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HELP ! This problem is driving me *#%~:nuts!
Here's the situation, I have a SBF with EFI. I can't get it to fire.
I have double checked the timing, the electrical and the fuel All seem good. When the key is switched on the fuel pump runs for a short time then quits. I assume it has pressured up and ready to go. I have a spark lite hooked up to #1 and it indicates a very strong fire. It just will not hit a lick when cranked. I unhooked the gas line and turned the key on and plenty of fuel pumps out. So my question is... Does the injectors require a certain amount of pressure before they fire? And is it possible the pump can still pump but not up to the recommended pressure for the injectors I have replaced the battery, cables, and checked all the fuses. Any help is appreciated. Hersh:) |
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Hey Hersh,
I have been meaning to call and check up on you and Miss Paula but never remember when things are calm. What injection do you have ... port or throttle body ? I think you have a MSD ignition? Most of the systems use the tach signal to trigger the injector pulses and bandwidth. MSD has a quirk or some systems care if you are using the yellow trigger or the white trigger. The MSD can be made to send a trigger signal by tapping the the wire just like you would check the MSD box for coil output voltage. Another got ya can be = does tach signal continue while cranking the engine or not. You must have a ignition source that does not drop out while cranking the engine over. Hang a volt meter on ignition source wire and watch it when you crank the engine over. hope this helps............ call me if you get a chance. Jeff C |
Thanks guys for the quick reply. My EFI is the Mass Flo Injection
System. I have a Magen pressure regulator with a gauge newly Installed. When the engine is cranked the gauge shows zero. I was going to adjust it When and if this darn thing runs. Believe me I have installed this system correctly. I have been over and over all the connections. It's pretty much a plug and play deal. As far as I can tell it's a good system. The customer service sucks though. Jeff, I'll be giving you call. It's good to hear from you. Hersh |
OK Hersh For an easy elimination hook a jumper wire from battery B+ directly to the ECM's connection for ignition B+. This will bypass all voltage drops and switching.
I will talk with you later. Jeff C |
If your F.I. setup uses 8 seperate injectos, 1 per cyl. they should have a 2 wire plug at each injector. Normally with the key on one wire should have 12volts, the other wire gets a ground pulse from the computor while cranking to fire the injector. Worth a check. Use a test light but dont jam the probe into the terminals or they will spread and not make a tight connection.
You also mentioned fuel pressure, you should have pressure with the key on and the pump should run for a few seconds and hold pressure, but should also maintain the pressure while cranking. This is how most o.e.m. systems work, I would think yours is the same. |
could it be as simple as having the lines reversed on the fuel rails? i know stupid idea but im a stupid guy who did just that.
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I have a MassFlo on mine as well. The pumps might be different, but on mine, if the pump isn't running, it will not start or run at all. The pump circuit has a return line and you can hear it build up pressure and then change sounds, but it is still running. If I let it build up pressure then shut off the pump, hit the starter, it still will not start. Mine needs the pump running and pressure on the gauge all the time. Yours might be different, but hope this helps.
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Know this...... If it was installed correctly it would be working......something is not right. Start at the beginning again and recheck.
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To me it sounds like injector not getting a trigger, or the MSD. So many problems with MSD ,I don,understand why you all do not use an HEI type ignition which is simple and reliable , not to mention that parts are available anywhere.
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All of you have given good points to look at and believe me I'm
Doing that. The pump is working properly as it runs for a few seconds In the start position then it starts up again while in the crank position. I have a start button not a spring switch. With mine you turn The key to start then push the start button. As soon as I can I'm going to Check the injectors pulse. As far as the fuel rail go they are correct. That was the first thing I went over. I just absolutely hate electronics so if this is the problem then I have problem. I'm willing to try but I just don't want to screw Anything up. I'll be back in the garage tomorrow to try again. I sure thank all of you guys for the help. It's great to have a place Like this where you have folks willing to lend a hand. Hersh:) |
Hersh
Do you have a pressure gauge in the engine compartment? |
Hi Dave,
Yeah, it's a Magen pressure reg with a gauge. The gauge has a liquid Filled face. So far it hasn't moved when the pump is running. Hersh:) |
I had one in mine and it was bad. Replaced it with the stock POS and everything worked after that. Had similar problems as you have.
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So you are saying the fuel pressure gauge needle hasn't moved yet? I would start there, bad gauge or no fuel pressure. The pump could be running but not pumping or all the fuel could be dumping out the return line to the tank. Has the system ever worked or is it new?
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Hersh, have alot of ideas
BT SNAKE Hersh You have the pump running and no pressure, How old is the car? Are there any RUBBER hoses inside the tanks between the pump and supply line? I think the gas has eaten the line in the tank. The presuure builds and you have a leak in the tank. Quick test. Put a little fuel in all the stacks and see if it fires up at a couple of seconds and stalls out like a motor with no gas. If yes, you are pulling the tanks for a test. Happened last year to my car with the pumps in the tank, meth in the gas kills rubber over time. Hope you and family are doing well. Rick L.
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So here's the latest, I now have fuel pressure when cranking
And the injectors are working properly. While cranking the engine to check the pressure I happen to notice that the starter Was warm when I went to retrieve a dropped screw driver . I touched The starter and Man!, was it hot. I knew that it should never get that Hot with just a few cranks. Earlier it was turning over Slower so I hooked up the charger thinking the battery was low because of all the cranking earlier. So my new question is... If the starter is pulling more current will that draw effect the amperage or voltage needed to run the ECU? Hersh:) |
Yes , The starter can totally get too hot to touch just by cranking...remember it is only supposed to turn over for a second or two.
Well .......What about the ignition trigger...how is that hooked up....crank or distributor or .... take a plug wire off and stick a plug into the wire and hold the body of the plug against ground and see if you get a spark while cranking,.....don't worry, you won't die even if it does shock you!:rolleyes: |
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