2G 98 GST starts with rough idle then dies

[42395_skyline]

Backstory: Just purchased a 98 GST stock other than injen intake, TurboXS RFL BOV, and a muffler. It needed a fuel tank, which I installed tuesday. I ran it fine wednesday-friday morning no issue. After work yesterday (friday) I get in my car to go home and it starts with a rough idle. I give it a little gas and decide to reverse it and see if the rough idle would go away once it warms up, it dies.

Problem: Car will start most the time but rough idle. If you give it gas it stays on but the rpms don't rise much. I floored it in neutral and it only went up to like 5k but very slowly and limp. If you don't gas it then it just dies in a few seconds. My co-worker was behind me when I first started it and reversed it and he said he could smell I was running rich.

I did a lot of searching last night and this morning and found many possibilities. As a full time college student and full time job, it's hard for me to go down a list of every single thing I found. I am hoping someone can help me pinpoint the issue. The possibilities that I found online are timing off, cam position sensor (this thread, exact problem I am having. Except my reader appears to be broken because it won't read the codes. I know I had P1105 since I got the car, not sure if any new codes popped up), and maybe fuel pump.

I took 2 videos just now. First one shows rough idle and die, second one won't even stay at idle anymore just dies.

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

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

Also, isn't the cam sensor supposed to be in this picture? Or is it located elsewhere? I don't see it.

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

 

[97 eclenger]

98 4g63 has the cam sensor located on the tranny side on the intake cam. only 95/96 had the cam sensor behind the cam gear. can't adjust either. whats your firing order? left to right should be 4 1 2 3

 

[42395_skyline]

98 4g63 has the cam sensor located on the tranny side on the intake cam. only 95/96 had the cam sensor behind the cam gear. can't adjust either. whats your firing order? left to right should be 4 1 2 3

Oh didn't know about that location. But could it be bad and cause this like that thread? Firing order is 4123. I'm thinking it might be the fuel pump since I had a feeling the old pump would go out. I was thinking of getting a Walbro 190 regardless so I am currently searching for the best price. Hopefully it's that. If not, any opinions on what to check?

 

[EclipseGst95Garage]

Before you go out buying a new pump and possibly not needing it. listen to hear if it primes or not. Your cam position sensor is going to be on the left side of the head. When you gave it gas did it sputter like you was out of gas? Check if your cylinders are getting fuel.

 

[TehRiceBandit]

Try cleaning your MAF

 

[o0GuitarKid0o]

Ohm those injectors they should be around 5ohms each if there not then boom problem solved ps. I went threw the same thing got one cel over a month b4 it got really bad to drive I changed them in my drive way -40 winnipeg weather

 

[inthemidst]

From the video it sounds like you have a faulty crank sensor the one in the bottom behind the main pulley

 

[97 eclenger]

don't go with a 190 fuel pump. for the same price if not just a few dollars more, you can get the 255 hp fuel pump. don't go buying stuff hoping it'll fix it. isolate the issue and correct it. a faulty crank sensor could cause issues like that. the crank sensor sends ignition spark signal. cam sensor sends fuel injector signals

 

[bmxfelon420]

don't go with a 190 fuel pump. for the same price if not just a few dollars more, you can get the 255 hp fuel pump. don't go buying stuff hoping it'll fix it. isolate the issue and correct it. a faulty crank sensor could cause issues like that. the crank sensor sends ignition spark signal. cam sensor sends fuel injector signals

Normally i'd agree with you but with a 255 you run a high chance of overwhelming the stock regulator. From the sound of it the OP doesnt have an extra $200 to throw down on an aftermarket regulator kit, so I'd recommend the 190 because it will work, be better than stock, and not overwhelm the FPR. As cheap as a fuel pump is, i'd just do it anyways. I got a 190 for 40 dollars used.

 

[97 eclenger]

true. didn't know if he can get one or not. isn't rewiring the stock fuel pump close to 190 lph?

 

[42395_skyline]

Before you go out buying a new pump and possibly not needing it. listen to hear if it primes or not. Your cam position sensor is going to be on the left side of the head. When you gave it gas did it sputter like you was out of gas? Check if your cylinders are getting fuel.

Well thing is the fuel pump was on it's way out anyway. When I got the car the tank was so rusted it ate fuel pumps in a couple weeks. When I replaced the tank I kept the pump that was already running like crap. I might as well just get a new pump, I will need it soon anyway. When I gave it gas it was like it would go up, drop a bit, then go up a bit. And I got the car with a TurboXS RFL BOV so you can hear the BOV really loud usually, but when I rev'd it there was like no boost. Just a small swoosh came out.

Try cleaning your MAF

I read on here these don't need to be cleaned? I will search how to clean it and try it out, thanks.

Ohm those injectors they should be around 5ohms each if there not then boom problem solved ps. I went threw the same thing got one cel over a month b4 it got really bad to drive I changed them in my drive way -40 winnipeg weather

I will search how to do that and try it out! Thanks.

From the video it sounds like you have a faulty crank sensor the one in the bottom behind the main pulley

There a way to check that?

don't go with a 190 fuel pump. for the same price if not just a few dollars more, you can get the 255 hp fuel pump. don't go buying stuff hoping it'll fix it. isolate the issue and correct it. a faulty crank sensor could cause issues like that. the crank sensor sends ignition spark signal. cam sensor sends fuel injector signals

I could get the 255 for $5 more, but I don't want an aftermarket fpr. 190 will be fine for what I want with the car, my plans are Evo 3 16G in the future once I get supporting mods.

Normally i'd agree with you but with a 255 you run a high chance of overwhelming the stock regulator. From the sound of it the OP doesnt have an extra $200 to throw down on an aftermarket regulator kit, so I'd recommend the 190 because it will work, be better than stock, and not overwhelm the FPR. As cheap as a fuel pump is, i'd just do it anyways. I got a 190 for 40 dollars used.

You are correct, I don't need the 255 for what I want to do with the car and so I don't want to spend the extra money.

 

[TalonDraukner]

If I were you, I would check the simple things before going too far, but if you think the fuel pump was going anyways, might as well replace it.

I would

• Clean MAF (Very easy, buy MAF cleaner for $7 at autopart store, unhook spray, let dry, and hook it back up. Directions are on the can)
• Check all filters. (Fuel & Air)
• Check spark plugs
• Have someone else start your car and listen to the engine, you may be able to tell what is wrong or at least where is it coming from by the sound.

 

[bmxfelon420]

I agree with most of what you say but I've heard from a lot of sources that Mitsu MAFS dont usually require cleaning. The reason there is MAF cleaner is that GM MAFS (and many others) operate by having a wire that is made of a material that changes in resistance when it is heated. A current is run through it to heat it, and by measuring the resistance of the wire which is being cooled by the airflow, they can calculate the airflow since the sensor is of a known size and shape.

In contrast, Mitsu MAF sensors use ultrasonic sound that is emitted from one point and listened to at another. Airflow changes the way the sound travels and this is how the MAF works. That, combined with the sensor being before the turbo usually means that something like MAF cleaner doesnt do anything. I have used it before and it didnt hurt, but i'd just make sure no major debris/crud is built up on the sensor inside, and if so leave it alone.

And as far as I remember the OEM pump is 160lph rewired. I dont see why you'd ever buy an OEM pump, when the 190 is so cheap, or you could get something like an OEM Evo 8 pump, which I dont have personal experience with but I have heard is a direct replacement on an OEM system as well.

Also if you want to do a cheap, worthwhile fuel system upgrade i'd recommend getting the AN fuel feed upgrade, since the banjo fitting at the top of the OEM fuel filter is the most restrictive part of the system. As cheap as the kit is i'd say it's worth it. I will be getting one in the spring.

 

[42395_skyline]

If I were you, I would check the simple things before going too far, but if you think the fuel pump was going anyways, might as well replace it.

I would

• Clean MAF (Very easy, buy MAF cleaner for $7 at autopart store, unhook spray, let dry, and hook it back up. Directions are on the can)
• Check all filters. (Fuel & Air)
• Check spark plugs
• Have someone else start your car and listen to the engine, you may be able to tell what is wrong or at least where is it coming from by the sound.

Like bmxfelon420 said, I read that they dont need to be cleaned. I'm going to take a quick look at it and see if it looks really dirty. I'll check everything else you recommended as well. Hopefully it's something simple..

I agree with most of what you say but I've heard from a lot of sources that Mitsu MAFS dont usually require cleaning. The reason there is MAF cleaner is that GM MAFS (and many others) operate by having a wire that is made of a material that changes in resistance when it is heated. A current is run through it to heat it, and by measuring the resistance of the wire which is being cooled by the airflow, they can calculate the airflow since the sensor is of a known size and shape.

In contrast, Mitsu MAF sensors use ultrasonic sound that is emitted from one point and listened to at another. Airflow changes the way the sound travels and this is how the MAF works. That, combined with the sensor being before the turbo usually means that something like MAF cleaner doesnt do anything. I have used it before and it didnt hurt, but i'd just make sure no major debris/crud is built up on the sensor inside, and if so leave it alone.

And as far as I remember the OEM pump is 160lph rewired. I dont see why you'd ever buy an OEM pump, when the 190 is so cheap, or you could get something like an OEM Evo 8 pump, which I dont have personal experience with but I have heard is a direct replacement on an OEM system as well.

Also if you want to do a cheap, worthwhile fuel system upgrade i'd recommend getting the AN fuel feed upgrade, since the banjo fitting at the top of the OEM fuel filter is the most restrictive part of the system. As cheap as the kit is i'd say it's worth it. I will be getting one in the spring.

I read the same as you.

I'll see how cheap the upgrade would be for the AN fuel feed. I don't know much about fuel and fuel lines, or even what that upgrade is. I'll search it. I want to get the car started before spending anymore money on it though.

 

[42395_skyline]

Today was finally my day off and first thing I did now is check the spark plugs. Def found a problem there

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

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

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

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

So I can tell I'm running rich and have a leak in 4 (going from left to right). Possibly just the valve cover gaskets?

EDIT: I just smelled the plugs and they smell like fuel.

 

[rough]

You are running rich because you have a boost leak

I just had the same symptoms as you.

Try unplugging the maf, does it want to idle somewhat now? If so you have a BOOST leak

 

[rough]

and holy cow I can't believe this many posts and no one has mentioned it!!

 

[42395_skyline]

You are running rich because you have a boost leak

I just had the same symptoms as you.

Try unplugging the maf, does it want to idle somewhat now? If so you have a BOOST leak

I'm charging my jump starter because all the cranking killed my battery, but I'm going to try to unplug it and see when it charges. I guess I'm going to have to get a boost leak tester. Where was your leak?

 

[95_gst_turbo]

It was hard to tell from the the video but is all 4 cylinders firing?

 

[42395_skyline]

It needs new wires but it starts now but there is a weird tick coming from the timing belt area. After speaking to a friend about it he thinks it's the timing belt tension that is off. Here is the video.

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

 

[bmxfelon420]

Check your crank sensor plate and make sure it's not wobbling around and hitting the sensor or the timing belt. I had a similar problem once and I thought I had a bad tensioner pulley or something, all it ended up being was the plate warped and was tapping on the timing belt. It sounded just like metal on metal.

 

[rough]

So you unplugged the Maf now it runs?


Once you get your boost leak fixed, and plug the maf back in that TICK will quiet down.


That tick you are hearing is lifter tick. Try adding 4 Cyl engine restorer, it will take that tick away if it's the lifters and it doesn't go away once your BLT is done and maf plugged it.

 

[rough]

Also, WD40 that door! POOR DOOR HINGE!!

To me your timing belt looks fine.

 

[42395_skyline]

Check your crank sensor plate and make sure it's not wobbling around and hitting the sensor or the timing belt. I had a similar problem once and I thought I had a bad tensioner pulley or something, all it ended up being was the plate warped and was tapping on the timing belt. It sounded just like metal on metal.

Let me go check that now. If it's something just hitting the belt that would be great.. The timing belt and tensioner is new so I really don't think it is bad.

So you unplugged the Maf now it runs?


Once you get your boost leak fixed, and plug the maf back in that TICK will quiet down.


That tick you are hearing is lifter tick. Try adding 4 Cyl engine restorer, it will take that tick away if it's the lifters and it doesn't go away once your BLT is done and maf plugged it.

Actually, 2 of the wires were swapped in the wrong way. Not sure why it took 3 days for it to stop running, but whatever. Maybe someone messed with me while I was riding hoodless... If it was lifter tick then I would hear it all around the engine, correct? It's only on the belt side.

Also, WD40 that door! POOR DOOR HINGE!!

To me your timing belt looks fine.

The door makes me want to rip it off every time I open it because of that annoying sound but I'm getting a new door anyway so that's why I haven't bothered with it.

 

[42395_skyline]

Sure it has to do with the tension on the belt. I leaned over it to check if anything was touching it and I put some pressure on the belt and it clicked out of time.