Failing to start when hot?
Discussion
Hi all,
Excuse the long mail but I want to be as specific as possible in an attempt to find the answer.
I was driving along in hot, slow traffic and the water temp climbed to 100. The fans were working and it didn't get any hotter or loose water so I carried on (it normally runs at 90 degrees).
After I stopped for fuel the car failed to start (engine turned over ok and it gave a brief splutter but wouldn't fire up). After waiting about 15 mins it started fine so I assumed under bonnet heat was the cause.
However this may not be related to heat as I first suspected. The other day I went for a 20 minute trip, the engine didn't get hot (90 degrees), I left the car for about 2 minutes then tried to re-start. It turned over but failed to fire up so I waited a minute, tried again and it started.
That night I did an hour and a half drive to Cambridge (cool air temp, engine under 90 degrees), pulled up outside the garage, turned the motor off, opened the door, returned to my car and yet again it turned over fine but wouldn't fire up. As expected a couple of minutes later it started no problem.
Has anybody had this happen and knows what to do? It may be a coincidence but this seems to have started at the same time as I had a new grille fitted with slightly smaller holes.
PLEASE HELP!!!!!! I love the car but am starting to wish I had not bought it!
Stephanie.
Excuse the long mail but I want to be as specific as possible in an attempt to find the answer.
I was driving along in hot, slow traffic and the water temp climbed to 100. The fans were working and it didn't get any hotter or loose water so I carried on (it normally runs at 90 degrees).
After I stopped for fuel the car failed to start (engine turned over ok and it gave a brief splutter but wouldn't fire up). After waiting about 15 mins it started fine so I assumed under bonnet heat was the cause.
However this may not be related to heat as I first suspected. The other day I went for a 20 minute trip, the engine didn't get hot (90 degrees), I left the car for about 2 minutes then tried to re-start. It turned over but failed to fire up so I waited a minute, tried again and it started.
That night I did an hour and a half drive to Cambridge (cool air temp, engine under 90 degrees), pulled up outside the garage, turned the motor off, opened the door, returned to my car and yet again it turned over fine but wouldn't fire up. As expected a couple of minutes later it started no problem.
Has anybody had this happen and knows what to do? It may be a coincidence but this seems to have started at the same time as I had a new grille fitted with slightly smaller holes.
PLEASE HELP!!!!!! I love the car but am starting to wish I had not bought it!
Stephanie.
Stephanie,
Two things spring to mind relating to your problem.
First thing to check is the water temp sensor. Have had cars when hot not start due to this sensor telling the ecu that the engine is cold, so injecting too much fuel which floods the engine. When it will not start see if you can smell any fuel, which could point to the engine flooding itself.
Another component that might be faulty could be the reluctor coil in the distributor. When it gets hot it has excessive resistance which could be affecting the strength of the ignition spark.
Only way to check this is to run the engine until hot then using a multimeter check the resistance of it.
Hope this helps you out
Claire
Two things spring to mind relating to your problem.
First thing to check is the water temp sensor. Have had cars when hot not start due to this sensor telling the ecu that the engine is cold, so injecting too much fuel which floods the engine. When it will not start see if you can smell any fuel, which could point to the engine flooding itself.
Another component that might be faulty could be the reluctor coil in the distributor. When it gets hot it has excessive resistance which could be affecting the strength of the ignition spark.
Only way to check this is to run the engine until hot then using a multimeter check the resistance of it.
Hope this helps you out
Claire
quote:
I read Claire's reply & realised that it fit the problem better than mine, so beat a swift retreat (but not swift enough)
I'd help preserve your dignity, but if I press delete, I thought I got a big ****MESSAGE DELETED***** sign!
No - my mistake. Done it!!
>> Edited by beljames on Tuesday 24th September 21:58
Coil is dead due to heat exhaustion. If it is oily, this is not suntan oil but coil guts spilling out as the unit has overheated. Common problem. Replacement is the only cure. When it cools down it starts working.
The ECU can also go into "Oh my god you are abusing this engine " and goes into sulk mode. A good stern talking to and no supper sorts that out.
The car should not be getting to 100 degrees even in traffic. This indicates to me that you have some form of cooling problem which needs to be looked at. when was the last time the water level was checked?
Steve
www.tvrbooks.co.uk
The ECU can also go into "Oh my god you are abusing this engine " and goes into sulk mode. A good stern talking to and no supper sorts that out.
The car should not be getting to 100 degrees even in traffic. This indicates to me that you have some form of cooling problem which needs to be looked at. when was the last time the water level was checked?
Steve
www.tvrbooks.co.uk
Yep steve, coolant level is quite critical in these engines .. the temp sensor is in the inlet manifold and can get a pocket of air around it.
another common one is the resistors which feeds the coil LT signal back to the ECU so it knows how many revs the engine is doing .. two small black jobbies on the loom across the breather pipe. It could be any number of electrical components breaking down with heat I guess but my main concern is : Claire .. are you married?????
another common one is the resistors which feeds the coil LT signal back to the ECU so it knows how many revs the engine is doing .. two small black jobbies on the loom across the breather pipe. It could be any number of electrical components breaking down with heat I guess but my main concern is : Claire .. are you married?????
Hi Steve,
Water levels and temperature sensor are fine but as you say - the engine shouldn't get above 90 degrees and it never used to (or I didn't notice) until I fitted a new grill with smaller holes (might be a coincidence). I am going to try refitting the original item to see if that sorts the problem. If it is and the smaller holes have raised the under bonnet temperature could I have damaged the coil permanently?
My thoughts were that the fuel had vapourised somewhere in the fuel supply pipes or injection system as this used to happen on a Lotus seven which was cured by moving the pump and filter out of the engine bay.
Cheers, Stephanie.
Water levels and temperature sensor are fine but as you say - the engine shouldn't get above 90 degrees and it never used to (or I didn't notice) until I fitted a new grill with smaller holes (might be a coincidence). I am going to try refitting the original item to see if that sorts the problem. If it is and the smaller holes have raised the under bonnet temperature could I have damaged the coil permanently?
My thoughts were that the fuel had vapourised somewhere in the fuel supply pipes or injection system as this used to happen on a Lotus seven which was cured by moving the pump and filter out of the engine bay.
Cheers, Stephanie.
Smaller hole grill... Recipe for disaster I'm afraid. This dramtaically increase the heat strain on the car and underbonnet components and yes the coil could well be dead as could a lot of other components. If the car was fine before then something has died. The new grill could be the last straw as they say and this has lead to the stuff to die and your problems. Replacing the original will help but it may not ressurect the dead bits.
Fuel vapourisation etc is often sited as a problem but is pretty rare compared to heat stroke killing other bits.
Steve
Fuel vapourisation etc is often sited as a problem but is pretty rare compared to heat stroke killing other bits.
Steve
So I've been told - If it is a series two, when the cars get hot the relays start to fail in the imobiliser system, and the most common one is on the fuel pump. It is a bitch to sort if you still want that relay to work on the imobiliser - or you cab by pass it so that the imobilser does not cut power to the fuel pump. Mine does it occasionally - best to just walk away from the car for 15 mins (dont keep trying it) then will always fire up after this. If a series 2 then the above might apply (Raven can sort) - if not most likley one of the other posts - Cheers Jon
quote:
Ditto for Joolz. Well, apart from the young bit
Anyway Joolz, you've not got time for a love life, you're married to your job......
No .. I've decided I do have time for a love life if I only have two hours sleep a night and don't stop for breakfast or tea .. you only need one meal a day after all. Now all I have to do is convince someone to have me .. any tips Squirrel me ol' fella????
Thanks Steve,
I am going to change the grill this weekend so I hope the car stops overheating. It has only done it 2 or 3 times so I am hoping I will get away with any permanent damage.
P.S. Love the book - it has been a great help!
Stephanie
P.S. Jellison - It is a series 1, 94 L reg. Does this mean I won't have the problems you suggest?
I am going to change the grill this weekend so I hope the car stops overheating. It has only done it 2 or 3 times so I am hoping I will get away with any permanent damage.
P.S. Love the book - it has been a great help!
Stephanie
P.S. Jellison - It is a series 1, 94 L reg. Does this mean I won't have the problems you suggest?
quote:
Thanks Steve,
I am going to change the grill this weekend so I hope the car stops overheating.
Some people go to great lengths to improve the airflow on TVRs. Unfortunately, the Chimp's radiator is prone to stone damage so people try to enclose them causing more cooling problems.
Big engine and small engine bay results in things getting very hot under the bonnet...having the exhaust down pipe combiner and catalysers under there as well doesn't help matters.
I suspect a LT problem and would start with the cheapest things first; the coil and resistors.
Good luck and don't give up on the Chimp...hang in there and sort it, you will have loads of fun.
I suggest that you join TVRCC,
www.tvrcc.com The Cambridge group are pretty active and I am sure you would find lots of friendly help and advice there.
They meet the first Sunday of each month at the Ferry Boat Inn at Holywell (near St Ives).
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