Need help with cold start problem.
 

Ok, I searched, but all the threads I found were about problems starting when the weather is very cold.

I live in Florida and it never gets cold here, so what I mean is that when the car has been sitting and is "room temperature" it wont start, it just cranks and cranks. usually after about 10-15 seconds of cranking it will FINALLY start.
After its been driven and it gets to normal operating temperature it will start right up imediately.

Ok, now for a little info on my car, so we can rule out what's not the problem:
It has a brand new rebuilt motor in it, still very much in the break-in period.
Obviously the plugs are brand new, with less than 100 miles on them.
The battery is brand new and so is the starter, so I know the problem isn't on that end.

So I guess what I'm asking is where should I start? Should I be looking for Vacuum leaks, or a faulty BAC, or what?

are you sure its not flooding?

Well I don't touch the gas at all before starting it, so would it be possible for it to flood it's just been sitting there?

if your injectors are leaking, have you had them cleaned/replaced lately? how many miles are on them?

Jeremy i have heard that you can touch the gas a little because that will blow it out. I really do not believe its the injectors because they never gave me a prob whatsoever.

I am also begining to wonder about the fuel pump too. Sometimes when the y are weak they will not prime properly. So whenever the car is shut off for awhile the fuel sets back down, and your fuel pump will struggle to prime again.

yea i would check the injectors..?

cuz they leak, you fail.

low compression

hmm, ok well the cars P.O. (91verty) has told me he never had any probs with them and he thinks they are good. Is there any quick way to check if the injectors are ok without pulling them out?

hmm that fuel pump thing sounds logical. I was planning to put a walbro in there anyway, so I wonder if that would fix the problem.

still, i'd like to know all possible things that could be causing this problem. Any other suggestions?

timing set ok?

one thing you could do is make a diagnostic check lamp thingie to see if it's got any codes.

[QUOTE=jurr1981]Ok, I searched, but all the threads I found were about problems starting when the weather is very cold.

I live in Florida and it never gets cold here, so what I mean is that when the car has been sitting and is "room temperature" it wont start, it just cranks and cranks. usually after about 10-15 seconds of cranking it will FINALLY start.
After its been driven and it gets to normal operating temperature it will start right up imediately.

A classic case of the water themo sensor not connected up or an open wire from the water thermo sensor to the ECU.

You are allowed to floor the pedal when starting. It effects NOTHING other than allowing more air to the engine. No more fuel, just more air.

The AFM is NOT used during the start cycle.

What is used is the following: 1. The roms under 500 rpm......2 the temperature of the water sensed by the water thermo sensor..........3. a 12vdc signal from the ignition switch to the ECU when the key is HELD to START.

IF the water themo sensor has an open circuit to the ECU, then the water temp will be defaulted by the ECU to 175 degrees F.

The higher the temp sensed by the water thermo sensor, the less fuel injected. The lower the temp sensed by the water thermo sensor means more fuel .injected during start.

A cold engine such as you describe would be harder to start if the water thermo sensor was disconnected but would readily start once warmed up.

Seems I wrote this same thing in the past about a dozen times. Oh well. JPG attached as to how the START cycle works. It's not in the FSM. Should have been there.

thanks HAILERS you rock as always dude. Happy New Year!!

Thanks alot man. I guess I shoulda searched better, oops. hehe.
Well, hopefully thats all it is, I'll check tomorrow.

Hmm, I did a quick visual and the thermo sensor is definitely connected. Time to bust out the multi meter I guess...

I cant seem to get access to the sensor plug so I can check it for continuity. Is there any easy way to get to this plug without taking off the darn alternator?

Also, while checking this out, I noticed a few other things that are quite obviously disconnected. YIKES!! heres a link to the thread I posted about them right here:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/some-things-disconnected-need-help-610678/

Could any of those things cause my car to not be starting right?

Well I reconnected some wires (I believe related to the cold start assist) that weren't connected well, and now it starts up like a champ!

I would have missed it if I hadnt really been looking for it tho, cuz the connector was physically connected, but the contacts inside weren't connecting. So I had to take the plug apart and fix the contacts.

Yay, I love it when things work.

i had that problem and i think the problem was bad compression

Well I knew I could rule out bad compression since my motor has a brand new rebuild with less than 200 miles on it.

But yeah I guess that could do it too.