have to play with throttle to keep it running

[Lotus907efi]

I am still trying to diagnose a problem with mt 1987 XR4Ti. It starts just fine everytime but then dies immediately unless I play with the throttle a lot. I.E. continually move the throttle around a little, no goosing the throttle but rather just continuously moving it around at low throttle positions. If I do this it runs but it runs like crap.

I have checked the fuel pressure and that is right where it is supposed to be. It has a standard narrow band O2 sensor but has a gauge to show the mixture from that O2 sensor. This gauge has 6 - 8 lit bars on it and when the car first starts it displays two bars for half a second or so but then all bars immediately go off which to me seems like it would be running lean but I am not really sure about the signal from a narrow band O2 sensor. I seem to recall that the signal should in theory have enough bars lit to keep the gauge in the center of the meter.

I have pulled the injectors and sent them out for cleaning but that made zero difference and the guy who cleaned them said they were not plugged up at all.

Anyone have any suggestions?

[zxr250cc]

Hi all,

Have you checked the idle air control valve or the pigtail for it. My pigtail gets loose and it dies immediately when expected to idle. It runs fine when under throttle, just won't idle. I used a zip tie or a rubber band as times to keep it in place. I have a new pigtail but have not installed it yet since it does not look stock. Silly me.

Cheers

[hEaT]

Have you set idle?

http://www.turbotbird.com/techinfo/Idle ... e2005.html

I'd do this first if you haven't already.

[merkurdriver]

Usually something simple in this scenario...like a vacuum leak or a connector is not in 100% contact.

Does the car have an intercooler / BOV or BPV? If yes, start there. Bypass all the variables and pipe the turbo straight to the throttlebody (like stock) and cap off the vac line to the BOV....If a BPV, make sure the recirculating side at the front of the turbo is closed off air tight as well.

Pull the codes yet?

[Lotus907efi]

Yes, I pulled the codes. It said the air meter voltage was low.
I did check this and sure enough, the voltage output from the air meter is way lower than I would expect.
I have looked at air leaks and I do not find any.

I am now wondering if I might have a clogged catalytic converter or muffler.
This car sat in the garage for just about 10 years so I wonder if some rodent might have gotten into the exhaust or perhaps the intake system.

[Ed Lijewski]

Would appear it's experiencing asthma...difficulty receiving proper air flow through the VAM. At least remove and clean the bore and door so it moves easily.

YMMV

[zxr250cc]

Hi all,

Mine acted as if it had asthma when the fuel filter plugged up. At partial throttle it was fine, wheezing when WOT. I changed the fuel filter and it was great after that. Perhaps two issues at once?

Cheers

[my8950]

Hi all,

Mine acted as if it had asthma when the fuel filter plugged up. At partial throttle it was fine, wheezing when WOT. I changed the fuel filter and it was great after that. Perhaps two issues at once?

Cheers

I had the fuel filter one too recently, wow what a difference!