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Mr. D · 04-06-2015, 11:59 AM

I have made it to Florida but as the trip went on my 454 began to stall when stopped and now won't maintain an idle once the engine warms up. This is an '88 345 with a carbed Bank power pack system, it has always idled at very low RPMs (500/600) but until now has never had a problem. Runs well in every other way except idle, thinking it may be a filter problem? Mr D.

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realpank · 04-06-2015, 01:39 PM

Have you been able to look at the filters?

Been trying to get mine on the road after finding out the tank was full of particulate. Guy I bought it off said he could not keep in running, we found a lot of crap in the carb, now we've got a new tank and trying to find the right fuel sending unit. Where in FLA are you?, I found a guy that does tank cleaning near Tampa.

Best of luck,
Chris

HowieE · 04-06-2015, 01:52 PM

Was this progressive or just after the last fuel fillup?

I doubt it is a filter if the engine will run at road speeds there is no filter blockage.

Did you get a load of corn starch, ethanol, and those effect the idle adjustment?

Any white smoke at road speed? If so there may be water involved.

n2916s · 04-06-2015, 03:46 PM

If you have a clogged EGR valve, it won't want to idle. Just a shot in the dark...

Mike

Protagonist · 04-06-2015, 04:26 PM

Will it idle with the dashboard air conditioner turned on? The engine should have a "high idle" setting that comes on to bump up the RPMs when the A/C is running, and those extra RPMs could mean the difference between stalling and not.

That's only an interim measure— if it works— but at least it will get you farther down the road until a more permanent solution presents itself.

Hummer · 04-06-2015, 04:40 PM

My guess is a fuel problem. I would go to Wally World and get a can of Sea Foam, put 3/4ths in tank and pour rest into carb.

The ethenol stuff is terrible on the older engines.

Actually I would get two cans and keep one in trunk because one bad fill up after a tanker just left a station and you could get another bad load of crap from bottom of tank.

Mr. D · 04-07-2015, 11:14 AM

P.S. Where is the EGR valve?

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Mr. D · 04-07-2015, 11:32 AM

Thanks to all, yes my rig did have some ethanol 89 in it for most the winter. Tried to run that trough in Ohio, added two cans of Seafoam before leaving. In Tenn. went 93 octane and the power and running temp both improved, but idle got progressively worse. No on board air on this rig beside the two on top. Tried to kick up the idle with the set screw on the throttle assembly side. Choke works well but once it warms up and idles down the rig stalls. Have sprayed the entire carb with cleaner and still can't get the idle. I can keep it running with a steady foot on the pedal, all it needs is a few more RPMs, I think if I could kick up the RPMs at idle the problem would be fixed. Power breaking at lights and in traffic is a real pain. Anyone know what the little device with the two wire plug attached to the side of the air cleaner shroud does? Thank to all for the help, I will try to keep you informed as things develop. Mr. D.

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n2916s · 04-07-2015, 11:34 AM

In most applications, they are plumbed into the valve cover (s) and a black hose is attached that will lead to the manifold. Again, a shot in the dark but worth looking at as they are cheap and (usually) easy to replace.

Mike

NavyCorpsman · 04-07-2015, 11:45 AM

Check all of the antique vacuum lines, esp at the flange/fitting. Is your brake booster ok? A quick way to find a hidden vacuum leak is take a 1 LB propane bottle with the torch attachment, turn it on (without firing it up) and work each line from the source to its terminus. If there is a crack or leak, the idle will pick up. Check the carb mount too. A coked up EGR can cause problems as well. Also check the short rubber hoses that connect to the transmission modulator. I hope it's an easy fix
Clayton

dadstoy · 04-07-2015, 11:54 AM

Mine is a 1982 "Federal" model with no EGR...yours may not have one...if it does, it is located between the carb and thermostat on the intake manifold.

Quote:

Originally Posted by Mr. D

P.S. Where is the EGR valve?

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dadstoy · 04-07-2015, 12:27 PM

I'm assuming your '88 has a Quadrajet carburater. Sounds like you have checked for all the long shots. Many times idling issues can be attributed to a vacuum leak. Check all vacuum lines at and around the carburater and all the vacuum hoses connected to the intake manifold and your air cleaner. Also check to see that there is no vacuum leak between the carb body and the carb throttle plate and also between the carb and the intake manifold. You may have a large vacuum hose running to your transmission. If this hose is leaking, it is large enough to cause the idle issue. If you have a vacuum operated door step, also check that hose...it is also a large hose. I'm going to guess on the '88 rig, there still is a vacuum hose going to the distributor vacuum advance as well...make sure it is connected. Also make sure the vacuum line going down to the smog pump diverter valve is also connected (unless someone has wrongfully removed it

).

You will probably have to remove the air cleaner to check all the vacuum lines. If you have the tall replacement air cleaner housing from the Banks system, it can be difficult to remove it with the little room between it and the dog house. Just lift up the top of the air cleaner housing and work the filter out, then you will be able to remove the air cleaner top.

A spray can of carb cleaner can be used judiciously to spray around the carb and vacuum lines to check for a vacuum leak.

You mentioned the problem got worse along the trip. The heat from the engine will do a number on the old vacuum lines and you may have developed a leak by the time you got to Florida.

If you can't find a vacuum leak, my next bet is the quadrajet carburater itself. It probably needs to be rebuilt. I rebuild my own, but it can be a daunting task for the inexperienced. Sometimes the plugs in the casting holes between the carb body and throttle plate leak...not as much of an issue by '88. Float level, dirty needle and seat, clogged idle circuit, and many other things with these carbs. Twice, these little tubes inside the upper cover have fallen out and into the fuel bowl on mine. There are too many things to guess at inside the carb...it will need to be taken apart to find out.

You will need to find a competent shop to rebuild the quadrajet and many shops wont work on them.

Best wishes and keep us informed. Whatever you find out will be good info for the rest of us!

dadstoy · 04-07-2015, 12:31 PM

Your '88 has what is known as a hydro-boost system for power steering and power brakes, so you don't have a typical vacuum brake booster that you would find on autos.

Quote:

Originally Posted by NavyCorpsman

Check all of the antique vacuum lines, esp at the flange/fitting. Is your brake booster ok? A quick way to find a hidden vacuum leak is take a 1 LB propane bottle with the torch attachment, turn it on (without firing it up) and work each line from the source to its terminus. If there is a crack or leak, the idle will pick up. Check the carb mount too. A coked up EGR can cause problems as well. Also check the short rubber hoses that connect to the transmission modulator. I hope it's an easy fix
Clayton

dadstoy · 04-07-2015, 12:36 PM

Word of caution...if you do find a vacuum leak between the carb throttle plate and the intake manifold...not likely, but!

There are four large bolts on top of the carb that bolt it to the intake manifold. You can snug these down a bit, but do not overtighten or you could possible warp the carb and that will create a vacuum leak.

Wolf Alaska · 04-07-2015, 04:22 PM

Due to engine "run on", the dreaded "clunk" in clunker; many late 70 & 80s engines have a kicker electric device that works in reverse to a choke pulloff.
When ignition switch is ON, kicker opens throttle to idle position. When ign switch is OFF, kicker pulls back & throttle closes below idle speed. SO engine will quit & not clunk !
I think U should see if Ur carb has a kicker & if it is working.
Good luck, Wolf
Let's Roll !

Mr. D · 04-08-2015, 05:53 AM

Thanks, will take a look and check it out. Mr D.

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perryg114 · 04-08-2015, 06:08 AM

My guess is that the idle jets are clogged with corrosion from sitting with ethanol in the carb over the winter. I have been through this many times with motorcycle carbs. If a carb sits with ethanol in it, then you have a problem. Taking the carb apart and cleaning the jets, might be a skill you want to learn. Also the ethanol can cause rubber parts and gaskets to swell. If you get it running better consider a fuel cutoff and run the engine till it stops after shutting of the fuel. I have had to do this on all of my motorcycles.

Perry

Mr. D · 04-08-2015, 06:08 AM

Lots of good ideas to work with, thanks again, I may need to replace a power steering pump on my Tracker(toad) as well. Luckily, I have a well stocked tool box, just need the right place to work, Mr. D.

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perryg114 · 04-08-2015, 06:18 AM

My advice is to block the ERG valve off unless you are in a state that does inspections. These things stick open and cause all sorts of problems. You can test the operation with a hand operated vacuum pump hooked to the vacuum port on the EGR. When you pump the vacuum the idle will get worse but since yours won't idle you can't do this test.

Perry

Mr. D · 04-12-2015, 07:47 AM

Again, thanks to all, spent 8 days at my last spot and during that time tried to cover as many of the suggestions as possible. Checked all vacuum lines, added another can of Seafoam, used carb spray to clean everything I could see and reach, adjusted my idle linkage, everything but the EGR. Drove to the next camp and for that 15-20 mile drive it ran great. By the time I got the next camp it was idling when I stopped. I might just spray the carb one more time and let it set a day or two before my next drive, but I think my problem may be solved! Thanks again, will up date further down the road, Mr.D.

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