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I have read a number of posts in several threads trying to track down the source of my problem. I posted in an old 2008 thread with no response and another thread but it was suggested to start a new thread.
I have (2) 1997 birds with 4.6, one just turned over 200K and the other with 100K. The CEL came on the one with higher mileage with PO172 and 175 codes (rich both banks). Both short and long term fuel was high. My friend scanned and isolated several areas of possible concern. I replaced the EGR solenoid, checked and replaced several vacuum lines and replaced the ECT sensor as it was thought the engine was running too hot. After each replacement the CEL would stay offf for a short period but eventually came back on but did end up showing rich condition on Bank 1 only. Ran with AC on to keep cooling fans running seemed to help some but CEL is now back on. I read in one of the posts the IAC could be the culprit. The car runs good but the engine will surge at low speed and at idle (stopped for traffic light, etc) the engine speed will rev up several times especially in warm or humid weather. When shifting to park the engine will also rev up. These latter conditions have occurred since I got the car over 10 years ago. I have cleaned the MAF recently and IAC a while ago. Any suggestions
 

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MAF sensor is in good condition? O2 sensor condition? How's fuel economy? Excessive black soot in exhaust?
 

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Discussion Starter #3
MAF appears to be in good condition. I have not inspected O2 sensors but scan data would indicate these are not a problem. Fuel mileage is down due to CEL and rich condition but not excessive plus adding the use of AC reduces mpg. No soot in pipes. Fuel trims were high b4 adjustments outlines previously and were reduced to normal but will spike when engine temp rises. Coolant is probably 4-5 years old and I tested with VOM but do not have data on what the resistance should be.
 

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Hijacking this thread.
My car is running extremely rich. I even checked the cylinders and there was a puddle of fuel in each cylinder. All the spark plugs were covered too. Talking with the tuner who made my chip he said that it could be my MAF or the chip isnt making a good connection with the J3. So I swapped to my stock MAF and even a Mark 8 MAF I had sitting around and the issue persists. I noticed theres even a fuel vapor in the intake tube. I turned to Power Hungry Performance who had a how to on adding solder to J3 the connections to make a tighter fit so I did that. I even tried the chip on a second computer with the same calibration code as mine. The only difference that either made was a slightly better throttle response but its still dumping fuel. The engine has probably 30 minutes on it. The only other sensors I can think to change are the o2s which are brand new Bosch sensors but after that I can only think of the tune to blame. Whats done to my car is in my signature. The injectors arent leaking, I built up pressure in the system and used the camera to see any fuel coming from up top and couldnt, maybe that is a laughable way to do things. After about 15 minutes the pressure hadnt dropped in the system. Just trying to figure this out and Id like some help.
 

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Try this: Put a NOID light on the injector, see if it's hot without the engine cranking or running.

94/95 ECUs had a problem with the injector drivers shorting, meaning that they ran 100% duty cycle. That was supposedly fixed by 1996, but ...

Of course, the obvious questions - 1: The tune is for a 30# injector, not the stock 19# or 24#, right? 2: For a 1996, why a chip? You can get a tune that uploads via the OBDII port instead of using a chip. 3: Have you tried data logging to see what the MAF, TPS, and injectors are doing?

RwP
 

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Just because your 02 sensors are new doesn't mean they are good. Twice had had bad 02 sensors out of the box.
Even the ones I just ordered for my m8 came with instructions telling me test them just encase,lol I thought that was funny and ironic .
 

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Try this: Put a NOID light on the injector, see if it's hot without the engine cranking or running.

94/95 ECUs had a problem with the injector drivers shorting, meaning that they ran 100% duty cycle. That was supposedly fixed by 1996, but ...

Of course, the obvious questions - 1: The tune is for a 30# injector, not the stock 19# or 24#, right? 2: For a 1996, why a chip? You can get a tune that uploads via the OBDII port instead of using a chip. 3: Have you tried data logging to see what the MAF, TPS, and injectors are doing?

RwP
I went with a chip because it was a cheap way to make the car run until I could get it to a dyno tuner. So far I have been proven wrong. The tuner says it is tuned for the 30s and they are on the mod sheet I sent to him. He says he doesnt like the MAF that I am using, he made that very clear. He didnt give me a reason he just said he doesnt like it. I dont have any of the equipment to datalog and as of right now cant afford it. My EEC is an MBE2 and both had 1995 printed on the board. My car is an early 1996.
 

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You need a cheap datalogging setup. I've seen them at ~$20, the full sw is more...

There are a dozen OBDII datalogging apps; get a cheap bluetooth OBDII dongle that will work with your phone, and find out WTF is going on.

Take a quick look at GM's datalogging tutorial; everything is applicable, even if you don't use an xcal.

I have a wideband in the cars I'm tuning, 'cause I'm an idiot at times, and need a comparison to reality.

The stock sensors being pegged lean or rich don't tell you squat, lol.

Right now, due to some input, your O2's are screaming lean, covered in fuel. You need to know why.
 

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You need a cheap datalogging setup. I've seen them at ~$20, the full sw is more...

There are a dozen OBDII datalogging apps; get a cheap bluetooth OBDII dongle that will work with your phone, and find out WTF is going on.

Take a quick look at GM's datalogging tutorial; everything is applicable, even if you don't use an xcal.

I have a wideband in the cars I'm tuning, 'cause I'm an idiot at times, and need a comparison to reality.

The stock sensors being pegged lean or rich don't tell you squat, lol.

Right now, due to some input, your O2's are screaming lean, covered in fuel. You need to know why.
You can also measure duty cycle at the injectors on some multi-meters
Sears.com

I've done this on my tbird (pre-OBD2).
-g
 

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Right now, due to some input, your O2's are screaming lean, covered in fuel. You need to know why.
This presumes it's going closed loop; we don't know for sure he's running it long enough!

And if it's not going closed loop (and Torque Free and a ELM327 OBDII adapter) will tell him (and us!) if they're even being read.

RwP
 

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I went with a chip because it was a cheap way to make the car run until I could get it to a dyno tuner. So far I have been proven wrong. The tuner says it is tuned for the 30s and they are on the mod sheet I sent to him. He says he doesnt like the MAF that I am using, he made that very clear. He didnt give me a reason he just said he doesnt like it. I dont have any of the equipment to datalog and as of right now cant afford it. My EEC is an MBE2 and both had 1995 printed on the board. My car is an early 1996.
You absolutely NEED a way to datalog.

Grog6 is right; I used to use a (2013 vintage!) $75 ELM327 OBDII/Bluetooth adapter (currently they're more like under-$20) and a copy of Torque Pro (cost $5; they have a free variant) to monitor my 2000 Malibu.

I'd grab that, and possibly swap in some stock injectors, to make SURE it's not the tuning screwed up.

What MAF does he say to use? If a competent tuner says "I don't like that MAF", I'd listen to him; if you don't trust him that much, why are you letting him tune your car?

(Shucks, I tell people to talk to their tuner on picking cams / headers / gears / MAF / injectors ANYWAY; you want what they have a proven quality record with if you're using mail tunes.)

RwP
 

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You need a cheap datalogging setup. I've seen them at ~$20, the full sw is more...

There are a dozen OBDII datalogging apps; get a cheap bluetooth OBDII dongle that will work with your phone, and find out WTF is going on.

Take a quick look at GM's datalogging tutorial; everything is applicable, even if you don't use an xcal.

I have a wideband in the cars I'm tuning, 'cause I'm an idiot at times, and need a comparison to reality.

The stock sensors being pegged lean or rich don't tell you squat, lol.

Right now, due to some input, your O2's are screaming lean, covered in fuel. You need to know why.
I will look into finding a bluetooth OBDII plug thatll work; my phone doesnt seem to like using it. I know that the 4 wire o2s have a heater in them to try and bring them up to temp before the car starts, is there a possibility they arent warming up? Its been cold here and I havent run the car for more than hour total since its been done, not really bringing it up to temp.
 

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You absolutely NEED a way to datalog.

Grog6 is right; I used to use a (2013 vintage!) $75 ELM327 OBDII/Bluetooth adapter (currently they're more like under-$20) and a copy of Torque Pro (cost $5; they have a free variant) to monitor my 2000 Malibu.

I'd grab that, and possibly swap in some stock injectors, to make SURE it's not the tuning screwed up.

What MAF does he say to use? If a competent tuner says "I don't like that MAF", I'd listen to him; if you don't trust him that much, why are you letting him tune your car?

(Shucks, I tell people to talk to their tuner on picking cams / headers / gears / MAF / injectors ANYWAY; you want what they have a proven quality record with if you're using mail tunes.)

RwP
I dont know him. I got an SCT chip off of SCP and I have been talking through Bill. He wants me to get a 76mm MAF with interchangeable sample tubes. Im assuming he wants me to use the stock sensor since SCP doesnt sell sensors with the housings.
 

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That sounds like a C&L MAF, I thought those were a ***** to tune with because they had no transfer function.

Joe
It is a C&L. I didnt know they were hard to tune, raises a few questions to me though.


On a different note I downloaded an app and ordered a Bluetooth plug, hopefully I can start to get an understanding of whats going on.
 

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That sounds like a C&L MAF, I thought those were a ***** to tune with because they had no transfer function.

Joe
Yeah. That sounds more like a sales ploy than anything. Your MAF has a known transfer function, which the tuner can simply drop into the file. The tuner should love that, not hate it.
 

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...I know that the 4 wire o2s have a heater in them to try and bring them up to temp before the car starts, is there a possibility they arent warming up? ...
The heater is to maintain temp, not preheat anything. It keeps it at temp; O2 sensors don't really start to work unrtil ~2 minutes after start, and it assumes you're driving.

...I got an SCT chip off of SCP and I have been talking through Bill....
:facepalm:


:)

...That sounds more like a sales ploy than anything. Your MAF has a known transfer function, which the tuner can simply drop into the file. The tuner should love that, not hate it.

The tuning process is not that difficult; many have mastered it.

But there's always "The Rest of the Story". :)



I bought the SCT PRP because I'm an anal-retentive, Type-A *******, with major delusions of grandeur; after YEARS of incremental changes, I THINK I know how to tune my cars.

Don LaSota could have written ALL my tunes in an afternoon, lol.

He would ask for datalogs to fine tune it, but he's a Master.

:grin2:
 

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The heater is to maintain temp, not preheat anything. It keeps it at temp; O2 sensors don't really start to work unrtil ~2 minutes after start, and it assumes you're driving.
:grin2:
Im figuring now that the o2s do nothing for the first few minutes its either going to be the tune, the MAF, or the possible short in the EEC causing the injectors to run at 100% DC (which I am skeptical of that being the issue, one came out of my car and was perfect while the other one again came from a running car). I will check for the short first, then swap over to my stock 19s tomorrow to see what happens. Ill have more than a few words to say if the car magically starts working again with the 19s.
 

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If that fixes it (swapping to 19# injectors), then we know for a fact that's a bad tune for you.

Time to either figure out how to tune yourself (hint: LaSota's book and Banish's books are HIGHLY recommended!) or just bit the bullet and talk to LaSota.

RwP
 

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Just ran it on 19s and it barely keeps its idle. Without me touching the gas it jumps between 500 and 2000. It sounds horrible. The tune is working in some form. Another thing I noticed was that when I pulled the 30s out, the caps stayed in the injector well. They are billet bodies with the nozzle built in so I dont think it could mess with the spray pattern but thats something to note. I couldnt find a NOID light that doesnt have to be shipped so I didnt check for the 100% DC short today. I am leaning towards either the short or the o2s. I noticed that the spark plug and the cylinders Were still wet with gas after the 19s were installed so I am concerned about either the timing or an engine ground being bad. But it also make me lean more towards the o2s. Really hoping they arent bad since they werent cheap and I forget how long the warranty was
 
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