Before i address my problem i will list my car and the relevant specs that i "think" is causing my issue(s).

Car: 95 civic

Specs:
2.5 bar map sensor
450 Dsm injectors (blue tops + injector box)
15g greddy turbo kit
NGK plugs -7 (if i remember right?)
tuned on neptune
190 walbro fuel pump

Problem:

ever since i went turbo about 3-4 years ago, from day one, i've always had a "hard starting" problem. it was intermittent so i just took it all in and dealt with the issue. i checked my injectors and found out one was leaking. so i replaced them with another set of 450's (flow/leak tested and was good). the issue still persists. recently within the past month, it has gotten to the point where i have to hold down the accelerator while cranking for 3-5 seconds before the engine sputters to life. i do this 80% of the time (remember its intermittent), somedays its starts right up, like how it should start from the factory.

the other day it threw a check engine light. CODE 16. this is the first time i have ever seen this code. after some research it points to the main relay signal to injector. with the code 16 my car sputtered like it was on 3 cylinders and very lean! after a couple hours i started it again with zero check engine lights. i drove around all day with no issues. the next day after class i parked it. 30 minutes later i went to crank it and got the check engine light again, code 16. once again it dissappeared after letting it sit for a couple hours.

i then moved onto my fuel pump, thinking that it wasn't holding pressure. i replaced it with a USED known working pump out of my buddies car. issue still persists.

then i replaced my relay with a used main relay. guess what? issue still persists. tomorrow i'm going to have my distributor checked out, just to rule out that possibility.

so here i am asking for all you ht'rs for your help! sorry for the long post, but i had to list all the symptoms and what i have done so far.

 

Check whether the main relays may need to be resoldered:

http://techauto.awardspace.com/mainrelay.html

Also try cleaning the FITV:

https://honda-tech.com/forums/acura-integra-6/%2A%2A%2A-how-%2A%2A%2A-clean-your-fitv-aka-fast-idle-thermo-valve-1564019/

 

had this same problem with my ef with mpfi swap thought it was the hack job wiring harness but ended up being the main relay re soldered it then it ran great. only thing different was that i was running way rich to the point of flooding the motor

 

thanks for the replies!

i will be resoldering the original relay i took out. it was already on my list of things to do whenever time permits. i'll lookin into the FITV.

 

anyone with anymore insight?

 

resoldered my main relay. no change

checked voltage on my injector lines. all good

changed spark plug wires. no change

anyone have any insights?

 

i put in a new dizzy today, but it didn't help it either. i'm going to replace the fuel pressure regulator tomorrow, but its so damn expensive for such a little thing. in the mean time..............anyone? feel free to chime in.

 

man it seems like you are spending a lot of money trying to figure this out, do you still have the code 16 even after re soldering or did it go away but you still have the starting problem

 

haha, you don't even know how much this problem is costing me, in terms of money AND time. on top of that its frustrating diagnosing something that is your daily driver.

everything still remains the same. hard start and code 16.

 

Check whether there is battery voltage at each fuel injector connector.

Here's how to test the FITV:

 

oh yea, i have tested voltage at each injector connector. 11.87 volts for all 4.

and a new update: the car only throws a code 16 when its medium hot. let me explain...when the engine is hot (engine coolant temp = 180*+), and it has been shut off for 30 minutes "minimum" it WILL throw code 16 and idle like its on 3 cylinders, but idle is solid at 900 rpms. as soon as the engine cools (ect = < 60*), car will still have hard start, but NO check engine light.

and i'm not ruling out the FITV yet, but i don't think its the culprit at this point only because my idle is fine. unless you have a theory? i would love to hear you out.

thanks!

 

I agree. Your focus should be on code 16, although a problem with cold starts could be due to a clogged FITV.

Regarding code 16, I assume the resistance on the injectors is fine. If so, the next step is to test the wires between the injectors and the ECU and the ECU itself:

 

thanks for ur inputs Ron. i have that exact diagram too and have been waiting to do that after i tackle these steps first. i will eventually have to do that diagnosis.

 

So that dizzy didn't fix it huh. I thought you said it was all good when you stucked it on? Anyway, if you need an ecu you can borrow mine. You just have to put Neptune in since I haven't done that yet.

 

yea, im going to test my ecu later today, and if its the cause, then i'll hit you up.

no one else has had this problem?