I'm new on this forum and love the knowledge and insight shared here. I'm hoping someone can share their expertise with me now... My car is a ’97 Seville with 160K miles. I'm not really new to engines, but am totally new to the Northstar engine.

About 7,500 miles ago I studded the block to resolve a HG leak, and was pleased with the results. But just recently the engine began stalling when I come to stop at a light. Probably about 2/3 the time it is fine or very intermittent, but then sometimes it will die on every stop. Around the same time the engine was getting harder to start, so I replaced a Crank Position Sensor and now it starts immediately every time. But that didn't help the "dies at idle" issue. Here is what I've found so far:

>NO applicable CODES ARE SHOWING UP, other than the “engine stall / near stall detected” code (P1599). The only other codes are P0441 “Evap Emissions Purge Control” and B2120 “Lumbar Sensor Failed”
>This has probably happened about 50 – 75 times over the past 2 months.
>It NEVER dies if we shift it to Neutral and coast up to the stop.
>If the RPM’s stay above about 650, it is fine. If they drop down around that range and I flutter the gas it will pick right back up and be fine.
>When it does die, it doesn’t sputter – it just stops like you turned the key off.
>It ALWAYS starts right up again, instantly, without turning the key to the OFF position first. Only once have we had to turn the key to the OFF position first – and then it started right up.

After reading some other posts on this forum I have:
>Checked the fuel regulator for leakage. After letting the engine run, I pulled the vacuum line, but it was dry.
>I removed and cleaned the Idle Air Control valve. It was very dirty, and I sprayed it clean.
>I checked the MAF module – it’s clean.

I’m very much at a loss… Thank you in advance for any help you can offer, and thank you for your time.

 

With 160k miles, I'm thinking it's a fuel issue. Check the fuel filter. Also, clean the fuel injectors. You can do that yourself, or have a mechanic do it. My 2002 Deville (Northstar) was doing the same thing, stalling without warning. I tried running chemicals (from a parts store) through it, did not clean it out. The Cadillac dealer wanted around $200 to clean the fuel system, but Tire Kingdom did it for around $100, and it took an hour.

Since then (2 months ago), it has never stalled, runs like a dream!

TS

 

Hey, thanks for the input -- sure appreciate it. I have actually checked the fuel filter, and it was totally good. As for the injectors I ran a couple bottles of injector cleaner through them with no effect. The thing that makes me think it isn't injectors is that when it does quit it's like the key just got turned off. No hesitation, no stumbling, just instantly dead.

But I will go ahead and clean the injectors and hope you are right.

Gotta love computerized systems, huh? Best thing in the world when they work, and the most frustrating when they don't! I'll post my results, but it won't be till Saturday before I can get to it.