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Engine running rough 84S

 
Old 08-04-2010, 02:18 PM
  #16  
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Originally Posted by Hkp7 View Post
I noticed that I lost all fuel pressure when disconnecting the fuel relay jumper and suspected the check valve on fuel pump. Then I noticed I had a small fuel leak at the fuel sending unit. For some reason, I thought the fuel was supplied from the bottom of the tank and the line going to sending unit was a return. Then I thought of the earlier cars that had an additional fuel pump where my sending unit is. In that case, the fuel pump gets its fuel from the sending unit. When I removed the fuel pressure test port cap I had an unusual amount of air in the fuel rails and very little fuel. It is possible that I am pulling air from the leak and not enough fuel. Next step for me is to repair leak at sending unit and try again. I will post results. I hope this is the problem.
The fuel hose on the sender unit is the return line.
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Old 08-09-2010, 02:37 PM
  #17  
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Ok, I see your right about the return line. Repairing the leak at the sending unit fixed my pressure leak down. Still having problems. I removed a majority of the vacuum lines and plugged them for testing purposes. Removed the air venturi and connected brake booster directly to manifold, plugged TB in and out ports on the front, plugged off evap system. Kept throttle body advance and fuel pressure regulators connected. Drove car, less shaking but still has the wierd exhaust note and no power. Started reading up on Bosch fuel injection. Found the air flow meter is the most important variable. Looking further, I found the time temp switch has a lead connected directly to the air flow meter. I would guess, (correct me if Im wrong), It would tell the air flow meter that the car is no longer using the auxillary air valve for startup.??
My time temp switch reads 32ohms across the two connections, W reads 0 ohms, and G reads 31ohms. Book says W and G are both supposed to be zero. Moving further, the air flow meter test for the intake air temp sensor reads 2.3k ohms at 80 degrees F and is supposed to be 4-6k ohms at 68 degrees F. Well those are two factors which differ from the book I am stuck on and realizing I replaced the time temp switch with new less than a year ago for 109.00, I want to not guess here. I removed the entire upper intake, injectors fuel rails etc. I am cleaning up every part perfectly and re sealing. Hoping to send out injectors for rebuild if funds allow. Tonight, compression test while everything is apart and out of the way. Also going to change the drivers side cam cover gaskets and cam seal since I did the passenger side last winter. Any Ideas on the Bosch side or anything else would be appreciated. Thanks, Bill.
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Old 08-22-2015, 02:45 AM
  #18  
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Did you fix this? I have a similar issue and I am just wondering if you figured it out.
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Old 08-22-2015, 09:27 AM
  #19  
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not bad, this threads only 5 years old,
IIRC this owner sold the car or had it for sale a few years ago ,
though a search says he is still lurking

Awaino I would suggest to start your own thread for your running issues.
Post what the conditions are and the year and model and any things you have done ,
as well as the last thing you fixed
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