[honeybee]

My uncle in law has a Tata Indigo (not the CS version), purchased used. Today in a casual conversation he reported a weird problem:

When the engine has heated up (say after a couple of hours of driving at high speeds), if he halts someplace and switches off the engine, the engine won't start for about 15-20 minutes. He had driven back from Pune and reached his neighbourhood. He halted outside a shop to collect a few things, switched off the engine and went shopping. After he returned, he found the engine wouldn't start. He left the car and walked home. About half an hour later he went to collect the car. The engine started without problem and he drove home.

This has occurred a few times, so there's a pattern. The explanation given to him by a mechanic (don't know if this was a Tata service centre mechanic or roadside one) is when the engine is switched off, some fuel remains unburnt in the combustion chamber. Due to the heat buildup within the engine this fuel evaporates and is stuck in the chamber. When the engine is restarted, the piston cannot move within the chamber because of these vapours. So a cooling period is required before the vapour turns back into fuel droplets and the piston can move freely within the chamber.

I have driven a Premier Padmini Diesel and a Fiat Uno Diesel, both in very hot conditions (comparable to what my uncle in law has been driving in), also have travelled in many diesel vehicles including a Tata Indigo (for a five day tour in the South). But I have never heard of this "air lock" problem from anyone else. Does anyone here has a similar experience? Or can someone find out why the engine refuses to start when switched off while hot, and starts after a wait of about 15-20 minutes? Is it just a case of an overheating engine?

[dkamath]

Hi, am facing this very same issue with our Indica. After examining the stop solenoids, fuel inlet lines, etc, the dealer is of the opinion that the Fuel Injection Pump (FIP) needs an overhaul.

I have decided to wait and watch for a while before getting the FIP job done, as otherwise, there are no issues either with the pickup or fuel consumption, both of which are normal yet.

Will eagerly follow this thread, as am looking for comments from expert members. So guys, please do reply to honeybee's post

Cheers.

[mercedised]

Originally Posted by honeybee

My uncle in law has a Tata Indigo (not the CS version), purchased used. Today in a casual conversation he reported a weird problem:

When the engine has heated up (say after a couple of hours of driving at high speeds), if he halts someplace and switches off the engine, the engine won't start for about 15-20 minutes. He had driven back from Pune and reached his neighbourhood. He halted outside a shop to collect a few things, switched off the engine and went shopping. After he returned, he found the engine wouldn't start. He left the car and walked home. About half an hour later he went to collect the car. The engine started without problem and he drove home.

This has occurred a few times, so there's a pattern. The explanation given to him by a mechanic (don't know if this was a Tata service centre mechanic or roadside one) is when the engine is switched off, some fuel remains unburnt in the combustion chamber. Due to the heat buildup within the engine this fuel evaporates and is stuck in the chamber. When the engine is restarted, the piston cannot move within the chamber because of these vapours. So a cooling period is required before the vapour turns back into fuel droplets and the piston can move freely within the chamber.

I have driven a Premier Padmini Diesel and a Fiat Uno Diesel, both in very hot conditions (comparable to what my uncle in law has been driving in), also have travelled in many diesel vehicles including a Tata Indigo (for a five day tour in the South). But I have never heard of this "air lock" problem from anyone else. Does anyone here has a similar experience? Or can someone find out why the engine refuses to start when switched off while hot, and starts after a wait of about 15-20 minutes? Is it just a case of an overheating engine?

Not necessary that it is a vapor lock problem. Check if the SELF cranks slowly or didnot crank when the engine is hot, if it cranks slowly or did'nt at all then it is a SELF problem get it serviced. Becuz Kaput self also doesnot cranks when heated up but works like charm when the engine is cold.

[honeybee]

Originally Posted by mercedised

Not necessary that it is a vapor lock problem. Check if the SELF cranks slowly or didnot crank when the engine is hot, if it cranks slowly or did'nt at all then it is a SELF problem get it serviced. Becuz Kaput self also doesnot cranks when heated up but works like charm when the engine is cold.

Err, what's a self?

I am sorry but I am a little challenged when it comes to the automotive geek terms.

[mercedised]

Originally Posted by honeybee

Err, what's a self?

I am sorry but I am a little challenged when it comes to the automotive geek terms.

Self, The automotive part that rotates the engine when you insert and move keys to start car.

[baddy]

got reminded of the time when we had an indica DLX. i have faced the very same problem as your uncles car did. our car used to develop air lock in the fuel line every time we stop after a long drive, so it will never fire up back again. i used to always carry tools to open up the banjo bolt near the FIP and prime the system until fuel start pumping, gave me a good experience on disel engines lol. i even checked the feed pump and replaced them, still had the same problem, then atlast got the FIP overhauled at lucas and the problem reduced, but the performance also dropped from then on. it was also a major reason why we sold the car. so its better u get the FIP replaced instead of an overhaul. other wise the vapour lock inside a combustion chamber which the mechanic says is hard to believe, becos vapourized charge is good for combustion.

[honeybee]

Originally Posted by mercedised

Self, The automotive part that rotates the engine when you insert and move keys to start car.

So you are referring to the starter motor?

[mercedised]

Originally Posted by honeybee

So you are referring to the starter motor?

Yes.
Clean all fuel lines if the starter motor is fine.

[honeybee]

Originally Posted by baddy

got reminded of the time when we had an indica DLX. i have faced the very same problem as your uncles car did. our car used to develop air lock in the fuel line every time we stop after a long drive, so it will never fire up back again. i used to always carry tools to open up the banjo bolt near the FIP and prime the system until fuel start pumping, gave me a good experience on disel engines lol. i even checked the feed pump and replaced them, still had the same problem, then atlast got the FIP overhauled at lucas and the problem reduced, but the performance also dropped from then on. it was also a major reason why we sold the car. so its better u get the FIP replaced instead of an overhaul. other wise the vapour lock inside a combustion chamber which the mechanic says is hard to believe, becos vapourized charge is good for combustion.

So you are saying the problem of vapour locks is in the fuel line that runs from the fuel injection pump to the engine? Is there no way to fix it other than replace the fuel pump? I believe the pump would not come cheap.

[deutscheafrikar]

Originally Posted by honeybee

When the engine has heated up (say after a couple of hours of driving at high speeds), if he halts someplace and switches off the engine, the engine won't start for about 15-20 minutes.

After he returned, he found the engine wouldn't start. He left the car and walked home. About half an hour later he went to collect the car. The engine started without problem and he drove home.

honeybee, do you mean the starter wont turn the engine at all when the car is hot, or do you mean the starter cranks the engine but the engine refuses to start at all? Or does it crank very weakly...?