I'm having a warm hard start problem and I haven't been able to pinpoint the cause. I'm using a 165 and I have tried ARAP code and a 89 TA bin file as well as the 88 TPI code. It's a 350/300 hp crate motor with a 88 TPI setup and a painless TPI harness
Here is the symptoms:
If the truck sets overnight - fires right up
If it sets for say less than 5 minutes - fires right up
If it sets for say over 5 minutes - cranks forever then starts

Here is what I have done to remedy the possible problem:
New rebuilt distributor w/ign module and PU coil
New cap and rotor AC Delco
Tried different ign coil
New Coolant Temp sensor AC Delco
New R45TS plugs
Removed the zeros in the injector pulse 1-8 locations vs startup code
Played with the code to lean and enrichen the start up PW
Timing set at 6 deg base
Cleaned and flowed the Injectors
Checked the CS injector for leaks
CS injector is not plugged in

I have noticed on my scanner that when I crank the engine the injectors do not show any PW untill it actually fires. At that point, there is a PW. I know that the ign module controls the PW below 400 RPM and its spinning fast enough to start. But I have tried a couple of different Ign Modules prior to going with a rebuilt large cap distributor

What else controls the injectors at start-up?
What am I overlooking?
Runs fine otherwise.

Any help would be appreciated.

 

Forgot to mention, Fuel pressure is stock at 42 psi and it has a fairly new filter.

 

Try adjusting the "Crank PW" table. You should note the coolant temp, etc and then play with those values. You probably need to add a bit more fuel.

 

Thanks Glenn,
I've added and subtracted fuel in the 1-8 slots for crank PW multiplier. I'll play around some more there to see if it helps. but I'm not showing any PW untill the engine actually fires.
Don

 

I'll go out on a limb and state what I believe to be the obvious.
Hot starts require more voltage from the battery, it is likely that:

a) Your battery needs replacement or you need to clean/replace your battery cables or

b) replace the starter or starter solenoid.

Hope this helps in some way, shape, or form.

Brian P
89 IROC-Z 355

 

LS1,

What scanner are you using. I have a very similar prob, except that mine does not fire at all. The question I have is, does the scantool show rpm when cranking, I am using winaldl. I did not know that the ign module in the distributor controls pulse during cranking. That could be my problem. Do you know how to test the module? My distributor/module is a reman, have you had any probs with em?

 

Greenshamrock77 and Sena'sIROC,
Thanks for the post's. Sena'sIROC, the battery is less than 6 months old, Alternator died and was replaced last weekend, starter is a couple of years old however, I will check my scanner to make sure I've got enough RPM's but I feel confident the starter is okay.

Greenshamrock77, I'm using an Autoxray for my scanner and I'm pretty sure it will show cranking RPM's. As far as testing a module, most of your parts stores can test them for you. And yes, the ign module tells the injectors to fire while cranking. Also if you get into your distributor check the pick-up coil for resistance and look at your reluctor (sp?) ring for cracks. Good luck and thanks for the replies.
Don

 

Check out the crank fuel pulse width vs cool. temp table-if it's a "hot soak" problem try decreasing at those temps.
Oh yea-when it's hitting the long crank-will it fire up quicker if you open the throttle 1/2 to 3/4?

 

Drive it,
Thanks for the post. Yes, it does seem to fire right up if I give it 1/4 to half throttle. If the 1/4 to 1/2 throttle leads you to something else let me know. Also, I've been in the coolant temp vs Cranking PW but I will have to check to see if I raised the PW or lowered it. I believe I've only tried it once and I think I raised it. I'm not on that computer right now but I will check my notes. Thanks again for your reply
Don

 

Sounds like your engine isn't getting enough air at start-up if opening the throttle allows it to start right up. I'd make sure the IAC passages aren't clogged and that the IAC motor is working properly. You also can adjust the TB set screw so that the IAC count is at 15-20 with a warmed-up engine at idle in Drive.

 

GregWestphal,
Good point, the last time I checked, which has been a while the IAC was at 30 but I'll double check that again. Thanks,
Don