Gremlins under the hood playing with the throttle linkage

[tom37]

My trusty oll truck is acting up when I coast to maintain speed on the highway or when I let the motor slow me down.

This in on my 87 6.9 4 speed

This seems to happen when the revs are over 2000, when I let off the skinny to keep from gaining speed. It feels like there is someone under the hood moving the throttle from idle to WOT over and over again.

If I gently ease back into the pedal the problem goes away but I gain speed.

For instance, while on the highway today. Approaching a on ramp, some nice fellow pulls right into my lane. Running 65 mph the revs were up around 2750 ish. I come off the gas and hit the brakes. About as fast as I start to slow down, it feels like someone is slapping the throttle. The only way to make it stop is to either get back into the gas or hit the clutch and take it out of gear.

I can let the motor slow me down all I want if the revs are under 2000.

My mind wants to think this is in the IP. But I hope not.
I am limping along on the last leg of my clutch right now and really hoping not to have to buy an IP as well.

Second thought is,
Could this be a DMF problem?

Thank You Gents.

 

[hairyboxnoogle]

Mine was doing something similar to this. ATF + diesel clean helped alot, but it came back. Swapped IP out and never had the problem since. Hard to say if we have the same problem or not, but might see if its a cheap solution to clean it up rather than resign and buy a new pump.

 

[tom37]

Thank You. and I will try that and see what happens. Not sure if this has come on slow or if its that I am paying closer attention now. Or maybe its that I had no trailer today and wasn't on the pedal hard the whole time.

Part of me what hoping that someone would say that it was a symptom of the DMF getting ready to fail. That way I would maybe kill two birds with one stone. Its bad enough the wife's gonna say (OMG not more money for that thing.) when I get the clutch parts.

 

[Agnem]

How many miles are on your IP? Hate to say it, but it sounds like your timing advance is worn way out of spec.

 

[tom37]

Mel, the clock shows 53,000 but I really don't have a clue. A lot of things have me thinking that the motor is sitting at 153,000. But who knows.

I was planning on getting it running to pull my trailer and as I saved my pennys, then i could baby moose it along with a set of injectors. Then decide if I wanted to put a cam in it.

With the clutch on the fritz, I guess I can see what a rebuild on the IP will cost me if done here local. Money is gonna be kinda scarce until the end of summer billings come in, around early December.

Slightly off topic here.
Did the 87's have the DMF from the factory?

 

[OLDBULL8]

If you need an IP. Instead of rebuilding locally, get this one. Should be just fine even tho it's listed for 88-90. No core needed, then you would have a core to send to Mel for a Moose rebuild when you get ready to do that.

http://cgi.ebay.com/ebaymotors/ws/e...0607815723&viewitem=&sspagename=STRK:MEWAX:IT

 

[anthonyj]

As far as l know the 4 speeds did not come with a DMF.

 

[tom37]

Glad to hear that.
Anthonyj, have you ever experienced where the clutch trys to grab with the pedal just a few inchs off the floor. Then feels like the pressure plate releases again and does not grab until the top few inchs of pedal travel.

My trailer is 9K, and before I started putting it in low range to back in, I would have it slip a little, my doings of course. But man, I never heard a clutch howl quite like this one does.

 

[icanfixall]

Thats a great deal on a pump for $270.00. No shipping, handleing nor core charge... Just pay and play.... Free is about the only better price across the US at this time... Buy two and have a spare or a core to send to Mel for a Moose upgrade....

 

[tom37]

Thanks for the input, at this given time I can't buy much anything I did get a IP off an 89, so I will pop it on and see if it happens to be in any better shape. If not, I will have an extra core, and it was free.

This is the point where my questions start again.

If my life depended on adjusting a carb on a small engine, I think I'd be dead. Straight up.

And I think my timing by ear skills are about as good.

Still with the old IP, I bumped the timing. Top of pump to the pass side. The light blue exhaust at idle went away but it almost felt like I lost power.
Tonight I bumped it again, 1 1/2 dimes now.
When I crack the throttle, the rpm's dont snap back down right away. Kinda delayed on return to idle.

Is this to much?

For now I dropped it back to the original setting and now the light blue is back most of the time its at idle.

I know my pump is junk and on the way out, but I am trying to get a better idea of getting the timing close.

BTW the gremlins aren't as bad but still there with the timing back at original setting.