Well... a while back, I was having problems with hard starting, rough idling, stuttering, etc.

https://www.thirdgen.org/techbb2/sho...hreadid=245901

Anyway I haven't had trouble since that last post, but in the last few days the problem has come back with a vengance.

I am having the same problems as originally described, BUT today I noticed that as I went a round a 90* corner, the engine started to stumble and almost stall. Right before I got home, two 90* right hand turns - did the same thing BUT it actually stalled and let out a big nasty backfire. I proceeded to coast to my house - embarrassed....

Anyway! this time I can at least duplicate the problem - slowing down and going around corners causes stumbling/stalling.

Any takers?

Thanks in advance!

 

It sounds like a massive drop in fuel pressure. What is your feed line pressure? A dying pump will show up even more whenever the vehicle is cornering or accelerating.

 

Thanks. You confirmed my first suspicion that it may be a fuel problem.

I honestly haven't check my fuel pressure - I would like to go to an external FPR and upgraded pump; so I didn't want drop the cash on a fuel pressure tester.

Do you think it's kinda strange that it's run fine for about 3.5 months without any other signs of problems?

 

yes, sounds like fueling. Funny that it only does slowing down or turning.

how much fuel do you have in the tank? these cars have always had a pickup problem with 1/4 tank or less, when turning.

 

The problem is actually happening on my K5 TBI. My gauge says that I have about 1/2 a tank and I don't believe there is a problem with the gauge.

My thinking is that it is either:
1) Something mechanical in the pump failing
2) a loose electrical wire that is shorting out causing either the fuel pump or injectors not to work properly.


I was just on acdelco.com, and it looks like the thirdgen's and blazers use a different fuel pump - but 5.7 tbi Caprices DO have the same pump as the blazer.. hmmm

Any suggestions on a good performance direct replacement pump (190 or 255lph) - not walbro though as I can't seem to find anywhere in Canada that stocks them.

Also... can anybody point me in the direction of a 15+ psi external FRP? I can only find 0-15 and 30+ psi FPR's but nothing in between. (Yes, I plan on chipping)

 

on the FPR aeromotive makes a unit with interchangible springs. like 10-20 and 20-60 lbs. i think $130.00. and easily adjustable with an allen wrench and pretapped for FP gauge. looks pretty too.

 

Cool. I also was able to find a NOS FPR for around that price. Looks like they use different springs to adjust the ranges of Pressure.

 

The problem ended up being a very close to dead ignition coil. The resistance read 26,000,000 ohms instead of 6,000 - 30,000 ohms. There was a spark when I tested it, but it was far too little.


I threw a MSD Blaster Coil in to replace the dead one, and it fired up first turn of the key. There was an amazing amount of carbon build up as well for a motor that only has 10,000 miles on it. And my fuel mileage has increased significantly from 9MPG highway towing to 14MPG towing on the highway (imperial gallons)