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General Information => Troubleshooting => Topic started by: wdkingery on August 20, 2011, 04:50:10 pm

Title: unstable RPM's
Post by: wdkingery on August 20, 2011, 04:50:10 pm
Captain Ignorant put an oil pan gasket only to find out it was the oil pressure sensor!  ::)

C ar is doing a slight surge now.. Put a new fuel filter but it didn't help. It's slightly off idle.it will kinda stop accelerating for a second then kinda take off. If I mash it alittle more it won't do it
Title: Re: Captain Ignorant
Post by: nathan_b on August 21, 2011, 01:29:02 am
throttle cable too tight?

Title: Re: Captain Ignorant
Post by: wdkingery on August 21, 2011, 10:27:02 am
No plenty of play there
Title: Re: Captain Ignorant
Post by: bajacalal on August 21, 2011, 11:40:37 am
To start with, make sure it's not ingesting its own oil, either from the turbo (if so equipped) or your PCV system, the later cars had the upgraded PCV and and valve cover baffle so consider the upgrade if it doesn't have these.

Have any screws on the injection pump been turned?

Mine also does this from time to time, where it sticks at a higher idle than where it should be (but it's nothing near a full blown run away). A dose of diesel fuel system cleaner seems to make it go away for a few months so my guess is that something is getting gummed up in there.
Title: Re: Captain Ignorant
Post by: wdkingery on August 21, 2011, 01:05:43 pm
Yes we must be on the right track. My idle can stick high to.. I've been putting all kinds of crap in the tank so who knows. It does alittle low speed buck at times too, and the diesel cleaner had cleared that up. I'm thinkin its related to the cold start.
Oh, and yes i've done dicked with all the screws on my pump :( i've actually got th. Fuel screw turned down past where it came..
Title: Re: Captain Ignorant
Post by: ORCoaster on August 21, 2011, 02:03:48 pm
Hey all that "crap" you have been throwing in the tank is doing your motor good.  I get that surge at idle after a long run on the highway too.  If I look at the IP gauge it drifts a bit.  A few pounds at most.  If I get out and look I see air in the lines.  Race it a time or two and they go away.  Think it might be time to pull the connections at the fuel filter and smooth them out and heat them up till they turn blue.  That should get rid of my problem.  May do the same for you. 

And turning the screws in and out is considered "tuning" and some people charge 100 an hour for that.  Some charge about the same for the term you used as well. 

Title: Re: unstable RPM's
Post by: wdkingery on August 21, 2011, 08:03:16 pm
i made a video but the sound turned out horrible.

what i found is that i can hold the gas pedal down slightly, and it will act like a obd-1 model honda with a vacuum leak... up and down rpm, very constant, stable, up and down, up and down.. then it will eventually break free and run up a good bit in RPM.

do you think having the fuel screw turned out too far will do this? but it didn't do this for the first 400 miles after i turned my smoke screen back out

EDIT: altho i got 46.7 MPG's last go round, my fuel gauge was reading waay high.. like i had barely used a quarter of a tank, but been 223 miles.. normally i break the 3/4 mark at 165ish miles.. and i heard a bearin squall like hell the other day after i fired it up. alternator?

but it does it a lot worse when it's cold.. it actually becomes a buckin then
(http://img585.imageshack.us/img585/7227/fueli.png)
Title: Re: unstable RPM's
Post by: R.O.R-2.0 on August 22, 2011, 01:32:33 pm
i made a video but the sound turned out horrible.

what i found is that i can hold the gas pedal down slightly, and it will act like a obd-1 model honda with a vacuum leak... up and down rpm, very constant, stable, up and down, up and down.. then it will eventually break free and run up a good bit in RPM.

do you think having the fuel screw turned out too far will do this? but it didn't do this for the first 400 miles after i turned my smoke screen back out

EDIT: altho i got 46.7 MPG's last go round, my fuel gauge was reading waay high.. like i had barely used a quarter of a tank, but been 223 miles.. normally i break the 3/4 mark at 165ish miles.. and i heard a bearin squall like hell the other day after i fired it up. alternator?

but it does it a lot worse when it's cold.. it actually becomes a buckin then
(http://img585.imageshack.us/img585/7227/fueli.png)

bearing could be the alternator, or more likely, the timing belt tensioner..
Title: Re: unstable RPM's
Post by: wdkingery on August 30, 2011, 02:00:05 pm
it appears my timin had slid retarded a tad
Title: Re: unstable RPM's
Post by: ORCoaster on August 30, 2011, 09:08:13 pm
And you paid the price of 45.3 mpg for it.  How did that happen?  Or was it the rebuild and reinstall that caught you?
Title: Re: unstable RPM's
Post by: wdkingery on August 31, 2011, 06:37:10 am
You know I don't know what happened! I don't think it was the reinstall. I don't know what it was.. Just don't know. Have to wait another 300 miles to see if it's better :(
Title: Re: unstable RPM's
Post by: wdkingery on August 31, 2011, 04:34:35 pm
yeah it must have been where things weren't right under the hood, cause me and wifey went to the beach today.. tooled around for a little while then drove home, 280 miles.. got'er done in 5.22 gallons; 52.4 mpg! so i think i got it back right. and that was on straight diesel; wish i had added some wax/2 stroke to it.. coulda got like 54

and we had some traffic waitin to go thru the tunnel; 20 minutes of stop and go.. I HATE STOP AND GO. makes me nervous cause my car gets right hot before the fan kicks in, and that only helps but so much.

idle still aint' right tho
Title: Re: unstable RPM's
Post by: ORCoaster on August 31, 2011, 07:32:55 pm
My idle is messing with me too.  I tried to set it different with a tweak, and I mean 1/16th of a turn of the fuel screw and I lost my extra power needed for the extended hills that seem to rob my car of momentum.  Once it got down to 63 I had no more pedal and was force to do a lot of dropping to 4th.  So my mileage suffered for it.  52?  now I am really going to have to think on the increase the mileage game.  You are again ahead of me.  Maybe the new paint I plan for this weekend will give me the coefficient of friction I need.  The body kit may as well.   8)
Title: Re: unstable RPM's
Post by: R.O.R-2.0 on August 31, 2011, 10:03:10 pm
i doubt the body kit will even affect the mileage, or if it does, be very minimal..

its not like you are making it any easier for the engine to get air in, or out of it, and thats where the efficiency comes from..

getting rid of that horrid toilet bowl, and getting a better intake setup.. that 1.25" snorkel is pretty much a joke air intake..

i have a mk1 header that i had on my diesel, helped mileage a bit.. i have no use for it.. pm me if you have any interest in it..

(its the header, and flex joint, just take your stock stuff off, and weld this stuff on.. i may even be persuaded to install it for you if you come to me)
Title: Re: unstable RPM's
Post by: wdkingery on September 01, 2011, 05:07:09 am
Well you gotta remember I'm 3% high too, so you are probably actually higher

Plus I never ever downshift, so you must have some hills I dont
Title: Re: unstable RPM's
Post by: ORCoaster on September 01, 2011, 11:35:21 am
ROR says:  I doubt the body kit will even affect the mileage, or if it does, be very minimal..

its not like you are making it any easier for the engine to get air in, or out of it, and thats where the efficiency comes from..

getting rid of that horrid toilet bowl, and getting a better intake setup.. that 1.25" snorkel is pretty much a joke air intake..

i have a mk1 header that i had on my diesel, helped mileage a bit.. i have no use for it.. pm me if you have any interest in it..

(its the header, and flex joint, just take your stock stuff off, and weld this stuff on.. i may even be persuaded to install it for you if you come to me

Coaster says:  The body kit does make a bit of a difference, I bet it changes the aerodynamics by about 15% so it is less of a box to push through the wind.  I can feel it. And if it slices better then the engine isn't working as hard so in effect it will demand less energy to do the same work.   Yes?

I am all about the header.  If we swing the deal for the 84 shell I can get it from you then.  Othewise later.  Was thinking on getting rid of the tiny pipe all the way back with a better muffler thrown in.  I have modded the intake to a 3 inch opening. 

Kingery, 3% of 52 is ?  1.5  Still over me by a bit.  My Fuelly is reflecting the long term not the recent tanks but I am not near the 50 mark as I was.  Long trip coming will update as I go along. 
Title: Re: unstable RPM's
Post by: wdkingery on September 01, 2011, 12:12:32 pm
where's this "body kit" comin from i might be interested in stealin this idea too.

speakin of which, how's yer water bubbler workin out for ya i forgot you had that goin
Title: Re: unstable RPM's
Post by: ORCoaster on September 01, 2011, 10:09:18 pm
Do a google search for Zender body kits or BBS body kit.  Then cruise Craigslist.  I found a deal a couple weekends ago.  So good I bought it and was going to take it to ROR if it would work for him.  Turned out it wouldn't so it is on my car now. 

http://s1087.photobucket.com/albums/j475/Orcoaster/    This is the current look but I will improve on that with two colors of paint and a ton of clearcoat. 

The bubbler is catching a ton of oil in the blowby.  That keeps the blue smoke down but I really can't see a great deal of extra miles to each tank.  I haven't gotten to make that really fine holed tube that would add more moisture to the air going to the intake.  I had to put on a check valve on it after I fixed my vac pump and brake booster.  The store vacuum was pulling the water out of the tank up the hose to the intake. Saw that and thought oh no there goes the engine with water on top the pistons.  Lucky for me i caught it the first time it happened.