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> Problem with fuel injection, Advice needed
cal914
post Mar 28 2017, 03:04 PM
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Hi there

Just put our 1970 914 back to fuel injection from carbs and it purred for the first 30 minutes in slow moving traffic but then it began to cough and then was quickly nearly kangarooing down the street. It was fine idling but trying to pull away and driving it, it sounded as though it was misfiring or coughing or not running on all cylinders.

What's the checklist for trying to solve the problem?

Thanks!
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jcd914
post Mar 28 2017, 03:15 PM
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I would start with fuel pressure.
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zipedadoo
post Mar 28 2017, 03:34 PM
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Check the throttle position sensor. Adjust, clean or rebuild.
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Dave_Darling
post Mar 28 2017, 07:14 PM
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Ignition. Always start with ignition. Also make sure the basic engine is in good shape, valves adjusted and decent compression, etc.

--DD
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Jeffs9146
post Mar 28 2017, 07:16 PM
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If it starts and runs fine when it is cold then starts sputtering check the CHT sensor.
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mgphoto
post Mar 29 2017, 12:01 PM
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Where there any mods to the engine, cam, displacement?
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cal914
post Mar 29 2017, 01:12 PM
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Took the car out again today,fine for the first 20mins then the problem returned.The engine has had no mods done to it and prior to fitting the Fuel Injection the car was running great
Thanks for any help that you can give
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Frankvw
post Mar 29 2017, 01:15 PM
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Did you change the fuelpump from the low pressure carb pump back to a higher pressure FI fuel pump again ?
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boxsterfan
post Mar 29 2017, 01:25 PM
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Sounds like CHT sensor.
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Rand
post Mar 29 2017, 01:26 PM
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If it had a carb pump, would it run great for 20 minutes?

Have you checked the CHT as suggested yet?
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mepstein
post Mar 29 2017, 01:41 PM
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Mine used to do that -intermitted bucking. I almost parted the car. I tried a bunch of things but I think it was just bad electrical connections.
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cal914
post Mar 29 2017, 01:43 PM
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Are the CHT sensor still available to buy new
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cal914
post Mar 29 2017, 02:14 PM
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Just found out The CHT censor was brand new out of a packet , that's one thing eliminated
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mepstein
post Mar 29 2017, 02:25 PM
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I can't be sure but I think it was the wires around the tach and making sure the timing was correct that eliminated the bucking. I pulled off all the ground wires and cleaned them as well as the wires for the coil, ect.

I had done the chts but it didn't fix it.
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mgphoto
post Mar 29 2017, 02:39 PM
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Are all the FI parts original and proper according to the rennlist site?
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cal914
post Mar 29 2017, 03:16 PM
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All the parts are original with NOS Bosch fuel injectors , we had 3 sets to choose from
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JeffBowlsby
post Mar 29 2017, 03:47 PM
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There are several FI troubleshooting guides here:

http://bowlsby.net/914/Classic/TechNotebook.htm

And if you determine that you need a new harness...let me know. (IMG:style_emoticons/default/wink.gif)
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mgphoto
post Mar 29 2017, 04:07 PM
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Your FI points in the distributor have grease on them.
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McMark
post Mar 29 2017, 04:18 PM
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Did you take the fuel tank out? Pinched fuel lines underneath are a common problem.
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cal914
post Mar 30 2017, 01:11 PM
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Yes ,removed the tank and cleaned, the sock was all clear.On top of the ECU there's a grey knob that turns and clicks is there a best position for the knob to be to help with the running of the FI
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