Kevin Shasteen Posted March 5, 2001 Share Posted March 5, 2001 1978 Inline6 4spd w/170,000 miles w/AC Alright guys; I was pulling out of a parking lot when my car died. Engine turns over very strong; amp gage shows full charge. It didnt give me any warning; as I shifted from 1st to 2nd it just.....d-i-e-d. Tried to start it immediately & eng.turned over but not even a hesitant start/spit/sputter...eng turns over fast but just "no start" at all. This car is so Bone-Stock its rather hard to believe. I bought it from the original owners who were not hotrodders & had every repair done by a Nissan Dealer or a Zshop; so I dont expect any cut/spliced wiring that may be a culprit or any surprises anywhere in its electrical system.! I say it didnt give me any warning; Now that I think about it; I have noticed in the past few weeks every now/then it would kind of not accelerate as quick in low gears as it should've....it was so slight tho (no backfire at all) I only acknowledged the hesitation & didnt do anything about it. I figured the injectors are just sluggish; Car still has 4 of the original 6 injectors! So I gave it no mind! I'm betting the fuel pump & the coil are still the original units & I have a tool for checking ignition spark. My question, is, if its the Fuel Pump what process should I go thru for checking a faulty pump or ruling out the fuel pump? I have recently replaced spark plugs, plug wires, cap/rotor...all that is mostly new. Please dont hesitate to add you .02c's worth even if it is .01c's worth. Any/all sugestions are appreciated. I'll check back here once more before I decide to go back into town to begin tinkering. Thanks for your help! Kevin (Now A Sick Inliner) Quote Link to comment Share on other sites More sharing options...
johnc Posted March 6, 2001 Share Posted March 6, 2001 Back to basics... Check for spark. Check for fuel. One of them is missing. Probably need to get a Bosch L-Jetronic fuel injection book. ------------------ John Coffey johnc@betamotorsports.com Quote Link to comment Share on other sites More sharing options...
jimzdat Posted March 6, 2001 Share Posted March 6, 2001 Kevin- One of the basics to remember with that system is that the AFM controls the fuel pump via a microswitch on the "flapper"--the fuel pump will not run until there is airflow. Also you should check the harness where it plugs into both the AFM and TPS--both are weak points, especially when it comes to water getting in them I have a copy of the 78 FSM at home, I can try to look stuff up for you if need be--email me direct -jimzdat@earthlink.net Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted March 6, 2001 Share Posted March 6, 2001 Kevin: Johnc does what I do: check for fuel and check for spark. I'll bet it's the fuel pump or the fuel pump relay. I know where the FP relays are on the 75-77Zs but not the 78 (I think it's near the fuse box). Also, if the air flo meter goes bad, it goes bad immediately! Fuel pump check: disconnect pos+ wire from pump. Set a battery nr rt rear of car. Hook up neg- lead from batt to neg- post on fuel pump. Hook pos+ lead to batt and touch pos+ to pos+ post on FP (or vice versa). If there's no "whirling" sound, then your FP is bad. Happy hunting!! PS: Also chk for dirty/clogged fuel filter. [This message has been edited by Fast Frog (edited March 06, 2001).] [This message has been edited by Fast Frog (edited March 06, 2001).] Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 6, 2001 Author Share Posted March 6, 2001 Thanks for all the suggestions; John-I forgot I had the L-Jetronic book till you mentioned it/thanks for reminding me. It had a suggestion about purging the fuel pressure system....Hook a hand held vacuum pump to the vacuum side of the Pressure Regulator-as you pump that will open the valve & purge the system....cool! I appreciate all comments about the AFM & the Offline tesing of the pump. I do have the L-Jetronic book & the factory 78 Service Manual. The factory service manual locates the Fuel Pump Relay, Fuel Pump Control Relay and the EFI Main Relay in the Relay Bracket in the engine compartment by the Fusible Links next to the passenger front strut mount. Thanks for all the suggestions & it looks like I'm being forced to learn EFI....extremely fast/been reading all morning. Thanks everyone for your help. Kevin. (Yes, Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 6, 2001 Author Share Posted March 6, 2001 Okay, doofus me; I left my Multi-Meter here at home so I'm back to retrieve it. However, I have made progress. I checked the spark; Plenty of spark. Jacked the rear up, supported it by stands & the fuel pump was off when the key was turned on. Turned the key off then disconnected the fuel pump leads & connected them to a jumper wire to a Battery....The Pump came on immediately. So I now know that either the Fuel Pump relay or the AFM (Ouch, Just thinking the problem may be the AFM-HURTS $$ Wise). I'm hoping for the Fuel Pump Relay. Everyone lay hands on your Monitor & Say In Unison "FUEL PUMP RELAY! The L-Jetronic book indicated that the Fuel Pump Relay comes on when the Ignition Key is turned to the on position but if the Fuel Pump Controller Relay senses that the engine is not running w/in 2 seconds it will then cut power to the Fuel Pump Relay. Further, the L-Jetronic book claimed that the Fuel Pump & Its relays obtain its power from the Ignition Key Circuit & not the ECM....Whewww! Going back out there now...should know something by tonight...starting to get dark & may have to wait till tomorrow. Keep the suggestions coming if anyone sees/thinks I'm doing something wrong. Normally not an EFI guy....but learning fast. Kevin (Yes,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
jimzdat Posted March 7, 2001 Share Posted March 7, 2001 Kevin--if it is that switch in the AFM, it usually just needs to have the contact strips bent into shape, and then just silicone the plastic lid on (gee-think maybe I've done this?)or, if you plan on yanking the motor to go v8--just clip and splice the 2 wires in the harness that are for the switch--not sure about a 78, but on my 76 they were the 2 on the end closest to the throttle body Jim Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 8, 2001 Author Share Posted March 8, 2001 Okay; Problem Solved! Just wanna thank everyone for your input. Turns out it was not the AFM; I had a gut feeling the AFM was okay...dont ask me how as I didnt even touch it & I'm not a EFI Guru; never put a meter to it..."Just Willed The AFM Into Being Okay" I guess. The culprit was the "Fuel Pump Control Relay". I decided to test the relays again...for the third time. The Fuel Pump Control Relay was fine until you allowed current to flow thru it for more than a minute; after that minute it would short out & quit working. Found another relay at the salvage yard, installed it & Engine Fired up immediately. Whewhooo! Auto Zone's Crossover book indicated that Nissan has used this exact same Relay in most of their cars from 75-95 & in the Infinity's as well; I did not know that....so if anyone ever needs this relay; dont think you have to get it from a 20-25 year old Z. AutoZone & NAPA both wanted @ $35 for a new one & said it would be a week for a special "Factory Order". I paid $25 at a salvage yard...kind of steep but he had it & I could get it now/not wait a week-so I paid the $25. Anyway, thanks again for everyones suggestions; its nice to know we have our very own "Tech Line" here at this site! Kevin, (Yes, Now a Healthy Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted March 8, 2001 Share Posted March 8, 2001 Kevin: Don't thro the old one away!!! I've salvaged 2 of those FI relays buy taking the cover off and adjusting the tension on the "flappers". Then they worked like new!! Rick Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 8, 2001 Author Share Posted March 8, 2001 Yea, I thought about that & have done that w/other relays in the past; just didnt want to take a chance of breaking the original prior to having another one. Thanks for the reminder tho. Kevin (Yes,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
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