Engine Car runs great without spout, plug it in and it dumps fuel and dies within seconds

baileygruwell

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May 22, 2019
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All I’ve got an 88 fox that I recently built from the ground up. For starters it has a 306 in it with Gt40 intake and an n41 camshaft. 75mm TB and a 90mm MAF. It’s a completely custom intake. 24lb injectors. A9p ECU and it’s a t5, (A9L is getting worked on, bad capacitors). The problem I’m having is I can get it to idle pretty decently with the spout unplugged and also the IAC unplugged. Got timing set at around 15 degrees. I plug in the IAC not much changes but when I plug the spout back in it just dumps fuel, and then dies within probably 10 seconds. It runs fantastic without the spout. Any insight would be helpful.
 

KRUISR

5 Year Member
Apr 16, 2015
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First thought, set time at 10 degrees and try again.

Second, you said the A9L ECU is getting worked on. Was it in before and now swapped for a A9P while A9L is getting fixed? Or was your MAF conversion done with a A9P and once the other ECU is fixed you will swap to the A9L?

I am running a combo close to yours with a A9P and a T5 as well.
 

baileygruwell

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May 22, 2019
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No the a9l has never been in the car. It was once a 4cyl and I bought it as a roller from a guy that included both ecu’s. I noticed the a9l had leaky capacitors so I sent it in. And I’ve had it around 10 degrees and this motor does not like it. Not sure if the cam is a little bit too much for stock timing
 

KRUISR

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Apr 16, 2015
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Is the harness for a A9P or A9L as the pin outs for the O2 sensors are different. So if harness is for A9L and you are using a A9P it could be contributing to the problem.

Secondly if the engine really doesn't like 10 degrees, is your cam installed correctly?
 
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baileygruwell

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May 22, 2019
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Okay so yes the o2 harness was for a t5 car but I just repinned for an AOD and it still runs super rich. I didn’t attempt to reconnect the spout connector. Is it possible that running the o2 harness for a t5 ecu fried my a9p and that’s why it’s running rich. Doesn’t explain the spout connector though
 

manicmechanic007

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Sep 26, 2017
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All that happens when you plug in the spout is that the processor takes over on the ignition timing
Running super rich is another problem entirely I believe
You can unplug the HEGO's and the car ( a working car ) will run fine ( the normal slight rich that a cold engine needs )
For the first 2 minutes of engine operation, before it goes into closed loop, the O2 's do not have any input
Damn straight make sure the wiring is correct
 

baileygruwell

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May 22, 2019
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Alright so it’s been a few weeks since I’ve been here but I’ve narrowed it down a little bit. The last time I was sure that my ECU was toast and it still could be, but I opened it up and all I found was a leaky capacitor. When I first start the car, it surges for about 2 minutes requiring me to feather the throttle unless it will die, until it takes over and idles by itself. After that happens it runs really good, keep in mind this is all while the spout is NOT connected. I let it get to operating temp and then seconds after I plug the spout in, it dies. And it will not start if the spout is connected. I pulled codes and all I got was: KOEO-31,81,82,85,84 KEOR-94,44,31,18

My scanner also detects how many cylinders are under test and it only detected 6. It’s an A9P ECU.


P.S.- base timing is set at 14
 

baileygruwell

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May 22, 2019
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The maf matches, as far as I know the grounds are in place. Isn’t there only the one ground right next to the ecu in the pass. Kick panel. How many other “ECU” grounds are there. And the custom part is that it just has a collection of couplers and 45s from the parts store. I drilled a spot for the ACT also.
 

baileygruwell

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May 22, 2019
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There’s a couple pics, not sure if that’s the stuff you were after but I can always take more
 

General karthief

wonder how much it would cost to ship you a pair
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Aug 25, 2016
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The maf matches, as far as I know the grounds are in place. Isn’t there only the one ground right next to the ecu in the pass. Kick panel. How many other “ECU” grounds are there. And the custom part is that it just has a collection of couplers and 45s from the parts store. I drilled a spot for the ACT also.
Where is the maf?
there is a ground in the injector harness, I think it is orange, bolts to the back of the passenger side head, also a ground from the drivers side head the the firewall. Appears you have the computer ground from the negative bat cable to the inner fender by where the solenoid would be and then connects to the cylindrical (black) connector in the harness under the solenoid area.
 
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