4.0 OHV upper and lower intakes not matching?

[SVO42]

After doing a lot of thread searching about spark knock and pinging (I problem I've had for a while), I saw a common problem was a loose intake. I was nosing around under the hood today, and saw two small gaps. They were on the passenger side of the motor, as if the upper intake had been shifted to the driver's side. I couldn't FEEL any vacuum there, and testing with paper or ribbon wasn't doable since it was windy here. Before I could even start investigating further, it started pouring rain.

The gaps were the ports in the lower intake, I'm sure. Could someone have improperly installed the gasket between the upper and lower, or could the upper just be loose, or what? Hopefully it won't be raining tomorrow and I can figure it out.

Any insight would be appreciated.

 

[Doubt Incarnate]

i dont understand, everything is bolted up and the ports are visable? if so the pingign you hear is probly from a lean condition, and you should have an ses light. i dont know how you would fix this unless you'r good with jb weld, or just replace it all with stuff you know matches. did you get this truck from someone you know or you know modded it? i wonder if the upper intake on your truck is from a different year.

 

[Creager]

Those 'gaps' you are looking at i believe are apart of the fuel rail, no worries, its sealed under there. It just 'looks' like holes.

If your 94 is pinging, you probably want to take the upper and lower intake off, and get a load of the HUGE amounts of carbon you got built up in there. I pulled mine of the other day, and litteraly a millimeter thick layer of carbon was caked on all the way down into the cylinder. I could flake enough off to bake myself a sheet of brownies. Cleaning that alone would make your engine run better 10 fold.

 

[Rhett]

I pulled mine of the other day, and litteraly a millimeter thick layer of carbon was caked on all the way down into the cylinder. I could flake enough off to bake myself a sheet of brownies.

Say what did you use to clean it? rotary-type/dremel grinder? I think I have asked this somewhere else before but I can't remember, senility setting in

 

[Creager]

Actually, for the most part it just flaked off... but underneith that i probably would of needed some kind of dentist tools or something to scrape the residue off...

actually, i remember i was messing around with my old heads and i was able to 'rub' off the residue layer for the most part, it was kinda slimey like pipe resin.

Salt & Rubbing alcohol? Pot-smokers pipe cleaner? I got some old 420 juice, i might give that a try... haha

you can always try hot-bathing?

i dunno, if i remember ill try and clean out my upper-intake tonight and ill tell ya if i accomplish anything, and how.

 

[Rhett]

I remember what it was now. A guy posted and said he used Sea Foam and a toothbrush, and that this worked great. Said the Seafoam was like "paint thinner to paint" in going thru varnish. I'll tell you what, Seafoam by itself doesn't cut thru the varnish on _my_ truck's upper intake manifold. At least not like "paint thinner through paint". That would be nice if it did! My varnish is some tough stuff.

 

[SVO42]

It was just the fuel rail. I nice nice to have time to look and not get rained on. Of course, we got tornadoes later in the afternoon. The upper intake manifold bolts were tight.

I bought it used from a dealer, so full history is unknown.

Now I still need to figure out my pinging problem. It's only when on the highway under load, esp. uphill. I'm going to replace the plug wires and plugs (plain copper, one heat range colder than stock), and the O2 sensors, since they're probably the originals, AFAIK. I've already done Seafoam through the intake.

 

[94explorer2x4]

run 91 octane or get a preformance chip here is the write up that states it stops pinging

 

[Creager]

Yeah i used to run 89 octane if i ever wanted get my truck to stop pinging... eventually it got around to pinging agian. At that point, if i ever ran 87 again the truck would detonate at all engine speeds, other then idle.

The chips for OBD-1 trucks are now highly unsupported... i would be surprised if you found a dealer still willing to burn OBD1 chips. im sure they are out there, although you would end up spending big $$$

Cleaning the upper and lower intake souldnt take but a saturday afternoon, and about $200 less. I would just take them off, run them up to a machine shop to get them hotbathed, and reinstall them with quality gaskets. Problem solved...

 

[SVO42]

I normally run 89 octane--here I can get it some places for the same price as 87 (the 89 is 10% ethanol). But, if I'm going on the highway I'll fill it with premium. I'm not sure if it's pinged on 91, but I can get 93 at some places, so that's what I'll use if it's going to be a loaded down highway trip. I figure if I need even MORE octane, I'll dump a few gallons of E-85 in the tank (105 octane, baby! And $0.20 cheaper than 87). There have been a few times where I had to take a highway trip and didn't want to buy more gas, so I'll pull the octane shorting bar (heard it retards timing about 3* which I'd believe--the power goes down and the ping goes away), but then the truck is even more gutless than it already is.

I'd rather make sure everything is in order on the truck before I start worrying about chips & tuning. If I was going to shell out the cash for something like that, I'd just ditch the EEC-IV altogether and get a Megasquirt kit and tune it myself.

I probably will try cleaning the intake eventually, but that will be further down the list. Plus my weekends are pretty booked up. So, I'll just be buying premium for a while.

 

[94explorer2x4]

Yeah the first thing I tried was to pull the jumper and the truck was totally a guttles wonder I went a few blocks and pulled over and put it back in. I would be careful with the ethenol, running too much could cause it to ping that stuff burns hot hot hot and I think it can cause the rubber seals and "O" rings to swell/shrink/and crack thats including intake gaskets that will leak and cause it to ping also as well as a load of other problems.
I ran a full tank of 100 octane VP gas (I hade a bunch left over from my dirt bike now the bike is gone) and it nearly stopped the pinging even when I started running 89 again.

 

[Creager]

SeaFoam definatly helps

cleaning the MAF is the next best thing

 

[Rhett]

Running premium gas on a stock-computer'ed engine is just masking the problem. It will do nothing to fix the problem. Over time it will dirty up the intake even more as the stock PCM is not set up to burn premium fuel.

The solution to the problem is to stop air leakage in the manifold, and to use Sea Foam or its equivalent on occasion as a part of routine maintenance.

 

[SVO42]

Actually, ethanol burns cooler than gasoline, hence its higher octane rating. The owner's manual states that ethanol concentrations of up to 10% are perfectly fine. I have heard of others experimenting with higher concentrations (on EFI vehicles NOT designed as flex-fuel vehicles) of up to 30% with no problems. More ethanol is required for a given amount of air for combustion, so you have to keep in mind how much the stock computer can compensate. The 4.0 OHV's 19 lb/hr injectors seem to be adequate for some ethanol according to the quickie calculations I've done.

I know it's best to find the solution to the pinging problem, and I will eventually. Normally I just run 89 around town and premium only for highway trips. I have already done one can of Seafoam through the intake, checked the MAS (filament's clean), checked the air filter (fine), and done a voodoo dance. New plugs, wires, and O2 sensors are next.

 

[Creager]

Where do i get ethonal? I am about to up my compression to 10:1, 93 octane is going to be a must... and at times i might want to run over 93, if ethanol ups the octane rating for cheap, ill definatly give it a try.

But cleaning out the carbon build-up is probably going to be the best bet for fixing the pinging. The upper and lower intakes come off with like 10 nuts. Gaskets are like $20, and it wont take you longer then a couple hours get it all clean. warm-soapy water is your best bet.

 

[Doubt Incarnate]

im not familiar with the ohv 4.0, but if it has a distributor you should check the timing with a light/gun and make sure its right first off, the only reason i say that is my brother had a 3.0 sable and we couldnt figure out why it stumbled and would overheat till we noticed the distributor wobbling around, it wasn't tight and the timing was doing whatever it wanted.

 

[SVO42]

Your buildup has been giving me ideas, Creager! Here's a map for you : http://www.e85fuel.com/database/search.php