cmac2012

Just a couple of months ago I was marveling at how well my engine was running. It’s at 173k, Pretty sure it’s not 273k, I bought it with an odo reading of 29k, Not from the original owner, but from a broker. It seemed in far too good of shape for 229k.

I must have had multiple deferred maintenance items creeping up on me. About 10 days ago, I started having severe missing and lurching. I had been needing to call my mechanic with an issue about my Mercedes diesel so while I had him on the line I picked his brain on the Chev. He asked me when was the last time I did a tuneup. It dawned on me it had probably been 20 to 30,000 miles. Driving diesels most of the time has skewed my thinking.

So I put in plugs, cables, cap and rotor, and air filter. It miraculously started running much better. I’ve never had so dramatic a change from a tuneup, but then again I used to do them more regularly.

Then last night it started displaying the same symptoms again. And me all WTF? It’s more than the missing of a single cylinder, the whole engine loses power for a second, then regains it for a moment.

It occurred to me that a few times in the last year I had left the ignition key on for a spell w/o the engine running. DOH! Years ago on some other gasser I burnt a coil out in that fashion.

I did a search for symptoms of a bad coil, and it sounds a little bit like what I had going on, these especially:

#3 – Engine Misfiring.
#4 – Vehicle Stalling.
#5 – Engine Jerking, Rough idling, Poor Power.

It seems logical that the tune up could have improved enough with the ignition system for a temporary improvement but if the coil had been part of the overall problem, it was bound to reveal itself.

Also, I had never put a new coil in this rig, there is a chance it was still the original unit. I put one in, didn’t even bother to test the old one. It ran quite a bit better but still some hesitation and lurching.

The next morning I fired it up and it ran almost perfectly. I don’t understand the misbehavior the evening before just after the coil was installed but I’m not complaining.

There is something in the behavior still not quite right. At around 50 mph I seem to detect a little bit of missing and slight faltering when trying to speed up. It will indeed speed up, but something feels funny.

I am ashamed to confess that I’ve never changed the fuel filter, and never gave a thought to the fuel pump.

I’m thinking at this mileage, not a bad idea to put in a new fuel pump, not even test the old one, and definitely a new filter.

FWIW it received a new distributor a few years back, was stalling at stop signs and red lights. When reversing I needed to keep one foot on the gas and one on the brake. I had tried everything I could think of including new cap and rotor. I am usually always DIY but one should accept one’s limitations.

My mechanic, a real find, very good and honest as the day is long discovered it was the distributor itself. It would barely turn. Ran like a champ immediately after and still does in most regards.

Long story short, too late for that, does anyone know the optimal fuel pump to buy? Getting at it is too much trouble to replace to skimp on some aftermarket cheapie.

hanky

A wise move would be to stay with OEM.. AC Delco.

cmac2012

Good advice, I wasn't sure what OEM was. Amazing how much I either don't know or forgot. I see online one of those can be had for around $240 - aftermarket are about $90. Way too little to save given the work involved to get at it.

William Kisselstein

GM, AC Delco or Delphi is what I would go with. Rock Auto has a Delphi for about $200 that includes the whole sender and so forth, or you can buy just the pump for around $40. .

cmac2012

Thanks! Sounds like good advice. I hear all the time about the folly of being a “parts replacer.“ That is, not having adequately tested to know that this or that part is really not functioning properly. On the other hand, given the age of the rig, it might be irrationally optimistic to think that a device like an electric fuel pump will last forever. I’m sort of a Mercedes diesel head, and some of those mechanical pumps are pretty incredible, but even they need service.

if I want my truck to run like new, might need an important part like the pump to be new.
I was really into the BMW E30, Had two 325i models, great car in many ways, but a weak spot was the electric fuel pump issues. Mine were 1987, had an intank pump, the sender pump, and an in-line pump. Twice I had the in-line pump fail - tow truck time, The first time anyway. The second time was on I-5 in Oregon and I had a spare with me, swapped it in and off I went.

Triaged

Replace the fuel filter with a good non-China brand. Check the pressure of the fuel pump and if it's good it's hard to justify replacing the pump. If you do replace it go with OEM!