93 explorer idles rough and surges help please

[bruce119]

I have just bought another 93 explorer almost identical to the one I have now both are 93 white explorer just different color interior.

My old truck ran fine just starting to get a fuel pump issue would run for a wile then die start rite up and do it again. But it ran and idled just fine.

The new truck runs good cruses just fine smooth good acceleration no missing has better power than my old one. BUT does not idle very good surges, and rough low rpm idling. I know a little very old old school I read up a bit. I changed out the MAF mine just had a new one put in a year ago no change. I changed out the IAC and actually it ran a little worse but then got better as I drove it and now is the same. From the little read I understand when you change something like this the computer needs to relearn and resets or adjust something. I don't know about that that stuff. But anyway the IAC didn't change anything.

Anymore suggestions I do have another truck rite next to it to swap parts. It's a real good truck just doesn't have a reliable idle.

Ideas ???

Thanks Guys & Gals

 

[safn1949]

Clean the throttle body,pull the hose off and spray it down.Crud will build up on the plate just like the plates in a carburetor.Go online and find a BG dealer,buy a can of BG 44K and add it to a full tank of fuel,take it out and run it down the interstate for a while.It will be $25 for the can of 44K but it will really clean your injectors.That's where I would start,stop throwing parts at it.You already have spent over $200 for nothing.

 

[bruce119]

Clean the throttle body,pull the hose off and spray it down.Crud will build up on the plate just like the plates in a carburetor.Go online and find a BG dealer,buy a can of BG 44K and add it to a full tank of fuel,take it out and run it down the interstate for a while.It will be $25 for the can of 44K but it will really clean your injectors.That's where I would start,stop throwing parts at it.You already have spent over $200 for nothing.

Thanks I will do that But is not costing me nothing for parts yet. I do own two 93 almost identical trucks. So I am just swapping parts yes it's $200.00 worth of parts but I can play this guessing game with the spare truck next to it.

Lucky me I have a distributer about 5 miles down the road. Just got off the phone with the and have a can for $13.75. I guess I just a a can of carb. cleaner to clean out the throttle body.

Keep suggestions coming like I said it is easy for me to swap parts.

thanks

 

[Maniak]

When its idling rough, see if the exhaust smells rich. If so (or even if it doesn't) throw a Fuel pressure gauge on there and see if your FPR died. Ours died right after a motor rebuild and the Fuel pressure was around 60psi which is way too high. It ran great but it would almost "lope" at idle but not consistently.

~Mark

 

[safn1949]

I would assume his fuel mileage would go out the window but that's a good check also.I don't mean to pick on you,it's just that we see guys just start replacing parts with no rhyme or reason costing them $$$$.

A spare truck is a smart way to go,that 44K twice a year is just good maintenance even if it doesn't fix this problem.

 

[Maniak]

With the fuel pressure at 60 psi our mileage didn't drop as much as I would have expected. Freeway mileage dropped to about 13.. Normally its 15 (33's, locker and spare on roof don't help) but it was a new/tight motor so I wasn't sure. Also, I only drove it 150 more miles before I fixed it. Once I smelled the exhaust I knew what it was, I just used a FP tester to make sure before I put more money into it.

~Mark

 

[bruce119]

Thanks

I got the 44K.

Now to add to the symptoms. It does run real rich and black smoke on idle. But when the MAF is unplugged it runs much better. It stumbles a little when accelerating but runs good. Hook up the MAF and the problems really show with the bad idle and real rich and smoking. Unhook the MAF and it for the most part clears up just stumbles a little. Now I have put another MAF from my truck on it and it is just a year old. No change same thing.

Just thought I would add that bit of info. I only had this truck 2 days now. But previous owner said pretty much same thing a mechanic said MAF and they changed it and it did not fix the problem. So I am open to suggestions.

The FPR fuel pressure relay I heard this come up in another thread I searched mite try that. I will search around to find out were it is. And I will get a fuel pressure gage like I said I am very old school points, carburetor with a float, butterfly, choke and no computers. Any body remember those boy I am felling old.

Thanks

 

[Maniak]

I'm not talking about the fuel pressure relay. I'm talking about the fuel pressure regulator (FPR is Fuel pressure regulator)

When the regulators go bad they either let gas through the vacuum line which of course goes into the intake and makes it run bad OR they just let much higher fuel pressure run to the injectors which makes them leak and run rich.


~Mark

 

[bruce119]

Now I was just looking at my FPR on the new 93 truck and the vacuum line was very lose and felt like it had a lot of rot. Now I checked the same line on my old 93 truck and it felt solid normal. Maybe I found something I didn't get a chance to look farther but this does not look like a normal vacuum line. I didn't pull it off yet but it looks like a 1/8" cable that goes or couples into a regular size 1/4" or so rubber vacuum tube then hooks into the FPR. I am guessing is this a special vacuum line anything I should know is there a special reducer or something that couples to that small line. Or is it a whole assembly line.

any help
Thanks

 

[Maniak]

From the factory its a fancy plastic line molded with rubber ends.

Over time the plastic breaks and you can just replace it with normal vacuum line.

On the problem vehicle, pull off the vacuum line and see if there is gas in that line. If there is, get a new FPR and probably replace that vacuum line as gas does wonders to non fuel resistant hose.

~Mark

 

[safn1949]

From the factory its a fancy plastic line molded with rubber ends.

Over time the plastic breaks and you can just replace it with normal vacuum line.

On the problem vehicle, pull off the vacuum line and see if there is gas in that line. If there is, get a new FPR and probably replace that vacuum line as gas does wonders to non fuel resistant hose.

~Mark

What he said,that would be nice if it was such an easy fix.

 

[nitro71]

Does your check engine light come on? I'd start there. Take a look at the EGR on it also. I haven't monkeyed with a Explorer one yet but my GF's car had a bad one that made the idle and low end poor.

 

[maroon93limited]

How's the fuel filter?

 

[bruce119]

Thanks for some of the the tips.

A quick update now I only had this truck 3 days so I am still getting to know it. The good thing is I have another identical truck that runs good but had a bad body and bad suspension.So I can swap parts. I put the 44K in and sprayed the throttle body inside real good and made a 100 mile trip today. Now I have the MAF unplugged it runs much better no real problems just a little hesitation on initial acceleration. Now when I hook the MAF up it runs with a loss of power and bad idle. But unplug the MAF and it runs good. Now the MAS is good it is off the other truck and only one year old and the one off of this truck on my other trucks and it runs just fine.

I got a fuel pressure gage so I can get my own numbers and start some testing. I figure this mite take a wile. I should probably do a typical tune up. It is summer here and it is HOT not the time of year to be doing this. The fuel filter is new less than a year old. I mite swap out the FPR but I got the gage now so I can do some testing.

There is another problem I would like some advise. The Trany 2 things when I put it in reverse it goes rite into gear. When I put it in drive there is a delay of about a good 3-4 seconds (my other tuck went rite in) then it goes into gear no problem and drives and shifts fine. Except it does not go into overdrive I was hoping this is maybe something I mite be able to swap out from the other truck. Any ideas on the no overdrive.

There more issues but we'll deal with that latter and a new thread.

Thanks

 

[zero_psi]

wheres the fpr even at

 

[Maniak]

wheres the fpr even at

Fuel Pressure Regulator is on top of the motor (about valve cover height) on the passenger side of the plenum.

~Mark

 

[92exp4x4]

One of my trucks had a similar problem. It would shift right into drive but was slow to shift into reverse. I swaped in a manual trans so I never figured out what exactly was wrong with it.

The 3-4 shifting and Torque converter lock up are controlled by the engine computer (PCM). There are solenoids inside the transmission that make this process work. You could swap them from truck to truck, but its kind of involved. Make sure you are getting the proper signals to the trans harness before tearing into the tranny.

It could probably use a fluid and filter change anyway. I would change out the pressure regulator and the fuel filter. Even if it is only a year old, thats a years worth of time to trap crud from the tank- rusty sending unit lines ect.

My other passion is my 1922 Model T roadster. I understand your love for simplicity. That car is as simple as it gets, think lawnmower!