charliegt

I have been troubleshooting this problem for at least a year. Here is the most current and accurate description of what is happening :



- cold starts are rough (feels like its running on 1 rotor), but smooth out with a little throttle. once the car has been running for 15-20 seconds everything is smooth and perfect. It almost seems like for 10-15 seconds something isn’t functioning, then it clicks on and everything is great.



- hot starts are worse. I'll crank the car and it will fire, then quit. After that I can get it to start by cranking with the throttle wide open, pause, then crank normally and it starts - I then need to apply WOT to keep it from stalling, it misses for a few seconds then rpms start to build and I can let off the throttle. This seems to have gotten progressively worse with the hot weather leading me to believe that whatever is failing is performing even worse once it is heat soaked.



- one strange thing that I did notice is that the fuel system doesn’t prime for 2 seconds when I first switch the ignition on. I originally thought this was the problem, so I removed the fuel pump relay and put in a paperclip (powering the pump whenever the ignition is on) – however the problem persisted.



Aside from the first 10-15 seconds after starting – the car runs and idles pretty much perfect. At idle warmed up I am at about -14 vacuum. No smoke or bubbles in the coolant.



I currently have a fuel pressure gauge hooked up to the car. The pressure is good and the hot start solenoid is functioning properly (pressure is above 40 when the engine is hot, then drops to 32 after about 30 seconds of idle). The fuel system holds pressure great (35psi for an hour or so).



Here is a list of everything that I’ve tested/replaced:



Replaced plugs and plug wires

Replaced coolant temp sensor

Replaced fuel pressure regulator

Replaced fuel pump

Replaced most of the vacuum hoses

Had injectors cleaned, rebuilt, flow/leak tested

Compression test (95psi on 3 faces of front rotor / 90psi on 3 faces of rear)

Tested fuel pump relay and fuel pump (speed) relay

Tested fuel temp sensor

Tested intake air temp sensor

Tested TPS

Tested MAP

Tested AWS valve

Visually inspected double throttle control, idle control, ect.

The battery is less than a year old, and I just had it tested today and it checked out OK.



I've spent a considerable amount of money (and a ton of time) trying to figure this out, and I'm getting pretty frustrated. I'm wondering if I have a bad coil, but I want to see what you guys think before I buy yet another new part on a hunch.



If anyone in the Cincinnati or Columbus area has a spare set of coils or a spare stock ecu that I could borrow I'd really appreciate it.



My car is almost completely stock (its a 94) with the exception of a downpipe, catback, af gauge, and boost gauge.



Thanks in advance, I appreciate any advice that you guys have to offer.

-Charlie

charliegt

I should also mention that the only code I'm getting is 16 (egr). I've done a lot of searching and haven't come across anything that would indicate the egr can lead to these types of problems - but if it can, please educate me.

charliegt

BUMP + I tested for spark on each wire this weekend and they are all sparking.



-Charlie

charliegt

I just bought another ECU, coils and igniter. They should be here this weekend - maybe one of those will fix my problem.



-Charlie

Veritas

You can try my old ECU and see if that works. It worked fine last time I checked and im up in columbus. Sorry I would of replied sooner but I didn't see this thread until just now.



PM me and we'll see about having you come up this weekend and try it out.



T.c.

Fd3BOOST

Sounds like a serious Gremlin you have there. I dont have any advice for that one other than you might want to start to think about calling a shop with a lot of experience and can possibly hunt it down for you.

I would reccomend PFS but I don't know that you want to trek all the way to Maryland.



Update the forum to your findings if you don't mind.

RX8Guy

I think the minimum spec compression is 95. So your running minumum on one and less on the other. Bad news. Usually caused by the apex springs finally giving out from the high temps of turbo charged motors. Been there. Thats proubly your starting problem.

charliegt

Just an update. I am convinced that the problem is heat related, and it is getting worse. Now when the car sits and idles after driving the idle begins to get unsteady (starts to stall, rpms drop to 500 and then it catches itself). Reving results in a sudden drop in RPMs and a near stall.



I've also begun to notice that the only time I have trouble starting it is after it has sat and heat soaked. I replaced the ignition coils and ECU last weekend and the cold startup no longer seems to be an issue.



Any ideas what parts would cause bad idle once they are heat soaked? Another thing I noticed is that when I jump the TEN and GND terminals at idle when the car is warmed up, there is no change. Just steady 800 idle and -14 vacuum. Does this indicate anything?



Thanks,

-Charlie

FikseRxSeven

did you try to clean the idle control valve, a similar problem happenned to my car and after i replaced the idle control valve (thinking it was broken) the car ran much better.



i cleaned and placed the older idle control valve back on and the car kept running the same.

FikseRxSeven

check the voltage at your battery also when you first start up the car.... you might have new battery but your terminals might be dirty..... pretty remote, but worth a check