302 efi Stumbles when cruising,

[Krafty]

Howdy folks, Krafty has internet again.

Any who to the point. 89 302 efi 4x4 with auto tranny, when slowly accelerating you can tell its kinda holding back sometimes, cruising at (conversion works out to) say 50 to 60 mph the truck physically stumbles and hesitates, sometimes more than others, but if I give it more gas or just floor it it goes back to 100% smoothness and power.

just noticed it starting after changing air filter, ( not likley connected) anyways i'll go through all the motions and check my fluids and do a visual inspection of my fuel and ignition systems, but has anyone run into this before and what was your fix?

 

[AdamDude04]

Mine does the same thing. Done it for a couple years now.. some days it's smooth and perfect..others it's annoying. I thought it was just a loose rear end..I notice it esp when the RPMs are under 1300 and cursing..

 

[Krafty]

I don't have a tach soI don't know where is does it, but its irritating. i've been sick the lst couple of days so I havn't checked into it yet, this weekend perhaps I will have a good look see

 

[miesk5]

yo Krafty! WB!

I'd do a Self Test for Diagnostic Trouble Codes (DTCs)anyway, such as this by our good friend, BroncoJoe http://broncozone.com/topic/14269-code-reader/page__p__74587entry74587

I run it around to heat the engine up and shift thru all gears incl Reverse.

then; turn off all accesories/lights, etc.

Do KOEO portion first

For Key On Engine Running (KOER) portion, the engine has to be @ normal operating temp.

Post any codes found here or look em up in my broncolinks.com site.

Check Timing;

Adjustment in Ford EFI Engines

Source: by Ryan M (Fireguy50) at http://fordfuelinjection.com/index.php?p=71

Scroll down to; HOW TO CHECK AND SET TIMING

your SPOUT connector is @ Distr; such as here;

Spark Output (SPOUT) Connector Location pic @ distributor in an 88

Source: by Jem270 at http://www.supermotors.net/registry/media/249442



Of course there are more that could be tested; do that stuff first

GL!

 

[AdamDude04]

I would like to know the cause too..

I also forgot to add that mine does the same then when accelerating in 3rd/4th gear. Pulls hard in 1st and 2nd, and as I let off the gas it bumps down into 3rd or 4th (pending speed) it'll struggle until the RPMs are up to around 1400rpm

I thought about it being a timing issue..do these timing belts/chains strech?

 

[miesk5]

Adam;

Noise from inside the timing chain cover is a good indication that there is too much slack in the chain. Another way to spot excessive play in the timing chain is to remove the distributor cap and turn the crankshaft in one direction until the rotor moves, then turn it in the opposite direction until the rotor starts to turn the other way. If the crank has to be turned more than about half an inch to move the rotor, chances are the timing gears and chain need to be replaced. Still iffy on exact measurement so;

If the chain is making a rattling sound along with ticks or slaps, you should buy a cheap stethoscope ( I use a short length of garden hose; BEWARE OF FAN & SERPENTINE BELT!)to aid the listening process. Listen also for the sound to rise and fall with the engine RPMs.

If the rattling ticking slapping sound is coming from the very front of your engine (or the side that has the belts on it) and gets louder or faster when you rev the engine, chances are you have a loose timing chain.

You will hear the chain if it is slapping.

I think you could also put a timing light on the engine to check for a very sloppy chain. The timing mark should "wander" all over the place under the light

 

[miesk5]

Adam,

One more; have you ever tried the Self Test for Codes?

I believe you asked similar Qs here recently; but I have not seen you answer whether you have run the Test as well as checked timing.