Help Needed with 1g running Rough!! Have CEL codes

[whiteonwhitegst]

heres the deal...ive been stressed out trying to figure out my problem. I just put a cyclone 4g63 in my 91 talon

I finally got it to start, its running on all 4 cylinders, im getting spark, and fuel. It idles at about 600rpms

I have a 2g pigtail wired in to the harness with a 2g MAF. The car runs terrible and im getting symptoms of a bad maf, (sputter, Slow acceleration, stalling ect.) I have (2) 2g mafs and no changes between the two.

After car runs for few seconds i get CEL.
I pulled the codes and its as follows

12. Air Flow Sensor
13. Intake Air Temperature Sensor
25. Barometric Pressure Sensor

I re-checked the wiring for the 2g maf and its as described on the Vfaq directions.
If i unplug the maf while its running it makes no changes in the way it runs.

**i noticed if i unplug the tps sensor while its running the motor sounds like it clears up and the idle raises to about 1200rpm but if i give it gas it wants to stall**

Please help if anybody has advise please let me know.

 

[viprez586]

Double check your wiring, there is obviously a problem with that.

 

[whiteonwhitegst]

ive tripled check the wiring and all wires are connected where should be

couple more things ive checked..

i tried 2 different MAF's, ive tried 2 different tps sensors and nothing. I checked each wire from the maf all the way to the ecu and each wire is good ive got connectivity all across from one side to the other. I did the same for the tps and everything is good.

i cut all 3 wires from the tps pigtail i started the car and it runs alot smoother but when i give gas it wants to die which i think is normal since the ecu is not reading any signal from tps.

I grabbed the GRN/WHT wire from the engine harness and brushed it off against the GRN/WHT wire on the tps pigtail and i reved the motor and it reved free and smooth throughout the rpms like it fixed itself but after about 5 sec it went back to running crappy, if i repeat this same step it fixes itself but then ends up running shitty again

 

[viprez586]

Check out the Caps on the ecu. If the ECU is normal you have some wiring issue to the ecu.

 

[purpletalon]

The same thing happend to me with my 90 tsi, the caps on your ecu are fried Id almost bet on it.

 

[whiteonwhitegst]

Check out the Caps on the ecu. If the ECU is normal you have some wiring issue to the ecu.

what wiring issue could i have? ive checked the wiring it seems to be all good im 99% sure

 

[dsmdeliveryboy]

You should have just bought the harness off of dsmchips.com... And are you running the stock injectors?

 

[whiteonwhitegst]

You should have just bought the harness off of dsmchips.com... And are you running the stock injectors?

once again the wiring on the 2g pigtail for maf is fine unless the Vfaq directions are wrong

and yes stock 450cc

 

[steve]

It not an issue of the VFAQ being wrong, it's the application of the information in the VFAQ that seems to go wrong. There aren't too many other things that will cause the symptoms.

Make sure you clear the codes and look to see if they come back. If they do it's either the MAF, wiring, or damage to the ECU.

 

[viprez586]

Your not reading. What Steve said sums it up.

Make sure you clear the codes and look to see if they come back. If they do it's either the MAF, wiring, or damage to the ECU.

To OP:

Check the Capacitors on your ECU for leakage/fish smell.
http://www.ecmtuning.com/wiki/corrosion02
http://www.ecmtuning.com/wiki/corrosion02
http://www.ecmtuning.com/wiki/corrosion03

There's more wire past the pigtail at the MAF...How else does the ECU get the signal? Wiring.
A wire could've gotten pinched somewhere(like the wiring by the ECU !), or acquired corrosion in some cases if the insulation is pierced(thus restricting amperage &distorting the signal). NOT where you were just farting around with it, but perhaps somewhere else.
If you begin testing wiring, first off Ohm tests suck for this, do voltage drop tests. Exercise caution, don't blame me if you blow up your ECU.

Like Steve said, the interpretation of the wiring diagram of VFAQ is confusing to some, it shows a specific pinout from a specific view. Make sure you are viewing it correctly is the point others and myself are trying to suggest to you. That being said, it was probably running fine before you did this correct? Well that points to one thing - what you just did.

Are you using a power transistor connector to the MAF? 2G connector?
The easiest way would be to take a picture of your wiring and specify what ends you are using for what & where so everyone is on the same page.

Also the 2G MAF is near perfectly matched with 550cc injectors, so you will be running lean with 450s. And no, these codes wouldn't be on from running lean, esp. if you just started the car up and the CEL comes on right away.

 

[Sawboo]

I had those exact CEL codes on my car when I bought it and it ended up being the ECU capacitor leakage. I sent it off for repair ($80 or so) and car started first time with no CEL. Replacing the sensors did nothing.

Take the ECU out and look for damage.

 

[whiteonwhitegst]

Thanks for all the replys and advise guys. I checked the harness and everything looks good. I made sure i had connection from the pins on the side of the maf to ecu and from tps to ecu and its all good.

I took out the ecu from the casing and when i flipped it over i found this...seems like a circuit blew? But i dont know what its for, maybe this is my problem?

Steve i know your good with ecu's and always rebuilding them can you chime in?
(sorry for quality its my camera phone)

 

[Sawboo]

smell your ecu. Fried capacitors smell alot like fish, eventhough it may be a very subtle smell. Did you look at the base of the common capacitors that like to go?

When my ecu was goin i had to crank the car about 20 times to get it to start and id have to let it idle for a few minutes or it would die if i gave it any gas.

 

[steve]

That's a blown sensor ground trace on a 1G ECU. Either you messed up the MAF wiring at least once or you were also messing with the O2 sensor wiring.

 

[viprez586]

There's you're culprit. Now make sure you have a tuning and logging device so you don't blow something else up. Like your engine.