runs rough

OK first things first,Thanks Pete for the info on checking the fuel system and telling me to go back and check it again. I found the problem, well sort of. The car was running rough when ever I got on it. Like it was running out of fuel or missing. I up graded thefuel system to a Walbo high pressure 255 fuel pump. no help. I got an adjustable fuel regulator and fuel filter,got worse. Went back to the fuel system check and started over and found the fuel system problem. The hose on the fuel pump was almost off and leaking. Fix it and checked the fuel pressure ,everything was great. Took the caar for a spin, THE SAME PROBLEM....It misses like its on 3 cyclenders. New motorcraft wire, cap, and button. new Autolite 764 plugs. No improvement. I don't know where else to check. HELP.......I will try anything at this point.

i had a miss under boost over 10psia nd above 2000rpm, yea try drivign it liek that. but i also hear da stumbel at idle, so i unplug each injector one by one, #2 was not affectign the 3ay the motor ran when unplug, bought anew injector, boosted to 14psi no problems and was power full as hell, i went through everythign you did, new tune-up,255hp pump, afpr,vam, tfi, tps, until i tried injectors, now she runs good, but unfortunitly i havnt drivin her since april, buyut before she was runnign rpefect!

------------------
Brian J Larkin
1988 Non-Turbo Turbo Coupe
new paint job as of 12/8
med gray met. raven/gray interior, fully loaded minus leather and sunroof!
converted to N/A 2.3l by previuos owner, but its a nice driver with working A/C!
sequentail turn signals, 3g alt,afpr, k&n, 2 1/2in cold air intake.
custom 2in dual exhuast with SN95 SS tips. Tripcomputer, a/f and vac guages. color coded wheels
1988 Turbo Coupe 5spd
dark blue metallic (the original Turbo!)
gillis boost valve, k&n cone,AFPR, 255lph, HP pump,3G 130amp alt, 3.73 gears,mild torquie cam, factory DP, 2003 mustang take off SS mufflers and custom BJL 2 1/4 tails.
(needs a front frame pull) DOH!!!!!

How did you repair the leaky hose in the tank? Replace it? Use hose clamps?
Any valve train noise. Try what Brian did, see if it's an injector

The clamp wasn't as tight as it should have been. Put everything back in pace and tighten up the clamps. I'll do the injector check.
Anyother suggestions?

I hate to say this, but you probably should have replaced the hose. They have been known to split. Hard to see the split, as it will usually only open under pressure.

------------------
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 04 Taurus Duratec (wifes car)

The hose is fine, It was the new one that came with the fuel pump kit. I just didn't tighten the clamp. Wnen the weather imprves,no garage, I will go check the injectors.
I saw a fuel injector cleaner that you hooked up to the fuel rail at the valve. It was on one of those speed channel car how to shows. They said it worked great but I haven't seem anything in a store like it. Anyone know what I'm taking about, does it work, and where can you find it.

From the .02 department...

Assuming that the fuel filter was still in place, and not bypassed in the past, 99% of the injectors that I have pulled had deposits on the 'hat', but not in the injector itself.

Modern gas has detergents that remove deposits... My guess would be that the cleaning wouldnt necessarly do much.

Couple of random thoughts... take with a grain of caution...

If you really think its fuel, perhaps a A/F meter, even hooked temporary to check under boost.

I would guess that everything else is set ok (timing) and advancing with RPM....

Good Luck.

Steve

OK. It's not the injectors, or atleast when I checked them by pulling the plug off they all seamed to make the engine run the same, a miss . I pulled the codes and a "42" came up, O2 sensor reading rich all the time. It's a new O2 sensor so how can I lean it up a bit. I had the fuel pressure at 44lbs. but dropped it to 40lbs. Timing is at 12. I'm going to repace the computor next. The one in there now is from the automatic. I have a 5 speed LA3 that I want to try to se if that helps. .........Any thoughts.

i know that there were some '88 A4LD EECs that had a problem reporting Code 42 in error. Not sure your year of vehicle.

i doubt that replacing your EEC will help, despite the above. They rarely fail, and when they do, it usually is much more severe and noticeable. Because you say it feels like it is misfiring, that is a possible reason why the o2 sensor is reporting a rich condition.

What section was your code 42 in? CM or KOER? It makes a difference on how you resolve it.

Generally, while o2 sensors do age and become lazy to the point that they should be replaced, this code is likely not the o2 sensor itself. Leaking fuel injectors (internally sticking), high fuel pressure, a VAM that is reporting more aiflow than there actually is, or ignition issues (misfires), all can result in Code 42.

When you did the fuel diagnostics according to this site, did fuel pressure hold after the fuel pump had shut off?

My car is an "88. I was a KOER code 42. The fuel pressure only dropped 2 lbs. when I cut off the pump. This was after I fixed the leaking hose on the pump. The O2 sensor is only a year old or less. I pulled it out and it was black.I had the fuel pressure set at 44 lbs. but dropped it to 40.The only thing on the fuel system check I haven't done is the high speed test with the boost turned up. The hose on my gauge will not reach out side the hood to attach to the windshield, I will extend the hose over the week end. I'm at a loss where to look next. I do have another VAM I could try if you think it worth trying.