1G Talon Cold Start Idling Backfiring Problem CEL

[Shank666]

I tried to describe it in the other thread, only got one reply and he hasn't answered me yet. I made a video for you to see what I'm dealing with.

1992 Eagle Talon Problems - YouTube

 

[ChiTownHussla]

Do you have the fiav or egr blocked off? That can cause cold start issues. Try to put ## foot on the gas and see if you can keep her alive like that

 

[dexterholland04]

I eliminated the FIAV/ISC on my throttle body and any cold start required me to feather the gas to keep the car running. Once it got to normal operating temperature, it ran perfectly normal.

 

[Shank666]

Havn't touched anything I bought the car a couple days ago.
All i've been told is it ran fine 2 weeks ago, started to sputter and the guy took it into the shop and they screwed with it and it got worse. They said it needed a cts and I went out and bought and installed it. It made absolutely no difference so I'm stuck. Theres a pretty big hole in the muffler from it backfiring, I have a new muffler but I'm not gonna put it on till the backfiring issues fixed. I unplugged the MAF it runs worse. Unpluged the TPS it runs worse, reset ECU runs great now but wont idle, dies at stop everytime, and takes forever to start. You just gotta keep cranking it over till it gets up and goes on its own, if you touch the gas even with the tip of your shoe it dies. Once its warm its fine except for the dieing at stops and the check engine light

Starting to notice it runs different at different temps.
When it first turns over a few times it doesn't run at all
Gets a lil warmer starts to idle really rough.
Keeps at this temperature at night time and will idle and runs great
During the day when it the car gets warmer it dies as soon as you let off the gas, strangely if you dont touch the gas and leave it in gear even up hill it drives fine though.
Really stumpt.

 

[Shank666]

Havn't touched anything I bought the car a couple days ago.
All i've been told is it ran fine 2 weeks ago, started to sputter and the guy took it into the shop and they screwed with it and it got worse. They said it needed a cts and I went out and bought and installed it. It made absolutely no difference so I'm stuck. Theres a pretty big hole in the muffler from it backfiring, I have a new muffler but I'm not gonna put it on till the backfiring issues fixed. I unplugged the MAF it runs worse. Unpluged the TPS it runs worse, reset ECU runs great now but wont idle, dies at stop everytime, and takes forever to start. You just gotta keep cranking it over till it gets up and goes on its own, if you touch the gas even with the tip of your shoe it dies. Once its warm its fine except for the dieing at stops and the check engine light

Starting to notice it runs different at different temps.
When it first turns over a few times it doesn't run at all
Gets a lil warmer starts to idle really rough.
Keeps at this temperature at night time and will idle and runs great
During the day when it the car gets warmer it dies as soon as you let off the gas, strangely if you dont touch the gas and leave it in gear even up hill it drives fine though.
Really stumpt.

If anyone is still monitoring this thread, took it to a shop, they jumpered the plug and got the codes for it. All sensors are working fine and were tested 2 of which are brand new. Car runs perfect now once it fires but cranks for a very long time when cold (like 5-15 minutes) Codes are:

Intake air temp sensor
TPS
Coolant temp sensor
Barometric pressure sensor

TPS seems to work as when unplugged the car dies.
Coolent sensor is brand new
Intake runs worse when unplugged

Fun fact is car, when pushed down a hill, runs first time the engine turns over no matter how cold it is when you bum start it.

They believe it's a wiring issue because of this. Ran out of money for time being.

 

[undefined0000]

Hmm, puzzling.

That 10 vacuum is weird, should go to like 22-24 when you let off of the gas. Sounds like a vacuum leak. Did you ever do a boost leak test?

 

[Shank666]

No I haven't gotten that far.
I was told anything to do with the turbo would only affect boost after the car was running and would have nothing to do with cold start so we put it off till we figured out the cold start issue.
There is a very large leak right before the turbo though as far as boost leaks go
As for vacuum I haven't checked and I don't believe they did.
As far as I know they got the codes,
checked all sensors with ohm meter and traced them and checked all their wiring which was ok.
Checked the timing which was fine
Checked ignition timing which was off, changed and still doing it.
Said ECU was fine as the boost gauge registers to 0 when you turn on the key
and basically just adjusted a idle control screw.

 

[undefined0000]

a blt and maybe trying another ecu wouldn't hurt. boost registering 0 just means that the ecu is reading the maf well at that time.

massive pre o2 exhaust leak can cause issues, worst case is that there is a timing/head issue..

 

[steve]

They can say all sorts of things but they need to start measuring things. Seeing all those faults would make the chances of a blown ECU sensor ground or ECU capacitor leakage damage high. Just being a DSM makes the second case likely.

If you look at the wiring diagrams you should be able to figure out how to test the wiring between the various sensors and back to the ECU by measuring the resistance of the wires and looking for shorts.

 

[Shank666]

I cleaned all the terminals and went at it with an Ohm meter myself this morning figuring maybe the coil wasn't giving enough spark etc.
Didn't find anything but some ugly wires I repaired, didn't seem to make any major different though.
Going to take out the ECU and inspect for damages tomorrow morning.
Thanks for everyones help so far.

 

[Shank666]

They can say all sorts of things but they need to start measuring things. Seeing all those faults would make the chances of a ECU sensor group blown or ECU leakage damage high. Just being a DSM makes the second case likely.

If you look at the wiring diagrams you should be able to figure out how to test the wiring between the various sensors and back to the ECU by measuring the resistance of the wires and looking for shorts.

New information,
Went outside to mess around today. With ohm meter the plastic plug had perfect ohms.
The plug itself was at 5000 ohms when it was supposed to be between 23-2800 I believe.
The car wanted to but could not start for the first time ever.
I took a lighter to the metal part of the sensor, plugged the plastic cap back on and the car started right up perfect.
At operating temp both plug and sensor at proper ohms (within 50)

Can I get an aftermarket coolant sensor itself that registers warmer for aftermarket engines or what?

 

[Shank666]

Forgive my lack of knowledge.
I found out the 5k ohms was actually because it was negative 2 outside.
My next step was going to be a type of reverse coolant temperature resistor sensor with a toggle switch to register more ohms for cold starts and thus more fuel then switch to the way it is now after it warms up.
My now problem with this is that I realized that this would only work if it was constantly for example -2 degrees every time it was cold. I need something that fluctuates with the temperature like it was suppose to by default. I was thinking of a thermostat but it would be nice just to get it back to stock in this situation.

I am 99.9 someone has done this coolant temperature sensor "trick" to this car
The two dead give-aways are the cold start trouble and then running perfect after it fires. Also the fact the fans are wired to the key.
All my information is loosely sourced from

Here it is, coolant sensor mod instructions! - Mazda MX6 Forums: MX6 Forum

and

http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html

If there's anything you can think of, please let me know.

 

[steve]

At -2C the ECT sensor should be reading about 6k ohms but perhaps the coolant was a little warmer.

Are all your fault codes cleared now?
Have you pulled the ECU and checked the circuit board to leakage damage?

 

[Shank666]

At -2C the ECT sensor should be reading about 6k ohms but perhaps the coolant was a little warmer.

Are all your fault codes cleared now?
Have you pulled the ECU and checked the circuit board to leakage damage?

The codes still exist, they didn't believe anything was wrong with the coolant sensor or the wiring. I found if you spray quick start in the air filter it fires right up and runs fine. Have not taken out the ECU, not exactly sure what to look for, need to keep searching for info on it. Many people have told me they believe this is fine too since there's no problems with any other sensors or gauges etc.
The mechanic told me he believed a resistor was added but he has no idea where as the fans are wired to the key and the car runs perfect when warm / gets extra fuel.
I'm also considering an issue with a 5th injector?
Not sure.
Thank you for your help.

 

[Mischif]

Going off the video. From the sound of the engine during your first attempts to get it to start. And the way it sounds once it finally does start, and how its shaking your car, Its a timing issue. Either your mechanical timing(timing belt) isn't done right. Or the ignition timing isn't right. Cam sensor could not be installed correctly, or its 180* out of alignment. Also someone said something about the vacuum being at 10(i can't make out what your guage says). Vacuum that low is an indicator of improper timing...more specially something is set too retarded.

 

[Shank666]

Going off the video. From the sound of the engine during your first attempts to get it to start. And the way it sounds once it finally does start, and how its shaking your car, Its a timing issue. Either your mechanical timing(timing belt) isn't done right. Or the ignition timing isn't right. Cam sensor could not be installed correctly, or its 180* out of alignment. Also someone said something about the vacuum being at 10(i can't make out what your guage says). Vacuum that low is an indicator of improper timing...more specially something is set too retarded.

The ignition timing was off, also the air flow value was set retarded. It's now getting proper air and the mechanical and ignition timing are good. It runs now, better than before, doesn't backfire, idles etc. Still engine check lights and still will not start in the cold without spraying quick start into the cold intake 2 or 3 times.