RPM flutter

gjp

gjp

another post whore
For the first time today I got to cruse my sy at 85mph on the highway. I noticed the rpm would sometimes bounce from 2800rpm to 3200rpm. Its a fast spike that you can feel the truck jerking slightly and the turbo guage would too spike. What should I look for first.?? Thanks
 
gjp

gjp

another post whore
Re: RPM flutter

That was all done 6k miles ago. Also took my wife out for a little spin right now. Went to 7-11. when we got out of the store it would not start. would not turn over or anything 5 times. then it started. Then when I got home it had a rough idle and died 2 times in reverse. Looks like I am going to have fun with this truck :)
everything leads to ignition trouble to me. Might do a full tune up. put in a new battery and starter and go from there.
 
Jimmy

Jimmy

Banned
Re: RPM flutter

gjp said:
That was all done 6k miles ago. Also took my wife out for a little spin right now. Went to 7-11. when we got out of the store it would not start. would not turn over or anything 5 times. then it started. Then when I got home it had a rough idle and died 2 times in reverse. Looks like I am going to have fun with this truck :)
everything leads to ignition trouble to me. Might do a full tune up. put in a new battery and starter and go from there.
Click to expand...
The "no start" problem is probally the purple wire that hooks to the solenoid.It is stupid small and right beside the DP,which causes it to melt.Simple fix is to cut that wire out and run a new 10 gauge wire there.
Tach flutter is ignition related.
 
gjp

gjp

another post whore
Re: RPM flutter

I went to start again today and nothing. I shook the shifter and it started. I think the switch in the shifter for the park is bad. I will try it again later to see if thats it. It still idles bad, and is getting worse. The exhause sounds like its missing every 3 seconds or so. I will change plugs, cap, and rotor this weekend. Needs a battery too. Thanks for your help everyone. Now I have to find the right parts???
 
gjp

gjp

another post whore
Re: RPM flutter

After doing a search I guess the NGK UR5's are the best. Now for the gap. Everyone says between .32-.35. I will be adding a alky injection as soon as my tax return comes in. I know you can run down to .28 with the injection. I dont want to have to change plugs again in 2 months. Would it be ok to run .32 with and without the injection???
 
gjp

gjp

another post whore
Re: RPM flutter

Ok found out something today. When my lights are on the engine idle drops. The volt meter for a second drops to mid line then climbs back up.???WTF. The first owner had details on the work done to the sy. He put on UD pullies. Not a good thing I think for these trucks. Not sure if they are still on. Anyone know or can measure the stock ones.
 
Don W.

Don W.

Stab it and steer it
Re: RPM flutter

Not sure on the pulley size but check your grounds. A lot of what you describe can be caused by bad grounds.
 
gjp

gjp

another post whore
Re: RPM flutter

I will be spending all weekend working on it. is there any hidden ground wires I should be aware of??
 
Bill Z

Bill Z

Donating Member
Re: RPM flutter

A couple of ground wires off of the back of the head on the driver’s side. Some ground wires connect to the front intake manifold bolt on the driver's side. The battery ground is to the back of the head on the passenger’s side. There are grounds to the radiator core support from the battery itself.

Not a bad idea to add a couple of extra grounds and to replace the washers on the current grounds. Make sure the washers are the fluted ones made to ground connections (not the split washers).

Additionally, check the output of your alternator. Some won't put out the required 13.5 to 14.5 volts at very low idle especially with an undersize pulley.

Hope this helps and good luck.
 
gjp

gjp

another post whore
Re: RPM flutter

another question. sorry. I took the truck out this morning. It was idleing rough as always. the windows were fogging up and when I moved the heater knobs (both) up to defrost the car jumped. Idle went up to 1200rpm and the truck moved foward for a second. the idle dropped down again. Is this normal or do I have a vaccume problem??
 
Don W.

Don W.

Stab it and steer it
Re: RPM flutter

:2cents: Sticky IAC? When you went to defrost the AC compressor comes on. This puts some additional load on the engine which the IAC tries to control. Hence the kick up in RPM. Just my :2cents:
 
gjp

gjp

another post whore
Re: RPM flutter

after searching i thought that too. Paper clip trick pulled no codes, but if it sticks. Can it be cleaned??
 
gjp

gjp

another post whore
Re: RPM flutter

Ok now I got some weird things happening with my truck. I have done a lot of reading and searched this site many of times. I have learned a lot. (not enough to fix this myself) . First the symptoms. When the truck is cold it wont usualy start right away. It does the click thing. everything dims in the truck but no starter. Ok sounds like the purple wire, but when its warm the truck will start on the first try. that sounds backwards to be the purple wire. Anyways I bought a conrad remote starter solenoid to get rid of the purple wire. Next symptom, It idles rough. ok but when it gets warm, (over 30 min running) it idles bad. I stopped at the auto parts store and it kept dieing out. WHen I turn on the lights or adjust the heater controls the idle will move up for a few seconds and then drop back down. I got a IAC valve, new battery(cca test was low) and some cone washers to reground the truck. The alternator at idle puts out 13.7volts. I will put everything on this weekend. While I am at it anything else I should try.????? I am looking for the datamaster cables but I have had no response from the guy on this site about them. any tips on the solenoide mod. The search showed some pics but I would like to read more about it. Thanks
 
Don W.

Don W.

Stab it and steer it
Re: RPM flutter

gjp said:
Ok now I got some weird things happening with my truck. I have done a lot of reading and searched this site many of times. I have learned a lot. (not enough to fix this myself) . First the symptoms. When the truck is cold it wont usualy start right away. It does the click thing. everything dims in the truck but no starter.
Click to expand...

Everything dims is the clue I think. I would guess a bad starter. The clicking is the relay engaging, the dimming is from the current draw that a hung starter is putting on the system. Do a search for here for a 454 starter and get one of those.


From the manual "Rough, Unstable, or Incorrect Idle, Stalling"

Sticky throttle (not closing completely) which causes a high TPS voltage. Datamaster again

Anything and everything having to do with ignition

Grounds (again)

Improper Fuel Pressure

Leaky injector

Leaking EGR valve

Vacuum leaks

Hope this helps,
icon_rolleyes.gif
 
gjp

gjp

another post whore
Re: RPM flutter

Just seems weird that sometimes it runs perfect. Thanks for your help.
 
gjp

gjp

another post whore
Re: RPM flutter

had some time today so I replaced the IAC. The one that was it it felt lose. did not take much to break it lose. for a second there I thought I did not have the socket on it. If I could get my hand on it I could have removed it without a wrench. I replaced it with a new one and took a look at all the lines and grounds. Everythink looked good. all the vac line were replaced at some point as well as the hard ic lines. I reset the IAC and took it for a 10 min test drive. still idles rough but did not seem to hunt for a idle. Knock on wood its running better. I will know tomorow when I have multiple "honey do's" to take care of. The funny thing was it started fine five times???? I have a new bettery going in sunday. Starter too. Can you run the remote solenoid fix on the 454 starter????
 
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