GSR Cold Start Issues

[3VOLUTIONIST]

Hi guys

I've been having some tech problems lately that no one here in Australia seems to have had before, but I did see it mentioned on a DSM forum a while back, so maybe it's more common with your cars. I've got a 1995 Mitsubishi Lancer GSR, DOHC 4G93T 1.8L.

I had the ECU unplugged the other day, and had an Evo 6 ECU plugged in (was experimenting) and after I plugged it back in, the car decided it didn't want to start when cold, it will crank fine but won't start for a good 10/15 seconds or so, unless you depress the accelerator pedal a bit, then it coughs and splutters into life. Nothing was changed mechanically when the ECU was unplugged.
When it begins to start it coughs and splutters, but as soon as it gets above about 1000rpm it'll run fine from then on.
It also starts fine if the engine is warm.

Took the ISC off and inspected it, seems ok. All vacuum lines are fine too.

Any ideas, because I'm totally lost

 

[yoder]

i kinda have the same problem on my 92 talon i took off the factory FPR and put on aftermarket and it seems like i have to crank a little bit before it finaly turns over dont know if that helps but i would check to see if the FPR is stuck open and letting fuel run out of the rail and not staying pressurized

 

[3VOLUTIONIST]

That was suggested to me actually, forgot to mention that was checked, there is pressure in the rail upon cranking because if you loosen the bolts the FPR gets pushed out by the pressure. Had a rising rate one bolted on and that didn't seem to help so I put the standard one back on.
Fuel pump is stock, fuel filter was replaced ~2 years ago, car's done 10,000km's (6000 miles for you guys), Plugs (BK6RE's) were replaced only a few weeks ago too.

 

[yoder]

just a thought but i had problems with mine that it wouldnt run right until i adjusted the CAS it would run great above 1200 rpm but would act like it was going to die below that also had a bad idle surge due to it as well and also could be wrong size injectors had that problem to between tweeking with mine and going through countless forums on here i finaly got mine running good[DOUBLEPOST=1411918639][/DOUBLEPOST]here is a good site that might help u out with your problems as well its one that i found helpful if u dont know about it http://www.vfaq.com/

 

[3VOLUTIONIST]

Hmm yeh i see what you mean, but the only problem is I didn't change the CAS position, and injectors are standard 390's.

 

[yoder]

hmm dont really know then. if i find out anything else though i will be sure to post back if i have any new discoveries about it and let me know if u get it running smooth

 

[3VOLUTIONIST]

Bump
Anyone have any ideas?

 

[briansmith]

Yoder ur issue is from the lack of check valve in the fuel pressure regulator. When the car is off no check valve allows fuel to flow back to the tank u must crank a min to get fuel pressure back to the rail. As far as the original post. I would check to make sure the coolant temp sensor is reading correct. A bad temp sensor will run the motor in open loop all the time this floods the engine upon shutdown and causes hard start backs

 

[yoder]

thanx man and yeah i need to find a good check valve for it

 

[briansmith]

Yes sir other option is run a toggle switch to the fuel pump rewire or stock relay this will allow u to prime the fuel system prior to starts if u like the race car look