first the mechanic is an indy but w/12yrs experience as factory mechanic specializing w/ this model.

he replaced all injectors with quality remanufactured ones. cars runs great!

cars is 93 n/a 5 speed. it now starts pretty good when cold overnight, though sometimes revs drop low after good fast start but then quickly regains good idle. starts perfectly when off for up to about an hour. if over an hour it cranks for a good 8-15 seconds before catching weakly and seems to catch better when given a little throttle (strange for fuel injection).

fuel pressure doesn't seem to be an issue as it drops slightly but as soon as key is turned pressure is fine and starting better when sitting overnight would tend to rule this out. also fuel rails seems to be full so pressure check valve ruled out. idle control valve was an issue but checked out ok. cranks at fast speed so no battery or starter issues. plugs and air filters nearly new. car has 85k and has been serviced regularly; runs and drives nearly well as new.

any ideas appreciated...thanks

 

I'm not convinced the fuel pressure isn't the problem. Whatever is going on manages to right itself after running a short period, and if the fuel pump was weak it could do that. There could be a check valve in it leaking slowly too. Not saying it is the problem, just that I wouldn't rule it out yet. I'd consider checking thermo/time sw, cold start injector, temp sender and wiring for out of spec resistance too. If pushed hard enough, I might be forced to separate all electrical connections related to ign/injection and check for corrosion, etc.

 

and he hasent gone to electrical as a probable cause yet?

If all of your physical fuel systems are functioning as they should,
Im going strait to checking electrical systems, all of your connections, temp senders, sensors, ect.

 

Start with the basics... i car needs 3 things to run... air, fuel, and spark... if you know it's not air.... and you know it's not fuel... then it's spark aka eletrical.... Rule each of the three things out independantly...

 

While your not wrong, suck, squish, bang, and blow is a little more accurate, inclusive, and fun...

Oh, I don't know if those have the fan to cool injectors during heat soak or not, but if they do, ya might wanna check to see that that system is working right.

 

curious, was the timing belt done recently?

 

Uh huh, which why suck, squish, bang, and blow comes into play..

 

I was thinking more along the lines of all the sensors, plugs and crisply wiring that has to be removed in order to get the plenum off, but a timing belt that stretched or a failed/failing tensioner caused the cam/s to go off a tooth, that was band-aided by the mechanic by advancing/retarding the CAS, to make it run, also could be a failing ignitor. or everyone in this thread is dead wrong.

 

It's to early for that, at this point, all things are open...

 

timing belt done 2k ago. mechanic checked all electrical for resistance and corrosion. vacuum lines checked as well. again car runs great except for starting after a moderate off period.

 

Just a thought. When I first got my Z i had this kind of issue. I was using Bosch Platinum plugs and they arent as long as the NGK plugs so it was just flooding it self out and fouling the plugs.

It would start fine after sitting for a day or so, but sometimes it would just crank and then I had to wait a day for it to settle out and ****.