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1980 US Turbo Hesitation

 
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doolie72  



Joined: 01 Dec 2018
Posts: 27
Location: California, USA

PostPosted: Wed Mar 11, 2020 12:17 pm    Post subject: 1980 US Turbo Hesitation Reply with quote

So car has been running fine for a few hundred miles since replacement of plugs/leads/dizzy cap/lambda sensor/fuel filter Itís now developed a slight hesitation around 2000rpm on full throttle. Eventually the boost comes in after a couple of seconds but it seems a little down on power.
After some forum searching I carried out the following checks:

Plugs ok (Regular colour)
Vacuum leak test ok (using the starter fluid method)
Ignition Timing ok
WOT switch ok

Any other culprits I should look for? Could it be sticky wastegate or a clogged lambda sensor?
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bureau13  



Joined: 07 Sep 2017
Posts: 239
Location: South Florida

PostPosted: Thu Mar 12, 2020 12:58 am    Post subject: Re: 1980 US Turbo Hesitation Reply with quote

Do you have a boost gauge? I find it almost impossible to diagnose turbo issues without one. Even if it's a temporary install where you route the vacuum in via an open window or something, you can learn a lot about what is going on with the turbo/wastegate that way.

I had some weird behavior that I thought might be the lamda sensor. It wasn't the same as this but you can unplug the lambda and run it and see if the problem goes away or changes. I ended up installing a wideband and not bothering with the emulated narrowband signal at all, so as far as my car is concerned there's no longer an O2 sensor at all.

doolie72 wrote:
So car has been running fine for a few hundred miles since replacement of plugs/leads/dizzy cap/lambda sensor/fuel filter Itís now developed a slight hesitation around 2000rpm on full throttle. Eventually the boost comes in after a couple of seconds but it seems a little down on power.
After some forum searching I carried out the following checks:

Plugs ok (Regular colour)
Vacuum leak test ok (using the starter fluid method)
Ignition Timing ok
WOT switch ok

Any other culprits I should look for? Could it be sticky wastegate or a clogged lambda sensor?

_________________
-----------------------------------------
1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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doolie72  



Joined: 01 Dec 2018
Posts: 27
Location: California, USA

PostPosted: Sat Mar 14, 2020 1:37 pm    Post subject: Reply with quote

Problem solved! Looks like I may have filled the tank with low octane fuel. A can of octane boost did the trick.
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Mike9311  



Joined: 14 Dec 2004
Posts: 834
Location: Chicago-ish

PostPosted: Sat Mar 14, 2020 10:50 pm    Post subject: Reply with quote

doolie72 wrote:
Problem solved! Looks like I may have filled the tank with low octane fuel. A can of octane boost did the trick.


Looks like you dodged a bullet if dealt with this fast enough.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
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