Fast Idle but dying when driving

[Tonyd]

Hi Guys,

About 8 years ago I built a couple of AC Cobra replicas with a 1990 and 93 1uzfe in them with lots of help from this forum, and would you believe that one of them is now giving us some trouble.

We awoke it from its winters hibernation last week and it ran fine but yesterday it started playing ujp.

It starts lovely but then settles into a high idle , around 1500rpm. On the road however when you take foot off the accelerator, coming up to a junction or turn for example, the engine just dies.

The engine check light gives us a code of 13 which states camshaft position sensor, crankshaft position sensor or ecu.

Given that the engine starts beautifully, revs like a champ and only has a slight miss occasionally, I doubt its either the crankshaft sensor ( I had one of these go on the other Cobra and the engine would barely run) or the ECU, thus my money would be on an "iffy" camshaft sensor.

Do you guys agree?

Has anyone had any similar symptoms and what was the cause?

Cheers,

Tony

 

[cribbj]

Tony good to hear from you & glad to see you're still puttering with the 1UZ's.

Sorry, but I don't have much else to suggest other than the cam sensor.

Good luck with it and let us know what you find?

 

[lill daddy]

I had the exact same issue and it ended up being the tps... http://www.lexls.com/tutorials/EFI/tps.html I used this link to reinstall and worked a treat

 

[Tonyd]

Thanks for that. I have a spare engine in the shed with cam sensors and tps so I will srtart with the tps and see how that goes before stripping down the front of the engine.

As an aside I am waiting for a brand new new MAF sensor (without the housing) for my Lexus powered Cobra which I have bought from the USA delivered for $195 .

There were secondhand units available from car breakers here for £180, which could have been as bad as the original, and a brand new unit from Lexus was quoted to me at £1,042.

Ridiculous pricing from Lexus. I now only ask for their spares prices for comedic value.

I can see now why their cars residuals go into freefall after a few years. My mate has an LS 430 Hybrid in his company which he may want to sell but no one in the trade will touch it.

Cheers,

Tony

 

[Tonyd]

Finally got a chance to get over to my mates and have a look at this problematic cobra. MAF fault codes were now in ecvidence along with code 13 for tyhe crankshaft poosition sensor.

Turns out it was a failed EFi coolant temperature sender.

Put in a spare sender out of a spare engine and the situation improveda little bit but the engine was still dying when throttle was closed.

Went out this morning and bought a new aftermarket sensor for £9.00 from the local spare parts place and the engine is running brilliantly now.

Rule number one , never assume a secondhand sensor is good, always fit new ones.

Cheers,

Tony