fastwagn Posted June 20, 2012 Share Posted June 20, 2012 as stated, i need a bit of diagnostic help with my hitachi 2 bbl. 1984 brat. carb was replaced with a decent reman prior to me buying the car. once it warms up and has been warm for 15-20 minutes, the car starts to miss and run rough. nasty hesitation. i have a service manual and am going through all of the fine adjustments but was wondering if anyone had any ideas. and no, i will not remove and install a weber. i bought this car as a rolling shell to be the new home of my 83 turbo brat driveline. i refuse to put money into the non turbo engine/driveline. i only want to get it running so it can be moved from home to shop as needed to to finish the body work and details prior to the "great swap". well, that, and the injector driver let out magic smoke in the turbo ecm, waiting on the only manufacturer still making the chip to send from china. thanks guys! Link to comment Share on other sites More sharing options...
ivans imports Posted June 20, 2012 Share Posted June 20, 2012 i have 6 or more 84 turbo ecus and 8 85 mpi ones Link to comment Share on other sites More sharing options...
ivans imports Posted June 20, 2012 Share Posted June 20, 2012 oh and carb one the bottom of carb is two 12 mm plugs if removed you look striat in and there is two jets one main and one secondary any crap in carb like to get in there as is the lowest spot on carb check those jets and one the inlet line float valve seat is a small fillter that likes to plug up check that to Link to comment Share on other sites More sharing options...
fastwagn Posted June 21, 2012 Author Share Posted June 21, 2012 cool man, thanks much! i'm going to put some time into it this afternoon, so i'll check there first. i'll let you know about the ecu's. currently just waiting on the new driver chip to show. a friend/EE was able to remove and then source the chip (a transistor set basically), just on the slowboat from china, literally. Link to comment Share on other sites More sharing options...
Cougar Posted June 21, 2012 Share Posted June 21, 2012 Check for intake manifold air leaks if you haven't done that already. Link to comment Share on other sites More sharing options...
fastwagn Posted June 21, 2012 Author Share Posted June 21, 2012 yeah figured that would be an eventual step just based on the rat's nest of plugged vacuum lines. the manifold gaskets are damp, so thinking that could be a source of problems. drove today with a batch of fresh gas, hesitates, stalls, misses etc...pretty frustrating. makes me miss the joy of driving the 83 turbo... Link to comment Share on other sites More sharing options...
a2labs Posted June 22, 2012 Share Posted June 22, 2012 I have a rats nest of plugged and missing vacuum lines around my hitachi, but it seems to run fine. I test for vacuum leaks with a can of brake cleaner or carb cleaner, carefully and precisely spray the suspected area, wait and listen for changes in engine rpm. If the rpm goes up there's a leak. If all your vacuum/fuel tests don't solve the problem, might be a coil or igniter. I know the carb was replaced but stranger things have happened. Link to comment Share on other sites More sharing options...
naru Posted June 22, 2012 Share Posted June 22, 2012 as stated, i need a bit of diagnostic help with my hitachi 2 bbl. 1984 brat. carb was replaced with a decent reman prior to me buying the car. once it warms up and has been warm for 15-20 minutes, the car starts to miss and run rough. nasty hesitation. i have a service manual and am going through all of the fine adjustments but was wondering if anyone had any ideas. and no, i will not remove and install a weber. i bought this car as a rolling shell to be the new home of my 83 turbo brat driveline. i refuse to put money into the non turbo engine/driveline. i only want to get it running so it can be moved from home to shop as needed to to finish the body work and details prior to the "great swap". well, that, and the injector driver let out magic smoke in the turbo ecm, waiting on the only manufacturer still making the chip to send from china. thanks guys! This sounds very similar to a problem I had w/an 84. Pouring cold water over the underhood temp sensor near the egr was a temporary fix. Real problem was an upstream vacuum leak. Link to comment Share on other sites More sharing options...
fastwagn Posted June 23, 2012 Author Share Posted June 23, 2012 that would make some sense, going to smoke test monday when i get back into town. Link to comment Share on other sites More sharing options...
Gloyale Posted June 23, 2012 Share Posted June 23, 2012 (edited) First, like Ivan suggested remove the bowl drains. Next, Remove the top of the carb. you will see 4 brass pieces in the deck of the carb body. the ones that have holes are the Primary and Secondary main emulsion tubes. unscrew them and blow them out. these deliver the fuel/air mix to the venturis during open throttle driving. the 2 solid caps are the primary and secondary "slow" emulsion tubes. These supply fuel/air mix for idle, and transition to secondaries respectively. again, unscrew caps, unscrew the tubes under the caps, and blow them all out. If you can do it all without confusing any parts, it's best to take all out....as well as the accel pump.....and then blow out all the passages (carefull not to lose the ball in the bottom of the accel pump. That is ussually all it takes to make a hitachi run great. But if you have a rebuild kit....it's good to pull the air horns, and replace the tiny o-rings that seal them. Reassemble and be amazed at how well a 30 year old hitachi will run when it's not clogged up with crap. *note.....this can all be done with carb on the car.....no need to remove it. Edited June 23, 2012 by Gloyale Link to comment Share on other sites More sharing options...
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