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'08 DF 50 starting issue...need help

C

catfishin_welder

Contributing Member
I've checked for spark. Real Good spark on all 3 holes. Replaced plugs, 200-199-200 psi top to bottom. Cleaned VST, checked high pressure fuel pump, it's good, cleaned screen under it, cleaned float, needle n seat, new vst gasket. Replaced high pressure and low pressure fuel filters, cleaned throttle body, verified white wire fuse good, replaced main relays. Verified neutral switch operating. Replaced cam sensor. Tried swapping ecm with with known good ecm. All I can get it to do with either ecm is a small pop when cranking over but if I pull plugs and shoot juice in and put plugs back in she fires right up at instant from key turn. Im thinking fuel pressure regulator, or fuel injector issues? Anyone got any other ideas?
 
William01 said:
Check fuel pressure?
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No ive not. That was my next move. I ordered a pressure tester waiting its arrival. I cleaned the regulator but really had no way to test it. Ill pressure test fuel rail then if it's not in spec (ive got factory manual) then I'll replace regulator, if it is in spec, I'll try to clean injectors or replace
 
After cycling the key on/off a few times do you have fuel in the VST? Can you hear the high pressure fuel pump running for 3 seconds or so when you turn the key on? You said high pressure pump was good so I’m assuming you did hear the pump running for 3 seconds? If you disconnect the fuel line feeding the fuel rail and cycle the key on/off does the fuel pump squirt fuel? I’m ASSUMING you have a fuel supply issue and trying to determine how far the fuel is getting in the fuel system. When you squirt fuel into the plug holes the engine fires, that tells me you’re not getting fuel to the injectors but how far is the fuel getting?
 
William01 said:
After cycling the key on/off a few times do you have fuel in the VST? Can you hear the high pressure fuel pump running for 3 seconds or so when you turn the key on? You said high pressure pump was good so I’m assuming you did hear the pump running for 3 seconds? If you disconnect the fuel line feeding the fuel rail and cycle the key on/off does the fuel pump squirt fuel? I’m ASSUMING you have a fuel supply issue and trying to determine how far the fuel is getting in the fuel system. When you squirt fuel into the plug holes the engine fires, that tells me you’re not getting fuel to the injectors but how far is the fuel getting?
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Yes pump cycles on strong for 3 secs with key. I opened drain screw on bottom of VST and have good steady stream of clean fuel out drain tube. I popped out top injector and fuel sprayed out at me high pressure which leads me to believe it's probably injectors or regulator allowing too much pressure. Not sure if injectors are designed to operate within certain psi parameters. I could not find that range listed in manual although I may have missed it. Fuel pressure guage set to arrive by tomorrow so hopefully I'll know more then
 
Manual calls for around 36.4psi, im getting around 38.5 psi which isn't bad but supposed to hold at around 28psi after 5 minutes. It was at 8 psi. I looked through fuel lines, they look good. I believe regulator check valve is bad. Not sure why it's not starting though. Suspect maybe the injectors are clogged/bad as well
 
In my service manual(2009 DF90A) they outline a test procedure for the fuel regulator using a hand pump. Based on my service manual your fuel pressure is close to factory specifications. Loosing fuel pressure indicates a fuel leak somewhere but I would assume you would have found a fuel leak by now. Your fuel pressure is reasonable, you have spark, you have fuel exiting at least one fuel injector, it should at least fire. All I can suggest is double check all your lines/fittings for a leak.
 
William01 said:
In my service manual(2009 DF90A) they outline a test procedure for the fuel regulator using a hand pump. Based on my service manual your fuel pressure is close to factory specifications. Loosing fuel pressure indicates a fuel leak somewhere but I would assume you would have found a fuel leak by now. Your fuel pressure is reasonable, you have spark, you have fuel exiting at least one fuel injector, it should at least fire. All I can suggest is double check all your lines/fittings for a leak.
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Yea my manual has same hand pump procedure but states it should hold at approx 28 psi 5 minutes after key is turned to off position. If this test fails it is indication of faulty fuel pressure regulator. I get the 38 psi at cranking but immediately drops rapidly and at the 5 minute mark psi sits steady at 8 psi. I dont have the hand pump set up but ive ordered new FPR, needle valve and seat. Going to tear vst back off and rebuild it w new oem parts. It's got me stumped. I think I'll replace all the fuel lines and high strength fuel line clamps at that time as well. My injectors test in ohm range and am getting 11.7 volts to all 3 when key is on so im a bit puzzled. Im not sure if they're clogged. I couldn't find anything indicating if 11.7 volts at cranking is correct for injectors. I assume it is. Does your manual indicate the voltage range acceptable at cranking for injectors? Thanks for your input
 
Fuel injector RESISTANCE 10-14 ohms.

Fuel injector operating signal and I quote “6-10 Volts or over”. My service manual(genuine Suzuki) calls for a special tool Steven’s peak reading voltmeter CD 77 and a 36 pin test cord set.
 
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