Surgin Idle

[rubicon]

I've got a 94 and while sitting at stoplights the engine surges from about 500 to 800 rpm's continually. It does it when cold and warm. It doesn't do it in Neutral or Park. We ran the engine codes (the check engine light comes on intermittently but not at the same time as the surging necessarily) and the only things that shows is that the banks are running rich. The first thing I thought is that it feels like the A/C is turning on an off. But it does it in all HVAC modes so that's not it.

The only mods are 24# injectors and a K & N FIPK.

Any ideas?

Thanks...

 

[Red 93 L1 #3383]

Either your O2 is going south or you have to much fuel pressure (FPR going south)

 

[Steve]

Might also check the MAP sensor. Mine started doing that when my MAP sensor went south.

Steve

 

[rubicon]

Excellent. That gives me some direction to pursue...

Thanks.

John.

 

[MO351]

I'd bet those 24 lb. injectors might be a problem. How long have you had them in? There's been a few on here that have had that problem with the 24s. Switched back to the stock 19s and all was fine. The 24s are almost too much for the speeddensity with the stock computer and will cause some rough idle.

 

[rubicon]

I'd bet those 24 lb. injectors might be a problem. How long have you had them in? There's been a few on here that have had that problem with the 24s. Switched back to the stock 19s and all was fine. The 24s are almost too much for the speeddensity with the stock computer and will cause some rough idle.

Hmmm. Ok. I have been thinking along those lines as well. There's been a couple of things that seems to be going on since they were installed. Unfortunately I can't tell for sure. I only test drove the car for a short while before buying it. As a part of buying it they had to fix a couple of oil leaks and I had them install the injectors at the same time. So, I never really drove the car before the injectors were installed. Ever since I picked it up the idle surges and the check engine light comes on every once in a while. The tranny shifts really hard at times as well. Not firm but actually enough to slam my head back and be uncomfortable. It will also jump out of overdrive for a split second after being on the freeway for 20 min or more. It wasn't doing that before on my test drive. Could they all be related?

I'm thinking that a new chip may be in order before I try to actually fix anything. Does that seem reasonable?

Only problem is that I wanted to get headers installed before I got the chip so I don't have to redo the chip. Should I get the chip optimized for the headers even though I don't have them yet? Is that a bad idea?

 

[MO351]

Rather than go thru the trouble of getting a chip and then having it reburned everytime that you make a new mod you need to get a EEC Tuner. You can use it to reprogram your stock computer as many times as you want. It's well worth the investment. Especially when you add mods you don't have to have your chip reburned. Raymond B. of Performance Specialties is the guru on the EEC tuner and has his own forum on the board here. Go there and he can tell you all the crazy stuff you can do with it.

As for the tranny the L tranny shifts firmer than a regular E4OD but as far as your situation I don't know. If you can find another L owner around you to compare that will help tell you if it's shifting correctly. Where are you from? Are you in Cali? I noticed your name "rubicon" and was wondering if you might be part of the 4x4 group Pirates of the Rubicon. There's quite a few GEN 1 owners out there so you could hook up with one of them. As far as the OD jumping out it shouldn't do that. I'm not sure what to tell you on that.

I'd say the 24s are your problem with the motor not running correctly, though.

 

[rubicon]

I haven't mustered up the courage to go through the "newbie" status on the POR list yet. I live in SJ though, in answer to your question and I try to do the Rubicon at least once a year either with the TLCA or other clubs. I figured that was a safe username that wouldn't be taken on a Lightning list.

There's no way the shifting is normal. When it's happening the shifts are really hard. I am starting to feel play (U-Joints?) now when moving away from a stop. From the F-150 board someone suggested the transmission solenoid. I was hoping someone here might have some other input since this board is more specific. I'm going to have the solenoid checked in a week or so.

I've heard about the reprogrammable one but I don't know anything about it. What kind of computer do you need to reprogram it etc. I'll check the forum.

Thanks.

 

[BLoG]

Before you do anything else - check the vacuum line to your MAP sensor. Mine came off and it cause VERY rough idle, super hard shifts, and a check engine lgiht.

Hmmm. Ok. I have been thinking along those lines as well. There's been a couple of things that seems to be going on since they were installed. Unfortunately I can't tell for sure. I only test drove the car for a short while before buying it. As a part of buying it they had to fix a couple of oil leaks and I had them install the injectors at the same time. So, I never really drove the car before the injectors were installed. Ever since I picked it up the idle surges and the check engine light comes on every once in a while. The tranny shifts really hard at times as well. Not firm but actually enough to slam my head back and be uncomfortable. It will also jump out of overdrive for a split second after being on the freeway for 20 min or more. It wasn't doing that before on my test drive. Could they all be related?

I'm thinking that a new chip may be in order before I try to actually fix anything. Does that seem reasonable?

Only problem is that I wanted to get headers installed before I got the chip so I don't have to redo the chip. Should I get the chip optimized for the headers even though I don't have them yet? Is that a bad idea?

 

[rubicon]

Where do I find the MAP sensor? I don't have a clue about Fords yet since I just got this one.