Need 302 Help ASAP!!

[RedLariat85]

Well, today i put a new cap and rotor in it...cut the cat off, and it still runs like crap!! Could something be wrong with the fuel system?

 

[LEB Ben]

Did you check your timing yet?

 

[RedLariat85]

Did you check your timing yet?

Nope, not yet.

May i also add that after i got it back home and shut it off.. it was taking in coolant like crazy! Like it was overheating...but the gauge didn't say so...

 

[LEB Ben]

What do you mean taking in coolant?????? Like you had to add it, or like it was pouring into the blocK?

 

[1985 Ford F-150]

Gauge might not read right.

 

[airwaybill]

Nope, not yet.

May i also add that after i got it back home and shut it off.. it was taking in coolant like crazy! Like it was overheating...but the gauge didn't say so...

Oh boy, that's not good. That would've been good info to have.

Is any coolant leaking on the ground or just disappearing? And, do you have white to grey smoke?

 

[RedLariat85]

What do you mean taking in coolant?????? Like you had to add it, or like it was pouring into the blocK?

Well, it sounded like it was gargling. Like maybe it was boiling or something??

Gauge might not read right.

Maybe not...but this was the first time it happened.

Oh boy, that's not good. That would've been good info to have.

Is any coolant leaking on the ground or just disappearing? And, do you have white to grey smoke?

No, it isn't disappearing or leaking..nope Step-Dad said it was blowing black smoke.

 

[1985 Ford F-150]

Hows the level of the coolant?

 

[airwaybill]

Black is unburned fuel and carbon. Maybe water in the intake? But you are not losing coolant right?

 

[F 150Cobra]

No, it isn't disappearing or leaking..nope Step-Dad said it was blowing black smoke.

check your timing black smoke is sign when the timing jumped a tooth..

or a bad fuel pressure regulator... ( too much fuel )

start by check your timing dude

 

[conanski]

Step-Dad said it was blowing black smoke.

Check fuel presure and pull vacuum line off FPR to check for presence of gasoline. If there is the FPR is toast repalce it. Fuel pressure should be about 35psi at idle and 40psi wit vacuum removed from FPR.

I this a dual tank truck?

 

[LEB Ben]

check your timing black smoke is sign when the timing jumped a tooth..

start by check your timing dude

Damn...I'm pretty sure we both said that back on the first page.


Go to the chain parts store of your choice, ask if they have a timing light in their rent a tool program (some places don't)...check your timing right there in the parking lot...then more than likely buy the chain that you need, buy 3 gallons of antifreeze (unless you can catch your old stuff and it's still good), now is also a good time to replace your water pump too...and then I'm thinking you'll be good.


Disclaimer: If you hook up the timing light and it checks out good...void the rest of my post.

 

[airwaybill]

I agree. Gotta be timing. Check that out before doing anything else.

 

[airwaybill]

Check fuel presure and pull vacuum line off FPR to check for presence of gasoline. If there is the FPR is toast repalce it. Fuel pressure should be about 35psi at idle and 40psi wit vacuum removed from FPR.

I this a dual tank truck?

Fuel pressure should not make it run like crap and blow black smoke. Just make it run sluggish, I would think.

I could be wrong.....

 

[conanski]

Fuel pressure should not make it run like crap and blow black smoke.

What.. you never seen a carbed car running with oversized jets? Yes high fuel pressure will make it blow black smoke, all that extra fuel gotta go somewhere.

 

[airwaybill]

What.. you never seen a carbed car running with oversized jets? Yes high fuel pressure will make it blow black smoke, all that extra fuel gotta go somewhere.

Yes but if you look at his sig, his 302 is efi. I agree excess fuel will make a carb car run like crap and blow black smoke but I don't think it would with efi. Cause the amount of fuel is controlled by injectors.

 

[Old_Paint]

Yes but if you look at his sig, his 302 is efi. I agree excess fuel will make a carb car run like crap and blow black smoke but I don't think it would with efi. Cause the amount of fuel is controlled by injectors.

What you're not getting here, though, is that even if the FPR IS regulating pressure, it may have a hole in the diaphragm which is controlled by engine vacuum. Any guesses where that vacuum is picked up? Right there on the "tree" on the plenum. That said, with a hole in the diaphragm, he could be dumping raw fuel right into the upper intake, going AROUND the fuel injectors that would otherwise meter it in down near the heads.

Easy check for this, but make sure to do it on a cold engine. Hot engine plus leaking gasoline = melted face. Pull the vacuum line off the FPR, and see if the nipple on the FPR is wet or smells like fuel. There should be NO fuel there, not even the slightest hint. If there is, the diaphragm's shot, and you need a fuel pressure regulator. And yes, it will smoke like a locomotive if this happens, and mileage will be HORRIBLE. I burned half a tank of fuel (9 gallons) in a 60 mile drive because of a failed FPR. If none is found at first check, cycle the key to the ON position a few times (but don't start the engine) to let the fuel pump charge the rail. 2 or 3 times should be sufficient for fuel to start leaking out of that nipple, obviously depending on the severity of the rupture in the diaphragm.

As for the back-firing under load, that ain't always timing. Sometimes, it's lean miss/backfire. I had pretty much the same symptoms you're describing, and not only did I have a failing/ailing FPR, I also had a leaking plenum gasket, which actually sucked the rungs out between numbers 6, 7, and 8 runners. This makes for some ugly problems with intake on those cylinders. Think about it a minute, and it's evident that the ONLY way to change the timing on these engines (other than normal control by the ECM and TFI) is for the distributor to rotate (loose clamp bolt), the cap to come loose (umm, it has TWO screws holding it down), or for the rotor to spin on the dizzy shaft. (What did it hit inside the cap?) One other possibility is for the chain to jump a tooth, but if it's idling OK, that's not a likelihood.

It's about a 2 hour job to replace the gasket under the plenum, even if you've never done it before. If you elect to replace the O-rings on the injectors too, add another couple hours to clean the injectors up. Cost of the parts is less than $20 for the plenum gasket and the O's.

I did a write-up on this some time back, and posted pics, but dunno if it's still here. I may have even posted it on "that other site". I fought with driveability issues for a long time, and four dealerships couldn't figure it out. I hooked a vacuum gauge to the Cannister Purge vacuum connection near the throttle body, lo and behold, there's my problem. At idle, you should be pulling something near 20 inches of vacuum. Your favorite vacuum gauge will be calibrated in inches Hg (mercury). You can probably get away with 17 or higher, but don't accept anything lower than 17. If you see less than 17, to determine if it's really the gasket, unhook EVERYTHING except the MAP sensor and the FPR on the vacuum tree, and cap off all the nipples. Obviously, you'll still want your vacuum gauge on it. Try again. If the vacuum is OK then, well, you have split lines somewhere on the EGR/TAB/TAD, Cruise, HVAC, or brake booster vacuum supplies.. Hook 'em back up one at a time til you find the culprit. If no increase in vacuum at this point, though, next step, eliminate a stuck EGR. Loosen the EGR, and put a STEEL plate (made from a tin can or something thin) between it and the plenum, then tighten it back up. Assuming everything is still disconnected, try again. A stuck EGR SHOULD be throwing codes and a CEL though. If still bad, check the MAP and FPR lines to make sure they're not split. If neither is, you're looking at a shot upper intake (plenum) gasket. To verify, if you REALLY don't want to pull that plenum off, use an unlit propane torch to "scan" the intake. Start the engine and let it idle until it's warm (normal operating temperature). Direct the gas all along the bottom of the upper intake, left and right sides. If it's leaking there, you'll hear the engine idle up and smooth out even more.

I strongly urge using propane for this, because A.) it does not puddle; B.) it quickly disperses enough so that there won't be a flash fire; and C.) you're going to be working around a hot running engine. All of the above conditions spell disaster because of the fire risk of using liquid solvents that flash to vapor, but may still have a puddle somewhere. One leaky spark plug wire, and you've got a classic engine bay fire. If you think the truck runs bad now ....... Even if you do manage to ignite the propane, it's a quick blue flash, maybe singed eyebrows, maybe the torch lights, and you know what to do next. (pull the torch back). If you ignite a bunch of liquid throttle body cleaner or starter fluid, your next step is to call the fire department. You're going to need them. Perhaps an ambulance too.

The real problem, which is EXACTLY what stumped the dealership, is that the EEC will not flag vacuum leaks. It merely adjusts for them, which is why it doesn't capture high O2 sensor feedback. At idle, it will sense the high RPM, and close off the IAC trying to slow the engine. Then, it will start leaning the fuel mix as well as retarding the timing. Watch your timing with a light. If it's bouncing all over the place, that would be a classic sign of vacuum leaks, which can lead to pulsing on the MAP sensor. That generally causes oscillating idle, though. Depending on the location of the leak, it may only cause a fast idle. However, it can also cause hesitation, rough idle, back-firing, poor performance, and extreme power loss. Everyone targets the ignition electronics first, or something major internal when they experience backfiring. Timing has to be WAY off for it to cause backfiring. Check the simple cheap stuff first. Sometimes, the IAC will stick open, but that normally just manifests itself with high idle. Normal operation of the IAC is that it opens 100% under open throttle anyway, remains open until engine RPM decreases significantly enough to prevent sucking the whole truck in through the air box. One failure of the IAC to stay open on deceleration (engine braking) could cause the intake/plenum gaskets to give way.

If you do pull the upper plenum, that's a great time to clean the throttle body inside and out, replace those gaskets, pull and clean the injectors and install new o-rings, replace the TPS, and replace the FPR while you're at it. The FPR is a lot easier to get to with that plenum off, not to mention the plenum's gotta come off to get to the 1234 injectors anyway. Buy a handy-dandy vacuum pump to check the MAP, operate the EGR, and test all the vacuum circuits individually. A vacuum pump and vacuum gauge are your friends for finding the cause of backfire.

If you have time to let it sit overnight, drop the entire throttle body in a bucket of Seafoam and let it soak. That will make removing the crud a lot easier. Same goes for the injectors. The Seafoam will swell the old o-rings and make them easier to get off the injectors without scratching them. Total job cost me less than $100, including new FPR, new ACT, new ECT, new plenum gasket, new o-rings, new throttle body gasket, and new TPS (because it's easy to get to with the throttle body removed. You can actually get the entire upper gasket set in a kit from Felbro. The number escapes me at the moment, though.

My truck ran had new life after I fixed the vacuum leak. I never touched the dizzy during this process. However, I too, had already been through new plugs, wires, cap, rotor, timing, TFI, PANIC!!!!. A simple vacuum gauge showed me my problem.

 

[RedLariat85]

The truck will start up fine when cold, rev up when not in gear...once it goes into gear, no power.... and once it stalls, you have to put the pedal to the floor for it to start.

Still a fuel problem?

 

[F 150Cobra]

The truck will start up fine when cold, rev up when not in gear...once it goes into gear, no power.... and once it stalls, you have to put the pedal to the floor for it to start.

Still a fuel problem?

did you chek the timing?

 

[mtflat]

Have you checked out the stuff Oldpaint suggested?

Simple test for fuel press reg - pull the wire off the coil so you don't get spark to the plugs. Remove #8 plug and watch while someone cranks the engine over. If the diaphragm is bad and leaking, it dumps all the fuel into the #8 cylinder and fuel will shoot out the spark plug hole - big time. Symptoms are the engine starts but the cylinder loads up to near hydraulic lock condition. FPR going bad can happen in a short period of time.

It might be timing, but it usually goes south a little at a time when the chain stretches and timing will become erratic.

Cleaning the throttle body does wonders for poor performance on these early EFI experiments. This can show up fairly quickly. I've put 335K and 20 years on my 86 and have had to clean it several times.

Also don't discount the possibility of the ignition control module (TFI) being bad - even out of the box. Mine has done some really strange things that the service guys at Ford say isn't possible. Whatever.