1g Intake = Poor Idle & Stalling?

[WaRrIoRs16]

I did a few mods to my Galant about a month ago and ever since then, the car will not idle properly. It will idle just over 1k rpms, it will idle sub 500rps, it will act like its about to stall then shoot up to 1k+ rpms. Sometimes it will just stall out, and sometimes(rarely) it will idle at 750-850rpms. Most of the time its surging I guess, dropping and going back up, if graphed it would probably fit a sine wave quite nicely. If I let it surge for 15-30 seconds it will just stall.

Before I did the mods, the car would idle flawlessy, I would always make fun of my dsm friends that had poor idles because mine was so perfect 100% of the time. The only mod that I did that I could possibly associate with ruining my idle would be installing a 1g intake pipe, cutting the filter canister off, and removing a little cylindrical filter thing from the MAS right where it connects to the intake pipe. My battery is currently where the stock filter housing was.

I have a list of things I have tried to solve this issue over the past month(draining my college student wallet), nothing has seemed to fix the issue. If you would like to know what I have tried and the mods I did, I will post them, just didn't want my initial post too large becuase then people don't tend to help/reply. Prior to doing any mods, my only problem with the car and still is a problem is maxed fuel trims.

So my question is if there is anything else that I should check that could have messed with my idle when I changed the intake location. The MAS plug is not being pulled, but is reaching as far as it can to remain plugged in at the new spot. Oh and I didn't check for any errors until about a week ago and I noticed that I had "12: Airflow Sensor." I reset the ecu and it took a week for the error to pop up again. Thanks

 

[vtecds1]

Check for leaks? Is your hose from the bov connected back into the intake pipe?

 

[WaRrIoRs16]

Yeah I have check for boost leaks and eliminated all of them including some awfull throttle shaft seals and injector seals. I dont reallly know how to check the intake pipe itself for leaks though. I mean, its clamped down tight on both sides and the snorkel/pipe doesn't appear to have any cracks or holes on it. Yeah the BOV is recirculated, kind of tricky to make that one happen, but yes it is.

 

[vtecds1]

Only thing I can think of now is that maybe one of the plug wires might of came loose. My mas was throwing a code(25) and I couldn't figure out why. I went ahead and bought another mas and plugged it in. Same problem. Did a little more searching and found out that one of the wires came loose on the plug. I soldered it back on and the problem went away.

 

[WaRrIoRs16]

Yeah I have the MAS from my old 1g talon that I'm going to throw in there sunday night, only thing is my talon had issues too so I don't know if it will make any difference. Both of them are hacked. I might have access to a buddy's 1g MAS next week and his does work. I was trying to trace the wires back from the MAS plug but they are all wrapped and I can't see exactly where they go. I was tempted to cut the black stuff they are wrapped in and chase it back, but that would just create an ugly mess. Thank you for your help so far.

 

Is the 1G intake pipe the stock rubber one?

 

[WaRrIoRs16]

Yeah it's just the stock rubber one. It has a short 3" exaust pipe to extend the filter to where the battery was, it's all I have at the moment. I have a coupler between the exaust pipe and the MAS with tight clamps, then the other side of the exhaust pipe is clamped to the 1g intake pipe. It's a tight fit with the stock fan but it's in there.

 

[turbowop]

Doing a boost leak test will show leaks in the charge pipes, but not the intake pipe. Are you sure it isn't cracked or has an open nipple on it somewhere?

 

[WaRrIoRs16]

I haven't seen anything cracked on it. I ditched all my vacuum lines last weekend aiming to simplify things, and I put a cap over the nipple that went to the evap canister. The other one that goes to the valve cover is still hooked up like stock. Then the other tiny nipple thats right after the MAS is capped off. I will inspect it and will also swap it out with another 1g pipe I have when I try the other MAS.

I'm really hoping the MAS is bad or isn't reading properly because of it being hacked. That would be a simple fix. It could also explain why my fuel trims are all maxed out, maybe the MAS is having trouble measuring all of the air, seeing as how I've virtually eliminated all other possible sources of running lean that I can think of short of flow testing my injectors and swapping out my seemingly functional oscillating o2 sensor(getting done Sunday night). Thank you for the replies.

 

[steve]

How is the mas hacked? Stock gvr4 mas does not have the lower honeycomb.

 

[vtecds1]

I don't think his is hacked...But you can definitely hog it out.

click

 

Definitely double-check the emissions fittings where they enter the intake pipe to ensure the rubber is not cracked where they enter. Most DSM's I've encountered have this issue with the stock intake pipe although it is rarely bad enough to cause stalling.

 

[WaRrIoRs16]

I apologize, when I got rid of the GVR4 intake pipe I noticed there wasn't a lower honeycomb and forgot that I've never had one there, my mistake. So the MAS is indeed not in stock condition.

I swapped in my 1g hacked MAS, but it had no effect on my idle. I drove back to my apartment 70+ miles and haven't gotten the error code for the Airflow Sensor yet. Either way since my idle isn't fixed, I'm going to try one more MAS later this week that a friend has.

I examined the intake pipe thoroughly and could not find any cracks, holes, or any other imperfections. All of the clamps and vacuum plugs are on tight. The whole intake pipe is not a pretty sight and definitely not permanent. This was right before I pulled it out, thats why the plug, bov recirculation tube, and the other hose is disconnected.



If the code comes up again on this MAS and my friends, I guess I'll have to follow the plug and check the wires and connectors. Currently the plug is a little pulled but not to where the intake has no room for movement or anything. Also I just freed up a lot of space on the intake pipe with a slim fan last night.

 

[vtecds1]

Quote:
It will idle just over 1k rpms, it will idle sub 500rps, it will act like its about to stall then shoot up to 1k+ rpms.



Did you test the ISC?

 

[WaRrIoRs16]

Yeah I have tested the resistance on my ISC and it checked out good. I also checked the resistance on a friends Newer black ISC and it read a little higher, but I have read thats normal. I have been logging the ISC on my pocketlogger and the two ISCs do not behave any different. But the both of them behave completely different then when I logged another friends ISC in his car.

I have done many other things to try to fix the idle as well but nothing has worked so far. Thats why I was wondering if there was something with the 1g intake pipe that could have messed with my idle that I don't know about.

If you guys think that the intake can't be my problem, then I'll rule that out and try to move on. Thank you.

 

The intake is your problem. My car did the same thing when I switched to a metal 1g intake pipe. The pipe following the MAS is just as important to airflow readings as what is in front of it.

DSMLink has an idle air clamp feature to fix this issue, so it must be pretty common.

 

[2of9]

yeah, seems like you and I are having the same issues. Have you checked the TPS voltage? If I remember correctly, mine is at a mid-high .4x at idle or with the engine off. It's supposed to be at .63-.65 volts I believe. This could also be causing the bad idle but I don't see the relationship with the "12 CEL code".

 

[WaRrIoRs16]

If the intake is my problem, does that mean if I grab a 1G MAS, it should have a better time measuring the airflow? I have the 1G MAS in now and haven't got the error code to come up yet, but last time it did take a week for it to come back. I did intend on getting ECMlink this January when I get more money for school.

I have not checked the voltage at the TPS at all through this process. I'm not quite sure of the procedures for doing so. I see the VFAQ on how to measure the resistance, but not how to measure the voltage. But I did find a thread saying at idle the volts is suppose to be between .48-.49V. How do you accurately measure the voltage at the TPS? Pocketlogger only shows percentages for the TPS.

 

[WaRrIoRs16]

Something I forgot about was I also did swap out my alternator for a awd 1g alternator at the same time as the intake. I think the amps are a little lower than the galant alternator if I remember correctly. The voltage is good, atleast better than my oil covered galant one. It is typically 13.8-14.3V and occasionally drops to 12.xx when I push the clutch pedal in and let the rpms drop. Could that do something to my idle?

 

Even if you put a 1g MAS back in you're still not using a stock 1g intake. You have that metal pipe there. Do you still have the stock GVR4 intake pipes? You can clock them to get the filter in the location you need it. I ran it like that for a while. I would install the stock piping and see if the problem goes away. If so, then you know 100% it is your intake pipe. If the problem is still there you can look elsewhere.

If TPS voltage is where it should be I think the pocketlogger should read 10 or 11% at closed throttle. It's been awhile since I've used one.