Keoni1113 Posted May 4, 2015 Report Share Posted May 4, 2015 Hello again all,Turns out my MAS needs to be replaced. As well as a new airbox for the filter. The previous owner took the old airbox out for some reason. As a result the airfilter and MAS assembly has been held in place with a bungee cord. Found a new airbox and MAS on eBay for 70 bucks plus shipping. From the sellers info it seems that he owns an 88 tsi, I was wondering if that will fit in my 87esi-r?http://m.ebay.com/itm/261868747420?nav=SEARCH Link to comment Share on other sites More sharing options...
mikec Posted May 4, 2015 Report Share Posted May 4, 2015 US Spec intercooled StarQuest 87-88-89 fuel systems are virtually identical and almost all parts will interchange. The only significant differences are the ECU itself (87 is different from 88-later but 88-later will work in 87 cars just fine if you swap the cases; 87 ECUs though are a big downgrade for 88-later cars) and the turbo wastegate actuator. The ribbed "accordion hose" and the lid to the air filter canister are different on 88-later cars; the lid has an extra 1" port for a fine-tuning bypass hose that connects to the 88-later accordion hose. You'll have to make a cap for this port to install the air filter canister+lid on your 87 unless you get the 88's accordion hose too. No big deal to cap this port. The 88-later airflow sensor itself will work fine on your 87. mike c. Link to comment Share on other sites More sharing options...
G54Bstore Posted May 4, 2015 Report Share Posted May 4, 2015 Mike C. Explains things very well. Better than I could.Pm sent about your problem. Link to comment Share on other sites More sharing options...
pcristquester Posted May 5, 2015 Report Share Posted May 5, 2015 US Spec intercooled StarQuest 87-88-89 fuel systems are virtually identical and almost all parts will interchange. The only significant differences are the ECU itself (87 is different from 88-later but 88-later will work in 87 cars just fine if you swap the cases; 87 ECUs though are a big downgrade for 88-later cars) and the turbo wastegate actuator. The ribbed "accordion hose" and the lid to the air filter canister are different on 88-later cars; the lid has an extra 1" port for a fine-tuning bypass hose that connects to the 88-later accordion hose. You'll have to make a cap for this port to install the air filter canister+lid on your 87 unless you get the 88's accordion hose too. No big deal to cap this port. The 88-later airflow sensor itself will work fine on your 87. mike c.i have a question on the "fine- tuning bypass". Was it set however at the factory to allow a certain amount of flow either way under certain conditions, or strictly as added unmetered intake towards the turbo? I have 4 of these things and their all in different positions and don't know which way is best. Any tricks to adjust the plug in or out? Link to comment Share on other sites More sharing options...
mikec Posted May 5, 2015 Report Share Posted May 5, 2015 Nobody knows for sure (outside of Mitsu engineers anyway) on exactly what was tuned with the bypass. Was it to adjust air:fuel ratios at idle where the ECU is in open-loop mode? That's my guess, and what many others thought, since idle smog tests are common. This would allow fine-tuning of idle emissions to compensate for car-to-car variations in injector flow rates, airflow sensor readings, fuel pressures, etc. Once the ECU goes into closed loop (engine warmed up and running at a fairly steady part-throttle RPM) the ECU closed-loop logic will basically get the emissions as good as possible no matter what the bypass is set to... rendering it redundant. At full-throttle accel (ECU in open loop again) the bypass might have some effect but no state/county/city smog test I know about tests under this type of load - only the initial (and massive) vehicle smog certification testing done by the manufacturer before the new model goes on sale looks at wide-open-throttle emissions. I never really examined the amount of bypass air on my 88... and my car has the HKS turbo compressor bypass kit which replaces the accordion hose. Ergo I don't have the 1" port on the accordion hose so my bypass system is capped on the air filter lid. And I have no problems passing California emissions either on the "road dyno" method currently in use or the old style "at idle" sniffer test. mike c. Link to comment Share on other sites More sharing options...
pcristquester Posted May 5, 2015 Report Share Posted May 5, 2015 Great read and information as always mike c. thanks so much! Link to comment Share on other sites More sharing options...
Keoni1113 Posted May 5, 2015 Author Report Share Posted May 5, 2015 Thank you as well mikec. as far as info goes you have been a great help. I've also been working down the list of stuff you sent as for my bucking problem. Replaced the CTS and next step is to get my injectors cleaned and tested Link to comment Share on other sites More sharing options...
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