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car will only run for 4 seconds and caps are good

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
bought a parts car for with motor and other go fast bits for my galant. 93 talon turbo awd with socketed and chipped ecu with GM Maf and translator. initial issue was no spark, CAS replaced. -> car starts but only runs for 2 sec. ECU caps investigated and appeared to be good so I double checked with a fresh ECM link socketed board with fresh caps and stock tune...same result. Found O2 sensor unplugged...same result. found a vacuum leak (at the stock maf) and fixed, car now runs for ~4sec. any ideas? to be noted, I have no idea what tune if any this car has.
some specs on the motor/setup:
precision 1000cc injectors
precision 5557e turbo
fresh NGK spark plugs
vent to atmosphere BOV
...not sure what else to add

Any ideas?
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tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
Getting fuel at all? I must be getting some for it to run, however I do not know how much. Are you thinking fuel pressure check?
 

transparentdsm

Well-known member
Joined
Jul 27, 2011
Messages
3,679
Location
Klamath Falls, Or
just cause your getting fuel doesnt mean you getting enough fuel, or for that matter enough spark. what do the plugs look like? i know there new, but what did they look like after a few fires. did you pull the injectors and check the pintles?

also stock MAF + vent to atmosphere = big no no.
 
Last edited:

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
Not stock maf, gm maf with translator. Nothing fuel related has been checked. same for spark plugs since the initial 2 starts or so. As far as tuning I picked up the vehicle as is from someone else a few days ago so I do not know what is on the chip for the tune. That being said I have an ecm link v3 also and the cable so I can switch to that since it has a stock tune loaded currently iirc. I'll be Starting with fuses and fuel pressure check(can't currently hear fuel pump prime or anything so...???) over the next couple days and I'll move from there and keep posting updates...
 

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
so I had to put time towards some other projects for storage around the house and time towards my Datsun which is non-moving/broken in the driveway, but! I did check fuses which were good and I moved forward with getting a fuel pressure test kit from Oreilly's. I am unfamiliar with the specifications for fuel pressure on the car and if it is running an aftermarket pump will those factory pressure specifications be relevant? I will check plugs, take pics, clean plugs, run a few more times and take pics again. I will include what I find in the fuel pressure check also.
 

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
you can see that the spark plug seems to be quite black which I see as a sign of running rich(correct?). That being said I do not know what kind of O2 sensor is installed on the car whether it be wideband or other, but there is no gauge for it so that I could see what the AFR is. I could switch from the current ECU to the ECM link to monitor that I am guessing? I have never tuned anything before but done some research into it.

Other changes are that fuel pressure was checked and at around 42-44 psi but I was unable to get consistent readings off of the fuel pressure test kit. fyi: the kit was attached at the fuel filter banjo bolt on the firewall.

Since I assumed this supposed rich condition was caused by a stock tune with 1000cc injectors I pulled the fuel rail and replaced with a known good factory set with no change in running characteristics. I am going to do some small things tonight like make sure that there is plenty of fuel in the tank since I do not know if the sending unit is working or not. any other suggestions?
 

thomcasey

Well-known member
Joined
Sep 24, 2014
Messages
907
Location
Indianapolis, IN
DSMLink will give you an "estimated AFR" from the stock o2 sensor. Although, you can also install a wide-band and run it without the gauge, but that would still need to be wired in and calibrated for it to read correctly in link.
 

jepherz

Staff member
Joined
Aug 8, 2004
Messages
7,877
Location
KC, Missouri
Jumper the fuel pump test connector. I had an ecu that wouldn't turn on the fuel pump, but since the key does that while cranking it would always start then die.
 

brisvr4

Well-known member
Joined
Feb 13, 2004
Messages
955
Location
brisbane australia
Also check the coolant temp sensor that the ecu uses.
If it's dead it will default to a temp in the negatives and the Ecu will over fuel the motor causing it to start then stall.
 

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
jepherz, I am not familiar with the fuel pump test connector. will it be obvious when I get it out? Also, wouldn't this not be the case if a second ecu ran the same way?

brisvr4, on the thermostat housing (1st gen eclipse thermostat housing fyi) the upper temperature sensor was replaced because it was physically destroyed, this resulted in no change however. That being said I do not know which one is used by the gauge and which is used by the ecu. can u tell by the different connectors I am guessing?
 

brisvr4

Well-known member
Joined
Feb 13, 2004
Messages
955
Location
brisbane australia
It's the temp sensor on the front of the housing. It has 2 pins.
 

donniekak

Well-known member
Joined
Jan 1, 2009
Messages
748
Location
surprise az
Put the link Ecu in the car. You'll be able to see the sensor data, and won't just be randomly swapping parts. I'm betting it's just a bad tune from the mystery EPROM chip and maft.
 

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
ill put the link in and see what happens. also it looks like the large black orings arent on the end of the 1000cc injectors so I will fix that.
 

tacolibre

Active member
Joined
Dec 21, 2012
Messages
36
Location
Cheney, wa
ECM link is in the car and reading data (my 1st time ever using the program) stream shows accurate coolant temp close to oustside air temp on cold start, however stream also shows 5 deg timing when off and ~40deg timing @2500-3krpm. Also front O2 reads 0.06v constant. Timing seems off and O2 voltage suggests bad O2 sensor to me, thoughts?
 

marvinmadman

Well-known member
Joined
Nov 10, 2003
Messages
2,355
Location
Lafayette, Louisiana
Double check the wires on the MAFT harness. They can work themselves loose.
 

MuffinMan7580

Well-known member
Joined
Aug 6, 2011
Messages
142
Location
Fort Bragg, NC
Which MAS is plugged in? I'd try using a stock 1g MAS, and disconnecting the GM MAF. If the car is starting and then turning off, the CAS is getting a signal to the ECU, which is what turns the fuel pump on, not the key. However, the CAS may still be installed wrong. There's a dot on one ear of the CAS, make sure that it is towards the firewall when the motor is at TDC (make sure the crank and cams are aligned correctly.

If the car didn't have any tuning solution other than the MAFT, and then the injectors without any o-rings, then you could be dealing with a lot of work to correct from someone who didn't know what they were doing. It sounds like you may have better luck with posting logs from Link and getting help from others with a little more direction.
 

marvinmadman

Well-known member
Joined
Nov 10, 2003
Messages
2,355
Location
Lafayette, Louisiana
I'd also get the GM MAF direct connection harness from ECMLINK to eliminate the MAFT. Then use the built in features within Link.
 
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