topher87 Posted August 12, 2014 Report Share Posted August 12, 2014 ok so I finally got my quest back on the road friday . but I have been chasing this over boost problem for days now. car specs 87 quest full built engine with wiseco 8.1 race prepped rods etc, 88-89 ecu, aem wideband, prosport boost gauge, greddy ebc, 3 inch blown though maf and maf-t, modded stock IC with 2.5 hard pipes, turboxs rfl blow off before the maf, full works lower shores intake setup, stock mech head, JVE, valve job, stock exhaust manny and 12A, 3 inch exhaust. so after putting a few hundred on the clock it was time for boost and what I got was unexpected I saw over 20 psi before I pulled out of it. I had the greddy set to 14 psi with a stock 10 psi actuator ,removed the greedy and got the same thing. tested the waste gate with a home made manifold and was working well but I swapped it out for the factory 7 psi that I had removed and was known good ..... same thing it has me stomped. after I figure this out I have to see why I can't get the maf-t to change AFR I think it may not be going into closed loop cause no matter how much fuel I throw at out at idle I can't get it to run richer than 14.7 at warm idle. I'm thinking the cts is bad and will test that with the info i got from speedyquests post. also I noticed that the green light in the maf-t is dim while the car is idling and per the instructions it should be off. another question is can I the output from the wide band be hooked up to the ecu thanks in advance chris Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 12, 2014 Report Share Posted August 12, 2014 Are you running with out a muffler or just a down pipe maybe? I would double check you maft wiring if the lights are not doing what the instructions say they should. Link to comment Share on other sites More sharing options...
topher87 Posted August 13, 2014 Author Report Share Posted August 13, 2014 No muffler starght pipe all the way back I'll check the wiring today but I follow this to the t http://www.starquestclub.com/forum/index.php?showtopic=137492&hl=%2Bmaft+%2Btuning Link to comment Share on other sites More sharing options...
wrngwae Posted August 13, 2014 Report Share Posted August 13, 2014 I am thinking your nose switch is not working allowing the ecu to go into idle mode. which will make the ecu try and maintain the 14.7.... just a thought. Link to comment Share on other sites More sharing options...
Fuze Posted August 14, 2014 Report Share Posted August 14, 2014 Overboosting to 20PSI on a stock 12A seems to indicate a problem with the wastegate flapper inside the turbo if it does the same thing with and without the EVC connected. If you swapped wastegate actuators and nothing changed, make sure the wastegate lever moves freely. If it's stuck closed or doesn't open enough you will overboost. Link to comment Share on other sites More sharing options...
topher87 Posted August 14, 2014 Author Report Share Posted August 14, 2014 wrngwae: I found a broken wire that was between the connector and the isc repaired it and redid the tps isc reset and now have tunableity fuze: wastegate moves freely and if take the wastegate arm off and open the flap and drive the car I have no boost so while I was seacching yesterday I read something about "preloading" the gate. so from what I under stand you have close the flap and adjust the arm so you have to pull the arm onto the flap " preloading" it ... not sure if its ture but I'm going to try it today chris Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 15, 2014 Report Share Posted August 15, 2014 Preloading increases boost. You want to reduce the preload in your case. Also verify that there is boost pressure in the hose you have going to the waste gate. You made need to port the waste gate hole in the turbine housing. If all else fails, put a muffler on it. Are you mashing the gas from low rpm in high gears and expecting it not to boost spike? Link to comment Share on other sites More sharing options...
topher87 Posted August 15, 2014 Author Report Share Posted August 15, 2014 Starquestrescue I think your right about the porting since I figured out the tuning problem I have been able to rev it a little more and I found the it still boosts over 15psi around 3500 with the waste gate pulled open where it wasn't before cause I didn't bring the rpms up cause of the tune. I will be putting a muffler on it soon it's a little to much for my taste. Do you think a 16g waste gate flows enough cause I want to run a bigger turbo so I rather put the money into a new turbo rather port this one then end up buying a new one Link to comment Share on other sites More sharing options...
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