Help car takes forever to start

[Demon5spd]

Ok so i've had some problems with my car not starting and i thought i had fixed it by replacing the coolant sensor.

Sadly i get back from vaction and the car wouldn't start so i bought a spark plug tester and i had good spark on all cyclinders, and my fuel pressure guages reads 30psi.

so i'm assume i have a good fuel pump i'm not sure on the specs though, so after about 30 mins trying to get it to start i give up, oh and i checked the plugs and they look good and i could smell some fuel on them so i guess the injectors are working.

And then after about a hour a go out side and the car starts right back up it dosen't want to run for the first couple minutes after that it was fine.

The fuel pressure at idle is 29-30 psi which i thougt was low but i'm not sure and now i have a check engine light on but i can't figure out how to check.

so my main question is what going on the car wouldn't start all this morning then out of the blue it starts it's so confusing i not if the CAS can cause this but i do have a check engine light on does anybody know how to check it.

 

[FORMONTOYA]

When was the last time you changed the fuel filter? Just because you smell a little gas on the plug doesn't mean much.

Take it down to AutoZone and get them to pull the codes for you.

29-30inHg at idle with the hose ON sounds about right....37-38 with the hose OFF minus 9-10psi (2inHg = 1PSI roughly), idling at roughly 18-20inHg.

 

[Demon5spd]

the fuel filter was replaced about 100 miles ago before i went on vaction, and i did go to auto zone but they can only pull codes on obd2 vehicles or older domestic but not import's so i'm out of luck there.

I also went to other parts store's same deal they don't have the equipment to pull from 95 and older dsm. so i have the check engine light on but i can't get the code.

 

[FORMONTOYA]

Kind of weird as the 95 DSM IS OBD2. Mitsubishi started a year early as that was the year of the model change. If they can do OBD2 they should be able to pull codes off your car.

 

[brute]

But he has a 92. If you have a volt meter, you can check them yourself. This is what I do. You can either set your volt meter on an audible tone setting, or just buy a cheap buzzer at Radio Shack. Here's a great write-up: Link

 

[FORMONTOYA]

But he has a 92.

Damn, what was I looking at?

 

[Demon5spd]

Thanks man after taking about 30 mins to figure out how to read the codes here it goes i have 3 codes.

1. intake air temp sensor

2. throttle position sensor

3.engine coolant sensor

 

[brute]

The engine coolant sensor is the same CEL mine throws. It also has the hard cold starting problem. I've realized that the ECU cannot read that the coolant is cold, so it just keeps the fuel system in closed loop. There are different fuel maps (and I believe different timing maps as well). Because it's stuck in closed loop, it does not go in to open loop like it's supposed to on cold starts.

OPEN LOOP - This is the mode your ECU is in until the coolant temperature and a couple other sensors get to operating values. This is also true when you are at WOT or when throwing codes/ CEL's

CLOSED LOOP - The ecu uses information primarily from the Oxygen Sensor and adjusts fuel delivery and timing to achieve minimum emmisions, better gas mileage and power.

Now, on cold starts, your o2 sensor is not warmed up yet, so the fuel delivery is all messed up. All that said, I have not replaced the coolant temperature sensor yet.

 

[Demon5spd]

All right here's my update i removed my ecu to ck out to see if the caps were leaking since i know thats a common problem well when i opened the cover i can't tell if they had been leaking and they were replaced by the previous owner or what.

But i can tell that something has leaked there and corroded a couple and turned parts of the board black in area's where it leaked on.

So i'm not sure if that can be causing my no start conditions or not what you guys think.

 

[brute]

Well you have nothing to lose when you replace the caps. If you do the soldering yourself, it's like $4 in parts. Just for reference, here's the capacitors you need:

47uF @ 50V
22uF @ 50V
100uF @ 25V

Those are microfarads.

 

[Demon5spd]

cool will radio shack have those parts by any chance and also i have one main concern, after looking at the board it looks like the acidy gel stuff might have shorted out so compoents.

Is there a way to tell if my ecu is junk, the car will start and run but it's off and on and i'm not sure if the ecu is to blame but it looks like a start.

 

[brute]

I'm not sure if Radio Shack will have them, but I'd say no. My suggestion for buying those is Mouser. Electronics stuff is super cheap from them, and always very high quality.

 

[Demon5spd]

Ok so after all the caps were already replaced with 105 degree caps so the burn marks i see was probally from the old caps when ever they were replaced.

So now i'm back to square one.

I have good spark along with good fuel pressure, i'm not sure if the injectors are firing but when i remove the spark plugs i can smell fuel on them.

And now i know that my ecu is in good condtion also for fun i cleaned my intercooler out even though i'm sure it was point less but whatever and i also did a boost leak ck and there was no leaks at all.

So i'm stumped the only thing i think it could be is either the MFI relay or the CAS i'm not sure where the MFI relay is at or how to ck it along with how to ck the cas sensor, so does anybody know where the mfi relay is at or how to ck it along with the cas.

Sadly i'm running out of things it could be so any help would be great guys

 

[Auto RS T]

I would truly eliminate your ECU first. A visual inspection is not always the best. Just because the caps were replaced doesn't mean there wasn't any damage to the board. Like you said, it is burned, possibly more. I would actually swap ECUs to eliminate it.

Have you tried to swap the coolant temp sensor yet?

EDIT: I see about the coolant sensor swap now, post 1 sentence 1. How did I miss that?

 

[Demon5spd]

yeah i replaced the coolant sensor already

 

[steve]

I would truly eliminate your ECU first. A visual inspection is not always the best. I would actually swap ECUs to eliminate it.

Exactly. It's safer to put the questionable ECU in a good car and see what it does than it is to put a good ECU in a questionable car. This is because there are lots of problems like shorted ISCs that can blow up a good ECU in a fraction of a second.

Steve

 

[Demon5spd]

Exactly. It's safer to put the questionable ECU in a good car and see what it does than it is to put a good ECU in a questionable car. This is because there are lots of problems like shorted ISCs that can blow up a good ECU in a fraction of a second.

Steve

Yeah but sadly the spare ecu that i bought is for a auto transmission so i'm afraid to to plug it in and try to use it.

 

[Demon5spd]

Ok guya here's an update i bought another ecu this time one for a manual trans , i know the ecu i just bought is good one since just got rebulid.

So i plug it in and start the car and it still will not start it just turns over GRRRRRRR I'm pretty much at my wits end with this car, i have good fuel pressure and i have spark on all cyclinders i've replaced the coolant sensor and checked and redid the wiring for it.

And now i know i have a good ecu so what's left the only thing i haven't done is is check to see if my fuel injectors are firing at all, when i remove the plugs i can smell fuel on them but i don't know if there really working.

So what do you guys think it can be i thought it was the CAS sensor but i think it tells the spark plugs to fire and i know i'm getting spark so i think it's working and since my fuel pump is working i assume that the mpfi relay is good.

I'm lost guys i really need your help i've had this car for about 2 months now and i've been able to drive it for like 4 days.