TB42 efi not starting when hot

[afatboy]

TB42 efi. Starts fine when cold. Once up to normal running temp you can't turn it off or it won't start again. Will turn over no problems, you can smell it getting fuel, plenty spark from the coil and from dizzy to leads. Just won't fire. I was convinced it was the immobilizer, so I removed it. Still no success. Any ideas?

[Clunk]

Have you checked the dizzy cap for hairline cracks? Same thing happened to my old Golf......... Other than that mate, I can't help. Sorry.

[Woof]

Still playing up Neil, hopefully someone will be along with the answer mate

[threedogs]

What do you mean you cant turn it off ??
Check all vacuum hoses they may have perished or come loose

[afatboy]

What do you mean you cant turn it off ??
Check all vacuum hoses they may have perished or come loose

I can turn it off, but if I do, it won't start. therefor, I can't turn it off lol

[afatboy]

Still playing up Neil, hopefully someone will be along with the answer mate

Dunno Doggy. I can't seem to get an answer anywhere. Surely this can't be the first time this has happened with one of these.

[menace 2]

how does it run when it is going when it is hot ?....maybe the fuel system is not pressurising properly..though this normally creates the problem when cold starting ...the pressure relief is the square moulding with a bolt in the top of it on the front of the plenim .. have you played with the fuel system lately ?

[afatboy]

how does it run when it is going when it is hot ?....maybe the fuel system is not pressurising properly..though this normally creates the problem when cold starting ...the pressure relief is the square moulding with a bolt in the top of it on the front of the plenim .. have you played with the fuel system lately ?

fuel system seems fine. When the car is running it runs like a dream. hot or cold it runs fine. It just won't start when hot. Even gave it a squirt of the old "start ya bastard" and still it didn't even sound interested in starting

[menace 2]

if it has fuel and good spark then it would be electrical...something is breaking down when what ever it is gets hot....sorry I cant help any further...I get lost in that area

[afatboy]

Should mention too, it can be tow or roll started...

[Yendor]

When your trying to start it hot does the engine seem like it is turning over fast enough, at the same speed as when it's cold?. Or does it seem slower?

What voltage does the battery drop down to during cranking? both hot and cold?

[afatboy]

When your trying to start it hot does the engine seem like it is turning over fast enough, at the same speed as when it's cold?. Or does it seem slower?

What voltage does the battery drop down to during cranking? both hot and cold?

seems to be cranking over at the same speed as normal.

[threedogs]

Sounds like something is not re setting when hot. can you swap the AC relay with the ecm relay and try, probably wrong but all I have,
Yendor is the man, did you check the brake light switch??

[Parksy]

If you're spraying start ya bastard into the engine while hot and it still doesn't want to even show signs of life, then it does sound like an ignition problem. You said you have spark, was this even when hot? My first guess is to replace your spark plugs, might have the wrong heat range plug installed.

[zobee]

i currently have the exact same problem and am hoping that you guys may remember why it has happened... so confusing

[Avo]

i currently have the exact same problem and am hoping that you guys may remember why it has happened... so confusing

hello......

[dom14]

TB42 efi. Starts fine when cold. Once up to normal running temp you can't turn it off or it won't start again. Will turn over no problems, you can smell it getting fuel, plenty spark from the coil and from dizzy to leads. Just won't fire. I was convinced it was the immobilizer, so I removed it. Still no success. Any ideas?

Plethora of reasons that can produced the above scenario. Always start with electrical side of the story as a rule of thumb.
Chekc the spark when hot, which includes the spark out of the leads as well as each spark plug. After ruling out the ignition system, then you can check the sensor like MAF etc and then move onto fuel pressure etc. Since the problem happens after warm up, tests should be done in the same condition.

[Cogsy]

Hey guys, sorry did any of you guys end up working this issue out? I know a guy having this exact issue.

Cheers

[ReefMagnet]

Righto, I'll have a crack of figuring this out. Believe it or not, the ECU gets it's earth from the top of the engine, around the throttle body. There's two earth wires/connections adjacent to each other connected to 6mm bolts (from memory). If these connections become poor - and heat can turn them from just passable to problems - the lights and starter will work fine, but the car will absolutely not start. Check these connections and clean them up. May or may not be the problem, but it was on my old girl 10 years or so ago and after fixing this she didn't miss a beat and is still happily running today.

[Cogsy]

Righto, I'll have a crack of figuring this out. Believe it or not, the ECU gets it's earth from the top of the engine, around the throttle body. There's two earth wires/connections adjacent to each other connected to 6mm bolts (from memory). If these connections become poor - and heat can turn them from just passable to problems - the lights and starter will work fine, but the car will absolutely not start. Check these connections and clean them up. May or may not be the problem, but it was on my old girl 10 years or so ago and after fixing this she didn't miss a beat and is still happily running today.


Cheers reef, he gave that a go. They were a pretty poor connection but didn’t seem to solve it unfortunately