Resolved 95 GSX cranks but not start

[4G63_GSX]

Here is the story. One day I was driving from work just got done changing my oil and I was on a quarter tank so I drove about a 2 miles from my house to get gas at Shell. I finished gassing up and got back on the freeway and drove about a mile and was getting on the off ramp when my RPM's drop down to 0 and did not go back up, so when I got to the stop sign my car just died and would not start. I had to have it towed.

I emailed my dude at my tuning shop and he asked for a log to see why it just cranks and doesn't start. I checked all my connectors and wiring that I could and it all looks good. I even checked my crank position sensor thinking it was the problem but it wasn't. The sensor tested good. I am getting fuel, air and spark so I'm all out of ideas.

My tuning shop said check my IAT, and ECT sensors from what he saw on the log by the way its between 40 and 50 degrees here.

Heres the logs.

 

[ENICKB]

Ive had that exact same scenario, and it was my coolant temp sensor just beneath the radiator cap.. Wire frayed, shorted, and killed sensor, and car wouldnt work...

 

[92AWDHX40]

http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html

 

[4G63_GSX]

Ive had that exact same scenario, and it was my coolant temp sensor just beneath the radiator cap.. Wire frayed, shorted, and killed sensor, and car wouldnt work...

ya it is really wierd, i have never been in this type of scenario before so the only thing i could think of was my crank sensor because it sends signal to rpm gauge but that checked out good. Is their another way to test the ECT sensor without taking it out and testing it in water? thats the only way that i know of, how did you do it?

 

[92AWDHX40]

Have you tried to test it with a volt meter? Do you have fuel, spark, and compression?

 

[4G63_GSX]

Have you tried to test it with a volt meter? Do you have fuel, spark, and compression?

All 4 Injectors are all at 2.4 ohms and 11.40 V

All C.O.P are between .3 and .5 ohms
And cylinders 1 & 2 are at 10.80V and cylinders 3 & 4 are between 1 and 4 mV

ECT sensor is at 3.71K ohms (45 degrees outside) and 5.04V

IAT sensor is 5.04V and I couldn't measure the ohms ohms the sensor is under the elbow connected to the TB and I don't have a crescent wrench to take the sensor out and I couldn't get my ohmmeter leads on the prongs of the sensor and all the grounds are good in the engine bay.

Yes I am also getting fuel and my FPR gauge is reading 20psi fuel pressure when key is in the on position. Fuel pump kicks on. I have not physically taken the plugs out and set them on the valve cover to see if they spark I will do tomorrow, and I do not have a compression tester will get one either tomorrow or this weekend. Battery voltage is at 11.90V

 

[4G63_GSX]

UMS Tuning said to check my IAT, and ECT sensors from what he saw on the log.

I did, they are both getting correct voltage and ECT is correct ohms. I couldn't test IAT resistance because sensor is in a weird spot and can't get my ohmmeter leads onto the sensor terminals.

COP's ohms are in spec, cylinder 1 and 2 are getting battery voltage but 3 and 4 and at 4 mV. IDK what that's about. I checked the wiring and it's all fine under the coil pack plate I even ran my ohmmeter through it and the wires are fine.

The injectors are all getting battery voltage and ohms are within spec as well. The engine grounds are good as well as the grounds inside the cab.

I have an AEEM EMS v2, all the connections are snug to the ECU. I haven't checked the cam sensor or igniter yet but let me know what you think really need some help on this.

 

[stars]

First I would check your gas tank and make sure you have 1/4 of a tank like you think you have, add some if you have too. Did you check your coolant level too? With that done then next, I would check to see if you have spark or not to 1-4. If you have a no spark to half of the cylinders or none then at all then I would test the power transistor or replace it with a known working one then go on from there. Sounds like you have checked out the obvious causes but still a few more places left to test and check.

 

[4G63_GSX]

First I would check your gas tank and make sure you have 1/4 of a tank like you think you have, add some if you have too. Did you check your coolant level too? With that done then next, I would check to see if you have spark or not to 1-4. If you have a no spark to half of the cylinders or none then at all then I would test the power transistor or replace it with a known working one then go on from there. Sounds like you have checked out the obvious causes but still a few more places left to test and check.

No I filled up before it died u failed to read that properly I filled up and was on my way home. I do have coolant and my standalone is not going into stat sync'd. I had thought about the igniter as a problem as well.

 

[4G63_GSX]

I'm not getting spark because my AEM EMS standalone is not going into stat sync'd meaning it is not going to fire the injectors or the coil packs.

 

[4G63_GSX]

I have done my research and tested numerous different sensors.

I checked my crank position sensor thinking it was the problem but it wasn't the sensor tested good all within spec ("note" I am using a 30 dollars multimeter). I am getting fuel and air but haven't pulled out my plugs to see if they fire so I'm all out of ideas.

I have checked the cam sensor and it was a little out of spec but was hard to tell with all the fluctuations. I have not checked the igniter yet but let me know what you think really need some help on this.

I'm also not getting stat sync'd but I dont know why because I tested the sensors and both the crank and cam sensor get battery voltage, both have continuity to ground and I tested the signal wire to the ECU and their is continuity on both wires from sensor to ECU so I'm still stuck.

 

[jtmcinder]

I hate you people! This is the third time this month I've come into the office and found my husband passed out with blood leaking from his eyes. And this site has been up in his browser every time.

- Toby's wife

ps. he mumbled "check for spark" as they took him away in the ambulance

 

[tunermt]

CAS or related wiring my friend if you lost stat sync (in the AEM Tuner software) while you try to crank it over the first thing to trouble shoot is the sensor that tells the EMS what the engine position is.

Also be 110% sure to re sync the ignition timing (engine to EMS) after you get this worked out especially if you move/change anything with the CAS.

Good luck, hope you can get her back on the road stat!

 

[4G63_GSX]

I hate you people! This is the third time this month I've come into the office and found my husband passed out with blood leaking from his eyes. And this site has been up in his browser every time.

- Toby's wife

ps. he mumbled "check for spark" as they took him away in the ambulance

Can't get spark if ecu is not going into stat sync'd..

CAS or related wiring my friend if you lost stat sync (in the AEM Tuner software) while you try to crank it over the first thing to trouble shoot is the sensor that tells the EMS what the engine position is.

Also be 110% sure to re sync the ignition timing (engine to EMS) after you get this worked out especially if you move/change anything with the CAS.

Good luck, hope you can get her back on the road stat!

Now I have tested both the crank and cam sensor and the crank was in spec from what I saw and the cam was a little out of spec but it's hard to tell with all the fluctuation in volts while testing. When i had my computer plugged up, while cranking I would see a spike in rpm's about 1200 now that would tell me the crank because that sends signal to the ecu for rpm's but it tested within spec. If I did the 1G CAS conversion you think that would take care of the problem?

 

[eclipsegsx1736]

Open up AEMTuner and connect to the EMS. Go to ECU --> ECU Internal Logging Setup.

Using the image below, set up your internal logging parameters to exactly match ALL settings in the image, hitting Enter after each change.

Next, click Reset Log on EMS. Power cycle the EMS (turn off key for 10 seconds, turn back on and re-connect to EMS).

Take the logs by cranking the car over for 5-6 seconds at least 2 times. Then go to ECU --> Download Log Data. Save the file on the desktop and attach the log file to this thread in a new reply.

You must be logged in to view this image or video.

Beau

 

[4G63_GSX]

I will do this tomorrow but just out of interest what is this going to do exactly? for my own learning experience. One more thing this wont mess up any of my cals will it as long as I have my current cal saved I can just upload my current one right?

 

[tunermt]

log away logging wont mess with your tune/calibration

 

[4G63_GSX]

i downloaded two logs one ecu log and the other a pc log hope this helps...

 

[eclipsegsx1736]

Internal ECU logs are MUCH faster than PC-based logs, so they give us much more information to work with.

Looking at the log above, I can immediately see that the crank signal is not correct. It's counting extra teeth, usually caused by a bad/failing sensor or excess noise. The most common cause of noise, however, is from your ignition system, which isn't firing since Stat Sync'd isn't on, so noise is a bit less likely. If this is a 2g 7-bolt engine, then it's got a dedicated crank sensor under the timing cover.

Not to scare you, but I almost never see these sensors go bad. The DSM community knows all too well that crankwalk will eventually damage the crank sensor and kill the engine. Hopefully that is not the case in this situation.

 

[4G63_GSX]

Internal ECU logs are MUCH faster than PC-based logs, so they give us much more information to work with.

Looking at the log above, I can immediately see that the crank signal is not correct. It's counting extra teeth, usually caused by a bad/failing sensor or excess noise. The most common cause of noise, however, is from your ignition system, which isn't firing since Stat Sync'd isn't on, so noise is a bit less likely. If this is a 2g 7-bolt engine, then it's got a dedicated crank sensor under the timing cover.

Not to scare you, but I almost never see these sensors go bad. The DSM community knows all too well that crankwalk will eventually damage the crank sensor and kill the engine. Hopefully that is not the case in this situation.

So what do you suggest? I replace the crank sensor and see if it fires up?

 

[tunermt]

double check all the wiring for that crank sensor first. Wouldn't be fun to tear it all apart only to find the sensor is ok. (this is wishful thinking though)

Good luck my friend, I hope it turns out to be an easy fix for you!

 

[4G63_GSX]

double check all the wiring for that crank sensor first. Wouldn't be fun to tear it all apart only to find the sensor is ok. (this is wishful thinking though)

Good luck my friend, I hope it turns out to be an easy fix for you!

Funny thing is I have already checked the wiring well I checked the harness for continuity so I know the harness is fine. Haven't checked the sensor to connector wiring though maybe something melted. But I'd rather replace a crank sensor than a cam sensor..

 

[4G63_GSX]

Replaced crank sensor and fires right up!

 

[HaveBlue83]

when u can definitely switch to the 1g CAS and rewire if you have link. i had the crank and cam sensors go bad and i was NEVER going to redo a timing belt job for a sensor again. so much better now.

glad its running tho!

 

[4G63_GSX]

when u can definitely switch to the 1g CAS and rewire if you have link. i had the crank and cam sensors go bad and i was NEVER going to redo a timing belt job for a sensor again. so much better now.

glad its running tho!

Thanks it deff was frustrating not knowing what it was but I was told its getting harder an harder to find the 1G CAS and kinda pricey