on the list for a professional to check after a list of other things, although the fuel pressure has been checked and found to be fine. Whether it was tested long enough for the problem to trigger, I don't know. Think changing the pump is a bit of a nightmare as in the tank, which isn't easy to get access to.

If that is the problem, I wonder why disconnecting the CHTS would stop it happening?

Need to get someone to reset the timing now, so will see how we get on after that.

cheers

 

[chappo123]

Can anyone help me with ECU query (87 turbo z31). Background - car is currently only running when CHTS is disconnected - otherwise stalls when warms up.
Been doing some tests around harness wiring. Someone also directed me to look at injectors and wiring. On the 15 pin ecu connector, I checked pins 101-106 and 114 to ground - all should have battery voltage as per the workshop manual. The injectors all fine, but 114 showing no voltage. Pin 114 listed as fusible link 12v source for injectors.
I need to check the link wire and harness wire yet. Assuming no current on this connection - I am struggling to find out what the impact of this is - is this the mysterious fault causing my stalling problem, should the injectors not be working at all if this circuit is broken? Any ideas?

 

[Mr.F]

I may be wrong on this, but looking at the circuit diagrams and the description of the turbo fuel system, it would appear that the injectors can work either simultaneously or in two groups (1 2 3 and 4 5 6). Each injector has its own path into the ECU which grounds them in groups of three)
Pin 114 (red wire) is a separate path into the ECU, should show 12V and would act to trigger all six injectors in simultaneous mode.
In group mode, the two groups of injectors are grounded by the ECU alternately via their own paths (101 - 106) to fire each group once in each engine cycle.
In simultaneous mode, all six injectors are triggered twice in each cycle. If pin 114 shows no 12V, then simultaneous mode cannot operate and the engine will stall (?).
The conditions for the switch to simultaneous mode are any of:
1. Engine speed greater than 3000rpm
2.Injection pulse duration greater than 5.37milleseconds
3. Cylinder head temperature below 60 degrees C

Disconnecting the CHTS removes what may be the critical signal and leaves the engine in group mode (which will impede correct mixture for higher rpm / under load use).

 

[chappo123]

Thanks Mike, thats very helpful.
Checked the fusible links - which all appear fine today. Also ran a harness check between the chts connector points a and b and ECU pins 23 and 26 respectively. Was expecting 0 ohms reading, result was no reading at all, so no circuit. I also checked b23 and a26, both of which showed a resistance and circuit - 2 and 1 ohms.
Not sure if this could mean the circuit is wired incorrectly although colour coded wires are correct.

 

[chappo123]

Does anyone have a picture of where the temperature switch is - I've got an idea from the FSM but can't locate it - assuming it must be behind something. Frustrating thing I am finding so far is how difficult it is to get to things, without taking half of the engine apart. Thanks

 

[Mr.F]

In the front, hidden from view so you won't get a picture unless someone has a dismantled engine. Near the thermostat housing - follow the lead to the yellow plug...

 

[chappo123]

Thanks Mike. Yellow wire - I presume you don't mean the chts wire, rather than the temp switch?

On the attached picture I have a yellow wire that goes into a small connector - just to the right of the dist cap. The wire coming out is brown and bizarrely doesn't actually go anywhere - it is just taped to the side of a wire (not actually joined) that goes to the aircon unit. Is this the one?

The only FSM reference I can see for this wire in the harness is possibly the magnetic clutch - haven't a clue yet what that might be.

cheers

 

[Mr.F]

Sorry - the gauge temperature sender is mid inlet manifold on the RH side of the engine. Wire colour yellow with green stripe.
The magnetic clutch is on the air conditioning compressor - locks in the drive to the compressor when the A/C is turned on.

 

[chappo123]

Thanks Mike

 

[Stevey]

Did you sort this out in the end ?

I had a similar problem which was after a N/A to turbo swap , Was down to a mix of things Stupidly i had put the wrong ECU in , Secondly was the fact i had changed the engine and ECU from a earlier model which ment i didnt have a fuel controller , Cuts the fuel pump relay out after about 20 seconds ... Was a mega pain in the ass to find !!