Strange Starting Issues.. Please help

[tobeybauman]

I have a 96 420a eclipse. All summer I have fought with this problem. Sometimes when I go to start it, it will fire up and run just fine. Other times it will either, A) Continue to turn over but not start, or B) Start up and sound as if it is only firing on 2 cylinders for about 30 seconds then clean up. After this "missing" is done and cleaned up, it will idle very high (about 4000 rpm) for about 10 seconds if I even tap the throttle, then idle back down. After about 2 minutes, the car will run fine and I can drive it whereever for however long with no issues, until I shut it off again. I have replaced the ignition coil, TPS, an 02 Sensor that was bad, and replaced the timing belt and all its pulleys about 5,000 miles before this started. I have fuel (about 60 pounds), and spark. Anybody have any ideas please?

 

[DSM1G90]

Funky MAF sensor?

 

[TotalEclipse21]

420a has MAP sensor regulated air-fuel mixture, not MAF. Maybe a blown intake gasket since it stops when the car is warm.

 

[luv2rallye]

Have you tested the engine coolant temp sensor?
It almost sounds like vapor lock. Does it only happen when warm?

 

[DSM1G90]

True, if the fuel line is close to something rather warm to hot, wrap it with some styrofoam or fibreglass insulation to give that a shot.

aint gonna hurt anything to try this trick.

I had a '87 Dodge Aries with that throttle body system and the fuel line was close to the exhaust manifold causing me horrible vapor lock situations (I had to shoot starter fluid in the bore almost every time I had to do a hot start.) Thus I wrapped the fuel line with pipe insulation and that cured my vapor lock problems.

 

[tobeybauman]

I have not tested the engine coolant sensor, and never thought about a blown gasket.. An important detail I didnt include is that it doesnt seem to matter about the temp outside or the temp of the engine (other than the high idle deal). I could drive it to town one day and shut off and start it several times with no issues, or it could not want to start the first time. It seems to be completely random when it wants to start or not.. And would the coolant sensor or gasket affect the high idle?

By the way.. I appreciate all of the help guys.

 

[TotalEclipse21]

Now it sounds like more of a sensor issue, gasket would happen all the time when the engine is cold.

 

[uniqueTurbosRs]

ok well heres the problem. i just installed an obx intake got it all modded to where it needed to be so i could install. now when i start my car it high revves all the way up to 6000 rpm and stays there till i tap the gas . it finally goes back down and the go ight back up to 6000 rpm + im getting irriated with this thing . i have a code reader and its throwing the tps and map sensor and speed sensor as well as saying its running lean on bank one the only problem i cant figure out is the tps and map was fine before the new intake and 26lbh injectors now there acting up . please help

 

[jackblack65]

intake leak,
test it with starting fluid by spraying around intake with the TB routed outside the engine bay.
If it idles up when sprayed then you have a leak in your new manifold.