help guys!!
My 93 explorer with V-6 pulsates when I accelerate hard or pulling hard. It also does this when I first start it somestimes. I have considered the injectors but was wondering if a sensor or computer problem could cause this.

Thanks

Charlie

 

I would begin by first pulling codes. By pulsates, do you mean engine surge or erratic and maybe occasional misfire?

 

On a hard acceleration it feels like I am moving my foot up and down on the gas pedal. Sometimes when I first start it, it wil slow down like it is going to die and them pick back up. same thing as I put it in gear and start to move. it will kinda jump a little.

Thanks fro the reply

Charlie

 

I would begin by pulling code(s) and checking fuel pressure. When was the fuel filter last replaced?

 

Do I have to go t a dealer to pull the codes and is it expensive. Autozone will put on their computer for free but they say it only pulls codes if the check engine ligtht is on. It isn't .

Charlie

 

It seems that most of the people at Autozone don't have any clue about the EEC-IV system. They could pull codes any time they wanted to. They might all be pass codes, but they could pull them.
As easy as it is to DIY, I wouldn't mess with them. Hook up a paper clip/jumper wire from STI to Sig Ret and the codes come out as flashes of the check engine light. See tests at www.dalidesign.com/hbook/eectest.html to locate STI and Sig Ret and for detailed test procedures.
And when you do get the codes, be sure to note which type of code each code is: KOEO, KOER, or memory. If you don't make a note of it, that's the first thing I will ask when you post the codes. If you get any pass codes, that would also be nice to note.

 

Instructions for pulling the code(s) can also be found in the Ranger forum. Look under the sticky titled technical information. There are three way to do it; you can use a jumper and the CEL, a digital voltmeter, or get a scanner. When you are doing the KOER test and the time comes to floor it (WOT), floor it all the way and HOLD IT there for about 1/2 second and/or until it get's to 4,000 rpm. Failure to do this may in itself set off a code which will be bogus. Also, it is critical to pull code(s) in the sequence of KOEO, KOER, and CM (continuous memory) as they must be fixed in this order. A KOEO code may, for example, trip a CM code, one that goes away when the KOEO code is fixed.

Have you first checked fuel pressure and is the fuel filter good? When under acceleration, it sortta sounds like the engine is starving for fuel.

 

Hello, I have the same prob in my '93 4x4 4.0. I pulled the codes and got a low reading MAF. I changed that and it seemed better for a while, but it is definitley there still (placebo effect at first maybe??). Anyway, the fuel filter and spark plugs/ wires are changed now and the prob still exists. No vacuum leaks found either. Can/ will the FPR be faulty without leaking fuel into the vacuum line? Also will bad/ slow O2 sensors cause this prob? It seems that mine pulses at part throttle and not at WOT, where the EEC is in open loop. It will be $110 to change both of those so I wish there were a way to test that before buying them. What pressure should we see in the rail at idle? Thanks, Buck

 

cactusbuck: When you pulled codes which MAF code did you get? Was it a KOEO, KOER, and/or CM code?
"Can/ will the FPR be faulty without leaking fuel into the vacuum line?" -- Yes, the FPR can fail in ways that don't leak fuel into the vacuum line. Best check is with a fuel pressure gauge. You should see around 40+-5 psig KOEO. With vacuum applied to the FPR, fuel pressure should drop a few psi with the engine running, and fuel pressure should mirror engine vacuum. With vacuum disconnected from the FPR, it should maintain a steady 40 psig (or whatever the KOEO value was).
"Also will bad/ slow O2 sensors cause this prob?" -- Conceivably they could. I would start, though, with the MAF. Remember that the computer can't diagnose sensors, it can only diagnose circuits. The computer can't tell a bad sensor from a broken wire.

 

check the explorer forum, You will see what I had to do