 How much fuel should flow?, Out of fuel pump with EFI |
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| Rocky |
 Oct 4 2009, 07:27 PM
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#1
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From the cockpit  Group: Members Posts: 341 Joined: 24-March 04 From: Gig Harbor,WA Member No.: 1,845  |
My super reliable 75' 1.8 now will not start. It has stock injection. I do have spark! Injectors show no fuel outflow when cranked. I then went to the pump and when cranking over it shows a steady low flow of fuel. Shouldent I see a pretty high rate of pressurized fuel given these are putting out over 20 psi? This is the original fuel pump.
I know I havent posted in a while... Im a looser (IMG:style_emoticons/default/wacko.gif) Rocky |
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Replies(1 - 17)
| type47 |
Oct 4 2009, 08:02 PM
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#2
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
for a '75, I found in the workshop manual a figure of 62 liters per hour. Later on in the workshop manual, it shows testing the fuel pump, you should get at least .5 liter in 30 seconds of running the pump (into a measuring container).
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| 914Sixer |
Oct 4 2009, 08:23 PM
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#3
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914 Guru Group: Members Posts: 8,897 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region 
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Check L-Jet testing info. Fuel pump power does not come on until AFC activates it.
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| Rocky |
Oct 4 2009, 08:33 PM
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#4
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From the cockpit Group: Members Posts: 341 Joined: 24-March 04 From: Gig Harbor,WA Member No.: 1,845 |
If I assume fuel flow is adequate out of pump but no fuel out of injectors when engine is cranked, any idea next area(s) to check?
Thanks! |
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| zonedoubt |
Oct 4 2009, 09:49 PM
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#5
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Canadian Member Group: Members Posts: 668 Joined: 14-May 03 From: Vancouver, BC Member No.: 696 Region Association: Canada |
Check resistor pack, double relay.
Here's a good L-jet troubleshooting guide: http://manuals.type4.org/ljet/ |
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| type47 |
Oct 5 2009, 05:24 AM
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#6
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Viermeister Group: Members Posts: 4,254 Joined: 7-August 03 From: Vienna, VA Member No.: 994 Region Association: MidAtlantic Region |
QUOTE(Rocky @ Oct 4 2009, 06:33 PM)  If I assume fuel flow is adequate out of pump but no fuel out of injectors when engine is cranked, any idea next area(s) to check? Sounds like a sudden low flow condition. Any chance that recent work on the car caused a kink in a fuel hose somewhere along the line? |
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| Rocky |
Oct 5 2009, 09:51 AM
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#7
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From the cockpit Group: Members Posts: 341 Joined: 24-March 04 From: Gig Harbor,WA Member No.: 1,845 |
QUOTE(type47 @ Oct 5 2009, 04:24 AM) QUOTE(Rocky @ Oct 4 2009, 06:33 PM) If I assume fuel flow is adequate out of pump but no fuel out of injectors when engine is cranked, any idea next area(s) to check? Sounds like a sudden low flow condition. Any chance that recent work on the car caused a kink in a fuel hose somewhere along the line? Unfortunately or fortunately I havent touched it aside from adjusting the valves after rebuilding it 3 years ago. It has always ran great. |
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| davesprinkle |
Oct 5 2009, 10:47 AM
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#8
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Senior Member Group: Members Posts: 720 Joined: 13-October 04 From: Berkeley, CA Member No.: 2,943 Region Association: None
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QUOTE(Rocky @ Oct 4 2009, 07:33 PM) If I assume fuel flow is adequate out of pump but no fuel out of injectors when engine is cranked, any idea next area(s) to check? Thanks! The Ljet brain uses the coil signal to generate the fuel injector pulses. Make sure that the lead to the coil is still attached. |
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| Rocky |
Oct 5 2009, 11:12 AM
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#9
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From the cockpit Group: Members Posts: 341 Joined: 24-March 04 From: Gig Harbor,WA Member No.: 1,845 |
Yep, its connected.
BTW, nice bike. 400 supersport? |
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| davesprinkle |
Oct 5 2009, 03:24 PM
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#10
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Senior Member Group: Members Posts: 720 Joined: 13-October 04 From: Berkeley, CA Member No.: 2,943 Region Association: None
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Good eye. Yeah, it's a 400 four. My other project...
OK, if the coil lead is connected, you should verify that the injectors are properly powered by the dual relay. Also, the injector resistor pack leads will fail over time. (I carry a spare dual relay and injector pack with me.) And have you verified fuel pressure in the rail? This requires a gauge and some method of tapping into the plumbing, either with the fiddly little OE pressure port (good luck finding that adapter) or with an in-line tee fitting. QUOTE(Rocky @ Oct 5 2009, 10:12 AM) Yep, its connected. BTW, nice bike. 400 supersport? |
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| r_towle |
Oct 5 2009, 04:00 PM
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#11
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Custom Member Group: Members Posts: 24,585 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
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The fuel pump does not come on in Ljet until after the car starts and air is moving enough to open the flapper in the AFM unit.
I think it is supposed to come on while cranking, but you need great compression and a fantastic battery to create enough draw to open the flapper....so old cars dont function like this anymore. I never liked that. Basically the system MUST stay up in pressure when parked, yet few really do over long periods of time....like winter storage. So, the fuel lines need to be checked and replaced, all of them. New metric hoses, new FI clamps (not hardware store clamps...get the good ones) when this happened to us, it was the fuel pump dying...so start shopping around for a fuel pump. You can remove the large intake hose at the AFM and with the key in the run position, stick your finger in the AFM and active the flapper door. You will hear the fuel pump run, and you will hear it change tone once the system is pressurized. Then put it back together and the car should start. Rich |
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| davesprinkle |
Oct 5 2009, 05:24 PM
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#12
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Senior Member Group: Members Posts: 720 Joined: 13-October 04 From: Berkeley, CA Member No.: 2,943 Region Association: None
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QUOTE(r_towle @ Oct 5 2009, 03:00 PM) The fuel pump does not come on in Ljet until after the car starts and air is moving enough to open the flapper in the AFM unit. I think it is supposed to come on while cranking, but you need great compression and a fantastic battery to create enough draw to open the flapper....so old cars dont function like this anymore. I never liked that. Basically the system MUST stay up in pressure when parked, yet few really do over long periods of time....like winter storage. So, the fuel lines need to be checked and replaced, all of them. New metric hoses, new FI clamps (not hardware store clamps...get the good ones) when this happened to us, it was the fuel pump dying...so start shopping around for a fuel pump. You can remove the large intake hose at the AFM and with the key in the run position, stick your finger in the AFM and active the flapper door. You will hear the fuel pump run, and you will hear it change tone once the system is pressurized. Then put it back together and the car should start. Rich Yeah, Rich, you're right about the flapper switching on the fuel pump. However, the pump should also run when the starter is activated. It's an OR-function: Pump IF starter OR flapper. Your suggestion about listening for fuel pressure is a good one -- if you move the flapper to power the pump, you can listen for the change in fuel pump tone when the system finally pressurizes after a few seconds of running. |
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| zonedoubt |
Oct 5 2009, 05:33 PM
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#13
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Canadian Member Group: Members Posts: 668 Joined: 14-May 03 From: Vancouver, BC Member No.: 696 Region Association: Canada |
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| Cap'n Krusty |
Oct 5 2009, 06:04 PM
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#14
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
I'm gonna try to get the factory troubleshooting guide scanned to a PDF this week, maybe even tonight. Make it easy for you. While you're waiting, check for vacuum leaks, especially the TWO o-rings in the oil filler cap. If they're deformed or missing, they have to be fixed before you move on to other possible problems. The Cap'n
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| Rocky |
Oct 5 2009, 08:01 PM
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#15
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From the cockpit Group: Members Posts: 341 Joined: 24-March 04 From: Gig Harbor,WA Member No.: 1,845 |
All great advice! I will give it a once over this weekend, hopefully. Work gets in the way of my true passion!
Thank you all and I will keep you posted! Rocky |
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| Rocky |
Oct 10 2009, 12:11 PM
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#16
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From the cockpit Group: Members Posts: 341 Joined: 24-March 04 From: Gig Harbor,WA Member No.: 1,845 |
Im on the road again!!! (IMG:style_emoticons/default/driving.gif)
Dual relay was the problem! This tub is a garage queen so for it to suddenly not start was baffeling as most of the engine and running gear are new. Corrosion on the relay must have frozen the points. I cleaned them up .. LP 1 and bang. I have been going through the whole system thanks to the L-Jet link. Im buying a new pump and spare relay anyway. Thanks for all the awsome advice! Great to have family! Rocky |
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| zonedoubt |
Oct 10 2009, 12:26 PM
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#17
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Canadian Member Group: Members Posts: 668 Joined: 14-May 03 From: Vancouver, BC Member No.: 696 Region Association: Canada |
Good stuff! (IMG:style_emoticons/default/aktion035.gif)
L-jet isn't as bad to maintain as many people think. |
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| davesprinkle |
Oct 10 2009, 01:22 PM
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#18
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Senior Member Group: Members Posts: 720 Joined: 13-October 04 From: Berkeley, CA Member No.: 2,943 Region Association: None
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QUOTE(zonedoubt @ Oct 10 2009, 11:26 AM) Good stuff! (IMG:style_emoticons/default/aktion035.gif) L-jet isn't as bad to maintain as many people think. Good work on getting your car sorted out. Congratulations. Yeah, L-jet isn't as well understood as D-jet, because there weren't as many made, but the system has some advantages. For example, it will accommodate increased engine displacement -- something D-Jet won't easily do. |
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