Won't Start

Engine won't start. Battery voltage is low, but engine still cranks it just won't turn over. RAC are stumped, they came out but couldn't help, had to get towed home. I haven't driven my Z for over 6 weeks as it was getting a re spray. The panel shop had it running this morning to drive it out of their workshop but now it just won't start. Any ideas? It's a 1990 2 slicktop TT manual

 

battery has to have a certain voltage to actually spark, otherwise it will just crank but not fire.

the voltage showing when the car is crnaking will be lower than the static value, because cranking the car draws power.

it could also be a connector thats been bumpes or broken, so check the obvious ones like crank angle sensor and ptu.

hope you sort it quickly.....

 

Thanks. RAC hooked up leads to the battery & gave it a quick charge prior to trying to start it. Was around 12v. Connectors all look ok to me but will double check again later

 

Whats the best way to check? There is fuel in the tank (2/3), do I need to pull the plugs to check the rest?

 

As rob said above, doing these things will isolate whether its actually fuel or spark ur lacking. Assuming all the lights on the dash are still coming on ie: immbolizer disarmed?

As already stated just check the plugs for your CAS, PTU.

Something else to try if you dont wanna pull the fuel lines off:

FPCU - bypass it and see if it makes a difference (this would be my guess if it hasnt been bypassed already)

 

Immobilizer disarmed when trying to start. I lack the tools & know how to pull the spark plugs & coil packs so that will have to wait until the weekend. In the meantime is there anything that would be prone to fail after sitting unused for over 6 weeks?

 

Not sure if it would help but Check your ENG CONT fuse.

 

Try a proper battery in place or crank test the battery

Yep - A battery with low volts can die very quickly being left alone without any charge being applied regularly! - once the battery goes under 11.5V for an extended period of time it may never recover ever again!

Some batteries will give a reading of 12V at the poles with a multimeter but have no amp capacity (CCA) because the plates are too thin - when this happens it appears as if the battery is working but there is not enough power to crank and provide electrical power.

Running jumper leads is no guarantee as the plates cannot hold enough power or may not supply enough power whilst trying to recharge a faulty battery in between that and the cranking/ engine power all at the same time

Unless it is crank tested (CCA) there is no way it can be discounted!

I would be surprised if this is not your problem given what you have said - simply put - if your car was working fine and then was left for a while without regular use - then this is the most common reason for it not starting!

Remember that a multimeter is only a guide not a proper test as the plates may be thin!

Suggest you test it with another good battery in place with secure fittings first before doing anything! (do not connect a good battery with the same battery in place as it will just drain the good battery) - alternatively crank test the battery with a crank battery tester.

I would be surprised if this is not your problem!

 

Unfortunately it's not the battery. I tried with a different higher CCA rated battery & still won't start. I also tried a different known working PTU & no luck there either...

 

Tested and we have spark, but unfortunately the battery is now too low to see if we are getting fuel, so have had to put the battery on charge & get to that later. Worth noting that we can hear the fuel pump priming, so the pump itself should not be the issue

 

ok - I am surprised as there is not much that goes wrong with a car when its sitting still other than a battery or if a very long time it can be stale fuel or water in the fuel- won't be fuse related given you have spark!

Given the fuel pump is working I think its unlikely to be fuel - whilst fuel can have water or even go stale you will still normally get some kick in the motor albeit even if intermittent - if its chock a block full of water it can stop an attempt to even start it but this is then visually easy to see once you check the fuel in the lines.
Do you have a stock regulator? If so its even more unlikely to be fuel and also injectors and plugs don't normally all fail at once

You state that the immobiliser is not the problem which is what I would have thought of next may be the problem but clearly the immobiliser is not connected to fuel or spark anyway - check the oil since its an easy check via a dipstick and look for and signs of contamination

As Rob says - it has to be spark/ air or fuel and so if you have fuel and spark - then air must be it

Air is not normally a problem - unless you have a major air leak - this can prevent the car from starting - have you disconnected any lines recently?

After checking for air lines and PVC/ Plenum area for air leaks and it were me (it would be audible if its a major leak and your looking from the MAF backwards to the plenum), I would be running diagnostics on the ECU - this may give an insight into what is happening - the manual will take you through how to run the diagnostics without ecu-talk - whilst it may not definitely tell you what the problem is - it will definately tell you what it is not and this may help narrow the problem down further!

Keep thinking Air, Fuel or Spark at all times!

Good luck!
JC

 

If you have spark and pull the plugs and they are wet you have fuel. If they are dry you would suspect a fuel related problem. Low compression usually won't stop a motor from starting unless it is a major failure. And air is almost a given. There is another thing that it could be but it would really surprise me but I will suggest it any way. I have seen cars crank, have fuel and spark but not start due to the valve adjustment being way way out. Usually on old push rod valves, I have never seen it on hydraulic valves but others could give you a better opinion on it. I would try a set of new copper plugs as just because you can see spark with a plug out it does not mean they will fire the motor under compression. Iridium plug are well known for causing this type of problem. Also have you filled up at Shell lately.
Cheers
Dave

 

Thanks. Oil on dipstick looks fine & shows no contamination. Also my ECU talk shows code 55. Yep stock regulator but new OEM fuel pump was installed when I had bigger turbos fitted a few months back. Compression is also good. As for air, no lines have been disconnected and it was running great prior to going in for the respray. How do I check for leaks when the car wont start - boost leak tester?

Dave, I never fill up at shell, my Z currently has 98 from BP in it, but I added some octane booster since sitting there for all those weeks would have lowered the octane somewhat

 

I always check for error codes and it usually looks clear.
Read this thread, read Jinxed suggestion, went out and my car won't start.
Touching the CAS plug and the car makes a few clicks, so it starts after that.
I can drive 2000km and then the car won't start. I looked at my CAS plug and socket and it is white and powdery again. I have been using contact cleaner but it doesn't fix it for long. Today I used some CPU paste that is supposed to have dielectric value = yes.
I haven't read that you checked it so maybe you should check the CAS plug, it takes 1 minute. With the ignition in ON position grab the plug and check for movement in and out, listen for engine clicks.

 

good point re sparks plugs being wet - easy test for him

unlikely to be valves or spark plugs as its unlikely all will fail at once to prevent a kick - timing issue would show up quickly if it was complete fail

Has there been problems with shell fuel lately?

 

Hi Marco, let me know what time your home and I'll come and help.