Hard starting only when warm
 

I have a 1995 Chevy Blazer 4WD with 4.3 L vin W engine.

Since recently installing a new CMFI module, it's been hard to start after warming up. I did not have trouble starting it warm or cold before the original CMFI failed. I also installed brand new spark plugs when I changed the CMFI module.

Starts fine cold.
Drives fine warm or cold.
Difficult to re-start after warming up. Have to crank for quite a while... it might putter & die once, then it starts up and smells rich for a few seconds.

Anything I can think of would also affect cold starting... so any new ideas would be much appreciated.

Thank-you!

How many miles are on it? Could be a timing issue. Maybe stretched timing chain or something like that.

210,000 miles. How common is a stretched timing chain? Wouldn't that cause all kinds of other issues when driving though?

Not necessarily. If it hasn't been changed before it needs to be more than likely. I could just start to be acting up. If you let it cool completely down will it fire right up? You can check the timing with a timing light and see where its at with the timing.

Yes, if it cools down enough it starts right up. When running errands, if the errand is quick, engine is still warm, it takes longer to start. If the errand is long, it cools down and it starts right up.

The only exception is if I shut it off and immediately restart it... no problem.

Yes, I can check the timing.

Could also be the fuel relay going bad. happened to me a few months ago. Same exact problems as yours, except, on top of that, on a hot summer day (I live in AZ) it would take a while for it to start up as well. Once it fired up, it would drive fine until I stopped the car and tried to crank it again. Then I would be there for a few minutes trying to start it. Once night rolled around, or once I let the engine cool, I would have no problems firing her up.

I've had the fuel-pump & pulsator fail so many times I'm familiar with those symptoms and you're right, it's similar. Starting when cold was easier.

It just not as bad as all that. It starts... just takes a little longer... instead of starting within a few seconds on the first attempt, it takes maybe 3 or 4 attempts during a 10 to 30 second period.

Plus I can hear the fuel pump engage when I turn the key so I don't think it could be the relay.

Thank-you.

Take the ignition control module (ICM) to AutoZone and have them test it through about 10 cycles to get it hot and see if it fails.

The ICM is in the distributor, right?

I have a 4.3 L vin (W)

According to the GM service manual, and I am quoting on page 6D4-2

"Vehicles equipped with the 4.3L (VIN W) engines are equipped with a high value ignition system. Refer to SECTION 6D4B"

However, the components in section 6D4B of the book do not look like mine... my distributor cap just looks like a normal cap with the nibs sticking straight up from the cap. And my ignition coil does not have a heat sink like the one in the picture in the book.

So I'm really not sure how this is possible to not have the proper ignition system for my engine. The book must be wrong as I bought this truck new and it's a Vin W.

Hello just kinda wondering my problem is very simalar when i first got the truck it started fine. had it about 3months now when i goto start it the starter would just click like its going bad.After about 30sec to 1min of clicking it will slowly start to turn over. It has been decently warm here in Vegas lately but after some cool weather coming by i went outside to move the truck and it fired right up. I have the 4.3l W code blazer.