nolicense Posted August 1, 2009 Share Posted August 1, 2009 ok...I was looking for a vacuum leak on my ea81, so I hooked up my vac/boost gauge from my turbo probe. its got a 2bbl hitachi and I tapped into the manifold for vacuum reading. @ 1200rpms it reads 10 for vacuum, doesnt fluctuate at all (except when I hit the throttle then it goes to zero like normal, and off the throttle back to 10). I sprayed carb cleaner all around the carb and didnt get a rise in rpms at all, except when I sprayed it directly into the carb. it idles there (@1200rpms) for a minute or so, then it just dies on me. The vacuum reading does not get over 10. It should be between 20 and 25 IIRC. also I have a small delay from when I hit the gas to when the engine responds to me steppin on the gas. I have unplugged the feedback computer and still get the same problem. think my carb has pretty much taken a crap? I have a small rip in the accelerator pump boot, would that cause these symptoms? I would drop a weber on it, just dont have the money to pick one up...used or new. Unless someone knows what cars they came on stock back in the day. Quote Link to comment Share on other sites More sharing options...
ThirdEyeHatch Posted August 1, 2009 Share Posted August 1, 2009 The hole in the accelerator pump is definitaly giving the delay when you jump on the throttle. And check your pcv valve it could be stuck. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 1, 2009 Share Posted August 1, 2009 The accelerator pump boot is only there to keep dust out - it will not cause a problem if it's ripped. The seal for the pump is on the end of the shaft. GD Quote Link to comment Share on other sites More sharing options...
ihscout54 Posted August 1, 2009 Share Posted August 1, 2009 With these symptoms the first thing Ide do is check my timing. Should be 8 deg. BTDC. You need to also check your vacuum advance can for operation. They are a common failure point and can cause a stumble. You should also look past the carb for vacuum leaks to see if you find a bad circuit. Brake booster, cruise, line to firewall, both the vac valves, intake manifold, etc. If you trust this gauge (and its not timing related/vac leak) you will need to do a compression test. Quote Link to comment Share on other sites More sharing options...
nolicense Posted August 2, 2009 Author Share Posted August 2, 2009 i trust the gauge as it gives reliable readings in my turbo car, and Ive used it to check for vacuum leaks in other vehicles too. timing is dead on, first thing i checked after I got it running. tell me more about this vacuum advance can? Ive noticed the automatic choke butterfly valve doesnt move very much, like maybe between 1/16"-3/16" could it be thats the problem?, basically flooding the bastard and not getting enough air into the cylinders? the only thing about that is I dont blow black smoke or smell gas like it was flooding the engine. Im trying to convince my buddy to let me borrow his weber since he doesnt drive his hatch at all (been almost 6 months since he lost his license and stopped driving the thing.), but hes ignorant and says he needs it...that d*ck...i should tell him that the longer it sits the more chance that its gonna crap out..prolly wont crap out, but hopefully i can convince him. ill run a compression test on it and see what numbers I come up with. Quote Link to comment Share on other sites More sharing options...
ThirdEyeHatch Posted August 2, 2009 Share Posted August 2, 2009 Oops misunderstood rubber boot not diaphram. Still could be the accelerator pump causing the delay. Quote Link to comment Share on other sites More sharing options...
ihscout54 Posted August 2, 2009 Share Posted August 2, 2009 Follow the vac hose to the disty. The mushroom it goes into is your vacuum advance. Even if it is shot, it will not cause a vac leak at idle. Its easy to check with a vac pump or your mouth and long peice of hose (pop the cap suck and watch for movement). Your choke needs to be open when at operating temps. As noted befor check all gizmos and lines hooked to manifold vac, and the manifold gaskets themselves. Quote Link to comment Share on other sites More sharing options...
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