Resolved HELP!!! 2G Cranks and Starts, dumps fuel, low 02's?

[Musashi450]

Hey guys,

Ok so I've searched around A LOT and haven't been able to come up with a definitive solution for my problem. As the title states, I crank the car and it doesn't start.

I'm in the process of rebuilding my engine and after getting it all in and put together it was starting up (with a little hesitation at times) but it would start up none the less. I have an optima red top and I accidently left the lights on in the car so I left it charging overnight on a 2Amp charge, ever since then no start.

Thinking oh I messed up the battery, got it checked at Autozone and they said it was fine.

I just did a compression check and got 150-150-140-140 so that looks good. Needed to replace the starter and I did but that didn't help anything. Also had the alternator checked and that was fine.

Now the strange thing is that, while I'm cranking (I have a analog voltage gauge) I see it just drop which I don't recall it doing before. When I mean drop it just loses all voltage going to this circuit.

I know I'm getting fuel because the FPR gauge reads 45psi while cranking. Thinking maybe an injector was dirty I looked for fuel while doing the compression check and fuel was getting into the cylinders fine.

Also pulled the computer (I know its usually a 1G thing with the computer going bad, but figured I'd check) and it looks great. I also know that its getting spark because I shocked the shit out of myself while checking.

The only thing that I can think of maybe is that the battery load test wasn't very reflective of what my battery is actually doing, or maybe I'm not getting enough voltage to the coil, hence not a strong enough spark (Sure did hurt though). Plugs and wires are new however so maybe something in the coil?!

Something is grounding out but I don't know where!? Any help is appreciated guys. Damnit I'm gonna tackle this one. Thanks a bunch!

Edit: Also I've checked all the fuses except for the two 10A up near the ignition column but because it turns over, I doubt this is it.

guys this is driving me crazy!?! Apparently I have spark on all four plugs and its nice and blue. Then I put it back in and reattached the computer and it turned over for a sec!!!! Ever since then I've kept trying but then it started just turning over for a little bit and dying. Now its back to where I started!

For a bit it just started clicking when I went to turn it over but soon enough it started cranking again. WTF is wrong with this damn car! If I have fuel and spark that rules out several sensors right?

One thing that I'm confused about is when am I suppose to hear my fuel pump turn on because I only hear it turn on when I crank. Can someone please school me in the MPI relay because now I'm thinking maybe its that?

Ah I'm at a loss now someone please help!

 

[Musashi450]

I forgot to mention that as I was cranking I got a cel but it goes away once I'm done cranking. wont show up on my logger because I need to crank the car to get a connection to the logger and it takes a second to connect! is their anyway to get this code?!

 

[1Gtuner1G]

Hmm since no-one else is even trying I will throw something out there.
Check your coolant temperature sensor for broken wires/grounding itself out.

 

[I-luv-em-all]

here are some possibilities from the good old haynes manual.... empty gas tank, battery discharged(engine rotates slowly) leaking fuel injectors, faulty fuel pump, fpr, ect. fuel not reaching fuel rail, ingnition components damp or damaged, worn, fauly spark plugs, broken loose or disconnected wiring in the starting circuit, loose CAS, ECU.

 

[luv2rallye]

Sounds like poor battery cable connection. Check the voltage on the battery while cranking. It should be over 10v. It sounds like you may have a poor connection in one of the battery cables. Remove them and clean both ends and put back on tight. One of the big battery cables may also be just bad (internally partially broken or high resistance) and dropping the voltage if the starter turns slowly or not at all or just clicks. While cranking, the voltage at the starter should be the same as at the battery - if not the cable is bad or has poor connection (assuming the battery is good).

 

[Musashi450]

Well I know it can't be ignition related because I've tested to see if I'm getting spark in all 4 cylinders and I am.

As far as anything with the fuel, the pressure rises on start up and I see fuel in each of the cylinders. Now since these two components are their, now that I think about it, it can't be a sensor because a bad sensor or relay would cut either one or the other out of the equation (so not a bad CAS right?)

This leads me to think that it just has to be a problem with the battery. At the same time though it doesn't sound like the normal "loosing voltage as I crank". After trying to crank several times it gets to that point though. The last known thing that I did since this was remove the alternator and have it tested then put it back together. I think I may try disconnecting it all and see if I can get the car to start up without the alternator. idk guys any more ideas? Where's my wiseman!!!

OK so here's an update for anyone that cares. I was rechecking lots of connections, charging the battery etc, and it eventually started up!

I think this is because I took the plugs out and let the cylinders air out. I'm pretty damn sure that the engine was flooding itself on start up. When I took out the plugs, the fuel was actually bridging the gap on the spark plug.

Anyway so its starting up but man does it feel like SHIT! I'm sure we've all forgotten to plug back in our MAS at some point that that's pretty much what the car feels like. It virtually does not idle, REAKED of fuel, and the throttle was unresponsive.

I do have a SAFC but I don't believe this is the problem because messing with the idle setting had no affect on the idle what so ever. I'm actually afraid to keep it on more than a couple seconds because if feels like I'm getting detonation.

Anyone have any ideas on this? I do not want to destroy what I just spend my sweet time (a good year) rebuilding. I will test any items ASAP.

Thanks,
-Chris

 

[1Gtuner1G]

Did you ever check that temp sensor like I said? The temp sensor is incredibly important in starting the car because it tells the ECU how much fuel to dump on a cold start. It could very easily be messed up and telling the ECU to throw WAY TOO MUCH fuel causing an instant cylinder flooding from cranking only a few seconds. I'm just relating what happened to me because it took me forever to figure it out and when I finally did it made me feel dumb

 

[Musashi450]

yes I used my logger to look at the temp sensor and it showed the temp at like 46-50F. Just went to go try it again and now it wont start........this is REALLY pissing me off now. I know its because it running rich but would this cause it feel like its goign to explode?! I'm really lost on what I'm doing. Please someone help me with this. Also what should a proper air flow signal be? when I crank the car I see the meter hit a max of like 40hz. Is this normal?!
-Chris

smelled my oil and it smells like fuel!!! WTF is going on?! Mods?!?!

Is everyone else just stumped? Their are like 11 people viewing this forum?

The car is again turning over but just barely, I need to add fuel in order for it to due so. A/f guage is reading super lean when the car starts up (just though it was cold start) but even after the sensor warms up, it still stays in the red. So maybe the engine is monitering lean, and dumping fuel. Why though!?? What is the proper air signal (hz reading) during idle I'm getting like 140. If I dont keep applying gas at idle, the car will flood itself out and its smoke as it does this, the smoke appears white but the compression checked out fine and its just cold outside so I'm assuming its not coolant. It reaked of fuel. Again please help.

Still talking to myself......

Went ahead and realized that the car was only starting up when the fuse to the ECU was pulled (the two 10A fuses under the yellow clip) Something that the ECU is seeing is most likely causing the car to change something and cause it not to start. I am still getting both fuel and spark when the ECU is in the equation. I would love to try swapping the ECU but no other ECU's are readily available (better not be the ecu.....its an eprom....) Does anyone know anything about 2G ecu's going bad? Is their anyway to send them in to get tested?

I am bumping my own diary of a thread......Can someone please explain to me what a bad mpi relay would do?

 

[luv2rallye]

Can someone please explain to me what a bad mpi relay would do?

The MPI relay supplies power to the ECU and all engine injectors, sensors, idle air control motor, and solenoid valves.

 

[Musashi450]

Thanks luv2rallye.
I ask because I was thinking maybe the computer its getting power intermitently but I realize that if that was the case, my safc would be turning on and off while cranking. I'm am shit out of ideas for this. I have never heard of a 2g computer going bad so it makes me think its not that but more importantly I have nothing to compare it to. I still am going to test the CAS (even though I'm getting spark....) and then tonight run a couple of other tests. I need to change the oil because I fear gas has entered it (I was reading about how its not to uncommon for this to happen when the engine floods and its cold) but I dont want to wash the rings.

I'm taking the rest of the day off to try and figure out whats wrong with this thing. I'm going to run the tests on some of the other sensors that haven't been checked out and i'll get back with some results. Does anyone know if this could be an ECU problem or not? I though that a bad ecu would show a code? As I said before the only time the car doesn't start is when the ECU is part of the equation (although runs like complete crap, if it is taken out) Still waiting for my wiseman

ok so I checked all the injectors and that isn't it. Also I was curious to see if my computer was messed up and screwing with the timing of the injectors but I can disconnected my maf for a second while doing some tests and was able to pull an error code from that. Does this mean the computer is good. Also I'm noticing some strange symptoms with the fuel pressure. I dont have any fuel leaks (I have an aeromotive fpr) and the pressure after a bit will get down to 0. The fuel pump also isn't coming on while the car is in the on position, only when I crank. Any input like always is appreciated.

 

[boostvr4]

the fuel pump should prime when at the "on" position. The MPI relay would cause this not to happen. In my experence, your type of problem was beacuse of the coolent temp sensor. either something is telling it to put in a ton of gas, or its not getting any spark.

 

[jjbrasil]

the fuel pump should prime when at the "on" position. The MPI relay would cause this not to happen.

Correct me if I'm wrong, but on all 4 DSM's I've had, the fuel pump never primed for a few seconds with the key in the "on" position?

But yea for the prob, are u getting a injector pulse? Get a noid light and check for a pulse on all 4 plugs. Just a thought

 

[Musashi450]

Well I see fuel getting to all cylinders, and I put a screw driver to each of the injectors and felt them clicking. Also I tested the resitance on each injector and they were just under 3 ohms (right in spec) I dont believe then that my injectors are the problem. I wish I had another ecu to plug in to check.............but I dont. Oddly enough it does sound like a coolant temp sensor problem but I have checked it out with my logger and the sensor is reading just fine. not the -170 that everyone gets when its shot or no plugged in.

 

[jjbrasil]

well if your gonna be replacing the Coolant temp sensor..definatly go to the dealer...u get what u pay for, but anyways im sorta dealing with the same exact problem only my car would just run bad b4 but now it wont even start if u find anything out..Please let me know!!

 

[Musashi450]

Sure will! This is seriously driving me crazy. I wish their were people in the champaign area because I would have a cookout and they could all tinker with this damn problem! Kinda cold though. Anyways, yeah I think my next move is the coolant sensor and the MFI relay. I may open up the relay and see if its engaging when I'm cranking. If not I'm gonna manually flip it and see what that does.

 

[jjbrasil]

cool sounds good, and we both have the same year..so maybe this is a similar prob? hopefully its solved soon!!!! i miss drifting

 

[luv2rallye]

Sounds like it's not the MFI relay otherwise your injectors would not be getting power.

 

[Musashi450]

yeah you know what your right, This is why I ruled out the mfi relay before. Still nothign new with this. What do other people think. Could someone go through how the engine controls when to inject the fuel. Its all in the computer isn't it? The only other thing I could think of is that (and this may be somewhat farfetched) the knock sensor is broken and the engine changing the timing so much that it wont turn over? probably not it.

 

[Musashi450]

alright so I'm getting worried about this, I checked the wiring on a lot of things took out the safc and my turbo timer. Of course it didn't do anything. I haven't replaced the spark plugs yet, so I'm going to do that tomarrow. This REALLY needs to get fixed because it was suppose to have already gone in for paint (350Z pearl blue!) So this is a call to anyone that wants to help a fellow tuner out, throw me your tests and suggestions! I have never heard of 2G ecu's going bad, does anyone have any examples?
-Chris

 

[boostvr4]

Did you install the afc? You said you took it out as well and no change. Did you just unplug the harness? Or did you re solder the connections to the ecu's wiring harness? The only other thing i can think of is that you have the wrong sensor type on the afc. Reinstall the afc and make sure it is set to Karmen.

 

[Musashi450]

yeah, I actually took out all splices I had made to the ecu (I had done them when I first got the car, and wasn't feeling to confident about them). I didn't solder them this time, which I know I should have but I'm going to be putting the connections in again, and just wanted to rule it out as a problem. One thing I wanted to check to see if someone could do for me is run their logger while the car is starting up and look at their timing. It just shows mine as being a static +5. I'm also very curious about this fuel pressure dropping to 0 after a while. Like I said though no fuel leaks, and injector resistance is in spec. I've heard that aftermarket fpr's have trouble sealing though. Where does the pressure go to then? Sorry for all the questions. Thanx guys

 

[Musashi450]

So I came across something in another post that I believe may be related

http://www.dsmtuners.com/forums/showthread.php?t=162130&highlight=fuel+pressure+leak

The first post says something to the affect of having a disrupted ignition signal can disrupt the fuel timing. actually luv2rallye replaid to this and I was hoping that maybe (if your still reading the post) you would have more information on this. Also is this a 1G specific thing. Before I had the vein on the intake cam just barely tapping the sensor and maybe it messed it up enough to where something is going wrong. Although I ruled that out before simply because I was getting spark and I thought that if the sensor was bad, ignition in 2 of the 4 cylinders would go bad, as it has in so many other cases.

On another note, I HATE the stupid CAS on the 95's. I was reading something on road race's site about swapping out the CAS to a different model, but is this only possible on 6 bolts?

 

[jjbrasil]

hey Musashi450 , im gonna be replacing the cas on my car pretty soon..cuz yea its a BIA to replace on our years...ill let u know if i get any results...by monday i should have it in...its soooo cold outside now it sucks :thumbdown

 

[RedRain]

Is everyone else just stumped? Their are like 11 people viewing this forum?

The car is again turning over but just barely, I need to add fuel in order for it to due so. A/f guage is reading super lean when the car starts up (just though it was cold start) but even after the sensor warms up, it still stays in the red. So maybe the engine is monitering lean, and dumping fuel. Why though!?? What is the proper air signal (hz reading) during idle I'm getting like 140. If I dont keep applying gas at idle, the car will flood itself out and its smoke as it does this, the smoke appears white but the compression checked out fine and its just cold outside so I'm assuming its not coolant. It reaked of fuel. Again please help.

I believe the proper air signal should be reading 30-35hz at idle. It depends on what you are idling at.

 

[Musashi450]

Thanx carlo I was still curious about that!