Another surging engine

[D-dog357]

So the deal is the truck has been parked for a while and it's time to get it smogged. I turned the IP back to stock and now it surges badly when cold. Sometimes it coughs then dies then catches again before the engine stops turning. Also it stumbles badly if I rev it up and down to clear it's throat as it slows.

I'm thinking it's a bad lift pump. Is there a banjo-nut that is tapped for a fuel press gauge for the out-put line of the fuel filter available ?

Is there something else could it be ??

Any help would be greatly appreciated.

[PToombs]

For about $7 you can buy a good tapped banjo bolt from www.genosgarage.com I tapped one and it was a bitch, it's really hard. I then bought 2 so I have one at work for testing. Is this after you found the KSB wire off? Did you put it on?

[D-dog357]

Hey Toombs - yup, The wire fun was found while trying to track down the surge fun. Will have to splice it tomorrow. Maybe I'll get lucky and it will stop the surging.

I'm still not sure about my LP and I just bought a used Holley blue pump off CL for $40. I understand they put out a max of 15psi and flow enough for about 300hp, 70gph at 9psi (110gph free flow) so it should work for me. It'll be nice to be able to purge the system, drain the tank etc and know when it goes bad there won't be fuel going in the CC. I'll ad a pre-filter to it so it has a happy life.

One more thing - the block off plate for the oem fuel pump is the same as for a SBC right ?


BTW; sorry for the multi posts - ain't we newbs just to much fun ?

[RCCUMMINS89]

Block off plate is the same as the sbc, correct.

[PToombs]

Plan on that Holley blue as being a temporary pump. It's been posted that they don't like diesel.

[oldestof11]

How does it run at lower RPM's?

[D-dog357]

This has turned in to a nightmare. I started out to get this beast ready for a road trip after sitting unused for close to a year with an fuel empty tank. I fixed the KDP and replaced those seals, new fan bearing, new alt, installed boost and ET gauges, flushed the rad and new water pump seal and drive belt. Adjusted the throttle linkage. Even drilled 4 holes in the air box and in the core support to get more cold air. Here I thought I was doing good before all this other fun started.

So now I got the wire replaced and still have hard/rough start and minor surging at idle up to around 1500rpm while cold. Heck it won't even start unless you step on the peddle just a bit even if it's warmed up. Once warm it still has minor surging just above idle - to aprox 1200 rpm. Also it stalls if you get off the peddle too fast or floor it and release the peddle like what is needed for a smog "snap test" I need to get.

Something else that came up while pulling my hair out was that the engine coolant didn't seem to be circulating properly, temp gauge in middle - cold hose, no coolant flow. So I pulled the t-stat. It works fine but was installed with the bleed hole at the bottom trapping air in the head.

[SuperiorRam]

Run like this?

http://www.youtube.com/watch?v=jXx1KqZL ... ata_player

Cause the pump had broken goodies inside

[D-dog357]

No it doesn't sound like in the vid, but it does just keeps get'n better !

I forgot to mention that it smoked a good puff at start-up. Figured it was from unburned and hazed on acceleration. Kind'a like an old gasser opened up on the freeway for the first time in years - clearing it's throat.

I fired it up again and let it warm-up before taking it for a drive. Seemed the more I drove it the better it ran. Got to the point were there was no more hazing and idled nice but would still stall if you side stepped the fuel peddle. Also had a slight surge if you slowly raised rpm just above idle but smoothed out again with just a bit more peddle. Here's a zinger though - it won't start unless you gave it at least a little bit of peddle but once running it idled nice.

Then it turned ugly - cruz'n about 45 and let up on the peddle for stop sign and died ! Three tries to get it started get's it home, idles fine. Rev it just a bit and let off - it stumbles and dies.

Now no start no matter what I do - WTF

Checked power to blue wire on pump - OK, power to thermo-switch - OK. No power coming out of it. Is that right ?

Checked for fuel going into filter at banjo by pumping lever - small squirt. Check it coming out of filter and at IP - the same. Cracked loose an injector line and turned over engine - baby drool. I know that ain't right !

Is there a screen in the IP that could be clogged ? Any other suggestions ???

[PToombs]

If the engine is warm there will be no power on that wire to the KSB.

There is sometimes a screen in the LP. I thought you put the holley on, but you mentioned pumping the lever, so, you didn't? It sounds like the LP is bad or you have a bad air leak.

[D-dog357]

Couldn't get the engine to fire so I checked it cold. Sounds like it might be bad too. What temp does it cut out at ?

I held off on the Holley so not to add to the confusion. I guess I shouldn't have second guessed myself. I'll install it tomorrow and hope for the best.

What would happen if I pulled the FSS and cranked the engine would it blow any junk in the IP out or could it damage something ? There was some kind of gummy junk inside the banjo fitting I pulled and just want to be sure there's nothing floating around in the IP.

[m880cummins]

Run a jumper wire from the FSS to the KSB and see if it runs better. This test is a good way to check the IP. Sounds similar to the truck I just replaced the IP on. Before, It wouldn't idle and had low power. Wired, It idled and had some more power.

Charlie

[Deathrod]

Is it the old fuel that has been in there while it's been parked this whole time??......could be watery/ bad fuel.

[SuperiorRam]

No it doesn't sound like in the vid, but it does just keeps get'n better !

I forgot to mention that it smoked a good puff at start-up. Figured it was from unburned and hazed on acceleration. Kind'a like an old gasser opened up on the freeway for the first time in years - clearing it's throat.

I fired it up again and let it warm-up before taking it for a drive. Seemed the more I drove it the better it ran. Got to the point were there was no more hazing and idled nice but would still stall if you side stepped the fuel peddle. Also had a slight surge if you slowly raised rpm just above idle but smoothed out again with just a bit more peddle. Here's a zinger though - it won't start unless you gave it at least a little bit of peddle but once running it idled nice.

Then it turned ugly - cruz'n about 45 and let up on the peddle for stop sign and died ! Three tries to get it started get's it home, idles fine. Rev it just a bit and let off - it stumbles and dies.

Now no start no matter what I do - WTF

Checked power to blue wire on pump - OK, power to thermo-switch - OK. No power coming out of it. Is that right ?

Checked for fuel going into filter at banjo by pumping lever - small squirt. Check it coming out of filter and at IP - the same. Cracked loose an injector line and turned over engine - baby drool. I know that ain't right !

Is there a screen in the IP that could be clogged ? Any other suggestions ???

Hate to tell ya but that's how this one ran before this vid

[Sutter1stgen]

It sounds like a fuel related problem to me. I would drain and replace the old fuel first. Then check the fuel supply lines with some regulated air. I've seen trucks run like crap and give the owner a real hassle. Put a little regulated air to the tank, crawl under the truck and looked for leaks. It is almost alway old, dry, cracked rubber. These are only suggestions, but I looks like your headed in the right direction.