September 21, 2016 at 2:23 pm #11731
Okay guys, I hope this forum is still active. I have what is probably a classic failure on Nissan vans VG33e. The engine of my van does not start, just cranks over. Last time the engine started, it started good as usual, after two or three minutes appeared it misfired during acceleration, then the engine started to cough and the apparent misfire was more frequent to the point the engine quit. After that, the engine turns over, coughs like wanting to start, and then nothing. This is not a distributor failure by the way. I know that for sure because I tested my distributor in another quest and it fired up right away and normal.
Now with my engine, during my troubleshooting I have found the distributor is good, the MAF is good, EGR valve is good and holds vacuum, there is spark, fuel pump pressure is good to 40 psig, pistons compression is good to 180 psig, it does not start with “staring fluid”. I even tried removing the upstream O2 sensor to let the exhaust manifold breath. Timing belt is new replaced 20K miles ago. Another indication of good belt is cylinders compression.
The suspect is the crankshaft position sensor, however, the service manual says it is not used for engine control. That has kept me to not wanting to replace this sensor. I was leaning toward a ECM failure, but I have not confirmed this.
Anyone with a similar behavior?
PedroOctober 3, 2016 at 4:21 pm #11931
After an extensive troubleshooting, I concluded the problem is the ECM (computer). I have sent the ECM for repair and expect to have it back within a week. I will post the results after the computer comes back.October 6, 2016 at 4:41 pm #11952
Man Pedro. I saw this and was hoping to help, but you are so good at the whole process that it becomes hard to see anything that you didn’t already cover. I will ask if you have a power probe? I bought one after using one that my buddy owns. He is a mechanic that’s specializes in automotive diagnostics and the power probe is awesome. It helps so much in all issues with a car not functioning he precise way it should. I love mine and it’s really helped me. I’m trying to get the forum for our vans to notify me via email whenever anyone posts cause it’s seeming pretty dead around here lately and I love my van. And want to help others who love theirs.October 6, 2016 at 8:11 pm #11961
I sent the ECM to FL for repair. I am awaiting for their call to let me know what they found or to ask me additional questions to understand the issue.
I love this van too, this is the first time it fails on me like this at 237,000 miles. I was impressed with the compression test with this hi mileage at 180 psig, that is awesome. I can say it is a tribute to using AMSOIL 5W30 signature full synthetic which, by the way, I change only once a year as AMSOIL recommends. I also sent the oil to an independent lab for analysis and it really works.
The crankshaft sensor was good, I got a very nice sine wave in the oscilloscope. I also checked all other inputs and outputs at the ECM terminal block. The one signal that was not convincing was the firing signal to the distributor. That probed the whole thing, the problem was inconsistent spark.October 11, 2016 at 7:55 pm #12041
UPDATE: It has been confirmed, the ignition coil driver was bad in the ECM. It has been repaired and it is coming back to me. I will have my van in working order again this weekend. My ECM is MECM-C703-A1.
By the way, there is a very good article in http://www.easyautodiagnostics.com with the title “Power Transistor Test and Ignition Coil Test 3.3L Nissan”. I found it later and it is very good. My final diagnostic came after going through all computer inputs and outputs with an oscilloscope comparing wave forms per service manual.October 14, 2016 at 11:04 pm #12091
The computer is back installed in the van. After few turnings and burning old fumes of fuel, the van started slowing and then it picked up rpm. Woo Hoo, the van is back in business now. The problem was the computer output that controls the firing of the distributor. All is good now!!!
So, 237,000 miles and counting ….
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