fuel pump surging, why?? |
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fuel pump surging, why?? |
Tab914 |
Aug 1 2005, 06:52 PM
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#21
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Member Group: Members Posts: 158 Joined: 25-April 04 From: Alexandria, Ontario, Canada Member No.: 1,978 Region Association: Canada |
Another one for you guys...........
Here is the problem I am trying to fix. Whenever the needle in the temp guage gets to about 1/4 the fuel pump starts surging. This causes the idle to start to go up and down in rythm with the fuel pump. Also when under load the car stutters and shudders and kinda wants to choke. Before the car gets up to that temp. it runs nice and smooth, strong on acceleration and no poping or backfiring on decel or anything. Just sounds great and runs fine. Idle is where it should be and fuel pump does not surge. Here is what has been done. -Valve adjustement -Dwell adjustement -Timing adjustement -Tested MPC as per proper ohms. Parts I have changed- coil, plugs, ignition points, trigger points, condenser, rotor, cap and wires. Questions:- what could make the pump surge like that? -does it make a difference how the MPC wire goes into it's conector? -How do I properly check the head temp sensor. -Could the intake temp. sensor be the cause. I am at a lost. Feel like I am going in circles. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif) Has anyone had this kind of problem?? Desperate for advice. (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif) Thanks, Dominic. forgot to add. car is a 1974 2.0 with stock fuel injection. |
Dr Evil |
Aug 1 2005, 10:19 PM
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#22
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Send me your transmission! Group: Members Posts: 23,002 Joined: 21-November 03 From: Loveland, OH 45140 Member No.: 1,372 Region Association: MidAtlantic Region |
Well, you have obviously attended to the ignition aspect of this. The valve adjust is a good idea as well. Now, you will best be served by a fuel pressure gauge hooked up tellign you/us exactly what pressure you are dealing with. It should be 29 or 39 IIRC (Check to make sure as it needs to be exact.) Things that will affect your fuel pressure after warm up: 1-blockage in the line 2-faulty pressure regulator 3-your brain having siezures causeing the injectors to fire erretically 4-Head temp sensor IMHO, changing the engine will change nothing fuel, or electrically related. The fact that your engine seems to be having fits after warmed up leads me to think that it may be your brain as fault 1 will likely be non intermittant, 2 might be and is an easy replace as we all have a few of these parts lying around, 3 would suck but seems to me to be likely, 4 would be a constant rich condition (again, not intermittant). If it is doing the exact same thing each time then many of these faults are far less likely than a brain issue. The major symptom is SURGING when hot. We do need more info on your fuel pressure situation to make further prognostications. Things to look out for: -What is taken out or put into the FI circuit uppon warm up? Can you get a brain from someone else to test? |
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