2G Dies With MAF Plugged In

[smoked28]

Hi, guys!

After a few years of being out of the DSM scene, I finally picked up a 2G TSI AWD yesterday as a project. The guy I got it from had 3 DSM's. He said the MAF on the one he was selling was bad, so he unplugged it and hooked his DSM Link up to the car. It started right up and idled okay (very rich because it wasn't tuned to this car). However, as soon as he would plug in the MAF the car would die right away. The car has an HX35 turbo and 1200 cc injectors, so I know I'll need a way to tune it. The car has a black box ECU, so I was going to go about tuning with ECUFlash. He gave me literally 6 MAF's that he said were all bad. He told me I would need to get a new 2g MAF, hook up the black box ECU and get it tuned for it to start and run correctly. Does anyone have an opinion on this before I buy a new MAF? It just seems hard to believe that all 6 of these MAF's are bad. Could there be something else that is likely prohibiting it from starting? It just turns over, never really tries to start. Any help is much appreciated.

A pic of the engine bay for reference.

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

 

[LNS_325]

I had a similar issue but the car would still idle, but very poorly then load up and die. I tried 3 different mafs and all three did the same thing. Turned out to be bad egr valve stuck open. Did an STM block off plate and now it idles much better. Not sure if it’s the same problem, but worth a shot.

 

[chrysler kid]

So you bought a non running car and you have no idea what to do in order to get it running.

I mean, do you genuinely think you bought a running car that just needs a new mass air flow sensor? That a guy would build a car and have dsmlink, and not replace one part because.....why?

 

[smoked28]

So you bought a non running car and you have no idea what to do in order to get it running.

I mean, do you genuinely think you bought a running car that just needs a new mass air flow sensor? That a guy would build a car and have dsmlink, and not replace one part because.....why?

Yeah I probably should have elaborated on that. I bought the car very cheap (I felt even if the engine was shot, the body, mint interior, and bolt on's were worth the price to rebuild). Plus, I heard it run with dsmlink hooked up, so I know it does run. I figured I could get it going with the black box that I talked him into throwing into the deal because I heard they were similar tuning capabilities to dsmlink. I just wanted to see what you guys thought as far as the MAF being the culprit of the issue. Seems sort of unlikely that 6 MAF's are all bad sitting in the backseat of that car. I'm not a mechanic, however, so I was just looking for some pointers and places to check for issues starting, knowing that it'll start with link hooked up.

I had a similar issue but the car would still idle, but very poorly then load up and die. I tried 3 different mafs and all three did the same thing. Turned out to be bad egr valve stuck open. Did an STM block off plate and now it idles much better. Not sure if it’s the same problem, but worth a shot.

I'll check that out. Thanks for the input!

Looking at the engine bay, I see a lot of loose ends. Like the line coming off the wastegate (see pic above) going to no where. Could it be vacuum leaks causing it not to start? I've had leaks before but none that prohibited starting, would just make it run poorly.

 

[chrysler kid]

Looking at the engine bay, I see a lot of loose ends. Like the line coming off the wastegate (see pic above) going to no where. Could it be vacuum leaks causing it not to start? I've had leaks before but none that prohibited starting, would just make it run poorly.

It could be alot of things man. I see the fuse box has been relocated, it looks like an eBay half radiator, the steering pump bracket is bent to hell,and we have no idea what he actually did to get the car running.

You can unplug the mass air flow sensor and the car will start or at least run on the map sensor readings.

Setting a base for the ECU is a good start, I'd go a step further and just put some stock injectors back on the car before paying for ecuflash and tactrix setup.

BTW there is a huge difference between a dsmer and a Facebook dsmer. That whole engine bay reeks of stickers on the windshield Instagram build

Both radiator caps have the over flows hooked to each other

The wastegate isn't hooked up

Throttle body tps doesn't look like it's correctly adjusted.

Start with checking for boost leaks, but a stock ECU won't be able to make the car run with 1250cc injectors

 

[smoked28]

It could be alot of things man. I see the fuse box has been relocated, it looks like an eBay half radiator, the steering pump bracket is bent to hell,and we have no idea what he actually did to get the car running.

You can unplug the mass air flow sensor and the car will start or at least run on the map sensor readings.

Setting a base for the ECU is a good start, I'd go a step further and just put some stock injectors back on the car before paying for ecuflash and tactrix setup.

BTW there is a huge difference between a dsmer and a Facebook dsmer. That whole engine bay reeks of stickers on the windshield Instagram build

All he did was plug in his ECU and dsmlink to it and it fired right up. But when it was running, if he hooked up the MAF, it would die. Now, I tried unplugging the MAF and getting it to start in limp mode (safe mode? whatever it's called), but to no avail. It just turns over and doesn't start. As far as injectors, I have a set of blue tops I'll throw on and see what happens.

My stock injectors don't have all of the seals for the head of the injectors where they spray, I only have one. Will I be able to use the ones from the injectors in the car now?

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

Update:
I put the stock injectors on. Still wouldn't start with or without maf plugged in. From there, I decided to look up the "black box ECU" the guy gave me with the car. The numbers read MD345713. From my research, I found that this is an ECU out of a '98 2.4 N/A (Spyder?). Not only is this not flashable, but I'm assuming this is not compatible with my '95 TSI AWD. Huge bummer. Can anyone confirm this?

Link to ECU research thread:
http://www.dsmtuners.com/threads/ecu-identification-number.165900/

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

 

[chrysler kid]

To be honest the black box ECU really isn't very tunable and is not readily supported like the eprom chips put into a eprom ECU. With an hx35 you would probably be able to flash a base tune but again your information and support will be sparse.

There is a fuel injector resistor box on the firewall, you'll want to verify that it is indeed plugged in and being used. Those are also 1g injectors but I don't think that makes a difference.

I mean that engine has a 1g cam angle sensor on the head, and if it's a 95 you need to change the firing order based on what ecu you are using. The cam angle sensor would also need to be inverted I believe to run that cam angle sensor

 

[smoked28]

To be honest the black box ECU really isn't very tunable and is not readily supported like the eprom chips put into a eprom ECU. With an hx35 you would probably be able to flash a base tune but again your information and support will be sparse.

There is a fuel injector resistor box on the firewall, you'll want to verify that it is indeed plugged in and being used. Those are also 1g injectors but I don't think that makes a difference.

I mean that engine has a 1g cam angle sensor on the head, and if it's a 95 you need to change the firing order based on what ecu you are using. The cam angle sensor would also need to be inverted I believe to run that cam angle sensor

Yeah he just told me that he ran a 1g CAS on the car because of a bad crank sensor. Also, it is wired as a '97 (The motor is out of a '97 gst). I'm not familiar with inverting the CAS, but I'm going to assume that was all taken care of already? I'll check the fuel injector resistor tomorrow.

 

[chrysler kid]

Yeah he just told me that he ran a 1g CAS on the car because of a bad crank sensor. Also, it is wired as a '97 (The motor is out of a '97 gst). I'm not familiar with inverting the CAS, but I'm going to assume that was all taken care of already? I'll check the fuel injector resistor tomorrow.

No it depends what ecu you are using on the car, not what motor is in the car. You would also need to change the firing order depending on the ECU.

Again I will remind you the previous owner said you only need a mass air flow sensor, so buy a new one and see what happens

In dsmlink it's just clicking a box to invert cam angle sensor

It is not a good sign that the crank sensor is bypassed, that can also be a sign that there are more severe problems

 

[smoked28]

No it depends what ecu you are using on the car, not what motor is in the car. You would also need to change the firing order depending on the ECU.

Again I will remind you the previous owner said you only need a mass air flow sensor, so buy a new one and see what happens

In dsmlink it's just clicking a box to invert cam angle sensor

It is not a good sign that the crank sensor is bypassed, that can also be a sign that there are more severe problems

So I switched to my stock injectors and bypassed the ECU for the fuel pump and wired it to the battery. Car started right up, but idled rough and high. I unplugged the maf and the idle came down. Is it safe to say I do need a new maf?

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

 

[chrysler kid]

So I switched to my stock injectors and bypassed the ECU for the fuel pump and wired it to the battery. Car started right up, but idled rough and high. I unplugged the maf and the idle came down. Is it safe to say I do need a new maf?

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

Nice!

It's too early to assume, I would check for vacuum leaks and boost leaks first. Also make sure the throttle cable to the throttle body isn't over tightened. Loosen the two bolts that hold the cable to the intake manifold and press the throttle body closed.

From the brief under hood video I do hear the hiss of a vacuum leak, I also detect a bit of a miss fire, or ignition breaking up from weak spark. But let's track down the vacuum leak first.

It has a 1g throttle body on the intake manifold. That would be the next place to look for air leaks. When the motor is cold you can spray carb cleaner or brake cleaner around the ending bay and if the idle changes when you spray a certain spot you know youve sprayed a leak. The best way is to find any sort of leak is a boost leak test using an air compressor

Unplugging the maf lets the map sensor do some work, to be honest the map sensor is better able to determine vacuum at idle than the maf, so the car usually idles smoother with the maf unplugged.

Also verify your fuel pressure on the regulator is set correctly, I'm not sure what pump you have but a botched pump install is always a possibility in these cars. The fuel pumps are held in place by two flimsy o-rings that can cause pressure issues

 

[smoked28]

Nice!

It's too early to assume, I would check for vacuum leaks and boost leaks first. Also make sure the throttle cable to the throttle body isn't over tightened. Loosen the two bolts that hold the cable to the intake manifold and press the throttle body closed.

From the brief under hood video I do hear the hiss of a vacuum leak, I also detect a bit of a miss fire, or ignition breaking up from weak spark. But let's track down the vacuum leak first.

It has a 1g throttle body on the intake manifold. That would be the next place to look for air leaks. When the motor is cold you can spray carb cleaner or brake cleaner around the ending bay and if the idle changes when you spray a certain spot you know youve sprayed a leak. The best way is to find any sort of leak is a boost leak test using an air compressor

Unplugging the maf lets the map sensor do some work, to be honest the map sensor is better able to determine vacuum at idle than the maf, so the car usually idles smoother with the maf unplugged.

Also verify your fuel pressure on the regulator is set correctly, I'm not sure what pump you have but a botched pump install is always a possibility in these cars. The fuel pumps are held in place by two flimsy o-rings that can cause pressure issues

Yeah the hissing was actually a LOT louder than it came through on the video. I was assuming that was a vacuum leak. There are a lot of loosely fitted hoses and such which I was going to tighten up and see what it did. I do have a DIY boost leak tester which I made for my GST back in the day. I could get ahold of a compressor and look for leaks like that if I can remember how to do it.

That being said, the ECU in that car is from a 2.4 Spyder, so I don't believe I can use it. I just posted it for sale and am trying to decide whether I want to buy the correct black box for my car or get an EPROM and go DSMLINK...

 

[chrysler kid]

Yeah the hissing was actually a LOT louder than it came through on the video. I was assuming that was a vacuum leak. There are a lot of loosely fitted hoses and such which I was going to tighten up and see what it did. I do have a DIY boost leak tester which I made for my GST back in the day. I could get ahold of a compressor and look for leaks like that if I can remember how to do it.

That being said, the ECU in that car is from a 2.4 Spyder, so I don't believe I can use it. I just posted it for sale and am trying to decide whether I want to buy the correct black box for my car or get an EPROM and go DSMLINK...

It depends what you want to do with the car. Remember you still haven't driven the car still

 

[smoked28]

It depends what you want to do with the car. Remember you still haven't driven the car still

Right but if I want to drive it with the current mods, I need a tune. Do you think I could get away with a black box? I found a good deal on one with a 2g MAF and it would be a lot cheaper than link. Basically, I just want a base tune to be able to dial in these injectors and turbo. One thing to note, however, the car is set up to run E-85 (I'm assuming from the sticker on the back). It has a 340 Areomotive pump. Do ceddy mods or similar black box tuning methods support E-85?

 

[chrysler kid]

Right but if I want to drive it with the current mods, I need a tune. Do you think I could get away with a black box? I found a good deal on one with a 2g MAF and it would be a lot cheaper than link. Basically, I just want a base tune to be able to dial in these injectors and turbo. One thing to note, however, the car is set up to run E-85 (I'm assuming from the sticker on the back). It has a 340 Areomotive pump. Do ceddy mods or similar black box tuning methods support E-85?

The black box ECU is tunable similar to the evo8 ecu, depending on where you live the Evo shops typically wouldn't have any trouble tuning that ECU
Where I live in Texas, dsm's don't exist and shops that specialize in them don't exist. So the evo8/or the similar 98-99 black box is easier to get some one to tune

Now if you live in Ohio or the Midwest for example every shop has a tuner specializing in dsmlink, however it all depends on your dedication and if you're doing it yourself

Typically dsmlink is more user friendly and much easier to change and calibrate for a diy person, where as the evoscan and ceddy mods is not as user friendly, and can take time to become familiar with.

So dsmlink ECU with software can run $550~650.

Black box ECU should be $80, evoscan is $30, ceddy mods is free, tactrix with cable is around $130 so 200~250

I mean the fact that you can't run a speed density setup on the back box ECU, means to me it's an inferior setup. Speed density is more exact than using a mass air flow sensor. The black box can emulate the maf sensor readings by piggy backing on the calibrations. So you're running speed density but it is based on maf readings

 

[smoked28]

Typically dsmlink is more user friendly and much easier to change and calibrate for a diy person, where as the evoscan and ceddy mods is not as user friendly, and can take time to become familiar with.

So dsmlink ECU with software can run $550~650.

Black box ECU should be $80, evoscan is $30, ceddy mods is free, tactrix with cable is around $130 so 200~250

I mean the fact that you can't run a speed density setup on the back box ECU, means to me it's an inferior setup. Speed density is more exact than using a mass air flow sensor. The black box can emulate the maf sensor readings by piggy backing on the calibrations. So you're running speed density but it is based on maf readings

I do plan to tune myself. Don’t have any experience, so I’m hoping the forums will help me through. As far as SD, don’t think I’ll ever be going that route on this build. I’ve heard the 2g mafs can go up to higher numbers than I’m planning to push. That being said, the car is already set up on E85, so if ceddymods doesn’t support it, I’ll definitely go the dsmlink route.

 

[AlexGsxCummins]

With that setup shouldn't the car already have dsmlink on the ecu? If ot doesn't maybe the guy stole the ecu and threw in one he had laying around?

 

[smoked28]

With that setup shouldn't the car already have dsmlink on the ecu? If ot doesn't maybe the guy stole the ecu and threw in one he had laying around?

Yes, the latter. He had an EPROM with link in the car. He had many DSMs, so I assumed he only had one ECU and DSMLINK for them all. He sold me a blackbox with the car that ended up not being for a turbo DSM. Thus, I bought an EPROM ECU off somebody on here. Sent it to ECMTuning and just got the notification that it's on its way back.

 

[AlexGsxCummins]

Well yeah there's 99% of your issue. It was tuned and set to run off the ecu he showed you it works with. The stock ecu wont run with that 1g cas, the huge injectors ext... But if I had to guess something happened to the car he didn't want to fix so I would be ready for that. When you get the link back you should be able to get it running from just setting the computer correctly.

 

[smoked28]

Well yeah there's 99% of your issue. It was tuned and set to run off the ecu he showed you it works with. The stock ecu wont run with that 1g cas, the huge injectors ext... But if I had to guess something happened to the car he didn't want to fix so I would be ready for that. When you get the link back you should be able to get it running from just setting the computer correctly.

Yeah that's why I decided to go with link vs a blackbox and ceddymods, because I heard it run with that setup already. From what I understand, the 97-99 ECU would be fine with the 1G CAS since the wires have been swapped (that's why it started with the 98 non-turbo ECU it came with once I wired the fuel pump). I suppose link takes care of the inverting of the CAS signal required with the 95-96 ECU. I had put the stock injectors back in though so that I could hear it run, which I did by wiring the fuel pump. Now, I have a new MAF and link should be here by Friday, I have tied up most if not all of the boost leaks, and did some general maintenance (plugs, fluids, etc.). So, hopefully when I get my link package, I'll be good to get this thing rolling. Going to get some pictures today and start a DSM profile on here so that progress can be monitored and for when I inevitably need help with ECMLINK.

And yeah, I am prepared to find some reason he wanted to get rid of the car. I did a compression test last week and it was just about perfect across all cylinders (within 4 PSI of 178), which surprised me for an engine with 130k. Gave me some hope!

 

[AlexGsxCummins]

I may be wrong but I believe you still will have to check the "invert signal" box in ecmlink you just wont have to change the plug sequence. You will be able to get it to start up and run but you will need to either have it tuned (that's what I did to learn off a good tune rather than blow up my car learning) or learn to tune yourself. Compression is definitely good. Could possibly have been rebuilt at some point, never know I ended up finding a receipt in my car from a tire shop and in the notes it said the motor was rebuilt in April. But the seller said it never was rebuilt. Dis you end up getting v3 full?

Odds are that most of those MAF's are perfectly fine. He probably assumes they are bad because when you plug it in the car starts looking at airflow and your wideband and see's something bad and kills the car. Then unplugged the MAF and it started running. That doesn't necessarily mean the MAF is bad, could mean there's a issue with something else.. Perfect example I had the same issue where the car would die with my MAF plugged in, lots of parts and money later I found out the ecmlink MAF cable was sending a bad signal to the ecu causing it to die when plugged in.

 

[smoked28]

I may be wrong but I believe you still will have to check the "invert signal" box in ecmlink you just wont have to change the plug sequence. You will be able to get it to start up and run but you will need to either have it tuned (that's what I did to learn off a good tune rather than blow up my car learning) or learn to tune yourself. Compression is definitely good. Could possibly have been rebuilt at some point, never know I ended up finding a receipt in my car from a tire shop and in the notes it said the motor was rebuilt in April. But the seller said it never was rebuilt. Dis you end up getting v3 full?

On the threads I've read on here, there seemed to be some controversy over whether or not to swap plugs, injectors, invert signal, etc. Mine is kind of an odd issue because I have a 95 ECU with a 97 engine and harness and then a 1G CAS. So, I reached out to Tom from ECMTuning and he told me that I will need to swap the plugs and to select the invert option.

Wow, that's really lucky for you! I doubt I'll have the same luck though. Apparently it was driven by his wife, who left him and he doesn't want to look at it for obvious reasons. I did some research on the car and found videos of a woman with it (goes by ladi2g), so the story adds up. Possibly it just wasn't driven that hard for all 130k. As far as tuning, I did get V3 Full and I know nothing about it, nor do I know of any shops around me who deal in DSMs anymore. However, I am hoping that with the help of ECMTuning support forums as well as this site, I'll be able to figure it out.

Odds are that most of those MAF's are perfectly fine. He probably assumes they are bad because when you plug it in the car starts looking at airflow and your wideband and see's something bad and kills the car. Then unplugged the MAF and it started running. That doesn't necessarily mean the MAF is bad, could mean there's a issue with something else.. Perfect example I had the same issue where the car would die with my MAF plugged in, lots of parts and money later I found out the ecmlink MAF cable was sending a bad signal to the ecu causing it to die when plugged in.

Well, that's definitely good to know! I asked him that very question because I too thought it sounded unlikely that all of them were bad. He told me he tested them on other cars and they were all bad. Why he felt the need to included a pile of unusable MAfs in the trunk, I do not know. I did just receive my new MAF, however, and started the car with it installed. Although it didn't run great (likely because I was using the non-turbo ECU with different injector settings and such), it did idle a lot better than the other MAFs.

 

[AlexGsxCummins]

Well either way I would invert the signal, try to fire it up if it doesn't work (mine backfired) just swap the plug wires there's only 2 ways it can work. It should be only based off what ecu is in the car. Should be a fun setup once its all up and going though! Is the BOV vented to the atmosphere? Cars not going to like that with the 2g MAF. You can run a gm MAF or SD if you want to keep it like that.

 

[smoked28]

Well either way I would invert the signal, try to fire it up if it doesn't work (mine backfired) just swap the plug wires there's only 2 ways it can work. It should be only based off what ecu is in the car. Should be a fun setup once its all up and going though! Is the BOV vented to the atmosphere? Cars not going to like that with the 2g MAF. You can run a gm MAF or SD if you want to keep it like that.

Yeah that's something I noticed that is on my list of things to look into. On my other DSM, I had a recirculated Greddy Type S that worked well with the 2G MAF.

 

[chrysler kid]

Well either way I would invert the signal, try to fire it up if it doesn't work (mine backfired) just swap the plug wires there's only 2 ways it can work. It should be only based off what ecu is in the car. Should be a fun setup once its all up and going though! Is the BOV vented to the atmosphere? Cars not going to like that with the 2g MAF. You can run a gm MAF or SD if you want to keep it like that.

You have to remember he bought it non running.

He leaves the maf unplugged and it idles.

He needs to perform a boost leak test.

A major boost or vacuum leak will cause the mass air flow sensor to show inaccurate readings to the ECU, the map sensor takes over when the maf is unplugged and can tell the ECU exactly how much air is entering the combustion chamber at idle.

So again, the map sensor is part of the speed density setup, a calibrated map that senses boost and vacuum is far more accurate than a pre turbo mass air sensor that also has a pre turbo air temperature sensor.