Troubleshooting help 1.7 FI, Updated: I almost have defeated the D Jet Demons! |
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Troubleshooting help 1.7 FI, Updated: I almost have defeated the D Jet Demons! |
Robarabian |
Jul 13 2024, 08:52 PM
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#1
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914 A Roo Group: Members Posts: 622 Joined: 11-February 19 From: Simi Valley, Kalifornia Member No.: 22,865 Region Association: Southern California |
Thank you to the collective here, I learned alot. As of yesterday, the car starts, idles higher when cold, settles after the AAR opens. The throttle is responsive. The MPS works, the throttle position switch was re-set and the timing is spot on at 27 degrees and the 123 ignition is working well and playing along with its new friends. . No pops, no backfires.
I took a smart suggestion and did swap out the 71 non adjustable brain box for a 73 1.7 brain box with the knob. That particular setup (thank you @MM1 ) had a very intact wiring harness so I swapped mine for it. Having the knob certainly helps it run smoother. The last item to deal with is the air intake temperature sensor. It is unplugged right now and runs great. When I plug it in, the idle suffers and it hunts and hunts. So I have ordered a replacement and hope that will solve it. Everything else has been checked and / or replaced / upgraded so I'll cross my fingers there. The best troubleshooting process was to disconnect everything except the MPS and plug the holes to determine if there was a vacuum leak somewhere, and then plug things in 1 at a time. As I did that, I located the likely faulty sensor. Again, thank you to everyone who chimed in, your collective ideas kept me from ripping the FI off of it. I know how much better the car will be in stock FI form--in both MPG and value. This literally gets me to now assemble the interior and install the front windshield. Hopefully Hi-Hi Silver will be at a local 914 World Event soon. Robert __________________________________ I am trying to button up what I call "Hi Ho Silver" a 71 I bought during Covid. Motor is rebuilt by me and cam break in went well, 8-10 months ago. How time flies. I had an oil leak, so I pulled the motor today and located it, resealed it and put the drivetrain back in. Car now has a 1,2,3 ignition for FI cars. It has only one nipple for vacuum, so the hose from the top of the throttle body is connected to the nipple on the distributor, the bottom vacuum port on the throttle body is capped off. The timing has not been further adjusted, as it wont run long enough without throttle to do that. (I only have 2 hands). Turn the key, fuel pump kicks on, and the car will start pretty easily with the key turn. It will light, then die within a few seconds. Fuel pressure is at 30 PSI based on the inline gauge. I can start it and with throttle, keep it running. My best description is that with 0-1/4 throttle won't keep it running, I have to sort of put my foot in it. When it warmed up a bit, it sort of idled, but lobed up and down, to the point it wanted to stall but would catch itself at the last second, and lobe up again. I think this is my best symptom.... The MPS is stock, and holds vacuum and also checked out on the meter. I've looked at every vacuum line and things are plugged. The car is not driving as of yet in the build process, I am trying to stabilize it so I can work toward a drive down the street. Any FI info would be helpful. I really want to keep it as stock as possible. I will check all the valves again tomorrow and make sure they are in spec. Thoughts on where to troubleshoot? Thank you in advance. |
Robarabian |
Jul 20 2024, 01:21 PM
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#2
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914 A Roo Group: Members Posts: 622 Joined: 11-February 19 From: Simi Valley, Kalifornia Member No.: 22,865 Region Association: Southern California |
UPDATE: Still struggling.
I have a properly working MPS, a properly calibrated and working throttle position sensor. I put hose clamps on all the intake boots to eliminate any leaks there, sprayed soapy water while holding the throttle open enough to keep it running and didn't locate any leaks. The 123 dizzy vacuum line is disconnected, and the lines to the throttle body are plugged. IT cranks and fires with a revolution or two (ie., a second or less of cranking) runs for 2 seconds and still dies. The throttle is still sluggish and I cant really properly time it still. I have moved the dizzy a bit... retard it coughs through the intake, too much advance it dies immediately, so it is set right in the middle right now where it starts very easily. Valves were adjusted. Fuel pressure at 29 psi and does not drop while under load. Injectors were replaced as well during the rebuild (Fj 114) with new o rings / seals; No fuel leaking anywhere; Really the only things hooked up are fuel lines, MPS, cold start valve, thermo time switch, Cyl head temp sensor (made sure plugged in and also verified car won't start without it) and the AAR. I followed Ian KArr's procedure from his video, it Ohms out at 12.9 and the heat element works as well as the cylinder rotates freely inside. Any more thoughts? |
914_teener |
Jul 20 2024, 02:15 PM
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#3
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914 Guru Group: Members Posts: 5,245 Joined: 31-August 08 From: So. Cal Member No.: 9,489 Region Association: Southern California |
UPDATE: Still struggling. I have a properly working MPS, a properly calibrated and working throttle position sensor. I put hose clamps on all the intake boots to eliminate any leaks there, sprayed soapy water while holding the throttle open enough to keep it running and didn't locate any leaks. The 123 dizzy vacuum line is disconnected, and the lines to the throttle body are plugged. IT cranks and fires with a revolution or two (ie., a second or less of cranking) runs for 2 seconds and still dies. The throttle is still sluggish and I cant really properly time it still. I have moved the dizzy a bit... retard it coughs through the intake, too much advance it dies immediately, so it is set right in the middle right now where it starts very easily. Valves were adjusted. Any more thoughts? Yes: Get the timing set statically first per specs if you checked the valves since all the holes are plugged. Then make sure your fuel lines and or hoses aren't kinked. Make sure the fuel pressure is spec once you have eliminated a fuel problem. Make sure you are using the right coil per the 123 instructions. All electrical leads including the connector at the ECU...mine was loose once. Also the lead to the CHT...make sure it's not cracked or loose, along with ALL the FI connectors at the center spade underneath the plenum. Anything else you might have touched when you took the motor out...electrical connections ect. After all that then it's time to look at spark and the dizzy. |
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