Help with chugging/lagging

[JackStraw1]

Hi folks,

 

I was doing some cleaning/degreasing in the engine bay of my '94 SE today. Little bit a brushing. Little rinse with water - nothing too heavy duty and all done with the motor running.

Much later...................................................

 

When I went to go get gas - truck fires up no problem. Idle seems OK. When I put 'er in Drive - engine immediately lugs and chugs. Sounds like it's running on 5 cylinders.

 

So I'm thinkin' "you dumba$$, you prolly knocked off a vacuum hose or got some water where you shouldn't. Initial inspection of the hoses looks OK. I pulled apart several connectors - dry as a bone. Distributor - dry as a bone.

 

I wait. Eat more turkey. Watch some really bad football. Go out to garage.

 

Again, truck starts right up(starter relay mod works beautifully) So, I think that rules out electrical/water problems. Still drives like dogs**t as soon as its put under load (in gear).

 

I gotta drive this truck 1000 miles tomorrow.

 

I'm still thinkin' vacuum lines - so I may replace them tomorrow, but I would really like to know what others think. (Other than the obvious "ur a dumba$$")

 

Really, really appreciate any help.

 

Oh yeah, Happy Thanksgiving all.

[Kingman]

Probably got some water in the plug boots at the spark plugs and cap, and maybe a little inside that too.

[Precise1]

Check for vacuum leaks with a flammable aerosol. Spray briefly at suspected areas and if the idle increases, you have found something. Visually inspecting lines I find to be hit and miss.

 

As for the other, try WD-40 to make sure the electrical components are really dry and check your connectors for the MAF and TPS. Does the ECU show any fault codes?

 

B

[nige]

I agree with kingman. My engine always does that after you give it a good wash. It usually takes about 15-20 mins of running to dry it out., but you might need to spray some compressed air adn then wd-40 near the ignition stuff to completely dry it out. I tried dielectric grease on my boots and wire connections afterwards and it works better than nothing at all.

[JackStraw1]

Spot on Kingman and Nige. Thanks guys.

 

It was water in the plug-wire boot on # 5 cylinder. I woulda thought that this would give it trouble starting but like I said it fired right up every time.

 

So I pulled all the boots and blew 'em dry and then yanked the plugs and they looked like crap too. So gots me some new plugs. The plug-wire also had a little rust inside so I guess this has happened before and the water sat for awhile. Put it back together and test drove just fine. It even seems to have cured the upshift delay that I was getting where the AT seemed to want to hang on to its lower gear and not upshift without me backing off the pedal a smidge. But i need to drive it some more before giving it a complete pass.

 

I try to clean it when its hot and running to evaporate any water but I guess that didn't work so well.

 

Thanks for the tips Precise1. I understand the flammable aerosol for vacuum lines principle (I'm thinking carb cleaner would work well) but I'm not really following on the WD-40 for electrical connectors although I do remember hearing something about that before too. What do you do and how does it work?

 

BTW, I checked the MAF and TB connectors too - both dry. I also took the opportunity to pull the MAF sensor and clean the electrodes as posted elsewhere by 88pathoffroad I believe.

 

Maybe I should replace the plug wires too?

[nige]

that would be a good idea. Water causes them to arc on the manifold instead of sending the current to the plug. get some dielectric grease and fill the bottoms of the boots. That should keep extra water out of there and give a good, clean path for the current to follow

 

glad you figured it out

[Precise1]

Spot on Kingman and Nige. Thanks guys.

 

It was water in the plug-wire boot on # 5 cylinder. I woulda thought that this would give it trouble starting but like I said it fired right up every time.

 

Thanks for the tips Precise1. I understand the flammable aerosol for vacuum lines principle (I'm thinking carb cleaner would work well) but I'm not really following on the WD-40 for electrical connectors although I do remember hearing something about that before too. What do you do and how does it work?

 

BTW, I checked the MAF and TB connectors too - both dry. I also took the opportunity to pull the MAF sensor and clean the electrodes as posted elsewhere by 88pathoffroad I believe.

 

Maybe I should replace the plug wires too?

Cool, glad you figured it out fairly easily...

 

WD-40 for the electrical components as Water Displacement attempt #40 works really well!! It's an old dune buggy trick, when the engine splutters in the rain, pop off the dizzy cap (they are horribly exposed), give it a shot of WD-40, snap it back on and drive away. It does work for finding vacuum leaks also, but anything flammable will do that.

 

Good that you cleaned the MAF too. Plug wires can help too if they are really old, I like using STI wires, they are quite well made and not terribly expensive.

http://www.karlynsti.com/

 

B