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Discussion Starter · #1 ·
I have an '89T with the following upgrades: Lexus AFM, 550's, Walbro, AFPR, SAFC 1, Spearco I/C, CT26 54 trim. I drove it to a local club meet the other night and it ran great. 15 lbs solid boost with no issues. I parked it for about 4 hours, had dinner, did the show and shine thing. When I left and got on the highway I started to hit fuel cut at about 10 to 12 psi. I had to dial back the boost to about 10 psi to keep from hitting fuel cut again.

Yesterday and today, I checked the following: boost leaks = none, switched AFM's, checked CT26 waste gate actuator = ok, vacuum at idle = 20 in, engine code 34 - turbo pressure, found one vacuum line disconnected at the thermostat housing thanks to some idiot at the meet, fuel pressure 29 psi at idle with vacuum attached, no vacuum leaks. Bottom line is I can't find anything wrong.

Any thoughts about what might be causing this issue? Car pulls really strong at 10 psi, idles well and everything is great other than the fact that fuel cut keeps on coming back. Previously I could boost up to 17 to 18 psi before I hit fuel cut. Could my SAFC be causing this? Maybe it is pooched and is not correcting as much as it is supposed to. I will hook up the wideband and check AFR's later this week.

Any thoughts would be appreciated. I can only think that the jack a$$ that pulled my vacuum line and disconnected one of my relays also did something else to that car that I haven't figured out yet.

Thanks!
 

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131 Posts
Discussion Starter · #3 ·
Reset ECU and still the same. Previously checked for a boost leak up to the throttle body. Now I will check for a leak somewhere between the throttle body and head. When I check this I want to be sure that none of the valves are "overlapping" ie. intake and exhaust open at the same time. Anyone know what crank angle will avoid this condition.

thanks
 
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