After my recent postings about hesitation on my 90 J'Spec TT, I thought I'd cured the problems, I found, and fixed, the fuel leak. Cleanded the throttle position connectors, now, however the hesitation is getting worse.

 

It sometimes refuses to start cleanly, with an irratic tickover eventually dying, then, when it does seem to sort itself, 200 yds down the road I lose all power, lift the throttle and the tick over is steady but as soon as I apply some throttle it splutters all over the place.

 

Can someone please help, a step by step check would be excellent, I'm not a monkey but I'm not that familiar with the electrics on my Z yet.

 

It's due for a 60K service, is it a possibility that I have a duff plug? The odd thing is that once running it drives beautifully, steady tick over and smooth pick up.

 

Oh, I bought some contact cleaner in a can but it doesn't remover any of the verdegris corrosion, any idea what will?

 

Hope someone can help.

 

ta guyz

 

tim

Tim,

 

Sorry to hear about the mare your havin there - unfortunatly hesitation problems can come from a number of different things. Yours sound severe which usually means it is easier to spot than only mild ones.

 

I would suggest you check the TPS itself make sure it is givin sensible readings as that is what has changed recently in some shape or form.

 

A very good artical on diagonsing and finding these problems is here :

http://www.zhome.com/ZCMnL/PICS/hesitation/hesitation.html

 

Basically i would go thru that and see what you can eliminate.

 

Have fun

 

 

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Z ya

 

Nico91TT

 

Is is an auto? if so (sorry if it aint) then have you adjusted the throttle cable recently? I once adjusted this too much and it wouldnt start up, and when it did if you touched the accelerator the rpms would drop, then pick up. Loosened it off a bit and it was fine again.

That's a bit spookey!

 

I had the throttle cable replaced on the Kirk and that's exactly what that does on occasion

 

Cheers mate!

I would suspect the air idle regulator (or whatever its called)

Hello mate,

I had something similar, check your H T lead connections to yor sparks,sometimes they work lose as the clips that hold them in place are usually broken.

Hope this is some help to you

Tony

Tip for removing and reconnecting Throttle Cable - simply really but some people dont think to do it.

 

You have to bolts that thread up to the Butterfly brace - Dont touch the back one - just undo the Front - to reconnect simply snug up the front to the back and hey presto - you guarentee the same buttefly travel.

 

Tony, If you have HT leads on your Z i would check the engine. Electronic Igntion mate - no HT leads.

 

 

 

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Z ya

 

Nico91TT

 

Tip for removing and reconnecting Throttle Cable - simply really but some people dont think to do it.

 

You have to bolts that thread up to the Butterfly brace - Dont touch the back one - just undo the Front - to reconnect simply snug up the front to the back and hey presto - you guarentee the same buttefly travel.

 

Tony, If you have HT leads on your Z i would check the engine. Electronic Igntion mate - no HT leads.

 

 

 

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Z ya

 

Nico91TT

 

Sorry Nico, but you Know what I mean.

It's the cables that fit on top of the spark plugs.

Or if thats wrong speak to Dazz, he put mine right in a couple of seconds.

 

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I had a problem very similar to this, it turned out to be a dodgy fuel pump.

A problem with a car as complicated as the Z is that people automatically assume it's something complicated when more often than not, it's something simple

I hope this helps,

Brian.

I'm bringing this back to the top as I've spent the whole of today trying to sort this problem, to no avail, I've had the AAC valve off the car and in bits along with the air regulator and FICD valve, I've checked the voltage on the TPS and reset it to 0.42V, checked the resistance on water temp sender, and cleaned the Air Flow meter, I've also performed an ECU diag which returned 55 which I understand to be an okay.

 

The problem is getting worse and I'm at the end of my teather, any more ideas please guyz.

 

Thanks

 

Tim

Fuel pressure problem??? You need to get hold of a fuel pressure meter and measure the pressure on the fuel lines under idle and load conditions. The service manual has the relevant pressures but if you need me to dig them out I will...

 

Sounds to me like the fuel pump is not doing its job properly and starving the engine when it needs extra fuel pressure....

 

CheerZ,

 

Andy

Fuel pump!, if you have a friend with a Z, swap them over (quite an easy job, illustrated in the tech section of TwinTurbo.net) I reckon it will sort the problem out.

Cheers,

Brian

Andy, Brian and Everyone,

 

Thanks for the advise.

 

I've been thinking about the fuel pump proposition, if the symptoms I have described point to the pump not delivering the required fuel i.e. fuel starvation, how then did the pump keep up when I was blasting along a 'private road' on Christmas Eve for about 10 mls at 150mph, without a hickup and again on Christmas Day?

 

Wouldn't these be the circumstances when the pump would struggle to supply the required volume of fuel to match demand?

 

Thanks in anticipation.

 

Tim

 

P.S. Anyone got a, known good, pump I could try?

 

[This message has been edited by TT Tim (edited 30-12-2001).]

It sounds to me like your fuel pump voltage regulator. I had the same problems & it turned out that there were dry joints on the regulator circuit board which had also caused one of the transistors to blow, so it was half working intermittantly. It took me months to find!

By what you've said, I'd check the voltage to the pump & if it drops from about 6-8 volts (normal) down to 2-3 when it's stuttering then it's the regulator. If you find that it's faulty then I have a spare one!

Shaun

Thanks Shaun,

 

I'll check the voltages tomorrow AM, where is the voltage regulator situated?

 

Can't say I've had to look for it before

 

Tim

sound like fuel pump failure to me check pressures first.

Posible air flow meter ?

substitution the name of the game.

DAZZ

 

 

 

Thanks Darren,

 

Is the only way to test the Air Flow Meter to swap with another?

 

Will testing resistance etc, not be an alternative?

 

Are you back in Kent now or still teaching the Renault guys about cars?

 

Tim

Tim - I think you can test the voltage of the MAF at idle if I recall to get a reasonable idea..

 

Since my car is (largely!) in bits - if you want to swop any bits over to test then let me know - MAF/fuel pump controller - even fuel pump if we can get it out with the car in the garage! (Or if you came up, rolling the car out is no problem - needs two to get it back onto the planks though you see)..

 

Az

The fuel pump voltage regulator is located behind the passenger side rear quarter panel. If I remember rightly, it has IO stamped on it! You may be better checking the voltage as it goes into the pump though but remember there are 4 wires as the fuel level indicator is an intergral part of the fuel pump assembly. I can't remember off hand which two wires! Check the on-line manual.

Regards, Shaun