still sounds sick 3.8 cfi

Topic: still sounds sick 3.8 cfi (Read 6695 times) previous topic - next topic

still sounds sick 3.8 cfi

Reply #15 – June 07, 2015, 04:07:26 PM

If it doesn't throw a code and drives fine without the tps, then the computer isn't working or is in some type of fail safe mode and again would throw codes.between a bad headgasket, all the replaced parts you've done and a lack of fail codes and no concrete compression numbers, but it drives fine without the tps.

There is alot more at play then we are getting on our end. None of your information points to anything specific and the information provided doesn't make sense and contradicts itself.

With the tps unplugged you will get codes unless the computer is screwed, but the same goes for every other sensor that has anything to do with either a ground back to the computer or your 5v rail. The fact that you get a number 11 means everything is working fine and all sensors needed for the computer are fine.

Good luck.

still sounds sick 3.8 cfi

Reply #16 – June 07, 2015, 05:52:09 PM

i only unpluged the tps to warm up and pluged back in to run tests and have not driven it as the mot has expired.with tps unpluged car idles smoothly.the engine still sounds bad there is no black smoke or soot. with the tps pluged in it stumbles and cuts out but lots of soot and black smoke.the coumputer will give codes if any of the sensors are unpluged when i run tests.is it possible that the main program is corrupted and fail safe still works?

still sounds sick 3.8 cfi

Reply #17 – June 07, 2015, 06:01:27 PM

Its possible to have no codes with a bad sensor, but very unlikely. If the tps unplugged changes how the car runs, something is wrong. You should also get a stored memory code unless your clearing codes each time.

Essentially, the tps and iac are the only sensors that really have anything to do with idle quality. If you have too big of a vacuum leak, the iac will be unusable and the computer will try to cut timing or fuel to bring the idle back to an acceptable level.

You can get your car to idle okay with no iac by simply turning up the throttle screw, as long as the tps is still within spec.

Basically, check your tps voltage, check for iac operation and vacuum leaks, do a base idle reset, and then you should run codes once the car is able to actually maintain a proper idle, which should also throw a code if its not.

I honestly have no idea what you have or have not done, and i have less of an idea what the problem is then you do. I personally would start with the head gaskets, and make sure the car is worth fixing before i dropped a bunch of money into it that may or may not be an issue related to the head gaskets.

still sounds sick 3.8 cfi

Reply #18 – June 09, 2015, 04:28:33 PM

i know what you are saying but i still think there is another problem and what to make sure i dont spend time and money on the head gasket to find it still runs like a bag of .its expensive to get things shipped to england and takes over a week.reset the iac,tps showed 0.97v with the iac withdrawn when the iac has extended and set the tps shows 1.37v with a warmed up engine a bit high but so long as it returns from wot to same voltage its ok.will get the heads off next weekend and get them skimmed on that note i see on rockautos they do spacer gasket for heads i take it i will need one after skimming?. oh yeah found the problem with commpression tester the plug holes have a non-threaded space which means the threads on the tester are too short to pick up the thread.getting a long reach adapter so will have commpression figures next weekend again thanks for the help would be stuck with out it.

still sounds sick 3.8 cfi

Reply #19 – June 14, 2015, 01:37:25 PM

compression test no1 to no6 140 140 140 145 140 140 psi.with a little oil all incressed by 5-10 psi.to me it looks good but what should the compression be?

still sounds sick 3.8 cfi

Reply #20 – June 15, 2015, 12:43:27 PM

Quote from: mr glee;448882

compression test no1 to no6 140 140 140 145 140 140 psi.with a little oil all incressed by 5-10 psi.to me it looks good but what should the compression be?

140 is good, anything above 65-75 will run...

still sounds sick 3.8 cfi

Reply #21 – June 16, 2015, 12:03:15 PM

ok thanks for that.can anyone tell me what exactly happens when the tps is unplugged,how does the pcm react to this as may give me a better idear whats going on.

still sounds sick 3.8 cfi

Reply #22 – June 22, 2015, 11:54:51 AM

your injectors should be higher resistance than that.,, and should be green tops.

your fuel pressure regulator is also adjustable if you take out the plug on the top to expose the allen head adjustment.

Your TPS should be measured isolated or unplugged from the car and only tested with an buttstuffog meter, not digital.

The CFI system has a spacer plate and that can be purchased as a "CFI BASE PLATE GASKET KIT".

when you get it off, you will likely have carbon build up near the gold fitting at the driver side rear of the CFI, chip all that stuff away and re-assemble.

Measure your fuel pressure at the test port at the top of your CFI system with the car running.

my first gut feeling what that you had a bad fuel pressure regulator, but you mentioned you replaced it.

your oxygen sensor may be all dirty now as a result of the rich condition,, your computer may be compensating for a weak fuel pump "maybe".

The only way to really confirm the fuel pump is weak is to connect the tester, and add an extender and then tape it to the windshield of the car.
observe the fuel pressure while driving and going through all your gears. If the fuel pressure gets anywhere near 20psi,, the pump is on its way out.

still sounds sick 3.8 cfi

Reply #23 – June 22, 2015, 12:01:58 PM

here is your era injector chart

when you are ready,, just delete the screen that is in the top of each injector,, this will cure all your typical 3.8L hesitation when pressing the gas pedal.

your resistance readings are in specs

still sounds sick 3.8 cfi

Reply #24 – June 22, 2015, 12:02:55 PM

click on my diy link to reveal a lot of CFI specific things I have done or repaired plus also take advantage of the wiring diagrams as well.

still sounds sick 3.8 cfi

Reply #25 – June 22, 2015, 05:03:31 PM

the fuel pressure is good now.the gold fitting on the cfi i take it you mean the pipe which goes to the pcv if so i cleaned it all out when i done the pressure regulator.will check the tps and take out the 02 sensors and clean them can i use a wire brush for this?.also i was thinking of a leak on the intake manifold the map would see the vac drop and put more fuel in is there a known vac at idle so i can check?.the other thing i noticed when the tps is unpluged i can hear the injectors pulsing ,when pluged in the injectors just spray no pulsing.

still sounds sick 3.8 cfi

Reply #26 – June 23, 2015, 04:04:45 PM

Quote from: mr glee;449109

.the other thing i noticed when the tps is unpluged i can hear the injectors pulsing ,when pluged in the injectors just spray no pulsing.

Disconnecting the TPS will cause the EEC to go into a FMEM (Failure Mode Effects Management) strategy for a broke TPS. That seems to be working. I suspect it goes to fixed injector pulse width instead of trying to control it based on sensor inputs.
The question is why are they not pulsing with the TPS connected?
The fact that you get no self test codes makes it a real mystery.

Lean input from an O2 sensor = KOER code
TPS out of specs = KOEO code
ECT cold engine input = KOER code
MAP out of specs = KOEO KOER code

PIP input causing the EEC to sense the engine RPM to be much higher than it actually is. No code for this.
Makes me wonder if the PIP can be bad and screw up the RPM sensing and not screw up the ignition timing?

Would I try another TFI based on this? Yeah I think I would.

still sounds sick 3.8 cfi

Reply #27 – June 24, 2015, 08:05:28 AM

that could also mean there is high resistance on the green conductor of the TPS ckt as well,,,or even the orange ckt, check that also.
you may have to pull the covers off the harness but like softtouch said, he makes a good point.

still sounds sick 3.8 cfi

Reply #28 – June 25, 2015, 01:21:26 AM

ok just done the bench test on the tps green and black 1120 ohms .orange and black open circuit in your diy stuff states should be the same,does this mean at last i have my suspect?.also my cat blew theres nothing left of it this minor back pressure issue is it any real problem or will i not really notice?

still sounds sick 3.8 cfi

Reply #29 – July 07, 2015, 12:33:35 PM

just fitted a new tps and the injectors are pulsing and idle is smooth again.strange as i never got a code.thanks for all the help if you are ever in england i will buy you a warm beer(ale).