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The Acromonious life... VG Goon. Electrical BS. Why the car even runs at all. Cut into tiny pieces!

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So back in the beginning of 2018, I bought a white VG30 goon from ol' Datsunville Pimp daddy... James blah, blah, blah Datsun-Johnson. He picked up the car from Jason of Bend Oregon who started to install the VG30 from a 1991 Infinity M30. James bought it not running. So he took it to a shop that did absolutely noting but F things up. So he took it to another shop in Sacramento Cali, Fitted Garage, who "got it running." Then James brought it home, frustrated he spent so much time and money on the thing. I came along, the sucker I am for wagons, and bought his problems. Upon driving the thing home, it broke down twice. A day later I called James up and told him of my conundrum. He honestly didn't know how to help. He was just glad to get rid of the thing. I promptly pulled out the feeder carburetor fuel pump that fed into a Bosch VW Jetta surge tank that was installed. That did not fix anything as I found my car on the side of the freeway waiting for triple A. Next I replaced the surge tank with a cheep-o Ebay EFI fuel pump of which conked out a few months later, triple A Then I purchased a factory external Nissan EFI pump. That thing lasted for about a year then took a dump, triple A. Finally I bought a Bosch fuel pump 044 https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjRitPq_d_qAhUlGH0KHeW4AT0YABAHGgJwdg&ohost=www.google.com&cid=CAESQeD22ULTFG496dxS-VbUXQlpx9UjAjobtESjKAQgycGjra1uEj4xhIO02yru_cQBuwH_Ai_3gTLO6zDPvRnLBwy9&sig=AOD64_01KpygDp4NU4RSo3O8O2qfbShZqw&ctype=5&q=&ved=2ahUKEwj26svq_d_qAhXmFTQIHTwrC88Q9aACegQIDxA9&adurl=

This thing seems to work good so far except... The problem I'm having is a surge issue. The car will cut out or buck and if I go down a hill in neutral the car dies. When it is cold and I start it up it runs rough until it reaches a certain temperature and then runs smooth all of a sudden. Quite noticeable. Could be electrical, dunno. The car has the CANAM 3 relay box from Jeff. It has the 1991 ECU and wiring harness. The M30 was an automatic, as a side note. I recently replaced the thermostat, cylinder head sensor, cold idle unit on the side of the intake manifold, spark plugs, wires, distributor/crank angle sensor, rotor and cap, ignition coil, fuel pressure regulator, fuel temperature sensor, knock sensor, Air flow meter, cleaned the injectors, exhaust pipe and muffler, wheels and tires, blinker fluid and muffler bearing! I even rotated the air in my tires. And the car runs like shit! Can't figure out why the thing runs at all at this point. There have been a few moments where the thing ran good. Few and far between though.

The question is, am I having a grounding issue? I'm bout' to put an L-16 tired ass engine with a Hitachi carb back in the junker and be happy it runs good.

That's my rant. Crappy EFI junk, VG garbage clunker.

Anyone have a good or bad answer is welcome to comment. But seriously tho, I would like to get the thing running good.




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Pull off all the efi stuff and put on a Holley two barrel carb using Dave Carroll's VG30 intake manifold. you will also need a different distributor.


Here's one:


and here's mine in progress.



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8 hours ago, WAGON JON said:

 It has the 1991 ECU and wiring harness. The M30 was an automatic,



So you converted to a manual gear box?

Is it possible the ecu needs information from the automatic to make it run right?


Just a thought...


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Poor warm up


Idle Air Control valve IAC. Is in use when engine is not at operating temperature and is somewhat like a fast idle cam and electric choke on a carburetor. Engine runs slightly faster on richer mixture to speed warm up and make engine easier to drive when cold. This air MUST be piped from after the MAP or MAF (w/e) so it can account for all the air entering the engine. Once the IAC warms up (I think electrically heated) it closes and engine runs normally without it's help. Many people say they have installed KAs without it and they start and run fine (course this is not below zero where the benefits are more noticed) You could close off the air to the IAC valve and see if this helps or see if it is indeed connected up properly.





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Do you have any service manuals for the car the engine and transmission came from?  Is or was the engine OBD1 or OBD2?

Does the car still have O2 sensors?


Start with the basics.  What is the compression on the engine?  What is the fuel pressure?  Earlier EFI systems do not check the fuel pressure, they just assumed the fuel pressure was in a specific range.

EFI engine controls rely on getting accurate voltages from the various sensors, and part of that means the grounds not only have to all be good, in some cases they have to go to a common point.  A ground connected to an intake manifold, instead of the engine block can mess with the EFI computer.


Is the ignition system in good condition, I know you replaced a bunch of stuff, but it is good?   I do not know if your engine uses a distributor or not, but on some EFI systems with a distributor, even though the engine's computer is controlling ignition timing, the distributor still has to be clocked correctly for the ignition system to work good.


I used to work at a boat dealership around the turn of the century, and all our boat engine were EFI.  In winter we drained the blocks of the engines to prevent freezing damage, and on the engines that used the knock sensor, we has to use a specific sealer on the knock sensor that allowed the sensor to reliably ground to the block.


On the EFI engines I worked on, the IAC valve was used to set the idle speed.   The reason for the IAC is that the throttle butterfly is completely closed at idle, and trying to accurately control the small amount of air the engine needs at idle is impossible with a butterfly valve in a hole large enough to flow the full amount of air the engine needs a WOT max RPM.  Remember, carburetor engine use a idle mixture screw because the main circuits of a carb cannot accurately measure the air and gas flow at idle speed.


Getting back to ODB1 or OBD2.  Is it possible to pull codes from the engine's computer?  That may give you a lot of information that you need to get this thing running right. 

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@rosso Thanks for your reply. I have seriously thought about carbing the engine. I like carbs a lot. I am under the impression the issue I'm having with my EFI is simple. It has just alluded me thus far! If I come to a point I cannot figure it out, a carburetor is promptly being installed! :-)

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@Crashtd420 Yessir, it is a manual gear box. And perhaps the ECU may need additional info. Dunno either. The inquisitive thing is, this problem is hit and miss. It has had several spurts of running top notch. Then crappy again. Weird! It has, for the most part, been an issue with fuel supply and demand. I thought I fixed all the fuel issues. I really think I have. I feel that the issue is now focusing itself on the wiring. This is my next tackle. The car now cuts out under load.

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@datzenmike Thank you for the tid-bit of information. The problem with my cold idle is it runs very rough and will die. I do have an IAC that does work. Still drying to figure out why it wants to run rough when cold. It shouldn't.

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@DanielC No to all three of the first questions. No manuals, think it is OBD 2 not sure, and no O2 sensor of which I wish it had. The engine compression is 180-185 across. EFI pressure is between 30-40 psi according to the gauge. You stated "A ground connected to an intake manifold, instead of the engine block can mess with the EFI computer." I will look into that. I replaced the ignition goodies with factory goodies. It should be good. It better be good! I replaced the distributor with an aftermarket one (the factory one wasn't available) and no change in performance. Your knock sensor story probably had to do with corrosion secondary to a wet environment. Definitely will keep that in mind though. The IAC is set to factory specs to the best of my knowledge. I would have to figure out how to pull codes. No wires to connect to? Perhaps blinking lights? Dunno. I will look into the wiring and ground issues and see if I have faulty connections. Thank you for your info. It's much appreciated.

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21 hours ago, thisismatt said:

Post the ECU model/code. 



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Without OBD II

On G20 models, the ECU is located behind the center console. On J30, M30 and Q45 models, the ECU is located behind the RH kick panel.


If a malfunction occurs within the ECU/fuel injection system, a diagnostic trouble code may be stored in the ECU and the ‘‘Check Engine’’ lamp will blink. There is also a lamp built into the ECU which will concurrently blink.

To read Code output, proceed as follows:

1. Turn ignition On, but do not start engine.

2. Using a small screwdriver, turn diagnostic mode selector switch, located on side of ECU, fully clockwise.

3. Wait two seconds, then rotate switch to full counterclockwise position.

4. A malfunction code can be read as the long (0.6 second) blink, indicating the first digit of a two digit number and the short (0.3 second) blink, indicating the second digit.

Note: Ensure that the diagnostic switch is to the full counterclockwise position whenever the vehicle is in use.




11 Crank Angle Sensor

12 Mass Air Flow Sensor

13 ECT Sensor

14 Vehicle Speed Sensor

16 TCS Signal

21 Ignition Signal Circuit

25 Idle Air Control Valve

22 Fuel Pump Control

31 ECM

32 EGR Function

33 Heated Oxygen Sensor

34 Knock Sensor

35 EGR Temperature Sensor (RH)

41 Intake Air Temperature Sensor

42 Fuel Pump Sensor

43 Throttle Position Sensor

45 Injector Leak

46 Secondary Throttle Sensor

51 Injector Analysis

53 Exhaust Gas Sensor (LH)

54 Signal Circuit From A/T Control Unit To ECM

55 System OK (1990-1995 Q45 only)

65-71 Single Cylinder Or Multiple Cylinder Misfire

72 Three Way catalyst Function

76 Fuel Injection System Function

77 Rear Heated Oxygen Sensor

82 Crankshaft Position Sensor

84 A/T Diagnosis Communication Line

91 Front Heated Oxygen Sensor Heater

103 Park/Neutral Position Switch

105 EGR & Canister Control Solenoid

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@thisismatt Thanks for the diagnostic trouble code numbers. Now I have to figure out where to look and turn the screw...Like really, turn a screw first? Seems retarded. Doin turn table trix and a little beat-boxing with the screw driver. A-chew-it chew--it.

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8 minutes ago, WAGON JON said:

@thisismatt Thanks for the diagnostic trouble code numbers. Now I have to figure out where to look and turn the screw...Like really, turn a screw first? Seems retarded. Doin turn table trix and a little beat-boxing with the screw driver. A-chew-it chew--it.

Something like this



7b1ab94ea6456d4b560126428d720551 (1).jpeg


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Yep Matt nailed it. If you are going to run a car with an ecm you need to be able to read the codes. The engine diagnoses itself and what input it is not getting. No O2 sensor at all? Needs that, also the cutting out under load may be the need for a speed sensor input. You will have to determine whether that is a manual or automatic ecm. Manual ECMs of that era usually want a VSS input.

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@thisismatt, @bottomwatcher Now we're (I'm) getting somewhere! O2 sensor is going in! As for the speed sensor input, how do I do that? Another thing I'm having difficult finding is a wiring diagram.

Edited by WAGON JON

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If it's like more modern system's there are two oxygen sensors, one before and one after the catalytic converter. I'm not sure how important the second one is aside from telling the system if the cat is working properly. The first one is important to the ECU adjusting the mixture, though.

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Considering the m30 looks to have only come as an automatic, you may have trouble dealing with the speed sensor input to the ECU

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Here is the FSM. If this link doesn't work for you let me know and I will upload it on a different site. it will have everything you need to know about the wiring but it can be a little difficult to dig through.



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Ok, now I have 12, 22, 34


12: Mass air flow sensor.

22: Fuel pump control-fuel pump is hard wired to the ignition switch. I know not ideal but it works for now.

34: Knock sensor.

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